path: root/gdb/config/rs6000/tm-rs6000.h

/* Parameters for target execution on an RS6000, for GDB, the GNU debugger.
   Copyright 1986, 1987, 1989, 1991, 1992, 1993, 1994
   Free Software Foundation, Inc.
   Contributed by IBM Corporation.

This file is part of GDB.

This program 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 of the License, or
(at your option) any later version.

This program 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 this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */

/* Minimum possible text address in AIX */

#define TEXT_SEGMENT_BASE	0x10000000

/* Load segment of a given pc value. */

#define	PC_LOAD_SEGMENT(PC)	pc_load_segment_name(PC)

/* AIX cc seems to get this right.  */

#define BELIEVE_PCC_PROMOTION 1

/* return true if a given `pc' value is in `call dummy' function. */
/* FIXME: This just checks for the end of the stack, which is broken
   for things like stepping through gcc nested function stubs.  */
#define	PC_IN_CALL_DUMMY(STOP_PC, STOP_SP, STOP_FRAME_ADDR)	\
	(STOP_SP < STOP_PC && STOP_PC < STACK_END_ADDR)

#if 0
extern unsigned int text_start, data_start;
extern char *corefile;
#endif
extern int inferior_pid;

/* We are missing register descriptions in the system header files. Sigh! */

struct regs {
	int	gregs [32];		/* general purpose registers */
	int	pc;			/* program conter	*/
	int	ps;			/* processor status, or machine state */
};

struct fp_status {
	double	fpregs [32];		/* floating GP registers */
};


/* To be used by function_frame_info. */

struct rs6000_framedata {
  int	offset;				/* # of bytes in gpr's and fpr's are saved */
  int	saved_gpr;			/* smallest # of saved gpr */
  int	saved_fpr;			/* smallest # of saved fpr */
  int	alloca_reg;			/* alloca register number (frame ptr) */
  char	frameless;			/* true if frameless functions. */
  char	nosavedpc;			/* true if pc not saved. */
};

void 
function_frame_info PARAMS ((CORE_ADDR, struct rs6000_framedata *));

/* Define the byte order of the machine.  */

#define TARGET_BYTE_ORDER	BIG_ENDIAN

/* AIX's assembler doesn't grok dollar signs in identifiers.
   So we use dots instead.  This item must be coordinated with G++. */
#undef CPLUS_MARKER
#define CPLUS_MARKER '.'

/* Offset from address of function to start of its code.
   Zero on most machines.  */

#define FUNCTION_START_OFFSET 0

/* Advance PC across any function entry prologue instructions
   to reach some "real" code.  */

#define SKIP_PROLOGUE(pc)	pc = skip_prologue (pc)

/* If PC is in some function-call trampoline code, return the PC
   where the function itself actually starts.  If not, return NULL.  */

#define	SKIP_TRAMPOLINE_CODE(pc)	skip_trampoline_code (pc)

/* Number of trap signals we need to skip over, once the inferior process
   starts running. */

#define	START_INFERIOR_TRAPS_EXPECTED	2

/* AIX has a couple of strange returns from wait().  */

#define CHILD_SPECIAL_WAITSTATUS(ourstatus, hoststatus) ( \
  /* "stop after load" status.  */ \
  (hoststatus) == 0x57c ? (ourstatus)->kind = TARGET_WAITKIND_LOADED, 1 : \
  \
  /* signal 0. I have no idea why wait(2) returns with this status word.  */ \
  /* It looks harmless. */ \
  (hoststatus) == 0x7f ? (ourstatus)->kind = TARGET_WAITKIND_SPURIOUS, 1 : \
  \
  /* A normal waitstatus.  Let the usual macros deal with it.  */ \
  0)

/* In xcoff, we cannot process line numbers when we see them. This is
   mainly because we don't know the boundaries of the include files. So,
   we postpone that, and then enter and sort(?) the whole line table at
   once, when we are closing the current symbol table in end_symtab(). */

#define	PROCESS_LINENUMBER_HOOK()	aix_process_linenos ()
   
/* Immediately after a function call, return the saved pc.
   Can't go through the frames for this because on some machines
   the new frame is not set up until the new function executes
   some instructions.  */

