path: root/gas/config/tc-i960.c

/* i960.c - All the i80960-specific stuff
   Copyright (C) 1989, 1990, 1991 Free Software Foundation, Inc.
   
   This file is part of GAS.
   
   GAS is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.
   
   GAS is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with GAS; see the file COPYING.  If not, write to
   the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */

/* $Id$ */

/* See comment on md_parse_option for 80960-specific invocation options. */

/******************************************************************************
 * i80690 NOTE!!!:
 *	Header, symbol, and relocation info will be used on the host machine
 *	only -- only executable code is actually downloaded to the i80960.
 *	Therefore, leave all such information in host byte order.
 *
 *	(That's a slight lie -- we DO download some header information, but
 *	the downloader converts the file format and corrects the byte-ordering
 *	of the relevant fields while doing so.)
 *
 ***************************************************************************** */

/* There are 4 different lengths of (potentially) symbol-based displacements
 * in the 80960 instruction set, each of which could require address fix-ups
 * and (in the case of external symbols) emission of relocation directives:
 *
 * 32-bit (MEMB)
 *	This is a standard length for the base assembler and requires no
 *	special action.
 *
 * 13-bit (COBR)
 *	This is a non-standard length, but the base assembler has a hook for
 *	bit field address fixups:  the fixS structure can point to a descriptor
 *	of the field, in which case our md_number_to_field() routine gets called
 *	to process it.
 *
 *	I made the hook a little cleaner by having fix_new() (in the base
 *	assembler) return a pointer to the fixS in question.  And I made it a
 *	little simpler by storing the field size (in this case 13) instead of
 *	of a pointer to another structure:  80960 displacements are ALWAYS
 *	stored in the low-order bits of a 4-byte word.
 *
 *	Since the target of a COBR cannot be external, no relocation directives
 *	for this size displacement have to be generated.  But the base assembler
 *	had to be modified to issue error messages if the symbol did turn out
 *	to be external.
 *
 * 24-bit (CTRL)
 *	Fixups are handled as for the 13-bit case (except that 24 is stored
 *	in the fixS).
 *
 *	The relocation directive generated is the same as that for the 32-bit
 *	displacement, except that it's PC-relative (the 32-bit displacement
 *	never is).   The i80960 version of the linker needs a mod to
 *	distinguish and handle the 24-bit case.
 *
 * 12-bit (MEMA)
 *	MEMA formats are always promoted to MEMB (32-bit) if the displacement
 *	is based on a symbol, because it could be relocated at link time.
 *	The only time we use the 12-bit format is if an absolute value of
 *	less than 4096 is specified, in which case we need neither a fixup nor
 *	a relocation directive.
 */

#include <stdio.h>
#include <ctype.h>

#include "as.h"

#include "obstack.h"

#include "opcode/i960.h"

extern char *input_line_pointer;
extern struct hash_control *po_hash;
extern char *next_object_file_charP;

#ifdef OBJ_COFF
int md_reloc_size = sizeof(struct reloc);
#else /* OBJ_COFF */
int md_reloc_size = sizeof(struct relocation_info);
#endif /* OBJ_COFF */

/***************************
 *  Local i80960 routines  *
 ************************** */

static void	brcnt_emit();	/* Emit branch-prediction instrumentation code */
static char *	brlab_next();	/* Return next branch local label */
void	brtab_emit();	/* Emit br-predict instrumentation table */
static void	cobr_fmt();	/* Generate COBR instruction */
static void	ctrl_fmt();	/* Generate CTRL instruction */
static char *	emit();		/* Emit (internally) binary */
static int get_args();	/* Break arguments out of comma-separated list */
static void	get_cdisp();	/* Handle COBR or CTRL displacement */
static char *	get_ispec();	/* Find index specification string */
static int get_regnum();	/* Translate text to register number */
static int i_scan();	/* Lexical scan of instruction source */
static void	mem_fmt();	/* Generate MEMA or MEMB instruction */
static void	mema_to_memb();	/* Convert MEMA instruction to MEMB format */
static segT	parse_expr();	/* Parse an expression */
static int parse_ldconst();/* Parse and replace a 'ldconst' pseudo-op */
static void	parse_memop();	/* Parse a memory operand */
static void	parse_po();	/* Parse machine-dependent pseudo-op */
static void	parse_regop();	/* Parse a register operand */
static void	reg_fmt();	/* Generate a REG format instruction */
void	reloc_callj();	/* Relocate a 'callj' instruction */
static void	relax_cobr();	/* "De-optimize" cobr into compare/branch */
static void	s_leafproc();	/* Process '.leafproc' pseudo-op */
static void	s_sysproc();	/* Process '.sysproc' pseudo-op */
static int shift_ok();	/* Will a 'shlo' substiture for a 'ldconst'? */
static void	syntax();	/* Give syntax error */
static int targ_has_sfr();	/* Target chip supports spec-func register? */
static int targ_has_iclass();/* Target chip supports instruction set? */
/* static void	unlink_sym(); */	/* Remove a symbol from the symbol list */

/* See md_parse_option() for meanings of these options */
static char norelax = 0;		/* True if -norelax switch seen */
static char instrument_branches = 0;	/* True if -b switch seen */

/* Characters that always start a comment.
 * If the pre-processor is disabled, these aren't very useful.
 */
char comment_chars[] = "#";

/* Characters that only start a comment at the beginning of
 * a line.  If the line seems to have the form '# 123 filename'
 * .line and .file directives will appear in the pre-processed output.
 *
 * Note that input_file.c hand checks for '#' at the beginning of the
 * first line of the input file.  This is because the compiler outputs
 * #NO_APP at the beginning of its output.
 */

/* Also note that comments started like this one will always work. */

char line_comment_chars[] = "";

/* Chars that can be used to separate mant from exp in floating point nums */
char EXP_CHARS[] = "eE";

/* Chars that mean this number is a floating point constant,
 * as in 0f12.456 or 0d1.2345e12
 */
char FLT_CHARS[] = "fFdDtT";


/* Table used by base assembler to relax addresses based on varying length
 * instructions.  The fields are:
 *   1) most positive reach of this state,
 *   2) most negative reach of this state,
 *   3) how many bytes this mode will add to the size of the current frag
 *   4) which index into the table to try if we can't fit into this one.
 *
 * For i80960, the only application is the (de-)optimization of cobr
 * instructions into separate compare and branch instructions when a 13-bit
 * displacement won't hack it.
 */
const relax_typeS
    md_relax_table[] = {
	    {0,         0,        0,0}, /* State 0 => no more relaxation possible */
	    {4088,      -4096,    0,2}, /* State 1: conditional branch (cobr) */
	    {0x800000-8,-0x800000,4,0}, /* State 2: compare (reg) & branch (ctrl) */
    };


/* These are the machine dependent pseudo-ops.
 *
 * This table describes all the machine specific pseudo-ops the assembler
 * has to support.  The fields are:
 *	pseudo-op name without dot
 *	function to call to execute this pseudo-op
 *	integer arg to pass to the function
 */
#define S_LEAFPROC	1
#define S_SYSPROC	2

const pseudo_typeS
    md_pseudo_table[] = {
	    
	    { "bss",	s_lcomm,	1 },
	    { "extended",	float_cons,	't' },
	    { "leafproc",	parse_po,	S_LEAFPROC },
	    { "sysproc",	parse_po,	S_SYSPROC },
	    
	    { "word",	cons,		4 },
	    { "quad",	big_cons,	16 },
	    
	    { 0,		0,		0 }
    };

/* Macros to extract info from an 'expressionS' structure 'e' */
#define adds(e)	e.X_add_symbol
#define subs(e)	e.X_subtract_symbol
#define offs(e)	e.X_add_number
#define segs(e)	e.X_seg
    
    
    /* Branch-prediction bits for CTRL/COBR format opcodes */
#define BP_MASK		0x00000002  /* Mask for branch-prediction bit */
#define BP_TAKEN	0x00000000  /* Value to OR in to predict branch */
#define BP_NOT_TAKEN	0x00000002  /* Value to OR in to predict no branch */
    
    
    /* Some instruction opcodes that we need explicitly */
#define BE	0x12000000
#define BG	0x11000000
#define BGE	0x13000000
#define BL	0x14000000
#define BLE	0x16000000
#define BNE	0x15000000
#define BNO	0x10000000
#define BO	0x17000000
#define CHKBIT	0x5a002700
#define CMPI	0x5a002080
#define CMPO	0x5a002000
    
#define B	0x08000000
#define BAL	0x0b000000
#define CALL	0x09000000
#define CALLS	0x66003800
#define RET	0x0a000000
    
    
    /* These masks are used to build up a set of MEMB mode bits. */
#define	A_BIT		0x0400
#define	I_BIT		0x0800
#define MEMB_BIT	0x1000
#define	D_BIT		0x2000
    
    
    /* Mask for the only mode bit in a MEMA instruction (if set, abase reg is used) */
#define MEMA_ABASE	0x2000
    
    /* Info from which a MEMA or MEMB format instruction can be generated */
    typedef struct {
	    long opcode;	/* (First) 32 bits of instruction */
	    int disp;	/* 0-(none), 12- or, 32-bit displacement needed */
	    char *e;	/* The expression in the source instruction from
			 *	which the displacement should be determined
			 */
    } memS;


/* The two pieces of info we need to generate a register operand */
struct regop {
	int mode;	/* 0 =>local/global/spec reg; 1=> literal or fp reg */
	int special;	/* 0 =>not a sfr;  1=> is a sfr (not valid w/mode=0) */
	int n;		/* Register number or literal value */
};


/* Number and assembler mnemonic for all registers that can appear in operands */
static struct {
	char *reg_name;
	int reg_num;
} regnames[] = {
	{ "pfp",  0 }, { "sp",   1 }, { "rip",  2 }, { "r3",   3 },
	{ "r4",   4 }, { "r5",   5 }, { "r6",   6 }, { "r7",   7 },
	{ "r8",   8 }, { "r9",   9 }, { "r10", 10 }, { "r11", 11 },
	{ "r12", 12 }, { "r13", 13 }, { "r14", 14 }, { "r15", 15 },
	{ "g0",  16 }, { "g1",  17 }, { "g2",  18 }, { "g3",  19 },
	{ "g4",  20 }, { "g5",  21 }, { "g6",  22 }, { "g7",  23 },
	{ "g8",  24 }, { "g9",  25 }, { "g10", 26 }, { "g11", 27 },
	{ "g12", 28 }, { "g13", 29 }, { "g14", 30 }, { "fp",  31 },
	
	/* Numbers for special-function registers are for assembler internal
	 * use only: they are scaled back to range [0-31] for binary output.
	 */
#	define SF0	32
	
	{ "sf0", 32 }, { "sf1", 33 }, { "sf2", 34 }, { "sf3", 35 },
	{ "sf4", 36 }, { "sf5", 37 }, { "sf6", 38 }, { "sf7", 39 },
	{ "sf8", 40 }, { "sf9", 41 }, { "sf10",42 }, { "sf11",43 },
	{ "sf12",44 }, { "sf13",45 }, { "sf14",46 }, { "sf15",47 },
	{ "sf16",48 }, { "sf17",49 }, { "sf18",50 }, { "sf19",51 },
	{ "sf20",52 }, { "sf21",53 }, { "sf22",54 }, { "sf23",55 },
	{ "sf24",56 }, { "sf25",57 }, { "sf26",58 }, { "sf27",59 },
	{ "sf28",60 }, { "sf29",61 }, { "sf30",62 }, { "sf31",63 },
	
