Initial revision

1 files changed, 516 insertions, 0 deletions

diff --git a/gdb/m68k-tdep.c b/gdb/m68k-tdep.c
new file mode 100644
index 00000000000..d597efa0ec7
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+++ b/gdb/m68k-tdep.c
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+/* Target dependent code for the Motorola 68000 series.
+   Copyright (C) 1990, 1992 Free Software Foundation, Inc.
+
+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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+#include "defs.h"
+#include "frame.h"
+#include "symtab.h"
+#include "gdbcore.h"
+#include "value.h"
+#include "gdb_string.h"
+
+
+/* Push an empty stack frame, to record the current PC, etc.  */
+
+void
+m68k_push_dummy_frame ()
+{
+  register CORE_ADDR sp = read_register (SP_REGNUM);
+  register int regnum;
+  char raw_buffer[12];
+
+  sp = push_word (sp, read_register (PC_REGNUM));
+  sp = push_word (sp, read_register (FP_REGNUM));
+  write_register (FP_REGNUM, sp);
+
+  /* Always save the floating-point registers, whether they exist on
+     this target or not.  */
+  for (regnum = FP0_REGNUM + 7; regnum >= FP0_REGNUM; regnum--)
+    {
+      read_register_bytes (REGISTER_BYTE (regnum), raw_buffer, 12);
+      sp = push_bytes (sp, raw_buffer, 12);
+    }
+
+  for (regnum = FP_REGNUM - 1; regnum >= 0; regnum--)
+    {
+      sp = push_word (sp, read_register (regnum));
+    }
+  sp = push_word (sp, read_register (PS_REGNUM));
+  write_register (SP_REGNUM, sp);
+}
+
+/* Discard from the stack the innermost frame,
+   restoring all saved registers.  */
+
+void
+m68k_pop_frame ()
+{
+  register struct frame_info *frame = get_current_frame ();
+  register CORE_ADDR fp;
+  register int regnum;
+  struct frame_saved_regs fsr;
+  char raw_buffer[12];
+
+  fp = FRAME_FP (frame);
+  get_frame_saved_regs (frame, &fsr);
+  for (regnum = FP0_REGNUM + 7 ; regnum >= FP0_REGNUM ; regnum--)
+    {
+      if (fsr.regs[regnum])
+	{
+	  read_memory (fsr.regs[regnum], raw_buffer, 12);
+	  write_register_bytes (REGISTER_BYTE (regnum), raw_buffer, 12);
+	}
+    }
+  for (regnum = FP_REGNUM - 1 ; regnum >= 0 ; regnum--)
+    {
+      if (fsr.regs[regnum])
+	{
+	  write_register (regnum, read_memory_integer (fsr.regs[regnum], 4));
+	}
+    }
+  if (fsr.regs[PS_REGNUM])
+    {
+      write_register (PS_REGNUM, read_memory_integer (fsr.regs[PS_REGNUM], 4));
+    }
+  write_register (FP_REGNUM, read_memory_integer (fp, 4));
+  write_register (PC_REGNUM, read_memory_integer (fp + 4, 4));
+  write_register (SP_REGNUM, fp + 8);
+  flush_cached_frames ();
+}
+
+
+/* Given an ip value corresponding to the start of a function,
+   return the ip of the first instruction after the function 
+   prologue.  This is the generic m68k support.  Machines which
+   require something different can override the SKIP_PROLOGUE
+   macro to point elsewhere.