#define	SAVED_PC_AFTER_CALL(frame) read_register (LR_REGNUM)

/* Address of end of stack space.  */

#define STACK_END_ADDR 0x2ff80000

/* Stack grows downward.  */

#define INNER_THAN <

#if 0
/* No, we shouldn't use this. push_arguments() should leave stack in a
   proper alignment! */
/* Stack has strict alignment. */

#define STACK_ALIGN(ADDR)	(((ADDR)+7)&-8)
#endif

/* This is how argumets pushed onto stack or passed in registers. */

#define	PUSH_ARGUMENTS(nargs, args, sp, struct_return, struct_addr) \
  sp = push_arguments(nargs, args, sp, struct_return, struct_addr)

/* Sequence of bytes for breakpoint instruction.  */

#define BIG_BREAKPOINT { 0x7d, 0x82, 0x10, 0x08 }
#define LITTLE_BREAKPOINT { 0x08, 0x10, 0x82, 0x7d }

#if TARGET_BYTE_ORDER == BIG_ENDIAN
#define BREAKPOINT BIG_BREAKPOINT

#else
#if TARGET_BYTE_ORDER == LITTLE_ENDIAN
#define BREAKPOINT LITTLE_BREAKPOINT
#endif
#endif

/* Amount PC must be decremented by after a breakpoint.
   This is often the number of bytes in BREAKPOINT
   but not always.  */

#define DECR_PC_AFTER_BREAK 0

/* Nonzero if instruction at PC is a return instruction.  */
/* Allow any of the return instructions, including a trapv and a return
   from interrupt.  */

#define ABOUT_TO_RETURN(pc)  \
   ((read_memory_integer (pc, 4) & 0xfe8007ff) == 0x4e800020)

/* Say how long (ordinary) registers are.  This is a piece of bogosity
   used in push_word and a few other places; REGISTER_RAW_SIZE is the
   real way to know how big a register is.  */

#define REGISTER_SIZE 4

/* Number of machine registers */

#define NUM_REGS 71

/* Initializer for an array of names of registers.
   There should be NUM_REGS strings in this initializer.  */

#define REGISTER_NAMES  \
 {"r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",  \
  "r8", "r9", "r10","r11","r12","r13","r14","r15", \
  "r16","r17","r18","r19","r20","r21","r22","r23", \
  "r24","r25","r26","r27","r28","r29","r30","r31", \
  "f0", "f1", "f2", "f3", "f4", "f5", "f6", "f7",  \
  "f8", "f9", "f10","f11","f12","f13","f14","f15", \
  "f16","f17","f18","f19","f20","f21","f22","f23", \
  "f24","f25","f26","f27","f28","f29","f30","f31", \
  "pc", "ps", "cnd", "lr", "cnt", "xer", "mq" }

/* Register numbers of various important registers.
   Note that some of these values are "real" register numbers,
   and correspond to the general registers of the machine,
   and some are "phony" register numbers which are too large
   to be actual register numbers as far as the user is concerned
   but do serve to get the desired values when passed to read_register.  */

#define FP_REGNUM 1		/* Contains address of executing stack frame */
#define SP_REGNUM 1		/* Contains address of top of stack */
#define	TOC_REGNUM 2		/* TOC register */
#define FP0_REGNUM 32		/* Floating point register 0 */
#define	GP0_REGNUM 0		/* GPR register 0 */
#define FP0_REGNUM 32		/* FPR (Floating point) register 0 */
#define FPLAST_REGNUM 63	/* Last floating point register */  

/* Special purpose registers... */
/* P.S. keep these in the same order as in /usr/mstsave.h `mstsave' structure, for
   easier processing */

#define PC_REGNUM 64		/* Program counter (instruction address %iar) */
#define PS_REGNUM 65		/* Processor (or machine) status (%msr) */
#define	CR_REGNUM 66		/* Condition register */
#define	LR_REGNUM 67		/* Link register */
#define	CTR_REGNUM 68		/* Count register */
#define	XER_REGNUM 69		/* Fixed point exception registers */
#define	MQ_REGNUM 70		/* Multiply/quotient register */

#define	FIRST_SP_REGNUM 64	/* first special register number */
#define LAST_SP_REGNUM  70	/* last special register number */

/* Total amount of space needed to store our copies of the machine's
   register state, the array `registers'.

