diff options
Diffstat (limited to 'gas/config/tc-tahoe.c')
| -rw-r--r-- | gas/config/tc-tahoe.c | 2084 |
1 files changed, 2084 insertions, 0 deletions
diff --git a/gas/config/tc-tahoe.c b/gas/config/tc-tahoe.c new file mode 100644 index 0000000..6897623 --- /dev/null +++ b/gas/config/tc-tahoe.c @@ -0,0 +1,2084 @@ +/* tc-tahoe.c + Not part of GAS yet. */ + +#include "as.h" +#include "obstack.h" + +/* this bit glommed from tahoe-inst.h */ + +typedef unsigned char byte; +typedef byte tahoe_opcodeT; + +/* + * This is part of tahoe-ins-parse.c & friends. + * We want to parse a tahoe instruction text into a tree defined here. + */ + +#define TIT_MAX_OPERANDS (4) /* maximum number of operands in one + single tahoe instruction */ + +struct top /* tahoe instruction operand */ +{ + int top_ndx; /* -1, or index register. eg 7=[R7] */ + int top_reg; /* -1, or register number. eg 7 = R7 or (R7) */ + byte top_mode; /* Addressing mode byte. This byte, defines + which of the 11 modes opcode is. */ + + char top_access; /* Access type wanted for this opperand + 'b'branch ' 'no-instruction 'amrvw' */ + char top_width; /* Operand width expected, one of "bwlq?-:!" */ + + char *top_error; /* Say if operand is inappropriate */ + + expressionS exp_of_operand; /* The expression as parsed by expression()*/ + + byte top_dispsize; /* Number of bytes in the displacement if we + can figure it out */ +}; + +/* The addressing modes for an operand. These numbers are the acutal values + for certain modes, so be carefull if you screw with them. */ +#define TAHOE_DIRECT_REG (0x50) +#define TAHOE_REG_DEFERRED (0x60) + +#define TAHOE_REG_DISP (0xE0) +#define TAHOE_REG_DISP_DEFERRED (0xF0) + +#define TAHOE_IMMEDIATE (0x8F) +#define TAHOE_IMMEDIATE_BYTE (0x88) +#define TAHOE_IMMEDIATE_WORD (0x89) +#define TAHOE_IMMEDIATE_LONGWORD (0x8F) +#define TAHOE_ABSOLUTE_ADDR (0x9F) + +#define TAHOE_DISPLACED_RELATIVE (0xEF) +#define TAHOE_DISP_REL_DEFERRED (0xFF) + +#define TAHOE_AUTO_DEC (0x7E) +#define TAHOE_AUTO_INC (0x8E) +#define TAHOE_AUTO_INC_DEFERRED (0x9E) +/* INDEXED_REG is decided by the existance or lack of a [reg] */ + +/* These are encoded into top_width when top_access=='b' + and it's a psuedo op.*/ +#define TAHOE_WIDTH_ALWAYS_JUMP '-' +#define TAHOE_WIDTH_CONDITIONAL_JUMP '?' +#define TAHOE_WIDTH_BIG_REV_JUMP '!' +#define TAHOE_WIDTH_BIG_NON_REV_JUMP ':' + +/* The hex code for certain tahoe commands and modes. + This is just for readability. */ +#define TAHOE_JMP (0x71) +#define TAHOE_PC_REL_LONG (0xEF) +#define TAHOE_BRB (0x11) +#define TAHOE_BRW (0x13) +/* These, when 'ored' with, or added to, a register number, + set up the number for the displacement mode. */ +#define TAHOE_PC_OR_BYTE (0xA0) +#define TAHOE_PC_OR_WORD (0xC0) +#define TAHOE_PC_OR_LONG (0xE0) + +struct tit /* get it out of the sewer, it stands for + tahoe instruction tree (Geeze!) */ +{ + tahoe_opcodeT tit_opcode; /* The opcode. */ + byte tit_operands; /* How many operands are here. */ + struct top tit_operand[TIT_MAX_OPERANDS]; /* Operands */ + char *tit_error; /* "" or fatal error text */ +}; + +/* end: tahoe-inst.h */ + +/* tahoe.c - tahoe-specific - + Not part of gas yet. + */ + +#include "opcode/tahoe.h" + +/* This is the number to put at the beginning of the a.out file */ +long omagic = OMAGIC; + +/* These chars start a comment anywhere in a source file (except inside + another comment or a quoted string. */ +const char comment_chars[] = "#;"; + +/* These chars only start a comment at the beginning of a line. */ +const char line_comment_chars[] = "#"; + +/* Chars that can be used to separate mant from exp in floating point nums */ +const char EXP_CHARS[] = "eE"; + +/* Chars that mean this number is a floating point constant + as in 0f123.456 + or 0d1.234E-12 (see exp chars above) + Note: The Tahoe port doesn't support floating point constants. This is + consistant with 'as' If it's needed, I can always add it later. */ +const char FLT_CHARS[] = "df"; + +/* Also be aware that MAXIMUM_NUMBER_OF_CHARS_FOR_FLOAT may have to be + changed in read.c . Ideally it shouldn't have to know about it at all, + but nothing is ideal around here. + (The tahoe has plenty of room, so the change currently isn't needed.) + */ + +static struct tit t; /* A tahoe instruction after decoding. */ + +void float_cons (); +/* A table of pseudo ops (sans .), the function called, and an integer op + that the function is called with. */ + +const pseudo_typeS md_pseudo_table[] = +{ + {"dfloat", float_cons, 'd'}, + {"ffloat", float_cons, 'f'}, + {0} +}; + +/* + * For Tahoe, relative addresses of "just the right length" are pretty easy. + * The branch displacement is always the last operand, even in + * synthetic instructions. + * For Tahoe, we encode the relax_substateTs (in e.g. fr_substate) as: + * + * 4 3 2 1 0 bit number + * ---/ /--+-------+-------+-------+-------+-------+ + * | what state ? | how long ? | + * ---/ /--+-------+-------+-------+-------+-------+ + * + * The "how long" bits are 00=byte, 01=word, 10=long. + * This is a Un*x convention. + * Not all lengths are legit for a given value of (what state). + * The four states are listed below. + * The "how long" refers merely to the displacement length. + * The address usually has some constant bytes in it as well. + * + +States for Tahoe address relaxing. +1. TAHOE_WIDTH_ALWAYS_JUMP (-) + Format: "b-" + Tahoe opcodes are: (Hex) + jr 11 + jbr 11 + Simple branch. + Always, 1 byte opcode, then displacement/absolute. + If word or longword, change opcode to brw or jmp. + + +2. TAHOE_WIDTH_CONDITIONAL_JUMP (?) + J<cond> where <cond> is a simple flag test. + Format: "b?" + Tahoe opcodes are: (Hex) + jneq/jnequ 21 + jeql/jeqlu 31 + jgtr 41 + jleq 51 + jgeq 81 + jlss 91 + jgtru a1 + jlequ b1 + jvc c1 + jvs d1 + jlssu/jcs e1 + jgequ/jcc f1 + Always, you complement 4th bit to reverse the condition. + Always, 1-byte opcode, then 1-byte displacement. + +3. TAHOE_WIDTH_BIG_REV_JUMP (!) + Jbc/Jbs where cond tests a memory bit. + Format: "rlvlb!" + Tahoe opcodes are: (Hex) + jbs 0e + jbc 1e + Always, you complement 4th bit to reverse the condition. + Always, 1-byte opcde, longword, longword-address, 1-word-displacement + +4. TAHOE_WIDTH_BIG_NON_REV_JUMP (:) + JaoblXX/Jbssi + Format: "rlmlb:" + Tahoe opcodes are: (Hex) + aojlss 2f + jaoblss 2f + aojleq 3f + jaobleq 3f + jbssi 5f + Always, we cannot reverse the sense of the branch; we have a word + displacement. + +We need to modify the opcode is for class 1, 2 and 3 instructions. +After relax() we may complement the 4th bit of 2 or 3 to reverse sense of +branch. + +We sometimes store context in the operand literal. This way we can figure out +after relax() what the original addressing mode was. (Was is pc_rel, or +pc_rel_disp? That sort of thing.) */ + +/* These displacements are relative to the START address of the + displacement which is at the start of the displacement, not the end of + the instruction. The hardware pc_rel is at the end of the instructions. + That's why all the displacements have the length of the displacement added + to them. (WF + length(word)) + + The first letter is Byte, Word. + 2nd letter is Forward, Backward. */ +#define BF (1+ 127) +#define BB (1+-128) +#define WF (2+ 32767) +#define WB (2+-32768) +/* Dont need LF, LB because they always reach. [They are coded as 0.] */ + +#define C(a,b) ENCODE_RELAX(a,b) +/* This macro has no side-effects. */ +#define ENCODE_RELAX(what,length) (((what) << 2) + (length)) +#define RELAX_STATE(what) ((what) >> 2) +#define RELAX_LENGTH(length) ((length) && 3) + +#define STATE_ALWAYS_BRANCH (1) +#define STATE_CONDITIONAL_BRANCH (2) +#define STATE_BIG_REV_BRANCH (3) +#define STATE_BIG_NON_REV_BRANCH (4) +#define STATE_PC_RELATIVE (5) + +#define STATE_BYTE (0) +#define STATE_WORD (1) +#define STATE_LONG (2) +#define STATE_UNDF (3) /* Symbol undefined in pass1 */ + +/* This is the table used by gas to figure out relaxing modes. The fields are + forward_branch reach, backward_branch reach, number of bytes it would take, + where the next biggest branch is. */ +const relax_typeS + md_relax_table[] = +{ + { + 1, 1, 0, 0 + }, /* error sentinel 0,0 */ + { + 1, 1, 0, 0 + }, /* unused 0,1 */ + { + 1, 1, 0, 0 + }, /* unused 0,2 */ + { + 1, 1, 0, 0 + }, /* unused 0,3 */ +/* Unconditional branch cases "jrb" + The relax part is the actual displacement */ + { + BF, BB, 1, C (1, 1) + }, /* brb B`foo 1,0 */ + { + WF, WB, 2, C (1, 2) + }, /* brw W`foo 1,1 */ + { + 0, 0, 5, 0 + }, /* Jmp L`foo 1,2 */ + { + 1, 1, 0, 0 + }, /* unused 1,3 */ +/* Reversible Conditional Branch. If the branch won't reach, reverse + it, and jump over a brw or a jmp that will reach. The relax part is the + actual address. */ + { + BF, BB, 1, C (2, 1) + }, /* b<cond> B`foo 2,0 */ + { + WF + 2, WB + 2, 4, C (2, 2) + }, /* brev over, brw W`foo, over: 2,1 */ + { + 0, 0, 7, 0 + }, /* brev over, jmp L`foo, over: 2,2 */ + { + 1, 1, 0, 0 + }, /* unused 2,3 */ +/* Another type of reversable branch. But this only has a word + displacement. */ + { + 1, 1, 0, 0 + }, /* unused 3,0 */ + { + WF, WB, 2, C (3, 2) + }, /* jbX W`foo 3,1 */ + { + 0, 0, 8, 0 + }, /* jrevX over, jmp L`foo, over: 3,2 */ + { + 1, 1, 0, 0 + }, /* unused 3,3 */ +/* These are the non reversable branches, all of which have a word + displacement. If I can't reach, branch over a byte branch, to a + jump that will reach. The jumped branch jumps over the reaching + branch, to continue with the flow of the program. It's like playing + leap frog. */ + { + 1, 1, 0, 0 + }, /* unused 4,0 */ + { + WF, WB, 2, C (4, 2) + }, /* aobl_ W`foo 4,1 */ + { + 0, 0, 10, 0 + }, /*aobl_ W`hop,br over,hop: jmp L^foo,over 4,2*/ + { + 1, 1, 0, 0 + }, /* unused 4,3 */ +/* Normal displacement mode, no jumping or anything like that. + The relax points to one byte before the address, thats why all + the numbers are up by one. */ + { + BF + 1, BB + 1, 2, C (5, 1) + }, /* B^"foo" 5,0 */ + { + WF + 1, WB + 1, 3, C (5, 2) + }, /* W^"foo" 5,1 */ + { + 0, 0, 5, 0 + }, /* L^"foo" 5,2 */ + { + 1, 1, 0, 0 + }, /* unused 5,3 */ +}; + +#undef C +#undef BF +#undef BB +#undef WF +#undef WB +/* End relax stuff */ + +static struct hash_control *op_hash = NULL; /* handle of the OPCODE hash table + NULL means any use before md_begin() will + crash */ + +/* Init function. Build the hash table. */ +void +md_begin () +{ + struct tot *tP; + char *errorval = ""; + int synthetic_too = 1; /* If 0, just use real opcodes. */ + + if ((op_hash = hash_new ())) + { + for (tP = totstrs; *tP->name && !*errorval; tP++) + { + errorval = hash_insert (op_hash, tP->name, &tP->detail); + } + if (synthetic_too) + { + for (tP = synthetic_totstrs; *tP->name && !*errorval; tP++) + { + errorval = hash_insert (op_hash, tP->name, &tP->detail); + } + } + } + else + { + errorval = "Virtual memory exceeded"; + } + if (*errorval) + as_fatal (errorval); +} /* md_begin */ + +void +md_end () +{ +} /* md_end */ + +int +md_parse_option (argP, cntP, vecP) + char **argP; + int *cntP; + char ***vecP; +{ + char *temp_name; /* name for -t or -d options */ + char opt; + + switch (**argP) + { + case 'a': + as_warn ("The -a option doesn't exits. (Dispite what the man page says!"); + + case 'J': + as_warn ("JUMPIFY (-J) not implemented, use psuedo ops instead."); + break; + + case 'S': + as_warn ("SYMBOL TABLE not implemented"); + break; /* SYMBOL TABLE not implemented */ + + case 'T': + as_warn ("TOKEN TRACE not implemented"); + break; /* TOKEN TRACE not implemented */ + + case 'd': + case 't': + opt = **argP; + if (**argP) + { /* Rest of argument is filename. */ + temp_name = *argP; + while (**argP) + (*argP)++; + } + else if (*cntP) + { + while (**argP) + (*argP)++; + --(*cntP); + temp_name = *++(*vecP); + **vecP = NULL; /* Remember this is not a file-name. */ + } + else + { + as_warn ("I expected a filename after -%c.", opt); + temp_name = "{absent}"; + } + + if (opt == 'd') + as_warn ("Displacement length %s ignored!", temp_name); + else + as_warn ("I don't need or use temp. file \"%s\".", temp_name); + break; + + case 'V': + as_warn ("I don't use an interpass file! -V ignored"); + break; + + default: + return 0; + + } + return 1; +} + +/* The functions in this section take numbers in the machine format, and + munges them into Tahoe byte order. + They exist primarily for cross assembly purpose. */ +void /* Knows about order of bytes in address. */ +md_number_to_chars (con, value, nbytes) + char con[]; /* Return 'nbytes' of chars here. */ + long int value; /* The value of the bits. */ + int nbytes; /* Number of bytes in the output. */ +{ + int n = nbytes; + long int v = value; + + con += nbytes - 1; /* Tahoes is (Bleah!) big endian */ + while (nbytes--) + { + *con-- = value; /* Lint wants & MASK_CHAR. */ + value >>= BITS_PER_CHAR; + } + /* XXX line number probably botched for this warning message. */ + if (value != 0 && value != -1) + as_warn ("Displacement (%ld) long for instruction field length (%d).", v, n); +} + +#ifdef comment +void /* Knows about order of bytes in address. */ +md_number_to_imm (con, value, nbytes) + char con[]; /* Return 'nbytes' of chars here. */ + long int value; /* The value of the bits. */ + int nbytes; /* Number of bytes in the output. */ +{ + md_number_to_chars (con, value, nbytes); +} + +#endif /* comment */ + +void +tc_apply_fix (fixP, val) + fixS *fixP; + long val; +{ + /* char *place = fixP->fx_where + fixP->fx_frag->fr_literal; */ + /* should never be called */ + know (0); + return; +} /* tc_apply_fix() */ + +void /* Knows about order of bytes in address. */ +md_number_to_disp (con, value, nbytes) + char con[]; /* Return 'nbytes' of chars here. */ + long int value; /* The value of the bits. */ + int nbytes; /* Number of bytes in the output. */ +{ + md_number_to_chars (con, value, nbytes); +} + +void /* Knows about order of bytes in address. */ +md_number_to_field (con, value, nbytes) + char con[]; /* Return 'nbytes' of chars here. */ + long int value; /* The value of the bits. */ + int nbytes; /* Number of bytes in the output. */ +{ + md_number_to_chars (con, value, nbytes); +} + +/* Put the bits in an order that a tahoe will understand, despite the ordering + of the native machine. + On Tahoe: first 4 bytes are normal unsigned big endian long, + next three bytes are symbolnum, in kind of 3 byte big endian (least sig. byte last). + The last byte is broken up with bit 7 as pcrel, + bits 6 & 5 as length, + bit 4 as extern and the