	/* Numbers for floating point registers are for assembler internal use
	 * only: they are scaled back to [0-3] for binary output.
	 */
#	define FP0	64
	
	{ "fp0", 64 }, { "fp1", 65 }, { "fp2", 66 }, { "fp3", 67 },
	
	{ NULL,  0 },		/* END OF LIST */
};

#define	IS_RG_REG(n)	((0 <= (n)) && ((n) < SF0))
#define	IS_SF_REG(n)	((SF0 <= (n)) && ((n) < FP0))
#define	IS_FP_REG(n)	((n) >= FP0)

/* Number and assembler mnemonic for all registers that can appear as 'abase'
 * (indirect addressing) registers.
 */
static struct {
	char *areg_name;
	int areg_num;
} aregs[] = {
	{ "(pfp)",  0 }, { "(sp)",   1 }, { "(rip)",  2 }, { "(r3)",   3 },
	{ "(r4)",   4 }, { "(r5)",   5 }, { "(r6)",   6 }, { "(r7)",   7 },
	{ "(r8)",   8 }, { "(r9)",   9 }, { "(r10)", 10 }, { "(r11)", 11 },
	{ "(r12)", 12 }, { "(r13)", 13 }, { "(r14)", 14 }, { "(r15)", 15 },
	{ "(g0)",  16 }, { "(g1)",  17 }, { "(g2)",  18 }, { "(g3)",  19 },
	{ "(g4)",  20 }, { "(g5)",  21 }, { "(g6)",  22 }, { "(g7)",  23 },
	{ "(g8)",  24 }, { "(g9)",  25 }, { "(g10)", 26 }, { "(g11)", 27 },
	{ "(g12)", 28 }, { "(g13)", 29 }, { "(g14)", 30 }, { "(fp)",  31 },
	
#	define IPREL	32
	/* for assembler internal use only: this number never appears in binary
	 * output.
	 */
	{ "(ip)", IPREL },
	
	{ NULL,  0 },		/* END OF LIST */
};


/* Hash tables */
static struct hash_control *op_hash = NULL;	/* Opcode mnemonics */
static struct hash_control *reg_hash = NULL;	/* Register name hash table */
static struct hash_control *areg_hash = NULL;	/* Abase register hash table */


/* Architecture for which we are assembling */
#define ARCH_ANY	0	/* Default: no architecture checking done */
#define ARCH_KA		1
#define ARCH_KB		2
#define ARCH_MC		3
#define ARCH_CA		4
int architecture = ARCH_ANY;	/* Architecture requested on invocation line */
int iclasses_seen = 0;		/* OR of instruction classes (I_* constants)
				 *	for which we've actually assembled
				 *	instructions.
				 */


/* BRANCH-PREDICTION INSTRUMENTATION
 *
 *	The following supports generation of branch-prediction instrumentation
 *	(turned on by -b switch).  The instrumentation collects counts
 *	of branches taken/not-taken for later input to a utility that will
 *	set the branch prediction bits of the instructions in accordance with
 *	the behavior observed.  (Note that the KX series does not have
 *	brach-prediction.)
 *
 *	The instrumentation consists of:
 *
 *	(1) before and after each conditional branch, a call to an external
 *	    routine that increments and steps over an inline counter.  The
 *	    counter itself, initialized to 0, immediately follows the call
 *	    instruction.  For each branch, the counter following the branch
 *	    is the number of times the branch was not taken, and the difference
 *	    between the counters is the number of times it was taken.  An
 *	    example of an instrumented conditional branch:
 *
 *				call	BR_CNT_FUNC
 *				.word	0
 *		LBRANCH23:	be	label
 *				call	BR_CNT_FUNC
 *				.word	0
 *
 *	(2) a table of pointers to the instrumented branches, so that an
 *	    external postprocessing routine can locate all of the counters.
 *	    the table begins with a 2-word header: a pointer to the next in
 *	    a linked list of such tables (initialized to 0);  and a count
 *	    of the number of entries in the table (exclusive of the header.
 *
 *	    Note that input source code is expected to already contain calls
 *	    an external routine that will link the branch local table into a
 *	    list of such tables.
 */

static int br_cnt = 0;		/* Number of branches instrumented so far.
				 * Also used to generate unique local labels
				 * for each instrumented branch
				 */

#define BR_LABEL_BASE	"LBRANCH"
/* Basename of local labels on instrumented
 * branches, to avoid conflict with compiler-
 * generated local labels.
 */

#define BR_CNT_FUNC	"__inc_branch"
/* Name of the external routine that will
 * increment (and step over) an inline counter.
 */

#define BR_TAB_NAME	"__BRANCH_TABLE__"
/* Name of the table of pointers to branches.
 * A local (i.e., non-external) symbol.
 */

/*****************************************************************************
 * md_begin:  One-time initialization.
 *
 *	Set up hash tables.
 *
 **************************************************************************** */
void
    md_begin()
{
	int i;				/* Loop counter */
	const struct i960_opcode *oP; /* Pointer into opcode table */
	char *retval;			/* Value returned by hash functions */
	
	if (((op_hash = hash_new()) == 0)
	    || ((reg_hash = hash_new()) == 0)
	    || ((areg_hash = hash_new()) == 0)) {
		as_fatal("virtual memory exceeded");
	}
	
	retval = "";	/* For some reason, the base assembler uses an empty
			 * string for "no error message", instead of a NULL
			 * pointer.
			 */
	
	for (oP=i960_opcodes; oP->name && !*retval; oP++) {
		retval = hash_insert(op_hash, oP->name, oP);
	}
	
	for (i=0; regnames[i].reg_name && !*retval; i++) {
		retval = hash_insert(reg_hash, regnames[i].reg_name,
				     &regnames[i].reg_num);
	}
	
	for (i=0; aregs[i].areg_name && !*retval; i++){
		retval = hash_insert(areg_hash, aregs[i].areg_name,
				     &aregs[i].areg_num);
	}
	
	if (*retval) {
		as_fatal("Hashing returned \"%s\".", retval);
	}
} /* md_begin() */

/*****************************************************************************
 * md_end:  One-time final cleanup
 *
 *	None necessary
 *
 **************************************************************************** */
void
    md_end()
{
}

/*****************************************************************************
 * md_assemble:  Assemble an instruction
 *
 * Assumptions about the passed-in text:
 *	- all comments, labels removed
 *	- text is an instruction
 *	- all white space compressed to single blanks
 *	- all character constants have been replaced with decimal
 *
 **************************************************************************** */
void
    md_assemble(textP)
char *textP;	/* Source text of instruction */
{
	char *args[4];	/* Parsed instruction text, containing NO whitespace:
			 *	arg[0]->opcode mnemonic
			 *	arg[1-3]->operands, with char constants
			 *			replaced by decimal numbers
			 */
	int n_ops;	/* Number of instruction operands */
	
	struct i960_opcode *oP;
	/* Pointer to instruction description */
	int branch_predict;
	/* TRUE iff opcode mnemonic included branch-prediction
	 *	suffix (".f" or ".t")
	 */
	long bp_bits;	/* Setting of branch-prediction bit(s) to be OR'd
			 *	into instruction opcode of CTRL/COBR format
			 *	instructions.
			 */
	int n;		/* Offset of last character in opcode mnemonic */
	
	static const char bp_error_msg[] = "branch prediction invalid on this opcode";
	
	
	/* Parse instruction into opcode and operands */
	bzero(args, sizeof(args));
	n_ops = i_scan(textP, args);
	if (n_ops == -1){
		return;		/* Error message already issued */
	}
	
	/* Do "macro substitution" (sort of) on 'ldconst' pseudo-instruction */
	if (!strcmp(args[0],"ldconst")){
		n_ops = parse_ldconst(args);
		if (n_ops == -1){
			return;
		}
	}
	
	/* Check for branch-prediction suffix on opcode mnemonic, strip it off */
	n = strlen(args[0]) - 1;
	branch_predict = 0;
	bp_bits = 0;
	if (args[0][n-1] == '.' && (args[0][n] == 't' || args[0][n] == 'f')){
		/* We could check here to see if the target architecture
		 * supports branch prediction, but why bother?  The bit
		 * will just be ignored by processors that don't use it.
		 */
		branch_predict = 1;
		bp_bits = (args[0][n] == 't') ? BP_TAKEN : BP_NOT_TAKEN;
		args[0][n-1] = '\0';	/* Strip suffix from opcode mnemonic */
	}
	
	/* Look up opcode mnemonic in table and check number of operands.
	 * Check that opcode is legal for the target architecture.
	 * If all looks good, assemble instruction.
	 */
	oP = (struct i960_opcode *) hash_find(op_hash, args[0]);
	if (!oP || !targ_has_iclass(oP->iclass)) {
		as_bad("invalid opcode, \"%s\".", args[0]);
		
	} else if (n_ops != oP->num_ops) {
		as_bad("improper number of operands.  expecting %d, got %d", oP->num_ops, n_ops);
		
	} else {
		switch (oP->format){
		case FBRA:
		case CTRL:
			ctrl_fmt(args[1], oP->opcode | bp_bits, oP->num_ops);
			if (oP->format == FBRA){
				/* Now generate a 'bno' to same arg */
				ctrl_fmt(args[1], BNO | bp_bits, 1);
			}
			break;
		case COBR:
		case COJ:
			cobr_fmt(args, oP->opcode | bp_bits, oP);
			break;
		case REG:
			if (branch_predict){
				as_warn(bp_error_msg);
			}
			reg_fmt(args, oP);
			break;
		case MEM1:
		case MEM2:
		case MEM4:
		case MEM8:
		case MEM12:
		case MEM16:
			if (branch_predict){
				as_warn(bp_error_msg);
			}
			mem_fmt(args, oP);
			break;
		case CALLJ:
			if (branch_predict){
				as_warn(bp_error_msg);
			}
			/* Output opcode & set up "fixup" (relocation);
			 * flag relocation as 'callj' type.
			 */
			know(oP->num_ops == 1);
			get_cdisp(args[1], "CTRL", oP->opcode, 24, 0, 1);
			break;
		default:
			BAD_CASE(oP->format);
			break;
		}
	}
} /* md_assemble() */

/*****************************************************************************
 * md_number_to_chars:  convert a number to target byte order
 *
 **************************************************************************** */
void
    md_number_to_chars(buf, value, n)
char *buf;		/* Put output here */
long value;		/* The integer to be converted */
int n;		/* Number of bytes to output (significant bytes
		 *	in 'value')
		 */
{
	while (n--){
		*buf++ = value;
		value >>= 8;
	}
	