	32 4-byte gpr's
	32 8-byte fpr's
	7  4-byte special purpose registers, 

   total 416 bytes. Keep some extra space for now, in case to add more. */

#define REGISTER_BYTES 420


/* Index within `registers' of the first byte of the space for
   register N.  */

#define REGISTER_BYTE(N)  \
 (								\
  ((N) > FPLAST_REGNUM) ? ((((N) - FPLAST_REGNUM -1) * 4) + 384)\
  :((N) >= FP0_REGNUM) ? ((((N) - FP0_REGNUM) * 8) + 128)	\
  :((N) * 4) )

/* Number of bytes of storage in the actual machine representation
   for register N. */
/* Note that the unsigned cast here forces the result of the
   subtractiion to very high positive values if N < FP0_REGNUM */

#define REGISTER_RAW_SIZE(N) (((unsigned)(N) - FP0_REGNUM) < 32 ? 8 : 4)

/* Number of bytes of storage in the program's representation
   for register N.  On the RS6000, all regs are 4 bytes
   except the floating point regs which are 8-byte doubles.  */

#define REGISTER_VIRTUAL_SIZE(N) (((unsigned)(N) - FP0_REGNUM) < 32 ? 8 : 4)

/* Largest value REGISTER_RAW_SIZE can have.  */

#define MAX_REGISTER_RAW_SIZE 8

/* Largest value REGISTER_VIRTUAL_SIZE can have.  */

#define MAX_REGISTER_VIRTUAL_SIZE 8

/* convert a dbx stab register number (from `r' declaration) to a gdb REGNUM */

#define STAB_REG_TO_REGNUM(value)	(value)

/* Nonzero if register N requires conversion
   from raw format to virtual format.
   The register format for rs6000 floating point registers is always
   double, we need a conversion if the memory format is float.  */

#define REGISTER_CONVERTIBLE(N) ((N) >= FP0_REGNUM && (N) <= FPLAST_REGNUM)

/* Convert data from raw format for register REGNUM in buffer FROM
   to virtual format with type TYPE in buffer TO.  */

#define REGISTER_CONVERT_TO_VIRTUAL(REGNUM,TYPE,FROM,TO) \
{ \
  if (TYPE_LENGTH (TYPE) != REGISTER_RAW_SIZE (REGNUM)) \
    { \
      double val = extract_floating ((FROM), REGISTER_RAW_SIZE (REGNUM)); \
      store_floating ((TO), TYPE_LENGTH (TYPE), val); \
    } \
  else \
    memcpy ((TO), (FROM), REGISTER_RAW_SIZE (REGNUM)); \
}

/* Convert data from virtual format with type TYPE in buffer FROM
   to raw format for register REGNUM in buffer TO.  */

#define REGISTER_CONVERT_TO_RAW(TYPE,REGNUM,FROM,TO)	\
{ \
  if (TYPE_LENGTH (TYPE) != REGISTER_RAW_SIZE (REGNUM)) \
    { \
      double val = extract_floating ((FROM), TYPE_LENGTH (TYPE)); \
      store_floating ((TO), REGISTER_RAW_SIZE (REGNUM), val); \
    } \
  else \
    memcpy ((TO), (FROM), REGISTER_RAW_SIZE (REGNUM)); \
}

/* Return the GDB type object for the "standard" data type
   of data in register N.  */

#define REGISTER_VIRTUAL_TYPE(N) \
 (((unsigned)(N) - FP0_REGNUM) < 32 ? builtin_type_double : builtin_type_int)

/* Store the address of the place in which to copy the structure the
   subroutine will return.  This is called from call_function. */
/* in RS6000, struct return addresses are passed as an extra parameter in r3.
   In function return, callee is not responsible of returning this address back.
   Since gdb needs to find it, we will store in a designated variable
   `rs6000_struct_return_address'. */

extern CORE_ADDR rs6000_struct_return_address;

#define STORE_STRUCT_RETURN(ADDR, SP)	\
  { write_register (3, (ADDR));		\
    rs6000_struct_return_address = (ADDR); }