last nibble as 'undefined'. */ + +#if comment +void +md_ri_to_chars (ri_p, ri) + struct relocation_info *ri_p, ri; +{ + byte the_bytes[sizeof (struct relocation_info)]; + /* The reason I can't just encode these directly into ri_p is that + ri_p may point to ri. */ + + /* This is easy */ + md_number_to_chars (the_bytes, ri.r_address, sizeof (ri.r_address)); + + /* now the fun stuff */ + the_bytes[4] = (ri.r_symbolnum >> 16) & 0x0ff; + the_bytes[5] = (ri.r_symbolnum >> 8) & 0x0ff; + the_bytes[6] = ri.r_symbolnum & 0x0ff; + the_bytes[7] = (((ri.r_extern << 4) & 0x10) | ((ri.r_length << 5) & 0x60) | + ((ri.r_pcrel << 7) & 0x80)) & 0xf0; + + bcopy (the_bytes, (char *) ri_p, sizeof (struct relocation_info)); +} + +#endif /* comment */ + +/* Put the bits in an order that a tahoe will understand, despite the ordering + of the native machine. + On Tahoe: first 4 bytes are normal unsigned big endian long, + next three bytes are symbolnum, in kind of 3 byte big endian (least sig. byte last). + The last byte is broken up with bit 7 as pcrel, + bits 6 & 5 as length, + bit 4 as extern and the last nibble as 'undefined'. */ + +void +tc_aout_fix_to_chars (where, fixP, segment_address_in_file) + char *where; + fixS *fixP; + relax_addressT segment_address_in_file; +{ + long r_symbolnum; + + know (fixP->fx_addsy != NULL); + + md_number_to_chars (where, + fixP->fx_frag->fr_address + fixP->fx_where - segment_address_in_file, + 4); + + r_symbolnum = (S_IS_DEFINED (fixP->fx_addsy) + ? S_GET_TYPE (fixP->fx_addsy) + : fixP->fx_addsy->sy_number); + + where[4] = (r_symbolnum >> 16) & 0x0ff; + where[5] = (r_symbolnum >> 8) & 0x0ff; + where[6] = r_symbolnum & 0x0ff; + where[7] = (((is_pcrel (fixP) << 7) & 0x80) + | ((((fixP->fx_type == FX_8 || fixP->fx_type == FX_PCREL8 + ? 0 + : (fixP->fx_type == FX_16 || fixP->fx_type == FX_PCREL16 + ? 1 + : (fixP->fx_type == FX_32 || fixP->fx_type == FX_PCREL32 + ? 2 + : 42)))) << 5) & 0x60) + | ((!S_IS_DEFINED (fixP->fx_addsy) << 4) & 0x10)); + + return; +} /* tc_aout_fix_to_chars() */ + +/* Relocate byte stuff */ + +/* This is for broken word. */ +const int md_short_jump_size = 3; + +void +md_create_short_jump (ptr, from_addr, to_addr, frag, to_symbol) + char *ptr; + long from_addr, to_addr; + fragS *frag; + symbolS *to_symbol; +{ + long offset; + + offset = to_addr - (from_addr + 1); + *ptr++ = TAHOE_BRW; + md_number_to_chars (ptr, offset, 2); +} + +const int md_long_jump_size = 6; +const int md_reloc_size = 8; /* Size of relocation record */ + +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; +{ + long offset; + + offset = to_addr - (from_addr + 4); + *ptr++ = TAHOE_JMP; + *ptr++ = TAHOE_PC_REL_LONG; + md_number_to_chars (ptr, offset, 4); +} + +/* + * md_estimate_size_before_relax() + * + * Called just before relax(). + * Any symbol that is now undefined will not become defined, so we assumed + * that it will be resolved by the linker. + * Return the correct fr_subtype in the frag, for relax() + * Return the initial "guess for fr_var" to caller. (How big I think this + * will be.) + * The guess for fr_var is ACTUALLY the growth beyond fr_fix. + * Whatever we do to grow fr_fix or fr_var contributes to our returned value. + * Although it may not be explicit in the frag, pretend fr_var starts with a + * 0 value. + */ +int +md_estimate_size_before_relax (fragP, segment_type) + register fragS *fragP; + segT segment_type; /* N_DATA or N_TEXT. */ +{ + register char *p; + register int old_fr_fix; + /* int pc_rel; FIXME: remove this */ + + old_fr_fix = fragP->fr_fix; + switch (fragP->fr_subtype) + { + case ENCODE_RELAX (STATE_PC_RELATIVE, STATE_UNDF): + if (S_GET_SEGMENT (fragP->fr_symbol) == segment_type) + { + /* The symbol was in the same segment as the opcode, and it's + a real pc_rel case so it's a relaxable case. */ + fragP->fr_subtype = ENCODE_RELAX (STATE_PC_RELATIVE, STATE_BYTE); + } + else + { + /* This case is still undefined, so asume it's a long word for the + linker to fix. */ + p = fragP->fr_literal + old_fr_fix; + *p |= TAHOE_PC_OR_LONG; + /* We now know how big it will be, one long word. */ + fragP->fr_fix += 1 + 4; + fix_new (fragP, old_fr_fix + 1, fragP->fr_symbol, 0, + fragP->fr_offset, FX_PCREL32, NULL); + frag_wane (fragP); + } + break; + + case ENCODE_RELAX (STATE_CONDITIONAL_BRANCH, STATE_UNDF): + if (S_GET_SEGMENT (fragP->fr_symbol) == segment_type) + { + fragP->fr_subtype = ENCODE_RELAX (STATE_CONDITIONAL_BRANCH, STATE_BYTE); + } + else + { + p = fragP->fr_literal + old_fr_fix; + *fragP->fr_opcode ^= 0x10; /* Reverse sense of branch. */ + *p++ = 6; + *p++ = TAHOE_JMP; + *p++ = TAHOE_PC_REL_LONG; + fragP->fr_fix += 1 + 1 + 1 + 4; + fix_new (fragP, old_fr_fix + 3, fragP->fr_symbol, 0, + fragP->fr_offset, FX_PCREL32, NULL); + frag_wane (fragP); + } + break; + + case ENCODE_RELAX (STATE_BIG_REV_BRANCH, STATE_UNDF): + if (S_GET_SEGMENT (fragP->fr_symbol) == segment_type) + { + fragP->fr_subtype = + ENCODE_RELAX (STATE_BIG_REV_BRANCH, STATE_WORD); + } + else + { + p = fragP->fr_literal + old_fr_fix; + *fragP->fr_opcode ^= 0x10; /* Reverse sense of branch. */ + *p++ = 0; + *p++ = 6; + *p++ = TAHOE_JMP; + *p++ = TAHOE_PC_REL_LONG; + fragP->fr_fix += 2 + 2 + 4; + fix_new (fragP, old_fr_fix + 4, fragP->fr_symbol, 0, + fragP->fr_offset, FX_PCREL32, NULL); + frag_wane (fragP); + } + break; + + case ENCODE_RELAX (STATE_BIG_NON_REV_BRANCH, STATE_UNDF): + if (S_GET_SEGMENT (fragP->fr_symbol) == segment_type) + { + fragP->fr_subtype = ENCODE_RELAX (STATE_BIG_NON_REV_BRANCH, STATE_WORD); + } + else + { + p = fragP->fr_literal + old_fr_fix; + *p++ = 2; + *p++ = 0; + *p++ = TAHOE_BRB; + *p++ = 6; + *p++ = TAHOE_JMP; + *p++ = TAHOE_PC_REL_LONG; + fragP->fr_fix += 2 + 2 + 2 + 4; + fix_new (fragP, old_fr_fix + 6, fragP->fr_symbol, 0, + fragP->fr_offset, FX_PCREL32, NULL); + frag_wane (fragP); + } + break; + + case ENCODE_RELAX (STATE_ALWAYS_BRANCH, STATE_UNDF): + if (S_GET_SEGMENT (fragP->fr_symbol) == segment_type) + { + fragP->fr_subtype = ENCODE_RELAX (STATE_ALWAYS_BRANCH, STATE_BYTE); + } + else + { + p = fragP->fr_literal + old_fr_fix; + *fragP->fr_opcode = TAHOE_JMP; + *p++ = TAHOE_PC_REL_LONG; + fragP->fr_fix += 1 + 4; + fix_new (fragP, old_fr_fix + 1, fragP->fr_symbol, 0, + fragP->fr_offset, FX_PCREL32, NULL); + frag_wane (fragP); + } + break; + + default: + break; + } + return (fragP->fr_var + fragP->fr_fix - old_fr_fix); +} /* md_estimate_size_before_relax() */ + +/* + * md_convert_frag(); + * + * Called after relax() is finished. + * In: Address of frag. + * fr_type == rs_machine_dependent. + * fr_subtype is what the address relaxed to. + * + * Out: Any fixSs and constants are set up. + * Caller will turn frag into a ".space 0". + */ +void +md_convert_frag (headers, fragP) + object_headers *headers; + register fragS *fragP; +{ + register char *addressP; /* -> _var to change. */ + register char *opcodeP; /* -> opcode char(s) to change. */ + register short int length_code; /* 2=long 1=word 0=byte */ + register short int extension = 0; /* Size of relaxed address. + Added to fr_fix: incl. ALL var chars. */ + register symbolS *symbolP; + register long int where; + register long int address_of_var; + /* Where, in file space, is _var of *fragP? */ + register