	/* XXX line number probably botched for this warning message. */
	if (value != 0 && value != -1){
		as_bad("Displacement too long for instruction field length.");
	}
	
	return;
} /* md_number_to_chars() */

/*****************************************************************************
 * md_chars_to_number:  convert from target byte order to host byte order.
 *
 **************************************************************************** */
int
    md_chars_to_number(val, n)
unsigned char *val;	/* Value in target byte order */
int n;		/* Number of bytes in the input */
{
	int retval;
	
	for (retval=0; n--;){
		retval <<= 8;
		retval |= val[n];
	}
	return retval;
}


#define MAX_LITTLENUMS	6
#define LNUM_SIZE	sizeof(LITTLENUM_TYPE)

/*****************************************************************************
 * md_atof:	convert ascii to floating point
 *
 * Turn a string at input_line_pointer into a floating point constant of type
 * 'type', and store the appropriate bytes at *litP.  The number of LITTLENUMS
 * emitted is returned at 'sizeP'.  An error message is returned, or a pointer
 * to an empty message if OK.
 *
 * Note we call the i386 floating point routine, rather than complicating
 * things with more files or symbolic links.
 *
 **************************************************************************** */
char * md_atof(type, litP, sizeP)
int type;
char *litP;
int *sizeP;
{
	LITTLENUM_TYPE words[MAX_LITTLENUMS];
	LITTLENUM_TYPE *wordP;
	int prec;
	char *t;
	char *atof_ieee();
	
	switch(type) {
	case 'f':
	case 'F':
		prec = 2;
		break;
		
	case 'd':
	case 'D':
		prec = 4;
		break;
		
	case 't':
	case 'T':
		prec = 5;
		type = 'x';	/* That's what atof_ieee() understands */
		break;
		
	default:
		*sizeP=0;
		return "Bad call to md_atof()";
	}
	
	t = atof_ieee(input_line_pointer, type, words);
	if (t){
		input_line_pointer = t;
	}
	
	*sizeP = prec * LNUM_SIZE;
	
	/* Output the LITTLENUMs in REVERSE order in accord with i80960
	 * word-order.  (Dunno why atof_ieee doesn't do it in the right
	 * order in the first place -- probably because it's a hack of
	 * atof_m68k.)
	 */
	
	for(wordP = words + prec - 1; prec--;){
		md_number_to_chars(litP, (long) (*wordP--), LNUM_SIZE);
		litP += sizeof(LITTLENUM_TYPE);
	}
	
	return "";	/* Someone should teach Dean about null pointers */
}


/*****************************************************************************
 * md_number_to_imm
 *
 **************************************************************************** */
void
    md_number_to_imm(buf, val, n)
char *buf;
long val;
int n;
{
	md_number_to_chars(buf, val, n);
}


/*****************************************************************************
 * md_number_to_disp
 *
 **************************************************************************** */
void
    md_number_to_disp(buf, val, n)
char *buf;
long val;
int n;
{
	md_number_to_chars(buf, val, n);
}

/*****************************************************************************
 * md_number_to_field:
 *
 *	Stick a value (an address fixup) into a bit field of
 *	previously-generated instruction.
 *
 **************************************************************************** */
void
    md_number_to_field(instrP, val, bfixP)
char *instrP;	/* Pointer to instruction to be fixed */
long val;		/* Address fixup value */
bit_fixS *bfixP;	/* Description of bit field to be fixed up */
{
	int numbits;	/* Length of bit field to be fixed */
	long instr;	/* 32-bit instruction to be fixed-up */
	long sign;	/* 0 or -1, according to sign bit of 'val' */
	
	/* Convert instruction back to host byte order
	 */
	instr = md_chars_to_number(instrP, 4);
	
	/* Surprise! -- we stored the number of bits
	 * to be modified rather than a pointer to a structure.
	 */
	numbits = (int)bfixP;
	if (numbits == 1){
		/* This is a no-op, stuck here by reloc_callj() */
		return;
	}
	
	know ((numbits==13) || (numbits==24));
	
	/* Propagate sign bit of 'val' for the given number of bits.
	 * Result should be all 0 or all 1
	 */
	sign = val >> ((int)numbits - 1);
	if (((val < 0) && (sign != -1))
	    ||   ((val > 0) && (sign != 0))){
		as_bad("Fixup of %d too large for field width of %d",
		       val, numbits);
	} else {
		/* Put bit field into instruction and write back in target
		 * byte order.
		 */
		val &= ~(-1 << (int)numbits);	/* Clear unused sign bits */
		instr |= val;
		md_number_to_chars(instrP, instr, 4);
	}
} /* md_number_to_field() */


/*****************************************************************************
 * md_parse_option
 *	Invocation line includes a switch not recognized by the base assembler.
 *	See if it's a processor-specific option.  For the 960, these are:
 *
 *	-norelax:
 *		Conditional branch instructions that require displacements
 *		greater than 13 bits (or that have external targets) should
 *		generate errors.  The default is to replace each such
 *		instruction with the corresponding compare (or chkbit) and
 *		branch instructions.  Note that the Intel "j" cobr directives
 *		are ALWAYS "de-optimized" in this way when necessary,
 *		regardless of the setting of this option.
 *
 *	-b:
 *		Add code to collect information about branches taken, for
 *		later optimization of branch prediction bits by a separate
 *		tool.  COBR and CNTL format instructions have branch
 *		prediction bits (in the CX architecture);  if "BR" represents
 *		an instruction in one of these classes, the following rep-
 *		resents the code generated by the assembler:
 *
 *			call	<increment routine>
 *			.word	0	# pre-counter
 *		Label:  BR
 *			call	<increment routine>
 *			.word	0	# post-counter
 *
 *		A table of all such "Labels" is also generated.
 *
 *
 *	-AKA, -AKB, -AKC, -ASA, -ASB, -AMC, -ACA:
 *		Select the 80960 architecture.  Instructions or features not
 *		supported by the selected architecture cause fatal errors.
 *		The default is to generate code for any instruction or feature
 *		that is supported by SOME version of the 960 (even if this
 *		means mixing architectures!).
 *
 **************************************************************************** */
int
    md_parse_option(argP, cntP, vecP)
char **argP;
int *cntP;
char ***vecP;
{
	char *p;
	struct tabentry { char *flag; int arch; };
	static struct tabentry arch_tab[] = {
		"KA", ARCH_KA,
		"KB", ARCH_KB,
		"SA", ARCH_KA,  /* Synonym for KA */
		"SB", ARCH_KB,  /* Synonym for KB */
		"KC", ARCH_MC,  /* Synonym for MC */
		"MC", ARCH_MC,
		"CA", ARCH_CA,
		NULL, 0
	    };
	struct tabentry *tp;
	
	if (!strcmp(*argP,"norelax")){
		norelax = 1;
		
	} else if (**argP == 'b'){
		instrument_branches = 1;
		
	} else if (**argP == 'A'){
		p = (*argP) + 1;
		
		for (tp = arch_tab; tp->flag != NULL; tp++){
			if (!strcmp(p,tp->flag)){
				break;
			}
		}
		
		if (tp->flag == NULL){
			as_bad("unknown architecture: %s", p);
		} else {
			architecture = tp->arch;
		}
	} else {
		/* Unknown option */
		(*argP)++;
		return 0;
	}
	**argP = '\0';	/* Done parsing this switch */
	return 1;
}

/*****************************************************************************
 * md_convert_frag:
 *	Called by base assembler after address relaxation is finished:  modify
 *	variable fragments according to how much relaxation was done.
 *
 *	If the fragment substate is still 1, a 13-bit displacement was enough
 *	to reach the symbol in question.  Set up an address fixup, but otherwise
 *	leave the cobr instruction alone.
 *
 *	If the fragment substate is 2, a 13-bit displacement was not enough.
 *	Replace the cobr with a two instructions (a compare and a branch).
 *
 **************************************************************************** */
void
    md_convert_frag(headers, fragP)
object_headers *headers;
fragS * fragP;
{
	fixS *fixP;	/* Structure describing needed address fix */
	
	switch (fragP->fr_subtype){
	case 1:
		/* LEAVE SINGLE COBR INSTRUCTION */
		fixP = fix_new(fragP,
			       fragP->fr_opcode-fragP->fr_literal,
			       4,
			       fragP->fr_symbol,
			       0,
			       fragP->fr_offset,
			       1,
			       0);
		
		fixP->fx_bit_fixP = (bit_fixS *) 13;	/* size of bit field */
		break;
	case 2:
		/* REPLACE COBR WITH COMPARE/BRANCH INSTRUCTIONS */
		relax_cobr(fragP);
		break;
	default:
		BAD_CASE(fragP->fr_subtype);
		break;
	}
}

/*****************************************************************************
 * md_estimate_size_before_relax:  How much does it look like *fragP will grow?
 *
 *	Called by base assembler just before address relaxation.
 *	Return the amount by which the fragment will grow.
 *
 *	Any symbol that is now undefined will not become defined; cobr's
 *	based on undefined symbols will have to be replaced with a compare
 *	instruction and a branch instruction, and the code fragment will grow
 *	by 4 bytes.
 *
 **************************************************************************** */
int
    md_estimate_size_before_relax(fragP, segment_type)
register fragS *fragP;
register segT segment_type;
{
	/* If symbol is undefined in this segment, go to "relaxed" state
	 * (compare and branch instructions instead of cobr) right now.
	 */
	if (S_GET_SEGMENT(fragP->fr_symbol) != segment_type) {
		relax_cobr(fragP);
		return 4;
	}
	return 0;
} /* md_estimate_size_before_relax() */


/*****************************************************************************
 * md_ri_to_chars:
 *	This routine exists in order to overcome machine byte-order problems
 *	when dealing with bit-field entries in the relocation_info struct.
 *
 *	But relocation info will be used on the host machine only (only
 *	executable code is actually downloaded to the i80960).  Therefore,
 *	we leave it in host byte order.
 *
 **************************************************************************** */
void md_ri_to_chars(where, ri)
char *where;
struct relocation_info *ri;
{
	*((struct relocation_info *) where) = *ri; /* structure assignment */
} /* md_ri_to_chars() */

#ifndef WORKING_DOT_WORD

int md_short_jump_size = 0;
int md_long_jump_size = 0;

void md_create_short_jump(ptr, from_addr, to_addr, frag, to_symbol)
char *ptr;
long from_addr;
long to_addr;
fragS *frag;
symbolS *to_symbol;
{
	as_fatal("failed sanity check.");
}

void
    md_create_long_jump(ptr,from_addr,to_addr,frag,to_symbol)
char *ptr;
long from_addr, to_addr;
fragS *frag;
symbolS *to_symbol;
{
	as_fatal("failed sanity check.");
}
#endif

/*************************************************************
 *                                                           *
 *  FOLLOWING ARE THE LOCAL ROUTINES, IN ALPHABETICAL ORDER  *
 *                                                           *
 ************************************************************ */



/*****************************************************************************
 * brcnt_emit:	Emit code to increment inline branch counter.
 *
 *	See the comments above the declaration of 'br_cnt' for details on
 *	branch-prediction instrumentation.
 **************************************************************************** */
static void
    brcnt_emit()
{
	ctrl_fmt(BR_CNT_FUNC,CALL,1);/* Emit call to "increment" routine */
	emit(0);		/* Emit inline counter to be incremented */
}