+
+   Some instructions which typically may appear in a function
+   prologue include:
+
+   A link instruction, word form:
+
+	link.w	%a6,&0			4e56  XXXX
+
+   A link instruction, long form:
+
+	link.l  %fp,&F%1		480e  XXXX  XXXX
+
+   A movm instruction to preserve integer regs:
+
+	movm.l  &M%1,(4,%sp)		48ef  XXXX  XXXX
+
+   A fmovm instruction to preserve float regs:
+
+	fmovm   &FPM%1,(FPO%1,%sp)	f237  XXXX  XXXX  XXXX  XXXX
+
+   Some profiling setup code (FIXME, not recognized yet):
+
+	lea.l   (.L3,%pc),%a1		43fb  XXXX  XXXX  XXXX
+	bsr     _mcount			61ff  XXXX  XXXX
+
+  */
+
+#define P_LINK_L	0x480e
+#define P_LINK_W	0x4e56
+#define P_MOV_L		0x207c
+#define P_JSR		0x4eb9
+#define P_BSR		0x61ff
+#define P_LEA_L		0x43fb
+#define P_MOVM_L	0x48ef
+#define P_FMOVM		0xf237
+#define P_TRAP		0x4e40
+
+CORE_ADDR
+m68k_skip_prologue (ip)
+CORE_ADDR ip;
+{
+  register CORE_ADDR limit;
+  struct symtab_and_line sal;
+  register int op;
+
+  /* Find out if there is a known limit for the extent of the prologue.
+     If so, ensure we don't go past it.  If not, assume "infinity". */
+
+  sal = find_pc_line (ip, 0);
+  limit = (sal.end) ? sal.end : (CORE_ADDR) ~0;
+
+  while (ip < limit)
+    {
+      op = read_memory_integer (ip, 2);
+      op &= 0xFFFF;
+      
+      if (op == P_LINK_W)
+	{
+	  ip += 4;	/* Skip link.w */
+	}
+      else if (op == 0x4856)
+	ip += 2; /* Skip pea %fp */
+      else if (op == 0x2c4f)
+	ip += 2; /* Skip move.l %sp, %fp */
+      else if (op == P_LINK_L)
+	{
+	  ip += 6;	/* Skip link.l */
+	}
+      else if (op == P_MOVM_L)
+	{
+	  ip += 6;	/* Skip movm.l */
+	}
+      else if (op == P_FMOVM)
+	{
+	  ip += 10;	/* Skip fmovm */
+	}
+      else
+	{
+	  break;	/* Found unknown code, bail out. */
+	}
+    }
+  return (ip);
+}
+
+void
+m68k_find_saved_regs (frame_info, saved_regs)
+     struct frame_info *frame_info;
+     struct frame_saved_regs *saved_regs;
+{
+  register int regnum;							
+  register int regmask;							
+  register CORE_ADDR next_addr;						
+  register CORE_ADDR pc;
+
+  /* First possible address for a pc in a call dummy for this frame.  */
+  CORE_ADDR possible_call_dummy_start =
+    (frame_info)->frame - CALL_DUMMY_LENGTH - FP_REGNUM*4 - 4 - 8*12;
+
+  int nextinsn;
+  memset (saved_regs, 0, sizeof (*saved_regs));
+  if ((frame_info)->pc >= possible_call_dummy_start
+      && (frame_info)->pc <= (frame_info)->frame)
+    {
+
+      /* It is a call dummy.  We could just stop now, since we know
+	 what the call dummy saves and where.  But this code proceeds
+	 to parse the "prologue" which is part of the call dummy.