long int target_address; + /* Where, in file space, does addr point? */ + + know (fragP->fr_type == rs_machine_dependent); + length_code = RELAX_LENGTH (fragP->fr_subtype); + know (length_code >= 0 && length_code < 3); + where = fragP->fr_fix; + addressP = fragP->fr_literal + where; + opcodeP = fragP->fr_opcode; + symbolP = fragP->fr_symbol; + know (symbolP); + target_address = S_GET_VALUE (symbolP) + fragP->fr_offset; + address_of_var = fragP->fr_address + where; + switch (fragP->fr_subtype) + { + case ENCODE_RELAX (STATE_PC_RELATIVE, STATE_BYTE): + /* *addressP holds the registers number, plus 0x10, if it's deferred + mode. To set up the right mode, just OR the size of this displacement */ + /* Byte displacement. */ + *addressP++ |= TAHOE_PC_OR_BYTE; + *addressP = target_address - (address_of_var + 2); + extension = 2; + break; + + case ENCODE_RELAX (STATE_PC_RELATIVE, STATE_WORD): + /* Word displacement. */ + *addressP++ |= TAHOE_PC_OR_WORD; + md_number_to_chars (addressP, target_address - (address_of_var + 3), 2); + extension = 3; + break; + + case ENCODE_RELAX (STATE_PC_RELATIVE, STATE_LONG): + /* Long word displacement. */ + *addressP++ |= TAHOE_PC_OR_LONG; + md_number_to_chars (addressP, target_address - (address_of_var + 5), 4); + extension = 5; + break; + + case ENCODE_RELAX (STATE_CONDITIONAL_BRANCH, STATE_BYTE): + *addressP = target_address - (address_of_var + 1); + extension = 1; + break; + + case ENCODE_RELAX (STATE_CONDITIONAL_BRANCH, STATE_WORD): + *opcodeP ^= 0x10; /* Reverse sense of test. */ + *addressP++ = 3; /* Jump over word branch */ + *addressP++ = TAHOE_BRW; + md_number_to_chars (addressP, target_address - (address_of_var + 4), 2); + extension = 4; + break; + + case ENCODE_RELAX (STATE_CONDITIONAL_BRANCH, STATE_LONG): + *opcodeP ^= 0x10; /* Reverse sense of test. */ + *addressP++ = 6; + *addressP++ = TAHOE_JMP; + *addressP++ = TAHOE_PC_REL_LONG; + md_number_to_chars (addressP, target_address, 4); + extension = 7; + break; + + case ENCODE_RELAX (STATE_ALWAYS_BRANCH, STATE_BYTE): + *addressP = target_address - (address_of_var + 1); + extension = 1; + break; + + case ENCODE_RELAX (STATE_ALWAYS_BRANCH, STATE_WORD): + *opcodeP = TAHOE_BRW; + md_number_to_chars (addressP, target_address - (address_of_var + 2), 2); + extension = 2; + break; + + case ENCODE_RELAX (STATE_ALWAYS_BRANCH, STATE_LONG): + *opcodeP = TAHOE_JMP; + *addressP++ = TAHOE_PC_REL_LONG; + md_number_to_chars (addressP, target_address - (address_of_var + 5), 4); + extension = 5; + break; + + case ENCODE_RELAX (STATE_BIG_REV_BRANCH, STATE_WORD): + md_number_to_chars (addressP, target_address - (address_of_var + 2), 2); + extension = 2; + break; + + case ENCODE_RELAX (STATE_BIG_REV_BRANCH, STATE_LONG): + *opcodeP ^= 0x10; + *addressP++ = 0; + *addressP++ = 6; + *addressP++ = TAHOE_JMP; + *addressP++ = TAHOE_PC_REL_LONG; + md_number_to_chars (addressP, target_address, 4); + extension = 8; + break; + + case ENCODE_RELAX (STATE_BIG_NON_REV_BRANCH, STATE_WORD): + md_number_to_chars (addressP, target_address - (address_of_var + 2), 2); + extension = 2; + break; + + case ENCODE_RELAX (STATE_BIG_NON_REV_BRANCH, STATE_LONG): + *addressP++ = 0; + *addressP++ = 2; + *addressP++ = TAHOE_BRB; + *addressP++ = 6; + *addressP++ = TAHOE_JMP; + *addressP++ = TAHOE_PC_REL_LONG; + md_number_to_chars (addressP, target_address, 4); + extension = 10; + break; + + default: + BAD_CASE (fragP->fr_subtype); + break; + } + fragP->fr_fix += extension; +} /* md_convert_frag */ + + +/* This is the stuff for md_assemble. */ +#define FP_REG 13 +#define SP_REG 14 +#define PC_REG 15 +#define BIGGESTREG PC_REG + +/* + * Parse the string pointed to by START + * If it represents a valid register, point START to the character after + * the last valid register char, and return the register number (0-15). + * If invalid, leave START alone, return -1. + * The format has to be exact. I don't do things like eat leading zeros + * or the like. + * Note: This doesn't check for the next character in the string making + * this invalid. Ex: R123 would return 12, it's the callers job to check + * what start is point to apon return. + * + * Valid registers are R1-R15, %1-%15, FP (13), SP (14), PC (15) + * Case doesn't matter. + */ +int +tahoe_reg_parse (start) + char **start; /* A pointer to the string to parse. */ +{ + register char *regpoint = *start; + register int regnum = -1; + + switch (*regpoint++) + { + case '%': /* Registers can start with a %, + R or r, and then a number. */ + case 'R': + case 'r': + if (isdigit (*regpoint)) + { + /* Got the first digit. */ + regnum = *regpoint++ - '0'; + if ((regnum == 1) && isdigit (*regpoint)) + { + /* Its a two digit number. */ + regnum = 10 + (*regpoint++ - '0'); + if (regnum > BIGGESTREG) + { /* Number too big? */ + regnum = -1; + } + } + } + break; + case 'F': /* Is it the FP */ + case 'f': + switch (*regpoint++) + { + case 'p': + case 'P': + regnum = FP_REG; + } + break; + case 's': /* How about the SP */ + case 'S': + switch (*regpoint++) + { + case 'p': + case 'P': + regnum = SP_REG; + } + break; + case 'p': /* OR the PC even */ + case 'P': + switch (*regpoint++) + { + case 'c': + case 'C': + regnum = PC_REG; + } + break; + } + + if (regnum != -1) + { /* No error, so move string pointer */ + *start = regpoint; + } + return regnum; /* Return results */ +} /* tahoe_reg_parse */ + +/* + * This chops up an operand and figures out its modes and stuff. + * It's a little touchy about extra characters. + * Optex to start with one extra character so it can be overwritten for + * the backward part of the parsing. + * You can't put a bunch of extra characters in side to + * make the command look cute. ie: * foo ( r1 ) [ r0 ] + * If you like doing a lot of typing, try COBOL! + * Actually, this parser is a little weak all around. It's designed to be + * used with compliers, so I emphisise correct decoding of valid code quickly + * rather that catching every possable error. + * Note: This uses the expression function, so save input_line_pointer before + * calling. + * + * Sperry defines the semantics of address modes (and values) + * by a two-letter code, explained here. + * + * letter 1: access type + * + * a address calculation - no data access, registers forbidden + * b branch displacement + * m read - let go of bus - write back "modify" + * r read + * w write + * v bit field address: like 'a' but registers are OK + * + * letter 2: data type (i.e. width, alignment) + * + * b byte + * w word + * l longword + * q quadword (Even regs < 14 allowed) (if 12, you get a warning) + * - unconditional synthetic jbr operand + * ? simple synthetic reversable branch operand + * ! complex synthetic reversable branch operand + * : complex synthetic non-reversable branch operand + * + * The '-?!:' letter 2's are not for external consumption. They are used + * by GAS for psuedo ops relaxing code. + * + * After parsing topP has: + * + * top_ndx: -1, or the index register. eg 7=[R7] + * top_reg: -1, or register number. eg 7 = R7 or (R7) + * top_mode: The addressing mode byte. This byte, defines which of + * the 11 modes opcode is. + * top_access: Access type wanted for this opperand 'b'branch ' ' + * no-instruction 'amrvw' + * top_width: Operand width expected, one of "bwlq?