/*****************************************************************************
 * brlab_next:	generate the next branch local label
 *
 *	See the comments above the declaration of 'br_cnt' for details on
 *	branch-prediction instrumentation.
 **************************************************************************** */
static char *
    brlab_next()
{
	static char buf[20];
	
	sprintf(buf, "%s%d", BR_LABEL_BASE, br_cnt++);
	return buf;
}

/*****************************************************************************
 * brtab_emit:	generate the fetch-prediction branch table.
 *
 *	See the comments above the declaration of 'br_cnt' for details on
 *	branch-prediction instrumentation.
 *
 *	The code emitted here would be functionally equivalent to the following
 *	example assembler source.
 *
 *			.data
 *			.align	2
 *	   BR_TAB_NAME:
 *			.word	0		# link to next table
 *			.word	3		# length of table
 *			.word	LBRANCH0	# 1st entry in table proper
 *			.word	LBRANCH1
 *			.word	LBRANCH2
 ***************************************************************************** */
void
    brtab_emit()
{
	int i;
	char buf[20];
	char *p;		/* Where the binary was output to */
	fixS *fixP;		/*->description of deferred address fixup */
	
	if (!instrument_branches){
		return;
	}
	
	subseg_new(SEG_DATA,0);		/* 	.data */
	frag_align(2,0);		/* 	.align 2 */
	record_alignment(now_seg,2);
	colon(BR_TAB_NAME);		/* BR_TAB_NAME: */
	emit(0);			/* 	.word 0	#link to next table */
	emit(br_cnt);			/*	.word n #length of table */
	
	for (i=0; i<br_cnt; i++){
		sprintf(buf, "%s%d", BR_LABEL_BASE, i);
		p = emit(0);
		fixP = fix_new(frag_now,
			       p - frag_now->fr_literal,
			       4,
			       symbol_find(buf),
			       0,
			       0,
			       0,
			       0);
		fixP->fx_im_disp = 2;		/* 32-bit displacement fix */
	}
}

/*****************************************************************************
 * cobr_fmt:	generate a COBR-format instruction
 *
 **************************************************************************** */
static
    void
    cobr_fmt(arg, opcode, oP)
char *arg[];	/* arg[0]->opcode mnemonic, arg[1-3]->operands (ascii) */
long opcode;	/* Opcode, with branch-prediction bits already set
		 *	if necessary.
		 */
struct i960_opcode *oP;
/*->description of instruction */
{
	long instr;		/* 32-bit instruction */
	struct regop regop;	/* Description of register operand */
	int n;			/* Number of operands */
	int var_frag;		/* 1 if varying length code fragment should
				 *	be emitted;  0 if an address fix
				 *	should be emitted.
				 */
	
	instr = opcode;
	n = oP->num_ops;
	
	if (n >= 1) {
		/* First operand (if any) of a COBR is always a register
		 * operand.  Parse it.
		 */
		parse_regop(&regop, arg[1], oP->operand[0]);
		instr |= (regop.n << 19) | (regop.mode << 13);
	}
	if (n >= 2) {
		/* Second operand (if any) of a COBR is always a register
		 * operand.  Parse it.
		 */
		parse_regop(&regop, arg[2], oP->operand[1]);
		instr |= (regop.n << 14) | regop.special;
	}
	
	
	if (n < 3){
		emit(instr);
		
	} else {
		if (instrument_branches){
			brcnt_emit();
			colon(brlab_next());
		}
		
		/* A third operand to a COBR is always a displacement.
		 * Parse it; if it's relaxable (a cobr "j" directive, or any
		 * cobr other than bbs/bbc when the "-norelax" option is not in
		 * use) set up a variable code fragment;  otherwise set up an
		 * address fix.
		 */
		var_frag = !norelax || (oP->format == COJ); /* TRUE or FALSE */
		get_cdisp(arg[3], "COBR", instr, 13, var_frag, 0);
		
		if (instrument_branches){
			brcnt_emit();
		}
	}
} /* cobr_fmt() */


/*****************************************************************************
 * ctrl_fmt:	generate a CTRL-format instruction
 *
 **************************************************************************** */
static
    void
    ctrl_fmt(targP, opcode, num_ops)
char *targP;	/* Pointer to text of lone operand (if any) */
long opcode;	/* Template of instruction */
int num_ops;	/* Number of operands */
{
	int instrument;	/* TRUE iff we should add instrumentation to track
			 * how often the branch is taken
			 */
	
	
	if (num_ops == 0){
		emit(opcode);		/* Output opcode */
	} else {
		
		instrument = instrument_branches && (opcode!=CALL)
		    && (opcode!=B) && (opcode!=RET) && (opcode!=BAL);
		
		if (instrument){
			brcnt_emit();
			colon(brlab_next());
		}
		
		/* The operand MUST be an ip-relative displacment. Parse it
		 * and set up address fix for the instruction we just output.
		 */
		get_cdisp(targP, "CTRL", opcode, 24, 0, 0);
		
		if (instrument){
			brcnt_emit();
		}
	}
	
}


/*****************************************************************************
 * emit:	output instruction binary
 *
 *	Output instruction binary, in target byte order, 4 bytes at a time.
 *	Return pointer to where it was placed.
 *
 **************************************************************************** */
static
    char *
    emit(instr)
long instr;		/* Word to be output, host byte order */
{
	char *toP;	/* Where to output it */
	
	toP = frag_more(4);			/* Allocate storage */
	md_number_to_chars(toP, instr, 4);  /* Convert to target byte order */
	return toP;
}


/*****************************************************************************
 * get_args:	break individual arguments out of comma-separated list
 *
 * Input assumptions:
 *	- all comments and labels have been removed
 *	- all strings of whitespace have been collapsed to a single blank.
 *	- all character constants ('x') have been replaced with decimal
 *
 * Output:
 *	args[0] is untouched. args[1] points to first operand, etc. All args:
 *	- are NULL-terminated
 *	- contain no whitespace
 *
 * Return value:
 *	Number of operands (0,1,2, or 3) or -1 on error.
 *
 **************************************************************************** */
static int get_args(p, args)
register char *p;	/* Pointer to comma-separated operands; MUCKED BY US */
char *args[];	/* Output arg: pointers to operands placed in args[1-3].
		 * MUST ACCOMMODATE 4 ENTRIES (args[0-3]).
		 */
{
	register int n;		/* Number of operands */
	register char *to;
	/*	char buf[4]; */
	/*	int len; */
	
	
	/* Skip lead white space */
	while (*p == ' '){
		p++;
	}
	
	if (*p == '\0'){
		return 0;
	}
	
	n = 1;
	args[1] = p;
	
	/* Squeze blanks out by moving non-blanks toward start of string.
	 * Isolate operands, whenever comma is found.
	 */
	to = p;
	while (*p != '\0'){
		
		if (*p == ' '){
			p++;
			
		} else if (*p == ','){
			
			/* Start of operand */
			if (n == 3){
				as_bad("too many operands");
				return -1;
			}
			*to++ = '\0';	/* Terminate argument */
			args[++n] = to;	/* Start next argument */
			p++;
			
		} else {
			*to++ = *p++;
		}
	}
	*to = '\0';
	return n;
}


/*****************************************************************************
 * get_cdisp:	handle displacement for a COBR or CTRL instruction.
 *
 *	Parse displacement for a COBR or CTRL instruction.
 *
 *	If successful, output the instruction opcode and set up for it,
 *	depending on the arg 'var_frag', either:
 *	    o an address fixup to be done when all symbol values are known, or
 *	    o a varying length code fragment, with address fixup info.  This
 *		will be done for cobr instructions that may have to be relaxed
 *		in to compare/branch instructions (8 bytes) if the final address
 *		displacement is greater than 13 bits.
 *
 **************************************************************************** */
static
    void
    get_cdisp(dispP, ifmtP, instr, numbits, var_frag, callj)
char *dispP;	/*->displacement as specified in source instruction */
char *ifmtP;	/*->"COBR" or "CTRL" (for use in error message) */
long instr;		/* Instruction needing the displacement */
int numbits;	/* # bits of displacement (13 for COBR, 24 for CTRL) */
int var_frag;	/* 1 if varying length code fragment should be emitted;
		 *	0 if an address fix should be emitted.
		 */
int callj;		/* 1 if callj relocation should be done; else 0 */
{
	expressionS e;	/* Parsed expression */
	fixS *fixP;	/* Structure describing needed address fix */
	char *outP;	/* Where instruction binary is output to */
	
	fixP = NULL;
	
	switch (parse_expr(dispP,&e)) {
		
	case SEG_GOOF:
		as_bad("expression syntax error");
		break;
		
	case SEG_TEXT:
	case SEG_UNKNOWN:
		if (var_frag) {
			outP = frag_more(8);	/* Allocate worst-case storage */
			md_number_to_chars(outP, instr, 4);
			frag_variant(rs_machine_dependent, 4, 4, 1,
				     adds(e), offs(e), outP, 0, 0);
		} else {
			/* Set up a new fix structure, so address can be updated
			 * when all symbol values are known.
			 */
			outP = emit(instr);
			fixP = fix_new(frag_now,
				       outP - frag_now->fr_literal,
				       4,
				       adds(e),
				       0,
				       offs(e),
				       1,
				       0);
			
			fixP->fx_callj = callj;
			
			/* We want to modify a bit field when the address is
			 * known.  But we don't need all the garbage in the
			 * bit_fix structure.  So we're going to lie and store
			 * the number of bits affected instead of a pointer.
			 */
			fixP->fx_bit_fixP = (bit_fixS *) numbits;
		}
		break;
		
	case SEG_DATA:
	case SEG_BSS:
		as_bad("attempt to branch into different segment");
		break;
		
	default:
		as_bad("target of %s instruction must be a label", ifmtP);
		break;
	}
}


/*****************************************************************************
 * get_ispec:	parse a memory operand for an index specification
 *
 *	Here, an "index specification" is taken to be anything surrounded
 *	by square brackets and NOT followed by anything else.
 *
 *	If it's found, detach it from the input string, remove the surrounding
 *	square brackets, and return a pointer to it.  Otherwise, return NULL.
 *
 **************************************************************************** */
static
    char *
    get_ispec(textP)
char *textP; /*->memory operand from source instruction, no white space */
{
	char *start;	/*->start of index specification */
	char *end;	/*->end of index specification */
	
	/* Find opening square bracket, if any
	 */
	start = strchr(textP, '[');
	
	if (start != NULL){
		
		/* Eliminate '[', detach from rest of operand */
		*start++ = '\0';
		
		end = strchr(start, ']');
		
		if (end == NULL){
			as_bad("unmatched '['");
			
		} else {
			/* Eliminate ']' and make sure it was the last thing
			 * in the string.
			 */
			*end = '\0';
			if (*(end+1) != '\0'){
				as_bad("garbage after index spec ignored");
			}
		}
	}
	return start;
}