/* Extract from an array REGBUF containing the (raw) register state
   a function return value of type TYPE, and copy that, in virtual format,
   into VALBUF.  */

/* #define EXTRACT_RETURN_VALUE(TYPE,REGBUF,VALBUF) \
  memcpy (VALBUF, REGBUF, TYPE_LENGTH (TYPE)) */

#define EXTRACT_RETURN_VALUE(TYPE,REGBUF,VALBUF) \
  extract_return_value(TYPE,REGBUF,VALBUF)

/* Write into appropriate registers a function return value
   of type TYPE, given in virtual format.  */

#define STORE_RETURN_VALUE(TYPE,VALBUF) \
  {									\
    if (TYPE_CODE (TYPE) == TYPE_CODE_FLT)				\
									\
     /* Floating point values are returned starting from FPR1 and up.	\
	Say a double_double_double type could be returned in		\
	FPR1/FPR2/FPR3 triple. */					\
									\
      write_register_bytes (REGISTER_BYTE (FP0_REGNUM+1), (VALBUF),	\
						TYPE_LENGTH (TYPE));	\
    else								\
      /* Everything else is returned in GPR3 and up. */			\
      write_register_bytes (REGISTER_BYTE (GP0_REGNUM+3), (VALBUF),	\
						TYPE_LENGTH (TYPE));	\
  }


/* Extract from an array REGBUF containing the (raw) register state
   the address in which a function should return its structure value,
   as a CORE_ADDR (or an expression that can be used as one).  */

#define EXTRACT_STRUCT_VALUE_ADDRESS(REGBUF)	rs6000_struct_return_address

/* Describe the pointer in each stack frame to the previous stack frame
   (its caller).  */

/* FRAME_CHAIN takes a frame's nominal address
   and produces the frame's chain-pointer. */

/* In the case of the RS6000, the frame's nominal address
   is the address of a 4-byte word containing the calling frame's address.  */

#define FRAME_CHAIN(thisframe) rs6000_frame_chain (thisframe)
#ifdef __STDC__
struct frame_info;
#endif
CORE_ADDR rs6000_frame_chain PARAMS ((struct frame_info *));

/* Define other aspects of the stack frame.  */

/* A macro that tells us whether the function invocation represented
   by FI does not have a frame on the stack associated with it.  If it
   does not, FRAMELESS is set to 1, else 0.  */

#define FRAMELESS_FUNCTION_INVOCATION(FI, FRAMELESS) \
	FRAMELESS = frameless_function_invocation (FI, 0)

/* Functions calling alloca() change the value of the stack pointer. We
   need to use initial stack pointer (which is saved in r31 by gcc) in 
   such cases. If a compiler emits traceback table, then we should use the
   alloca register specified in traceback table. FIXME. */
/* Also, it is a good idea to cache information about frame's saved registers
   in the frame structure to speed things up. See tm-m88k.h. FIXME. */

#define	EXTRA_FRAME_INFO	\
	CORE_ADDR initial_sp;			/* initial stack pointer. */ \
	struct frame_saved_regs *cache_fsr;	/* saved registers	  */

#define INIT_FRAME_PC_FIRST(fromleaf, prev) \
  prev->pc = (fromleaf ? SAVED_PC_AFTER_CALL (prev->next) : \
	      prev->next ? FRAME_SAVED_PC (prev->next) : read_pc ());
#define INIT_FRAME_PC(fromleaf, prev) /* nothing */
#define	INIT_EXTRA_FRAME_INFO(fromleaf, fi)	\
  fi->initial_sp = 0;		\
  fi->cache_fsr = 0; \
  if (fi->next != (CORE_ADDR)0 \
      && fi->pc < TEXT_SEGMENT_BASE) \
    /* We're in get_prev_frame_info */ \
    /* and this is a special signal frame.  */ \
    /* (fi->pc will be some low address in the kernel, */ \
    /*  to which the signal handler returns).  */ \
    fi->signal_handler_caller = 1;