-:!" + * exp_of_operand: The expression as parsed by expression() + * top_dispsize: Number of bytes in the displacement if we can figure it + * out and it's relavent. + * + * Need syntax checks built. + */ + +void +tip_op (optex, topP) + char *optex; /* The users text input, with one leading character */ + struct top *topP; /* The tahoe instruction with some fields already set: + in: access, width + out: ndx, reg, mode, error, dispsize */ + +{ + int mode = 0; /* This operand's mode. */ + char segfault = *optex; /* To keep the back parsing from freaking. */ + char *point = optex + 1; /* Parsing from front to back. */ + char *end; /* Parsing from back to front. */ + int reg = -1; /* major register, -1 means absent */ + int imreg = -1; /* Major register in immediate mode */ + int ndx = -1; /* index register number, -1 means absent */ + char dec_inc = ' '; /* Is the SP auto-incremented '+' or + auto-decremented '-' or neither ' '. */ + int immediate = 0; /* 1 if '$' immediate mode */ + int call_width = 0; /* If the caller casts the displacement */ + int abs_width = 0; /* The width of the absolute displacment */ + int com_width = 0; /* Displacement width required by branch */ + int deferred = 0; /* 1 if '*' deferral is used */ + byte disp_size = 0; /* How big is this operand. 0 == don't know */ + char *op_bad = ""; /* Bad operand error */ + + char *tp, *temp, c; /* Temporary holders */ + + char access = topP->top_access; /* Save on a deref. */ + char width = topP->top_width; + + int really_none = 0; /* Empty expressions evaluate to 0 + but I need to know if it's there or not */ + expressionS *expP; /* -> expression values for this operand */ + + /* Does this command restrict the displacement size. */ + if (access == 'b') + com_width = (width == 'b' ? 1 : + (width == 'w' ? 2 : + (width == 'l' ? 4 : 0))); + + *optex = '\0'; /* This is kind of a back stop for all + the searches to fail on if needed.*/ + if (*point == '*') + { /* A dereference? */ + deferred = 1; + point++; + } + + /* Force words into a certain mode */ + /* Bitch, Bitch, Bitch! */ + /* + * Using the ^ operator is ambigous. If I have an absolute label + * called 'w' set to, say 2, and I have the expression 'w^1', do I get + * 1, forced to be in word displacement mode, or do I get the value of + * 'w' or'ed with 1 (3 in this case). + * The default is 'w' as an offset, so that's what I use. + * Stick with `, it does the same, and isn't ambig. + */ + + if (*point != '\0' && ((point[1] == '^') || (point[1] == '`'))) + switch (*point) + { + case 'b': + case 'B': + case 'w': + case 'W': + case 'l': + case 'L': + if (com_width) + as_warn ("Casting a branch displacement is bad form, and is ignored."); + else + { + c = (isupper (*point) ? tolower (*point) : *point); + call_width = ((c == 'b') ? 1 : + ((c == 'w') ? 2 : 4)); + } + point += 2; + break; + } + + /* Setting immediate mode */ + if (*point == '$') + { + immediate = 1; + point++; + } + + /* + * I've pulled off all the easy stuff off the front, move to the end and + * yank. + */ + + for (end = point; *end != '\0'; end++) /* Move to the end. */ + ; + + if (end != point) /* Null string? */ + end--; + + if (end > point && *end == ' ' && end[-1] != '\'') + end--; /* Hop white space */ + + /* Is this an index reg. */ + if ((*end == ']') && (end[-1] != '\'')) + { + temp = end; + + /* Find opening brace. */ + for (--end; (*end != '[' && end != point); end--) + ; + + /* If I found the opening brace, get the index register number. */ + if (*end == '[') + { + tp = end + 1; /* tp should point to the start of a reg. */ + ndx = tahoe_reg_parse (&tp); + if (tp != temp) + { /* Reg. parse error. */ + ndx = -1; + } + else + { + end--; /* Found it, move past brace. */ + } + if (ndx == -1) + { + op_bad = "Couldn't parse the [index] in this operand."; + end = point; /* Force all the rest of the tests to fail. */ + } + } + else + { + op_bad = "Couldn't find the opening '[' for the index of this operand."; + end = point; /* Force all the rest of the tests to fail. */ + } + } + + /* Post increment? */ + if (*end == '+') + { + dec_inc = '+'; + /* was: *end--; */ + end--; + } + + /* register in parens? */ + if ((*end == ')') && (end[-1] != '\'')) + { + temp = end; + + /* Find opening paren. */ + for (--end; (*end != '(' && end != point); end--) + ; + + /* If I found the opening paren, get the register number. */ + if (*end == '(') + { + tp = end + 1; + reg = tahoe_reg_parse (&tp); + if (tp != temp) + { + /* Not a register, but could be part of the expression. */ + reg = -1; + end = temp; /* Rest the pointer back */ + } + else + { + end--; /* Found the reg. move before opening paren. */ + } + } + else + { + op_bad = "Couldn't find the opening '(' for the deref of this operand."; + end = point; /* Force all the rest of the tests to fail. */ + } + } + + /* Pre decrement? */ + if (*end == '-') + { + if (dec_inc != ' ') + { + op_bad = "Operand can't be both pre-inc and post-dec."; + end = point; + } + else + { + dec_inc = '-'; + /* was: *end--; */ + end--; + } + } + + /* + * Everything between point and end is the 'expression', unless it's + * a register name. + */ + + c = end[1]; + end[1] = '\0'; + + tp = point; + imreg = tahoe_reg_parse (&point); /* Get the immediate register + if it is there.*/ + if (*point != '\0') + { + /* If there is junk after point, then the it's not immediate reg. */ + point = tp; + imreg = -1; + } + + if (imreg != -1 && reg != -1) + op_bad = "I parsed 2 registers in this operand."; + + /* + * Evaluate whats left of the expression to see if it's valid. + * Note again: This assumes that the calling expression has saved + * input_line_pointer. (Nag, nag, nag!) + */ + + if (*op_bad == '\0') + { + /* statement has no syntax goofs yet: lets sniff the expression */ + input_line_pointer = point; + expP = &(topP->exp_of_operand); + switch (expression (expP)) + { + /* If expression == SEG_PASS1, expression() will have set + need_pass_2 = 1. */ + case SEG_ABSENT: + /* No expression. For BSD4.2 compatibility, missing expression is + absolute 0 */ + expP->X_seg = SEG_ABSOLUTE; + expP->X_add_number = 0; + really_none = 1; + case SEG_ABSOLUTE: + /* for SEG_ABSOLUTE, we shouldnt need to set X_subtract_symbol, + X_add_symbol to any particular value. */ + /* But, we will program defensively. Since this situation occurs + rarely so it costs us little to do so. */ + expP->X_add_symbol = NULL; + expP->X_subtract_symbol = NULL; + /* How many bytes are needed to express this abs value? */ + abs_width = + ((((expP->X_add_number & 0xFFFFFF80) == 0) || + ((expP->X_add_number & 0xFFFFFF80) == 0xFFFFFF80)) ? 1 : + (((expP->X_add_number & 0xFFFF8000) == 0) || + ((expP->X_add_number & 0xFFFF8000) == 0xFFFF8000)) ? 