/*****************************************************************************
 * get_regnum:
 *
 *	Look up a (suspected) register name in the register table and return the
 *	associated register number (or -1 if not found).
 *
 **************************************************************************** */
static
    int
    get_regnum(regname)
char *regname;	/* Suspected register name */
{
	int *rP;
	
	rP = (int *) hash_find(reg_hash, regname);
	return (rP == NULL) ? -1 : *rP;
}


/*****************************************************************************
 * i_scan:	perform lexical scan of ascii assembler instruction.
 *
 * Input assumptions:
 *	- input string is an i80960 instruction (not a pseudo-op)
 *	- all comments and labels have been removed
 *	- all strings of whitespace have been collapsed to a single blank.
 *
 * Output:
 *	args[0] points to opcode, other entries point to operands. All strings:
 *	- are NULL-terminated
 *	- contain no whitespace
 *	- have character constants ('x') replaced with a decimal number
 *
 * Return value:
 *	Number of operands (0,1,2, or 3) or -1 on error.
 *
 **************************************************************************** */
static int i_scan(iP, args)
register char *iP;	/* Pointer to ascii instruction;  MUCKED BY US. */
char *args[];	/* Output arg: pointers to opcode and operands placed
		 *	here.  MUST ACCOMMODATE 4 ENTRIES.
		 */
{
	
	/* Isolate opcode */
	if (*(iP) == ' ') {
		iP++;
	} /* Skip lead space, if any */
	args[0] = iP;
	for (; *iP != ' '; iP++) {
		if (*iP == '\0') {
			/* There are no operands */
			if (args[0] == iP) {
				/* We never moved: there was no opcode either! */
				as_bad("missing opcode");
				return -1;
			}
			return 0;
		}
	}
	*iP++ = '\0';	/* Terminate opcode */
	return(get_args(iP, args));
} /* i_scan() */


/*****************************************************************************
 * mem_fmt:	generate a MEMA- or MEMB-format instruction
 *
 **************************************************************************** */
static void mem_fmt(args, oP)
char *args[];	/* args[0]->opcode mnemonic, args[1-3]->operands */
struct i960_opcode *oP; /* Pointer to description of instruction */
{
	int i;			/* Loop counter */
	struct regop regop;	/* Description of register operand */
	char opdesc;		/* Operand descriptor byte */
	memS instr;		/* Description of binary to be output */
	char *outP;		/* Where the binary was output to */
	expressionS expr;	/* Parsed expression */
	fixS *fixP;		/*->description of deferred address fixup */
	
	bzero(&instr, sizeof(memS));
	instr.opcode = oP->opcode;
	
	/* Process operands. */
	for (i = 1; i <= oP->num_ops; i++){
		opdesc = oP->operand[i-1];
		
		if (MEMOP(opdesc)){
			parse_memop(&instr, args[i], oP->format);
		} else {
			parse_regop(&regop, args[i], opdesc);
			instr.opcode |= regop.n << 19;
		}
	}
	
	/* Output opcode */
	outP = emit(instr.opcode);
	
	if (instr.disp == 0){
		return;
	}
	
	/* Parse and process the displacement */
	switch (parse_expr(instr.e,&expr)){
		
	case SEG_GOOF:
		as_bad("expression syntax error");
		break;
		
	case SEG_ABSOLUTE:
		if (instr.disp == 32){
			(void) emit(offs(expr));	/* Output displacement */
		} else {
			/* 12-bit displacement */
			if (offs(expr) & ~0xfff){
				/* Won't fit in 12 bits: convert already-output
				 * instruction to MEMB format, output
				 * displacement.
				 */
				mema_to_memb(outP);
				(void) emit(offs(expr));
			} else {
				/* WILL fit in 12 bits:  OR into opcode and
				 * overwrite the binary we already put out
				 */
				instr.opcode |= offs(expr);
				md_number_to_chars(outP, instr.opcode, 4);
			}
		}
		break;
		
	case SEG_DIFFERENCE:
	case SEG_TEXT:
	case SEG_DATA:
	case SEG_BSS:
	case SEG_UNKNOWN:
		if (instr.disp == 12){
			/* Displacement is dependent on a symbol, whose value
			 * may change at link time.  We HAVE to reserve 32 bits.
			 * Convert already-output opcode to MEMB format.
			 */
			mema_to_memb(outP);
		}
		
		/* Output 0 displacement and set up address fixup for when
		 * this symbol's value becomes known.
		 */
		outP = emit((long) 0);
		fixP = fix_new(frag_now,
			       outP - frag_now->fr_literal,
			       4,
			       adds(expr),
			       subs(expr),
			       offs(expr),
			       0,
			       0);
		fixP->fx_im_disp = 2;		/* 32-bit displacement fix */
		break;
		
	default:
		BAD_CASE(segs(expr));
		break;
	}
} /* memfmt() */


/*****************************************************************************
 * mema_to_memb:	convert a MEMA-format opcode to a MEMB-format opcode.
 *
 * There are 2 possible MEMA formats:
 *	- displacement only
 *	- displacement + abase
 *
 * They are distinguished by the setting of the MEMA_ABASE bit.
 *
 **************************************************************************** */
static void mema_to_memb(opcodeP)
char *opcodeP;	/* Where to find the opcode, in target byte order */
{
	long opcode;	/* Opcode in host byte order */
	long mode;	/* Mode bits for MEMB instruction */
	
	opcode = md_chars_to_number(opcodeP, 4);
	know(!(opcode & MEMB_BIT));
	
	mode = MEMB_BIT | D_BIT;
	if (opcode & MEMA_ABASE){
		mode |= A_BIT;
	}
	
	opcode &= 0xffffc000;	/* Clear MEMA offset and mode bits */
	opcode |= mode;		/* Set MEMB mode bits */
	
	md_number_to_chars(opcodeP, opcode, 4);
} /* mema_to_memb() */


/*****************************************************************************
 * parse_expr:		parse an expression
 *
 *	Use base assembler's expression parser to parse an expression.
 *	It, unfortunately, runs off a global which we have to save/restore
 *	in order to make it work for us.
 *
 *	An empty expression string is treated as an absolute 0.
 *
 *	Return "segment" to which the expression evaluates.
 *	Return SEG_GOOF regardless of expression evaluation if entire input
 *	string is not consumed in the evaluation -- tolerate no dangling junk!
 *
 **************************************************************************** */
static
    segT
    parse_expr(textP, expP)
char *textP;	/* Text of expression to be parsed */
expressionS *expP;	/* Where to put the results of parsing */
{
	char *save_in;	/* Save global here */
	segT seg;	/* Segment to which expression evaluates */
	symbolS *symP;
	
	know(textP);
	
	if (*textP == '\0') {
		/* Treat empty string as absolute 0 */
		expP->X_add_symbol = expP->X_subtract_symbol = NULL;
		expP->X_add_number = 0;
		seg = expP->X_seg = SEG_ABSOLUTE;
		
	} else {
		save_in = input_line_pointer;	/* Save global */
		input_line_pointer = textP;	/* Make parser work for us */
		
		seg = expression(expP);
		if (input_line_pointer - textP != strlen(textP)) {
			/* Did not consume all of the input */
			seg = SEG_GOOF;
		}
		symP = expP->X_add_symbol;
		if (symP && (hash_find(reg_hash, S_GET_NAME(symP)))) {
			/* Register name in an expression */
			seg = SEG_GOOF;
		}
		
		input_line_pointer = save_in;	/* Restore global */
	}
	return seg;
}


/*****************************************************************************
 * parse_ldcont:
 *	Parse and replace a 'ldconst' pseudo-instruction with an appropriate
 *	i80960 instruction.
 *
 *	Assumes the input consists of:
 *		arg[0]	opcode mnemonic ('ldconst')
 *		arg[1]  first operand (constant)
 *		arg[2]	name of register to be loaded
 *
 *	Replaces opcode and/or operands as appropriate.
 *
 *	Returns the new number of arguments, or -1 on failure.
 *
 **************************************************************************** */
static
    int
    parse_ldconst(arg)
char *arg[];	/* See above */
{
	int n;			/* Constant to be loaded */
	int shift;		/* Shift count for "shlo" instruction */
	static char buf[5];	/* Literal for first operand */
	static char buf2[5];	/* Literal for second operand */
	expressionS e;		/* Parsed expression */
	
	
	arg[3] = NULL;	/* So we can tell at the end if it got used or not */
	
	switch(parse_expr(arg[1],&e)){
		
	case SEG_TEXT:
	case SEG_DATA:
	case SEG_BSS:
	case SEG_UNKNOWN:
	case SEG_DIFFERENCE:
		/* We're dependent on one or more symbols -- use "lda" */
		arg[0] = "lda";
		break;
		
	case SEG_ABSOLUTE:
		/* Try the following mappings:
		 *	ldconst 0,<reg>  ->mov  0,<reg>
		 * 	ldconst 31,<reg> ->mov  31,<reg>
		 * 	ldconst 32,<reg> ->addo 1,31,<reg>
		 * 	ldconst 62,<reg> ->addo 31,31,<reg>
  		 *	ldconst 64,<reg> ->shlo 8,3,<reg>
		 * 	ldconst -1,<reg> ->subo 1,0,<reg>
		 * 	ldconst -31,<reg>->subo 31,0,<reg>
		 *
		 * anthing else becomes:
		 * 	lda xxx,<reg>
		 */
		n = offs(e);
		if ((0 <= n) && (n <= 31)){
			arg[0] = "mov";
			
		} else if ((-31 <= n) && (n <= -1)){
			arg[0] = "subo";
			arg[3] = arg[2];
			sprintf(buf, "%d", -n);
			arg[1] = buf;
			arg[2] = "0";
			
		} else if ((32 <= n) && (n <= 62)){
			arg[0] = "addo";
			arg[3] = arg[2];
			arg[1] = "31";
			sprintf(buf, "%d", n-31);
			arg[2] = buf;
			
		} else if ((shift = shift_ok(n)) != 0){
			arg[0] = "shlo";
			arg[3] = arg[2];
			sprintf(buf, "%d", shift);
			arg[1] = buf;
			sprintf(buf2, "%d", n >> shift);
			arg[2] = buf2;
			
		} else {
			arg[0] = "lda";
		}
		break;
		
	default:
		as_bad("invalid constant");
		return -1;
		break;
	}
	return (arg[3] == 0) ? 2: 3;
}

/*****************************************************************************
 * parse_memop:	parse a memory operand
 *
 *	This routine is based on the observation that the 4 mode bits of the
 *	MEMB format, taken individually, have fairly consistent meaning:
 *
 *		 M3 (bit 13): 1 if displacement is present (D_BIT)
 *		 M2 (bit 12): 1 for MEMB instructions (MEMB_BIT)
 *		 M1 (bit 11): 1 if index is present (I_BIT)
 *		 M0 (bit 10): 1 if abase is present (A_BIT)
 *
 *	So we parse the memory operand and set bits in the mode as we find
 *	things.  Then at the end, if we go to MEMB format, we need only set
 *	the MEMB bit (M2) and our mode is built for us.
 *
 *	Unfortunately, I said "fairly consistent".  The exceptions:
 *
 *		 DBIA
 *		 0100	Would seem illegal, but means "abase-only".
 *
 *		 0101	Would seem to mean "abase-only" -- it means IP-relative.
 *			Must be converted to 0100.
 *
 *		 0110	Would seem to mean "index-only", but is reserved.
 *			We turn on the D bit and provide a 0 displacement.
 *
 *	The other thing to observe is that we parse from the right, peeling
 *	things * off as we go:  first any index spec, then any abase, then
 *	the displacement.
 *
 **************************************************************************** */
static
    void
    parse_memop(memP, argP, optype)
memS *memP;	/* Where to put the results */
char *argP;	/* Text of the operand to be parsed */
int optype;	/* MEM1, MEM2, MEM4, MEM8, MEM12, or MEM16 */
{
	char *indexP;	/* Pointer to index specification with "[]" removed */
	char *p;	/* Temp char pointer */
	char iprel_flag;/* True if this is an IP-relative operand */
	int regnum;	/* Register number */
	int scale;	/* Scale factor: 1,2,4,8, or 16.  Later converted
			 *	to internal format (0,1,2,3,4 respectively).
			 */
	int mode; 	/* MEMB mode bits */
	int *intP;	/* Pointer to register number */
	