/* If the kernel has to deliver a signal, it pushes a sigcontext
   structure on the stack and then calls the signal handler, passing
   the address of the sigcontext in an argument register. Usually
   the signal handler doesn't save this register, so we have to
   access the sigcontext structure via an offset from the signal handler
   frame.
   The following constants were determined by experimentation on AIX 3.2.  */
#define SIG_FRAME_PC_OFFSET 96
#define SIG_FRAME_FP_OFFSET 284

/* Frameless function invocation in IBM RS/6000 is sometimes
   half-done. It perfectly sets up a new frame, e.g. a new frame (in
   fact stack) pointer, etc, but it doesn't save the %pc.  We call
   frameless_function_invocation to tell us how to get the %pc.  */

#define FRAME_SAVED_PC(FRAME)					\
	(frameless_function_invocation (FRAME, 1)		\
	 ? SAVED_PC_AFTER_CALL (FRAME)				\
	 : (FRAME)->signal_handler_caller			\
	   ? read_memory_integer ((FRAME)->frame + SIG_FRAME_PC_OFFSET, 4) \
	   : read_memory_integer (rs6000_frame_chain (FRAME) + 8, 4))

#define FRAME_ARGS_ADDRESS(FI)	\
  (((struct frame_info*)(FI))->initial_sp ?		\
	((struct frame_info*)(FI))->initial_sp :	\
	frame_initial_stack_address (FI))

#define FRAME_LOCALS_ADDRESS(FI)	FRAME_ARGS_ADDRESS(FI)


/* Set VAL to the number of args passed to frame described by FI.
   Can set VAL to -1, meaning no way to tell.  */

/* We can't tell how many args there are
   now that the C compiler delays popping them.  */

#define FRAME_NUM_ARGS(val,fi) (val = -1)

/* Return number of bytes at start of arglist that are not really args.  */

#define FRAME_ARGS_SKIP 8	/* Not sure on this. FIXMEmgo */

/* Put here the code to store, into a struct frame_saved_regs,
   the addresses of the saved registers of frame described by FRAME_INFO.
   This includes special registers such as pc and fp saved in special
   ways in the stack frame.  sp is even more special:
   the address we return for it IS the sp for the next frame.  */
/* In the following implementation for RS6000, we did *not* save sp. I am
   not sure if it will be needed. The following macro takes care of gpr's
   and fpr's only. */

#define FRAME_FIND_SAVED_REGS(FRAME_INFO, FRAME_SAVED_REGS)		\
{									\
  int ii;								\
  CORE_ADDR frame_addr, func_start;					\
  struct rs6000_framedata fdata;					\
									\
  /* find the start of the function and collect info about its frame. */\
									\
  func_start = get_pc_function_start ((FRAME_INFO)->pc) + FUNCTION_START_OFFSET; \
  function_frame_info (func_start, &fdata);				\
  memset (&(FRAME_SAVED_REGS), '\0', sizeof (FRAME_SAVED_REGS));		\
									\
  /* if there were any saved registers, figure out parent's stack pointer. */ \
  frame_addr = 0;							\
  /* the following is true only if the frame doesn't have a call to alloca(), \
      FIXME. */								\
  if (fdata.saved_fpr >= 0 || fdata.saved_gpr >= 0) {			\
    if ((FRAME_INFO)->prev && (FRAME_INFO)->prev->frame)		\
      frame_addr = (FRAME_INFO)->prev->frame;				\
    else								\
      frame_addr = read_memory_integer ((FRAME_INFO)->frame, 4);	\
  }									\
									\
  /* if != -1, fdata.saved_fpr is the smallest number of saved_fpr. All fpr's \
     from saved_fpr to fp31 are saved right underneath caller stack pointer, \
     starting from fp31 first. */					\
									\
  if (fdata.saved_fpr >= 0) {						\
    for (ii=31; ii >= fdata.saved_fpr; --ii) 				\
      (FRAME_SAVED_REGS).regs [FP0_REGNUM + ii] = frame_addr - ((32 - ii) * 8); \
    frame_addr -= (32 - fdata.saved_fpr) * 8;				\
  }									\
									\
  /* if != -1, fdata.saved_gpr is the smallest number of saved_gpr. All gpr's \
     from saved_gpr to gpr31 are saved right under saved fprs, starting	\
     from r31 first. */							\
									\
  if (fdata.saved_gpr >= 0)						\
    for (ii=31; ii >= fdata.saved_gpr; --ii)				\
      (FRAME_SAVED_REGS).regs [ii] = frame_addr - ((32 - ii) * 4);	\
}