2 : 4); + case SEG_TEXT: + case SEG_DATA: + case SEG_BSS: + case SEG_UNKNOWN: + break; + + case SEG_DIFFERENCE: + /* + * Major bug. We can't handle the case of a + * SEG_DIFFERENCE expression in a synthetic opcode + * variable-length instruction. + * We don't have a frag type that is smart enough to + * relax a SEG_DIFFERENCE, and so we just force all + * SEG_DIFFERENCEs to behave like SEG_PASS1s. + * Clearly, if there is a demand we can invent a new or + * modified frag type and then coding up a frag for this + * case will be easy. SEG_DIFFERENCE was invented for the + * .words after a CASE opcode, and was never intended for + * instruction operands. + */ + need_pass_2 = 1; + case SEG_PASS1: + op_bad = "Can't relocate expression error."; + break; + + case SEG_BIG: + /* This is an error. Tahoe doesn't allow any expressions + bigger that a 32 bit long word. Any bigger has to be referenced + by address. */ + op_bad = "Expression is too large for a 32 bits."; + break; + + default: + as_fatal ("Complier Bug: I got segment %d in tip_op.", expP->X_seg); + break; + } + if (*input_line_pointer != '\0') + { + op_bad = "Junk at end of expression."; + } + } + + end[1] = c; + + /* I'm done, so restore optex */ + *optex = segfault; + + + /* + * At this point in the game, we (in theory) have all the components of + * the operand at least parsed. Now it's time to check for syntax/semantic + * errors, and build the mode. + * This is what I have: + * deferred = 1 if '*' + * call_width = 0,1,2,4 + * abs_width = 0,1,2,4 + * com_width = 0,1,2,4 + * immediate = 1 if '$' + * ndx = -1 or reg num + * dec_inc = '-' or '+' or ' ' + * reg = -1 or reg num + * imreg = -1 or reg num + * topP->exp_of_operand + * really_none + */ + /* Is there a displacement size? */ + disp_size = (call_width ? call_width : + (com_width ? com_width : + abs_width ? abs_width : 0)); + + if (*op_bad == '\0') + { + if (imreg != -1) + { + /* Rn */ + mode = TAHOE_DIRECT_REG; + if (deferred || immediate || (dec_inc != ' ') || + (reg != -1) || !really_none) + op_bad = "Syntax error in direct register mode."; + else if (ndx != -1) + op_bad = "You can't index a register in direct register mode."; + else if (imreg == SP_REG && access == 'r') + op_bad = + "SP can't be the source operand with direct register addressing."; + else if (access == 'a') + op_bad = "Can't take the address of a register."; + else if (access == 'b') + op_bad = "Direct Register can't be used in a branch."; + else if (width == 'q' && ((imreg % 2) || (imreg > 13))) + op_bad = "For quad access, the register must be even and < 14."; + else if (call_width) + op_bad = "You can't cast a direct register."; + + if (*op_bad == '\0') + { + /* No errors, check for warnings */ + if (width == 'q' && imreg == 12) + as_warn ("Using reg 14 for quadwords can tromp the FP register."); + + reg = imreg; + } + + /* We know: imm = -1 */ + } + else if (dec_inc == '-') + { + /* -(SP) */ + mode = TAHOE_AUTO_DEC; + if (deferred || immediate || !really_none) + op_bad = "Syntax error in auto-dec mode."; + else if (ndx != -1) + op_bad = "You can't have an index auto dec mode."; + else if (access == 'r') + op_bad = "Auto dec mode cant be used for reading."; + else if (reg != SP_REG) + op_bad = "Auto dec only works of the SP register."; + else if (access == 'b') + op_bad = "Auto dec can't be used in a branch."; + else if (width == 'q') + op_bad = "Auto dec won't work with quadwords."; + + /* We know: imm = -1, dec_inc != '-' */ + } + else if (dec_inc == '+') + { + if (immediate || !really_none) + op_bad = "Syntax error in one of the auto-inc modes."; + else if (deferred) + { + /* *(SP)+ */ + mode = TAHOE_AUTO_INC_DEFERRED; + if (reg != SP_REG) + op_bad = "Auto inc deferred only works of the SP register."; + else if (ndx != -1) + op_bad = "You can't have an index auto inc deferred mode."; + else if (access == 'b') + op_bad = "Auto inc can't be used in a branch."; + } + else + { + /* (SP)+ */ + mode = TAHOE_AUTO_INC; + if (access == 'm' || access == 'w') + op_bad = "You can't write to an auto inc register."; + else if (reg != SP_REG) + op_bad = "Auto inc only works of the SP register."; + else if (access == 'b') + op_bad = "Auto inc can't be used in a branch."; + else if (width == 'q') + op_bad = "Auto inc won't work with quadwords."; + else if (ndx != -1) + op_bad = "You can't have an index in auto inc mode."; + } + + /* We know: imm = -1, dec_inc == ' ' */ + } + else if (reg != -1) + { + if ((ndx != -1) && (reg == SP_REG)) + op_bad = "You can't index the sp register."; + if (deferred) + { + /* *<disp>(Rn) */ + mode = TAHOE_REG_DISP_DEFERRED; + if (immediate) + op_bad = "Syntax error in register displaced mode."; + } + else if (really_none) + { + /* (Rn) */ + mode = TAHOE_REG_DEFERRED; + /* if reg = SP then cant be indexed */ + } + else + { + /* <disp>(Rn) */ + mode = TAHOE_REG_DISP; + } + + /* We know: imm = -1, dec_inc == ' ', Reg = -1 */ + } + else + { + if (really_none) + op_bad = "An offest is needed for this operand."; + if (deferred && immediate) + { + /* *$<ADDR> */ + mode = TAHOE_ABSOLUTE_ADDR; + disp_size = 4; + } + else if (immediate) + { + /* $<disp> */ + mode = TAHOE_IMMEDIATE; + if (ndx != -1) + op_bad = "You can't index a register in immediate mode."; + if (access == 'a') + op_bad = "Immediate access can't be used as an address."; + /* ponder the wisdom of a cast because it doesn't do any good. */ + } + else if (deferred) + { + /* *<disp> */ + mode = TAHOE_DISP_REL_DEFERRED; + } + else + { + /* <disp> */ + mode = TAHOE_DISPLACED_RELATIVE; + } + } + } + + /* + * At this point, all the errors we can do have be checked for. + * We can build the 'top'. */ + + topP->top_ndx = ndx; + topP->top_reg = reg; + topP->top_mode = mode; + topP->top_error = op_bad; + topP->top_dispsize = disp_size; +} /* tip_op */ + +/* + * t i p ( ) + * + * This converts a string into a tahoe instruction. + * The string must be a bare single instruction in tahoe (with BSD4 frobs) + * format. + * It provides at most one fatal error message (which stops the scan) + * some warning messages as it finds them. + * The tahoe instruction is returned in exploded form. + * + * The exploded instruction is returned to a struct tit of your choice. + * #include "tahoe-inst.h" to know what a struct tit is. + * + */ + +static void +tip (titP, instring) + struct tit *titP; /* We build an exploded instruction here. */ + char *instring; /* Text of a vax instruction: we modify. */ +{ + register struct tot_wot *twP = NULL; /* How to bit-encode this opcode. */ + register char *p; /* 1/skip whitespace.2/scan vot_how */ + register char *q; /* */ + register unsigned char count; /* counts number of operands seen */ + register struct top *operandp;/* scan operands in struct tit */ + register char *alloperr = ""; /* error over all operands */ + register char c; /* Remember char, (we clobber it + with '\0' temporarily). */ + char *save_input_line_pointer; + + if (*instring == ' ') + ++instring; /* Skip leading whitespace. */ + for (p = instring; *p && *p != ' '; p++) + ; /* MUST end in end-of-string or + exactly 1 space. */ + /* Scanned up to end of operation-code. */ + /* Operation-code is ended with whitespace. */ + if (p == instring) + { + titP->tit_error = "No operator"; + count = 0; + titP->tit_opcode = 0; + } + else + { + c = *p; + *p = '\0'; + /* + * Here with instring pointing to what better be an op-name, and p + * pointing to character just past that. + * We trust instring points to an op-name, with no whitespace. + */ + twP = (struct tot_wot *) hash_find (op_hash, instring); + *p = c; /* Restore char after op-code. */ + if (twP == 0) + { + titP->tit_error = "Unknown operator"; + count = 0; + titP->tit_opcode = 0; + } + else + { + /* + * We found a match! So lets pick up as many operands as the + * instruction wants, and even gripe if there are too many. + * We expect comma to seperate each operand. + * We let instring track the text, while p tracks a part of the + * struct tot. + */ + + count = 0; /* no operands seen yet */ + instring = p + (*p != '\0'); /* point past the operation code */ + /* tip_op() screws with the input_line_pointer, so save it before + I jump in */ + save_input_line_pointer = input_line_pointer; + for (p = twP->args, operandp = titP->tit_operand; + !