	/* The following table contains the default scale factors for each
	 * type of memory instruction.  It is accessed using (optype-MEM1)
	 * as an index -- thus it assumes the 'optype' constants are assigned
	 * consecutive values, in the order they appear in this table
	 */
	static int def_scale[] = {
		1,	/* MEM1 */
		2,	/* MEM2 */
		4, 	/* MEM4 */
		8,	/* MEM8 */
		-1,	/* MEM12 -- no valid default */
		16 	/* MEM16 */
	    };
	
	
	iprel_flag = mode = 0;
	
	/* Any index present? */
	indexP = get_ispec(argP);
	if (indexP) {
		p = strchr(indexP, '*');
		if (p == NULL) {
			/* No explicit scale -- use default for this
			 *instruction type.
			 */
			scale = def_scale[ optype - MEM1 ];
		} else {
			*p++ = '\0';	/* Eliminate '*' */
			
			/* Now indexP->a '\0'-terminated register name,
			 * and p->a scale factor.
			 */
			
			if (!strcmp(p,"16")){
				scale = 16;
			} else if (strchr("1248",*p) && (p[1] == '\0')){
				scale = *p - '0';
			} else {
				scale = -1;
			}
		}
		
		regnum = get_regnum(indexP);		/* Get index reg. # */
		if (!IS_RG_REG(regnum)){
			as_bad("invalid index register");
			return;
		}
		
		/* Convert scale to its binary encoding */
		switch (scale){
		case  1: scale = 0 << 7; break;
		case  2: scale = 1 << 7; break;
		case  4: scale = 2 << 7; break;
		case  8: scale = 3 << 7; break;
		case 16: scale = 4 << 7; break;
		default: as_bad("invalid scale factor"); return;
		};
		
		memP->opcode |= scale | regnum;	 /* Set index bits in opcode */
		mode |= I_BIT;			/* Found a valid index spec */
	}
	
	/* Any abase (Register Indirect) specification present? */
	if ((p = strrchr(argP,'(')) != NULL) {
		/* "(" is there -- does it start a legal abase spec?
		 * (If not it could be part of a displacement expression.)
		 */
		intP = (int *) hash_find(areg_hash, p);
		if (intP != NULL){
			/* Got an abase here */
			regnum = *intP;
			*p = '\0';	/* discard register spec */
			if (regnum == IPREL){
				/* We have to specialcase ip-rel mode */
				iprel_flag = 1;
			} else {
				memP->opcode |= regnum << 14;
				mode |= A_BIT;
			}
		}
	}
	
	/* Any expression present? */
	memP->e = argP;
	if (*argP != '\0'){
		mode |= D_BIT;
	}
	
	/* Special-case ip-relative addressing */
	if (iprel_flag){
		if (mode & I_BIT){
			syntax();
		} else {
			memP->opcode |= 5 << 10;	/* IP-relative mode */
			memP->disp = 32;
		}
		return;
	}
	
	/* Handle all other modes */
	switch (mode){
	case D_BIT | A_BIT:
		/* Go with MEMA instruction format for now (grow to MEMB later
		 *	if 12 bits is not enough for the displacement).
		 * MEMA format has a single mode bit: set it to indicate
		 *	that abase is present.
		 */
		memP->opcode |= MEMA_ABASE;
		memP->disp = 12;
		break;
		
	case D_BIT:
		/* Go with MEMA instruction format for now (grow to MEMB later
		 *	if 12 bits is not enough for the displacement).
		 */
		memP->disp = 12;
		break;
		
	case A_BIT:
		/* For some reason, the bit string for this mode is not
		 * consistent:  it should be 0 (exclusive of the MEMB bit),
		 * so we set it "by hand" here.
		 */
		memP->opcode |= MEMB_BIT;
		break;
		
	case A_BIT | I_BIT:
		/* set MEMB bit in mode, and OR in mode bits */
		memP->opcode |= mode | MEMB_BIT;
		break;
		
	case I_BIT:
		/* Treat missing displacement as displacement of 0 */
		mode |= D_BIT;
		/***********************
		 * Fall into next case *
		 ********************** */
	case D_BIT | A_BIT | I_BIT:
	case D_BIT | I_BIT:
		/* set MEMB bit in mode, and OR in mode bits */
		memP->opcode |= mode | MEMB_BIT;
		memP->disp = 32;
		break;
		
	default:
		syntax();
		break;
	}
}

/*****************************************************************************
 * parse_po:	parse machine-dependent pseudo-op
 *
 *	This is a top-level routine for machine-dependent pseudo-ops.  It slurps
 *	up the rest of the input line, breaks out the individual arguments,
 *	and dispatches them to the correct handler.
 **************************************************************************** */
static
    void
    parse_po(po_num)
int po_num;	 /* Pseudo-op number:  currently S_LEAFPROC or S_SYSPROC */
{
	char *args[4];	/* Pointers operands, with no embedded whitespace.
			 *	arg[0] unused.
			 *	arg[1-3]->operands
			 */
	int n_ops;	/* Number of operands */
	char *p;	/* Pointer to beginning of unparsed argument string */
	char eol;	/* Character that indicated end of line */
	
	extern char is_end_of_line[];
	
	/* Advance input pointer to end of line. */
	p = input_line_pointer;
	while (!is_end_of_line[ *input_line_pointer ]){
		input_line_pointer++;
	}
	eol = *input_line_pointer;	/* Save end-of-line char */
	*input_line_pointer = '\0';  	/* Terminate argument list */
	
	/* Parse out operands */
	n_ops = get_args(p, args);
	if (n_ops == -1){
		return;
	}
	
	/* Dispatch to correct handler */
	switch(po_num){
	case S_SYSPROC:		s_sysproc(n_ops, args);	break;
	case S_LEAFPROC:	s_leafproc(n_ops, args);	break;
	default:		BAD_CASE(po_num);		break;
	}
	
	/* Restore eol, so line numbers get updated correctly.  Base assembler
	 * assumes we leave input pointer pointing at char following the eol.
	 */
	*input_line_pointer++ = eol;
}

/*****************************************************************************
 * parse_regop: parse a register operand.
 *
 *	In case of illegal operand, issue a message and return some valid
 *	information so instruction processing can continue.
 **************************************************************************** */
static
    void
    parse_regop(regopP, optext, opdesc)
struct regop *regopP; /* Where to put description of register operand */
char *optext;	/* Text of operand */
char opdesc;	/* Descriptor byte:  what's legal for this operand */
{
	int n;		/* Register number */
	expressionS e;	/* Parsed expression */
	
	/* See if operand is a register */
	n = get_regnum(optext);
	if (n >= 0){
		if (IS_RG_REG(n)){
			/* global or local register */
			if (!REG_ALIGN(opdesc,n)){
				as_bad("unaligned register");
			}
			regopP->n = n;
			regopP->mode = 0;
			regopP->special = 0;
			return;
		} else if (IS_FP_REG(n) && FP_OK(opdesc)){
			/* Floating point register, and it's allowed */
			regopP->n = n - FP0;
			regopP->mode = 1;
			regopP->special = 0;
			return;
		} else if (IS_SF_REG(n) && SFR_OK(opdesc)){
			/* Special-function register, and it's allowed */
			regopP->n = n - SF0;
			regopP->mode = 0;
			regopP->special = 1;
			if (!targ_has_sfr(regopP->n)){
				as_bad("no such sfr in this architecture");
			}
			return;
		}
	} else if (LIT_OK(opdesc)){
		/*
		 * How about a literal?
		 */
		regopP->mode = 1;
		regopP->special = 0;
		if (FP_OK(opdesc)){ 	/* floating point literal acceptable */
                        /* Skip over 0f, 0d, or 0e prefix */
                        if ( (optext[0] == '0')
			    && (optext[1] >= 'd')
			    && (optext[1] <= 'f') ){
                                optext += 2;
                        }
			
                        if (!strcmp(optext,"0.0") || !strcmp(optext,"0") ){
                                regopP->n = 0x10;
                                return;
                        }
                        if (!strcmp(optext,"1.0") || !strcmp(optext,"1") ){
                                regopP->n = 0x16;
                                return;
                        }
			
		} else {		/* fixed point literal acceptable */
			if ((parse_expr(optext,&e) != SEG_ABSOLUTE)
			    ||   (offs(e) < 0) || (offs(e) > 31)){
				as_bad("illegal literal");
				offs(e) = 0;
			}
			regopP->n = offs(e);
			return;
		}
	}
	
	/* Nothing worked */
	syntax();
	regopP->mode = 0;	/* Register r0 is always a good one */
	regopP->n = 0;
	regopP->special = 0;
} /* parse_regop() */

/*****************************************************************************
 * reg_fmt:	generate a REG-format instruction
 *
 **************************************************************************** */
static void reg_fmt(args, oP)
char *args[];	/* args[0]->opcode mnemonic, args[1-3]->operands */
struct i960_opcode *oP; /* Pointer to description of instruction */
{
	long instr;		/* Binary to be output */
	struct regop regop;	/* Description of register operand */
	int n_ops;		/* Number of operands */
	
	
	instr = oP->opcode;
	n_ops = oP->num_ops;
	
	if (n_ops >= 1){
		parse_regop(&regop, args[1], oP->operand[0]);
		
		if ((n_ops == 1) && !(instr & M3)){
			/* 1-operand instruction in which the dst field should
			 * be used (instead of src1).
			 */
			regop.n       <<= 19;
			if (regop.special){
				regop.mode = regop.special;
			}
			regop.mode    <<= 13;
			regop.special = 0;
		} else {
			/* regop.n goes in bit 0, needs no shifting */
			regop.mode    <<= 11;
			regop.special <<= 5;
		}
		instr |= regop.n | regop.mode | regop.special;
	}
	
	if (n_ops >= 2) {
		parse_regop(&regop, args[2], oP->operand[1]);
		
		if ((n_ops == 2) && !(instr & M3)){
			/* 2-operand instruction in which the dst field should
			 * be used instead of src2).
			 */
			regop.n       <<= 19;
			if (regop.special){
				regop.mode = regop.special;
			}
			regop.mode    <<= 13;
			regop.special = 0;
		} else {
			regop.n       <<= 14;
			regop.mode    <<= 12;
			regop.special <<= 6;
		}
		instr |= regop.n | regop.mode | regop.special;
	}
	if (n_ops == 3){
		parse_regop(&regop, args[3], oP->operand[2]);
		if (regop.special){
			regop.mode = regop.special;
		}
		instr |= (regop.n <<= 19) | (regop.mode <<= 13);
	}
	emit(instr);
}