/* Things needed for making the inferior call functions.  */

/* Push an empty stack frame, to record the current PC, etc.  */
/* Change these names into rs6k_{push, pop}_frame(). FIXMEmgo. */

#define PUSH_DUMMY_FRAME	push_dummy_frame ()

/* Discard from the stack the innermost frame, 
   restoring all saved registers.  */

#define POP_FRAME	pop_frame ()

/* This sequence of words is the instructions:

	mflr	r0		// 0x7c0802a6
				// save fpr's
	stfd	r?, num(r1)	// 0xd8010000 there should be 32 of this??
				// save gpr's
	stm	r0, num(r1)	// 0xbc010000
	stu	r1, num(r1)	// 0x94210000

	// the function we want to branch might be in a different load 
	// segment. reset the toc register. Note that the actual toc address
	// will be fix by fix_call_dummy () along with function address.

	st	r2, 0x14(r1)	// 0x90410014 save toc register
	liu	r2, 0x1234	// 0x3c401234 reset a new toc value 0x12345678
	oril	r2, r2,0x5678   // 0x60425678	

				// load absolute address 0x12345678 to r0
	liu	r0, 0x1234	// 0x3c001234
	oril	r0, r0,0x5678	// 0x60005678
	mtctr	r0		// 0x7c0903a6 ctr <- r0
	bctrl			// 0x4e800421 jump subroutine 0x12345678 (%ctr)
	cror	0xf, 0xf, 0xf	// 0x4def7b82
	brpt			// 0x7d821008, breakpoint
	cror	0xf, 0xf, 0xf	// 0x4def7b82 (for 8 byte alignment)


  We actually start executing by saving the toc register first, since the pushing 
  of the registers is done by PUSH_DUMMY_FRAME.  If this were real code,
  the arguments for the function called by the `bctrl' would be pushed
  between the `stu' and the `bctrl', and we could allow it to execute through.
  But the arguments have to be pushed by GDB after the PUSH_DUMMY_FRAME is done,
  and we cannot allow to push the registers again.
*/
	
#define CALL_DUMMY {0x7c0802a6, 0xd8010000, 0xbc010000, 0x94210000, \
		    0x90410014, 0x3c401234, 0x60425678,		    \
		    0x3c001234, 0x60005678, 0x7c0903a6, 0x4e800421, \
		    0x4def7b82, 0x7d821008, 0x4def7b82 }


/* keep this as multiple of 8 (%sp requires 8 byte alignment) */
#define CALL_DUMMY_LENGTH 56

#define CALL_DUMMY_START_OFFSET 16

/* Insert the specified number of args and function address
   into a call sequence of the above form stored at DUMMYNAME.  */

#define FIX_CALL_DUMMY(dummyname, pc, fun, nargs, args, type, using_gcc) \
	fix_call_dummy(dummyname, pc, fun, nargs, type)

/* Usually a function pointer's representation is simply the address of
   the function. On the RS/6000 however, a function pointer is represented
   by a pointer to a TOC entry. This TOC entry contains three words,
   the first word is the address of the function, the second word is the
   TOC pointer (r2), and the third word is the static chain value.
   Throughout GDB it is currently assumed that a function pointer contains
   the address of the function, which is not easy to fix.
   In addition, the conversion of a function address to a function
   pointer would require allocation of a TOC entry in the inferior's
   memory space, with all its drawbacks.
   To be able to call C++ virtual methods in the inferior (which are called
   via function pointers), find_function_addr uses this macro to
   get the function address from a function pointer.  */
#define CONVERT_FROM_FUNC_PTR_ADDR(ADDR) read_memory_integer (ADDR, 4)

/* Flag for machine-specific stuff in shared files.  FIXME */
#define IBM6000_TARGET

/* RS6000/AIX does not support PT_STEP.  Has to be simulated.  */

#define NO_SINGLE_STEP