*alloperr && *p; + operandp++, p += 2) + { + /* + * Here to parse one operand. Leave instring pointing just + * past any one ',' that marks the end of this operand. + */ + if (!p[1]) + as_fatal ("Compiler bug: ODD number of bytes in arg structure %s.", + twP->args); + else if (*instring) + { + for (q = instring; (*q != ',' && *q != '\0'); q++) + { + if (*q == '\'' && q[1] != '\0') /* Jump quoted characters */ + q++; + } + c = *q; + /* + * Q points to ',' or '\0' that ends argument. C is that + * character. + */ + *q = '\0'; + operandp->top_access = p[0]; + operandp->top_width = p[1]; + tip_op (instring - 1, operandp); + *q = c; /* Restore input text. */ + if (*(operandp->top_error)) + { + alloperr = operandp->top_error; + } + instring = q + (c ? 1 : 0); /* next operand (if any) */ + count++; /* won another argument, may have an operr */ + } + else + alloperr = "Not enough operands"; + } + /* Restore the pointer. */ + input_line_pointer = save_input_line_pointer; + + if (!*alloperr) + { + if (*instring == ' ') + instring++; /* Skip whitespace. */ + if (*instring) + alloperr = "Too many operands"; + } + titP->tit_error = alloperr; + } + } + + titP->tit_opcode = twP->code; /* The op-code. */ + titP->tit_operands = count; +} /* tip */ + +/* md_assemble() emit frags for 1 instruction */ +void +md_assemble (instruction_string) + char *instruction_string; /* A string: assemble 1 instruction. */ +{ + char *p; + register struct top *operandP;/* An operand. Scans all operands. */ + /* char c_save; fixme: remove this line *//* What used to live after an expression. */ + /* struct frag *fragP; fixme: remove this line *//* Fragment of code we just made. */ + /* register struct top *end_operandP; fixme: remove this line *//* -> slot just after last operand + Limit of the for (each operand). */ + register expressionS *expP; /* -> expression values for this operand */ + + /* These refer to an instruction operand expression. */ + segT to_seg; /* Target segment of the address. */ + + register valueT this_add_number; + register struct symbol *this_add_symbol; /* +ve (minuend) symbol. */ + + /* tahoe_opcodeT opcode_as_number; fixme: remove this line *//* The opcode as a number. */ + char *opcodeP; /* Where it is in a frag. */ + /* char *opmodeP; fixme: remove this line *//* Where opcode type is, in a frag. */ + + int dispsize; /* From top_dispsize: tahoe_operand_width + (in bytes) */ + int is_undefined; /* 1 if operand expression's + segment not known yet. */ + int pc_rel; /* Is this operand pc relative? */ + + /* Decode the operand. */ + tip (&t, instruction_string); + + /* + * Check to see if this operand decode properly. + * Notice that we haven't made any frags yet. + * If it goofed, then this instruction will wedge in any pass, + * and we can safely flush it, without causing interpass symbol phase + * errors. That is, without changing label values in different passes. + */ + if (*t.tit_error) + { + as_warn ("Ignoring statement due to \"%s\"", t.tit_error); + } + else + { + /* We saw no errors in any operands - try to make frag(s) */ + /* Emit op-code. */ + /* Remember where it is, in case we want to modify the op-code later. */ + opcodeP = frag_more (1); + *opcodeP = t.tit_opcode; + /* Now do each operand. */ + for (operandP = t.tit_operand; + operandP < t.tit_operand + t.tit_operands; + operandP++) + { /* for each operand */ + expP = &(operandP->exp_of_operand); + if (operandP->top_ndx >= 0) + { + /* Indexed addressing byte + Legality of indexed mode already checked: it is OK */ + FRAG_APPEND_1_CHAR (0x40 + operandP->top_ndx); + } /* if(top_ndx>=0) */ + + /* Here to make main operand frag(s). */ + this_add_number = expP->X_add_number; + this_add_symbol = expP->X_add_symbol; + to_seg = expP->X_seg; + know (to_seg == SEG_UNKNOWN || \ + to_seg == SEG_ABSOLUTE || \ + to_seg == SEG_DATA || \ + to_seg == SEG_TEXT || \ + to_seg == SEG_BSS); + is_undefined = (to_seg == SEG_UNKNOWN); + /* Do we know how big this opperand is? */ + dispsize = operandP->top_dispsize; + pc_rel = 0; + /* Deal with the branch possabilities. (Note, this doesn't include + jumps.)*/ + if (operandP->top_access == 'b') + { + /* Branches must be expressions. A psuedo branch can also jump to + an absolute address. */ + if (to_seg == now_seg || is_undefined) + { + /* If is_undefined, then it might BECOME now_seg by relax time. */ + if (dispsize) + { + /* I know how big the branch is supposed to be (it's a normal + branch), so I set up the frag, and let GAS do the rest. */ + p = frag_more (dispsize); + fix_new (frag_now, p - frag_now->fr_literal, + this_add_symbol, 0, this_add_number, + size_to_fx (dispsize, 1), + NULL); + } + else + { + /* (to_seg==now_seg || to_seg == SEG_UNKNOWN) && dispsize==0 */ + /* If we don't know how big it is, then its a synthetic branch, + so we set up a simple relax state. */ + switch (operandP->top_width) + { + case TAHOE_WIDTH_CONDITIONAL_JUMP: + /* Simple (conditional) jump. I may have to reverse the + condition of opcodeP, and then jump to my destination. + I set 1 byte aside for the branch off set, and could need 6 + more bytes for the pc_rel jump */ + frag_var (rs_machine_dependent, 7, 1, + ENCODE_RELAX (STATE_CONDITIONAL_BRANCH, + is_undefined ? STATE_UNDF : STATE_BYTE), + this_add_symbol, this_add_number, opcodeP); + break; + case TAHOE_WIDTH_ALWAYS_JUMP: + /* Simple (unconditional) jump. I may have to convert this to + a word branch, or an absolute jump. */ + frag_var (rs_machine_dependent, 5, 1, + ENCODE_RELAX (STATE_ALWAYS_BRANCH, + is_undefined ? STATE_UNDF : STATE_BYTE), + this_add_symbol, this_add_number, opcodeP); + break; + /* The smallest size for the next 2 cases is word. */ + case TAHOE_WIDTH_BIG_REV_JUMP: + frag_var (rs_machine_dependent, 8, 2, + ENCODE_RELAX (STATE_BIG_REV_BRANCH, + is_undefined ? STATE_UNDF : STATE_WORD), + this_add_symbol, this_add_number, + opcodeP); + break; + case TAHOE_WIDTH_BIG_NON_REV_JUMP: + frag_var (rs_machine_dependent, 10, 2, + ENCODE_RELAX (STATE_BIG_NON_REV_BRANCH, + is_undefined ? STATE_UNDF : STATE_WORD), + this_add_symbol, this_add_number, + opcodeP); + break; + default: + as_fatal ("Compliler bug: Got a case (%d) I wasn't expecting.", + operandP->top_width); + } + } + } + else + { + /* to_seg != now_seg && to_seg != seg_unknown (still in branch) + In other words, I'm jumping out of my segment so extend the + branches to jumps, and let GAS fix them. */ + + /* These are "branches" what will always be branches around a jump + to the correct addresss in real life. + If to_seg is SEG_ABSOLUTE, just encode the branch in, + else let