/*****************************************************************************
 * relax_cobr:
 *	Replace cobr instruction in a code fragment with equivalent branch and
 *	compare instructions, so it can reach beyond a 13-bit displacement.
 *	Set up an address fix/relocation for the new branch instruction.
 *
 **************************************************************************** */

/* This "conditional jump" table maps cobr instructions into equivalent
 * compare and branch opcodes.
 */
static
    struct {
	    long compare;
	    long branch;
    } coj[] = {		/* COBR OPCODE: */
	    CHKBIT,	BNO,	/*	0x30 - bbc */
	    CMPO,	BG,	/*	0x31 - cmpobg */
	    CMPO,	BE,	/*	0x32 - cmpobe */
	    CMPO,	BGE,	/*	0x33 - cmpobge */
	    CMPO,	BL,	/*	0x34 - cmpobl */
	    CMPO,	BNE,	/*	0x35 - cmpobne */
	    CMPO,	BLE,	/*	0x36 - cmpoble */
	    CHKBIT,	BO,	/*	0x37 - bbs */
	    CMPI,	BNO,	/*	0x38 - cmpibno */
	    CMPI,	BG,	/*	0x39 - cmpibg */
	    CMPI,	BE,	/*	0x3a - cmpibe */
	    CMPI,	BGE,	/*	0x3b - cmpibge */
	    CMPI,	BL,	/*	0x3c - cmpibl */
	    CMPI,	BNE,	/*	0x3d - cmpibne */
	    CMPI,	BLE,	/*	0x3e - cmpible */
	    CMPI,	BO,	/*	0x3f - cmpibo */
    };

static
    void
    relax_cobr(fragP)
register fragS *fragP;	/* fragP->fr_opcode is assumed to point to
			 * the cobr instruction, which comes at the
			 * end of the code fragment.
			 */
{
	int opcode, src1, src2, m1, s2;
	/* Bit fields from cobr instruction */
	long bp_bits;	/* Branch prediction bits from cobr instruction */
	long instr;	/* A single i960 instruction */
	char *iP;	/*->instruction to be replaced */
	fixS *fixP;	/* Relocation that can be done at assembly time */
	
	/* PICK UP & PARSE COBR INSTRUCTION */
	iP = fragP->fr_opcode;
	instr  = md_chars_to_number(iP, 4);
	opcode = ((instr >> 24) & 0xff) - 0x30;	/* "-0x30" for table index */
	src1   = (instr >> 19) & 0x1f;
	m1     = (instr >> 13) & 1;
	s2     = instr & 1;
	src2   = (instr >> 14) & 0x1f;
	bp_bits= instr & BP_MASK;
	
	/* GENERATE AND OUTPUT COMPARE INSTRUCTION */
	instr = coj[opcode].compare
	    | src1 | (m1 << 11) | (s2 << 6) | (src2 << 14);
	md_number_to_chars(iP, instr, 4);
	
	/* OUTPUT BRANCH INSTRUCTION */
	md_number_to_chars(iP+4, coj[opcode].branch | bp_bits, 4);
	
	/* SET UP ADDRESS FIXUP/RELOCATION */
	fixP = fix_new(fragP,
		       iP+4 - fragP->fr_literal,
		       4,
		       fragP->fr_symbol,
		       0,
		       fragP->fr_offset,
		       1,
		       0);
	
	fixP->fx_bit_fixP = (bit_fixS *) 24;	/* Store size of bit field */
	
	fragP->fr_fix += 4;
	frag_wane(fragP);
}


/*****************************************************************************
 * reloc_callj:	Relocate a 'callj' instruction
 *
 *	This is a "non-(GNU)-standard" machine-dependent hook.  The base
 *	assembler calls it when it decides it can relocate an address at
 *	assembly time instead of emitting a relocation directive.
 *
 *	Check to see if the relocation involves a 'callj' instruction to a:
 *	    sysproc:	Replace the default 'call' instruction with a 'calls'
 *	    leafproc:	Replace the default 'call' instruction with a 'bal'.
 *	    other proc:	Do nothing.
 *
 *	See b.out.h for details on the 'n_other' field in a symbol structure.
 *
 * IMPORTANT!:
 *	Assumes the caller has already figured out, in the case of a leafproc,
 *	to use the 'bal' entry point, and has substituted that symbol into the
 *	passed fixup structure.
 *
 **************************************************************************** */
void reloc_callj(fixP)
fixS *fixP;		/* Relocation that can be done at assembly time */
{
	char *where;	/*->the binary for the instruction being relocated */
	
	if (!fixP->fx_callj) {
		return;
	} /* This wasn't a callj instruction in the first place */
	
	where = fixP->fx_frag->fr_literal + fixP->fx_where;
	
	if (TC_S_IS_SYSPROC(fixP->fx_addsy)) {
		/* Symbol is a .sysproc: replace 'call' with 'calls'.
		 * System procedure number is (other-1).
		 */
		md_number_to_chars(where, CALLS|TC_S_GET_SYSPROC(fixP->fx_addsy), 4);
		
		/* Nothing else needs to be done for this instruction.
		 * Make sure 'md_number_to_field()' will perform a no-op.
		 */
		fixP->fx_bit_fixP = (bit_fixS *) 1;
		
	} else if (TC_S_IS_CALLNAME(fixP->fx_addsy)) {
		/* Should not happen: see block comment above */
		as_fatal("Trying to 'bal' to %s", S_GET_NAME(fixP->fx_addsy));
		
	} else if (TC_S_IS_BALNAME(fixP->fx_addsy)) {
		/* Replace 'call' with 'bal';  both instructions have
		 * the same format, so calling code should complete
		 * relocation as if nothing happened here.
		 */
		md_number_to_chars(where, BAL, 4);
	} else if (TC_S_IS_BADPROC(fixP->fx_addsy)) {
		as_bad("Looks like a proc, but can't tell what kind.\n");
	} /* switch on proc type */
	
	/* else Symbol is neither a sysproc nor a leafproc */
	
	return;
} /* reloc_callj() */


/*****************************************************************************
 * s_leafproc:	process .leafproc pseudo-op
 *
 *	.leafproc takes two arguments, the second one is optional:
 *		arg[1]: name of 'call' entry point to leaf procedure
 *		arg[2]: name of 'bal' entry point to leaf procedure
 *
 *	If the two arguments are identical, or if the second one is missing,
 *	the first argument is taken to be the 'bal' entry point.
 *
 *	If there are 2 distinct arguments, we must make sure that the 'bal'
 *	entry point immediately follows the 'call' entry point in the linked
 *	list of symbols.
 *
 **************************************************************************** */
static void s_leafproc(n_ops, args)
int n_ops;		/* Number of operands */
char *args[];	/* args[1]->1st operand, args[2]->2nd operand */
{
	symbolS *callP;	/* Pointer to leafproc 'call' entry point symbol */
	symbolS *balP;	/* Pointer to leafproc 'bal' entry point symbol */
	
	if ((n_ops != 1) && (n_ops != 2)) {
		as_bad("should have 1 or 2 operands");
		return;
	} /* Check number of arguments */
	
	/* Find or create symbol for 'call' entry point. */
	callP = symbol_find_or_make(args[1]);
	
	if (TC_S_IS_CALLNAME(callP)) {
		as_warn("Redefining leafproc %s", S_GET_NAME(callP));
	} /* is leafproc */
	
	/* If that was the only argument, use it as the 'bal' entry point.
	 * Otherwise, mark it as the 'call' entry point and find or create
	 * another symbol for the 'bal' entry point.
	 */
	if ((n_ops == 1) || !strcmp(args[1],args[2])) {
		TC_S_FORCE_TO_BALNAME(callP);
		
	} else {
		TC_S_FORCE_TO_CALLNAME(callP);
		
		balP = symbol_find_or_make(args[2]);
		if (TC_S_IS_CALLNAME(balP)) {
			as_warn("Redefining leafproc %s", S_GET_NAME(balP));
		}
		TC_S_FORCE_TO_BALNAME(balP);
		
		tc_set_bal_of_call(callP, balP);
	} /* if only one arg, or the args are the same */
	
	return;
} /* s_leafproc() */


/*
 * s_sysproc:	process .sysproc pseudo-op
 *
 *	.sysproc takes two arguments:
 *		arg[1]: name of entry point to system procedure
 *		arg[2]: 'entry_num' (index) of system procedure in the range
 *			[0,31] inclusive.
 *
 *	For [ab].out, we store the 'entrynum' in the 'n_other' field of
 *	the symbol.  Since that entry is normally 0, we bias 'entrynum'
 *	by adding 1 to it.  It must be unbiased before it is used.
 */
static void s_sysproc(n_ops, args)
int n_ops; /* Number of operands */
char *args[]; /* args[1]->1st operand, args[2]->2nd operand */
{
	expressionS exp;
	symbolS *symP;
	
	if (n_ops != 2) {
		as_bad("should have two operands");
		return;
	} /* bad arg count */
	
	/* Parse "entry_num" argument and check it for validity. */
	if ((parse_expr(args[2],&exp) != SEG_ABSOLUTE)
	    || (offs(exp) < 0)
	    || (offs(exp) > 31)) {
		as_bad("'entry_num' must be absolute number in [0,31]");
		return;
	}
	
	/* Find/make symbol and stick entry number (biased by +1) into it */
	symP = symbol_find_or_make(args[1]);
	
	if (TC_S_IS_SYSPROC(symP)) {
		as_warn("Redefining entrynum for sysproc %s", S_GET_NAME(symP));
	} /* redefining */
	
	TC_S_SET_SYSPROC(symP, offs(exp)); /* encode entry number */
	TC_S_FORCE_TO_SYSPROC(symP);
	
	return;
} /* s_sysproc() */


/*****************************************************************************
 * shift_ok:
 *	Determine if a "shlo" instruction can be used to implement a "ldconst".
 *	This means that some number X < 32 can be shifted left to produce the
 *	constant of interest.
 *
 *	Return the shift count, or 0 if we can't do it.
 *	Caller calculates X by shifting original constant right 'shift' places.
 *
 **************************************************************************** */
static
    int
    shift_ok(n)
int n;		/* The constant of interest */
{
	int shift;	/* The shift count */
	
	if (n <= 0){
		/* Can't do it for negative numbers */
		return 0;
	}
	
	/* Shift 'n' right until a 1 is about to be lost */
	for (shift = 0; (n & 1) == 0; shift++){
		n >>= 1;
	}
	
	if (n >= 32){
		return 0;
	}
	return shift;
}


/*****************************************************************************
 * syntax:	issue syntax error
 *
 **************************************************************************** */
static void syntax() {
	as_bad("syntax error");
} /* syntax() */


/*****************************************************************************
 * targ_has_sfr:
 *	Return TRUE iff the target architecture supports the specified
 *	special-function register (sfr).
 *
 **************************************************************************** */
static
    int
    targ_has_sfr(n)
int n;	/* Number (0-31) of sfr */
{
	switch (architecture){
	case ARCH_KA:
	case ARCH_KB:
	case ARCH_MC:
		return 0;
	case ARCH_CA:
	default:
		return ((0<=n) && (n<=2));
	}
}


/*****************************************************************************
 * targ_has_iclass:
 *	Return TRUE iff the target architecture supports the indicated
 *	class of instructions.
 *
 **************************************************************************** */
static
    int
    targ_has_iclass(ic)
int ic;	/* Instruction class;  one of:
	 *	I_BASE, I_CX, I_DEC, I_KX, I_FP, I_MIL, I_CASIM
	 */
{
	iclasses_seen |= ic;
	switch (architecture){
	case ARCH_KA:	return ic & (I_BASE | I_KX);
	case ARCH_KB:	return ic & (I_BASE | I_KX | I_FP | I_DEC);
	case ARCH_MC:	return ic & (I_BASE | I_KX | I_FP | I_DEC | I_MIL);
	case ARCH_CA:	return ic & (I_BASE | I_CX | I_CASIM);
	default:
		if ((iclasses_seen & (I_KX|I_FP|I_DEC|I_MIL))
		    &&   (iclasses_seen & I_CX)){
			as_warn("architecture of opcode conflicts with that of earlier instruction(s)");
			iclasses_seen &= ~ic;
		}
		return 1;
	}
}


/* Parse an operand that is machine-specific.
   We just return without modifying the expression if we have nothing
   to do. */

/* ARGSUSED */
void
    md_operand (expressionP)
expressionS *expressionP;
{
}

/* We have no need to default values of symbols. */

/* ARGSUSED */
symbolS *md_undefined_symbol(name)
char *name;
{
	return 0;
} /* md_undefined_symbol() */

/* Exactly what point is a PC-relative offset relative TO?
   On the i960, they're relative to the address of the instruction,
   which we have set up as the address of the fixup too. */
long
    md_pcrel_from (fixP)
fixS *fixP;
{
	return fixP->fx_where + fixP->fx_frag->fr_address;
}

void
    md_apply_fix(fixP, val)
fixS *fixP;
long val;
{
	char *place = fixP->fx_where + fixP->fx_frag->fr_literal;
	
	if (!fixP->fx_bit_fixP) {
		
		switch (fixP->fx_im_disp) {
		case 0:
			fixP->fx_addnumber = val;
			md_number_to_imm(place, val, fixP->fx_size, fixP);
			break;
		case 1:
			md_number_to_disp(place,
					  fixP->fx_pcrel ? val + fixP->fx_pcrel_adjust : val,
					  fixP->fx_size);
			break;
		case 2: /* fix requested for .long .word etc */
			md_number_to_chars(place, val, fixP->fx_size);
			break;
		default:
			as_fatal("Internal error in md_apply_fix() in file \"%s\"", __FILE__);
		} /* OVE: maybe one ought to put _imm _disp _chars in one md-func */
	} else {
		md_number_to_field(place, val, fixP->fx_bit_fixP);
	}
	
	return;
} /* md_apply_fix() */

#if defined(OBJ_AOUT) | defined(OBJ_BOUT)
void tc_bout_fix_to_chars(where, fixP, segment_address_in_file)
char *where;
fixS *fixP;
relax_addressT segment_address_in_file;
{
	static unsigned char nbytes_r_length [] = { 42, 0, 1, 42, 2 };
	struct relocation_info ri;
	symbolS *symbolP;
	
	/* JF this is for paranoia */
	bzero((char *)&ri, sizeof(ri));
	
	know((symbolP = fixP->fx_addsy) != 0);
	
	/* These two 'cuz of NS32K */
	ri.r_callj = fixP->fx_callj;
	
	ri.r_length = nbytes_r_length[fixP->fx_size];
	ri.r_pcrel = fixP->fx_pcrel;
	ri.r_address = fixP->fx_frag->fr_address + fixP->fx_where - segment_address_in_file;
	
	if (!S_IS_DEFINED(symbolP)) {
		ri.r_extern = 1;
		ri.r_index = symbolP->sy_number;
	} else {
		ri.r_extern = 0;
		ri.r_index = S_GET_TYPE(symbolP);
	}
	
	/* Output the relocation information in machine-dependent form. */
	md_ri_to_chars(where, &ri);
	
	return;
} /* tc_bout_fix_to_chars() */

#endif /* OBJ_AOUT or OBJ_BOUT */

/* Align an address by rounding it up to the specified boundary.
 */
long md_section_align(seg, addr)
segT seg;
long addr;		/* Address to be rounded up */
{
	return((addr + (1 << section_alignment[(int) seg]) - 1) & (-1 << section_alignment[(int) seg]));
} /* md_section_align() */

#ifdef OBJ_COFF
void tc_headers_hook(headers)
object_headers *headers;
{
	/* FIXME: remove this line */ /*	unsigned short arch_flag = 0; */
	
	if (iclasses_seen == I_BASE){
		headers->filehdr.f_flags |= F_I960CORE;
	} else if (iclasses_seen & I_CX){
		headers->filehdr.f_flags |= F_I960CA;
	} else if (iclasses_seen & I_MIL){
		headers->filehdr.f_flags |= F_I960MC;
	} else if (iclasses_seen & (I_DEC|I_FP)){
		headers->filehdr.f_flags |= F_I960KB;
	} else {
		headers->filehdr.f_flags |= F_I960KA;
	} /* set arch flag */
	
	if (flagseen['R']) {
		headers->filehdr.f_magic = I960RWMAGIC;
		headers->aouthdr.magic = OMAGIC;
	} else {
		headers->filehdr.f_magic = I960ROMAGIC;
		headers->aouthdr.magic = NMAGIC;
	} /* set magic numbers */
	
	return;
} /* tc_headers_hook() */
#endif /* OBJ_COFF */

/*
 * Things going on here:
 *
 * For bout, We need to assure a couple of simplifying
 * assumptions about leafprocs for the linker: the leafproc
 * entry symbols will be defined in the same assembly in
 * which they're declared with the '.leafproc' directive;
 * and if a leafproc has both 'call' and 'bal' entry points
 * they are both global or both local.
 *
 * For coff, the call symbol has a second aux entry that
 * contains the bal entry point.  The bal symbol becomes a
 * label.
 *
 * For coff representation, the call symbol has a second aux entry that
 * contains the bal entry point.  The bal symbol becomes a label.
 *
 */

void tc_crawl_symbol_chain(headers)
object_headers *headers;
{
	symbolS *symbolP;
	
	for (symbolP = symbol_rootP; symbolP; symbolP = symbol_next(symbolP)) {
#ifdef OBJ_COFF
		if (TC_S_IS_SYSPROC(symbolP)) {
			/* second aux entry already contains the sysproc number */
			S_SET_NUMBER_AUXILIARY(symbolP, 2);
			S_SET_STORAGE_CLASS(symbolP, C_SCALL);
			S_SET_DATA_TYPE(symbolP, S_GET_DATA_TYPE(symbolP) | (DT_FCN << N_BTSHFT));
			continue;
		} /* rewrite sysproc */
#endif /* OBJ_COFF */
		
		if (!TC_S_IS_BALNAME(symbolP) && !TC_S_IS_CALLNAME(symbolP)) {
			continue;
		}  /* Not a leafproc symbol */
		
		if (!S_IS_DEFINED(symbolP)) {
			as_bad("leafproc symbol '%s' undefined", S_GET_NAME(symbolP));
		} /* undefined leaf */
		
		if (TC_S_IS_CALLNAME(symbolP)) {
			symbolS *balP = tc_get_bal_of_call(symbolP);
			if (S_IS_EXTERNAL(symbolP) != S_IS_EXTERNAL(balP)) {
				S_SET_EXTERNAL(symbolP);
				S_SET_EXTERNAL(balP);
				as_warn("Warning: making leafproc entries %s and %s both global\n",
					S_GET_NAME(symbolP), S_GET_NAME(balP));
			} /* externality mismatch */
		} /* if callname */
	} /* walk the symbol chain */
	
	return;
} /* tc_crawl_symbol_chain() */

/*
 * For aout or bout, the bal immediately follows the call.
 *
 * For coff, we cheat and store a pointer to the bal symbol
 * in the second aux entry of the call.
 */

void tc_set_bal_of_call(callP, balP)
symbolS *callP;
symbolS *balP;
{
	know(TC_S_IS_CALLNAME(callP));
	know(TC_S_IS_BALNAME(balP));
	
#ifdef OBJ_COFF
	
	callP->sy_symbol.ost_auxent[1].x_bal.x_balntry = (int) balP;
	S_SET_NUMBER_AUXILIARY(callP,2);
	
#elif defined(OBJ_AOUT) || defined(OBJ_BOUT)
	
	/* If the 'bal' entry doesn't immediately follow the 'call'
	 * symbol, unlink it from the symbol list and re-insert it.
	 */
	if (symbol_next(callP) != balP) {
		symbol_remove(balP, &symbol_rootP, &symbol_lastP);
		symbol_append(balP, callP, &symbol_rootP, &symbol_lastP);
	} /* if not in order */
	
#else
	(as yet unwritten.);
#endif /* switch on OBJ_FORMAT */
	
	return;
} /* tc_set_bal_of_call() */

char *_tc_get_bal_of_call(callP)
symbolS *callP;
{
	symbolS *retval;
	
	know(TC_S_IS_CALLNAME(callP));
	
#ifdef OBJ_COFF
	retval = (symbolS *) (callP->sy_symbol.ost_auxent[1].x_bal.x_balntry);
#elif defined(OBJ_AOUT) || defined(OBJ_BOUT)
	retval = symbol_next(callP);
#else
	(as yet unwritten.);
#endif /* switch on OBJ_FORMAT */
	
	know(TC_S_IS_BALNAME(retval));
	return((char *) retval);
} /* _tc_get_bal_of_call() */

void tc_coff_symbol_emit_hook(symbolP)
symbolS *symbolP;
{
	if (TC_S_IS_CALLNAME(symbolP)) {
#ifdef OBJ_COFF
		symbolS *balP = tc_get_bal_of_call(symbolP);
		
		/* second aux entry contains the bal entry point */
		/*		S_SET_NUMBER_AUXILIARY(symbolP, 2); */
		symbolP->sy_symbol.ost_auxent[1].x_bal.x_balntry = S_GET_VALUE(balP);
		S_SET_STORAGE_CLASS(symbolP, (!SF_GET_LOCAL(symbolP) ? C_LEAFEXT : C_LEAFSTAT));
		S_SET_DATA_TYPE(symbolP, S_GET_DATA_TYPE(symbolP) | (DT_FCN << N_BTSHFT));
		/* fix up the bal symbol */
		S_SET_STORAGE_CLASS(balP, C_LABEL);
#endif /* OBJ_COFF */
	} /* only on calls */
	
	return;
} /* tc_coff_symbol_emit_hook() */

/*
 * Local Variables:
 * comment-column: 0
 * fill-column: 131
 * End:
 */

/* end of i960.c */