GAS fix the address. */ + + switch (operandP->top_width) + { + /* The theory: + For SEG_ABSOLUTE, then mode is ABSOLUTE_ADDR, jump + to that addresss (not pc_rel). + For other segs, address is a long word PC rel jump. */ + case TAHOE_WIDTH_CONDITIONAL_JUMP: + /* b<cond> */ + /* To reverse the condition in a TAHOE branch, + complement bit 4 */ + *opcodeP ^= 0x10; + p = frag_more (7); + *p++ = 6; + *p++ = TAHOE_JMP; + *p++ = (operandP->top_mode == + TAHOE_ABSOLUTE_ADDR ? TAHOE_ABSOLUTE_ADDR : + TAHOE_PC_REL_LONG); + fix_new (frag_now, p - frag_now->fr_literal, + this_add_symbol, 0, this_add_number, + (to_seg != SEG_ABSOLUTE) ? FX_PCREL32 : FX_32, NULL); + /* + * Now (eg) BLEQ 1f + * JMP foo + * 1: + */ + break; + case TAHOE_WIDTH_ALWAYS_JUMP: + /* br, just turn it into a jump */ + *opcodeP = TAHOE_JMP; + p = frag_more (5); + *p++ = (operandP->top_mode == + TAHOE_ABSOLUTE_ADDR ? TAHOE_ABSOLUTE_ADDR : + TAHOE_PC_REL_LONG); + fix_new (frag_now, p - frag_now->fr_literal, + this_add_symbol, 0, this_add_number, + (to_seg != SEG_ABSOLUTE) ? FX_PCREL32 : FX_32, NULL); + /* Now (eg) JMP foo */ + break; + case TAHOE_WIDTH_BIG_REV_JUMP: + p = frag_more (8); + *opcodeP ^= 0x10; + *p++ = 0; + *p++ = 6; + *p++ = TAHOE_JMP; + *p++ = (operandP->top_mode == + TAHOE_ABSOLUTE_ADDR ? TAHOE_ABSOLUTE_ADDR : + TAHOE_PC_REL_LONG); + fix_new (frag_now, p - frag_now->fr_literal, + this_add_symbol, 0, this_add_number, + (to_seg != SEG_ABSOLUTE) ? FX_PCREL32 : FX_32, NULL); + /* + * Now (eg) ACBx 1f + * JMP foo + * 1: + */ + break; + case TAHOE_WIDTH_BIG_NON_REV_JUMP: + p = frag_more (10); + *p++ = 0; + *p++ = 2; + *p++ = TAHOE_BRB; + *p++ = 6; + *p++ = TAHOE_JMP; + *p++ = (operandP->top_mode == + TAHOE_ABSOLUTE_ADDR ? TAHOE_ABSOLUTE_ADDR : + TAHOE_PC_REL_LONG); + fix_new (frag_now, p - frag_now->fr_literal, + this_add_symbol, 0, this_add_number, + (to_seg != SEG_ABSOLUTE) ? FX_PCREL32 : FX_32, NULL); + /* + * Now (eg) xOBxxx 1f + * BRB 2f + * 1: JMP @#foo + * 2: + */ + break; + case 'b': + case 'w': + as_warn ("Real branch displacements must be expressions."); + break; + default: + as_fatal ("Complier error: I got an unknown synthetic branch :%c", + operandP->top_width); + break; + } + } + } + else + { + /* It ain't a branch operand. */ + switch (operandP->top_mode) + { + /* Auto-foo access, only works for one reg (SP) + so the only thing needed is the mode. */ + case TAHOE_AUTO_DEC: + case TAHOE_AUTO_INC: + case TAHOE_AUTO_INC_DEFERRED: + FRAG_APPEND_1_CHAR (operandP->top_mode); + break; + + /* Numbered Register only access. Only thing needed is the + mode + Register number */ + case TAHOE_DIRECT_REG: + case TAHOE_REG_DEFERRED: + FRAG_APPEND_1_CHAR (operandP->top_mode + operandP->top_reg); + break; + + /* An absolute address. It's size is always 5 bytes. + (mode_type + 4 byte address). */ + case TAHOE_ABSOLUTE_ADDR: + know ((this_add_symbol == NULL)); + p = frag_more (5); + *p = TAHOE_ABSOLUTE_ADDR; + md_number_to_chars (p + 1, this_add_number, 4); + break; + + /* Immediate data. If the size isn't known, then it's an address + + and offset, which is 4 bytes big. */ + case TAHOE_IMMEDIATE: + if (this_add_symbol != NULL) + { + p = frag_more (5); + *p++ = TAHOE_IMMEDIATE_LONGWORD; + fix_new (frag_now, p - frag_now->fr_literal, + this_add_symbol, 0, this_add_number, + FX_32, NULL); + } + else + { + /* It's a integer, and I know it's size. */ + if ((unsigned) this_add_number < 0x40) + { + /* Will it fit in a literal? */ + FRAG_APPEND_1_CHAR ((byte) this_add_number); + } + else + { + p = frag_more (dispsize + 1); + switch (dispsize) + { + case 1: + *p++ = TAHOE_IMMEDIATE_BYTE; + *p = (byte) this_add_number; + break; + case 2: + *p++ = TAHOE_IMMEDIATE_WORD; + md_number_to_chars (p, this_add_number, 2); + break; + case 4: + *p++ = TAHOE_IMMEDIATE_LONGWORD; + md_number_to_chars (p, this_add_number, 4); + break; + } + } + } + break; + + /* Distance from the PC. If the size isn't known, we have to relax + into it. The difference between this and disp(sp) is that + this offset is pc_rel, and disp(sp) isn't. + Note the drop through code. */ + + case TAHOE_DISPLACED_RELATIVE: + case TAHOE_DISP_REL_DEFERRED: + operandP->top_reg = PC_REG; + pc_rel = 1; + + /* Register, plus a displacement mode. Save the register number, + and weather its deffered or not, and relax the size if it isn't + known. */ + case TAHOE_REG_DISP: + case TAHOE_REG_DISP_DEFERRED: + if (operandP->top_mode == TAHOE_DISP_REL_DEFERRED || + operandP->top_mode == TAHOE_REG_DISP_DEFERRED) + operandP->top_reg += 0x10; /* deffered mode is always 0x10 higher + than it's non-deffered sibling. */ + + /* Is this a value out of this segment? + The first part of this conditional is a cludge to make gas + produce the same output as 'as' when there is a lable, in + the current segment, displaceing a register. It's strange, + and no one in their right mind would do it, but it's easy + to cludge. */ + if ((dispsize == 0 && !pc_rel) || + (to_seg != now_seg && !is_undefined && to_seg != SEG_ABSOLUTE)) + dispsize = 4; + + if (dispsize == 0) + { + /* + * We have a SEG_UNKNOWN symbol, or the size isn't cast. + * It might turn out to be in the same segment as + * the instruction, permitting relaxation. + */ + p = frag_var (rs_machine_dependent, 5, 2, + ENCODE_RELAX (STATE_PC_RELATIVE, + is_undefined ? STATE_UNDF : STATE_BYTE), + this_add_symbol, this_add_number, 0); + *p = operandP->top_reg; + } + else + { + /* Either this is an abs, or a cast. */ + p = frag_more (dispsize + 1); + switch (dispsize) + { + case 1: + *p = TAHOE_PC_OR_BYTE + operandP->top_reg; + break; + case 2: + *p = TAHOE_PC_OR_WORD + operandP->top_reg; + break; + case 4: + *p = TAHOE_PC_OR_LONG + operandP->top_reg; + break; + }; + fix_new (frag_now, p + 1 - frag_now->fr_literal, + this_add_symbol, 0, this_add_number, + size_to_fx (dispsize, pc_rel), NULL); + } + break; + default: + as_fatal ("Barf, bad mode %x\n", operandP->top_mode); + } + } + } /* for(operandP) */ + } /* if(!need_pass_2 && !goofed) */ +} /* tahoe_assemble() */ + + +/* We have no need to default values of symbols. */ + +/* ARGSUSED */ +symbolS * +md_undefined_symbol (name) + char *name; +{ + return 0; +} /* md_undefined_symbol() */ + +/* 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; +{ +} /* md_operand() */ + +/* Round up a section size to the appropriate boundary. */ +long +md_section_align (segment, size) + segT segment; + long size; +{ + return ((size + 7) & ~7); /* Round all sects to multiple of 8 */ +} /* md_section_align() */ + +/* Exactly what point is a PC-relative offset relative TO? + On the sparc, they're relative to the address of the offset, plus + its size. This gets us to the following instruction. + (??? Is this right? FIXME-SOON) */ +long +md_pcrel_from (fixP) + fixS *fixP; +{ + return (((fixP->fx_type == FX_8 + || fixP->fx_type == FX_PCREL8) + ? 1 + : ((fixP->fx_type == FX_16 + || fixP->fx_type == FX_PCREL16) + ? 2 + : ((fixP->fx_type == FX_32 + || fixP->fx_type == FX_PCREL32) + ? 4 + : 0))) + fixP->fx_where + fixP->fx_frag->fr_address); +} /* md_pcrel_from() */ + +int +tc_is_pcrel (fixP) + fixS *fixP; +{ + /* should never be called */ + know (0); + return (0); +} /* tc_is_pcrel() */ + +/* end of tc-tahoe.c */ |