+	 This is needlessly complex and confusing.  FIXME.  */
+
+      next_addr = (frame_info)->frame;
+      pc = possible_call_dummy_start;
+    }
+  else   								
+    {
+      pc = get_pc_function_start ((frame_info)->pc); 			
+
+      if (0x4856 == read_memory_integer (pc, 2)
+	  && 0x2c4f == read_memory_integer (pc + 2, 2))
+	{
+	  /*
+	    pea %fp
+            move.l %sp, %fp */
+
+	  pc += 4;
+	  next_addr = frame_info->frame;
+	}
+      else if (044016 == read_memory_integer (pc, 2))
+	/* link.l %fp */
+	/* Find the address above the saved   
+	   regs using the amount of storage from the link instruction.  */
+	next_addr = (frame_info)->frame + read_memory_integer (pc += 2, 4), pc+=4; 
+      else if (047126 == read_memory_integer (pc, 2))			
+	/* link.w %fp */
+	/* Find the address above the saved   
+	   regs using the amount of storage from the link instruction.  */
+	next_addr = (frame_info)->frame + read_memory_integer (pc += 2, 2), pc+=2; 
+      else goto lose;
+
+      /* If have an addal #-n, sp next, adjust next_addr.  */		
+      if ((0177777 & read_memory_integer (pc, 2)) == 0157774)		
+	next_addr += read_memory_integer (pc += 2, 4), pc += 4;		
+    }									
+  regmask = read_memory_integer (pc + 2, 2);				
+
+  /* Here can come an fmovem.  Check for it.  */		
+  nextinsn = 0xffff & read_memory_integer (pc, 2);			
+  if (0xf227 == nextinsn						
+      && (regmask & 0xff00) == 0xe000)					
+    { pc += 4; /* Regmask's low bit is for register fp7, the first pushed */ 
+      for (regnum = FP0_REGNUM + 7; regnum >= FP0_REGNUM; regnum--, regmask >>= 1)		
+	if (regmask & 1)						
+          saved_regs->regs[regnum] = (next_addr -= 12);		
+      regmask = read_memory_integer (pc + 2, 2); }
+
+  /* next should be a moveml to (sp) or -(sp) or a movl r,-(sp) */	
+  if (0044327 == read_memory_integer (pc, 2))				
+    { pc += 4; /* Regmask's low bit is for register 0, the first written */ 
+      for (regnum = 0; regnum < 16; regnum++, regmask >>= 1)		
+	if (regmask & 1)						
+          saved_regs->regs[regnum] = (next_addr += 4) - 4; }	
+  else if (0044347 == read_memory_integer (pc, 2))			
+    {
+      pc += 4; /* Regmask's low bit is for register 15, the first pushed */ 
+      for (regnum = 15; regnum >= 0; regnum--, regmask >>= 1)		
+	if (regmask & 1)						
+          saved_regs->regs[regnum] = (next_addr -= 4);
+    }
+  else if (0x2f00 == (0xfff0 & read_memory_integer (pc, 2)))		
+    {
+      regnum = 0xf & read_memory_integer (pc, 2); pc += 2;		
+      saved_regs->regs[regnum] = (next_addr -= 4);
+      /* gcc, at least, may use a pair of movel instructions when saving
+	 exactly 2 registers.  */
+      if (0x2f00 == (0xfff0 & read_memory_integer (pc, 2)))
+	{
+	  regnum = 0xf & read_memory_integer (pc, 2);
+	  pc += 2;
+	  saved_regs->regs[regnum] = (next_addr -= 4);
+	}
+    }
+
+  /* fmovemx to index of sp may follow.  */				
+  regmask = read_memory_integer (pc + 2, 2);				
+  nextinsn = 0xffff & read_memory_integer (pc, 2);			
+  if (0xf236 == nextinsn						
+      && (regmask & 0xff00) == 0xf000)					
+    { pc += 10; /* Regmask's low bit is for register fp0, the first written */ 
+      for (regnum = FP0_REGNUM + 7; regnum >= FP0_REGNUM; regnum--, regmask >>= 1)		
+	if (regmask & 1)						
+          saved_regs->regs[regnum] = (next_addr += 12) - 12;	
+      regmask = read_memory_integer (pc + 2, 2); }			
+
+  /* clrw -(sp); movw ccr,-(sp) may follow.  */				
+  if (0x426742e7 == read_memory_integer (pc, 4))			
+    saved_regs->regs[PS_REGNUM] = (next_addr -= 4);		
+  lose: ;								
+  saved_regs->regs[SP_REGNUM] = (frame_info)->frame + 8;		
+  saved_regs->regs[FP_REGNUM] = (frame_info)->frame;		
+  saved_regs->regs[PC_REGNUM] = (frame_info)->frame + 4;		
+#ifdef SIG_SP_FP_OFFSET
+  /* Adjust saved SP_REGNUM for fake _sigtramp frames.  */
+  if (frame_info->signal_handler_caller && frame_info->next)
+    saved_regs->regs[SP_REGNUM] = frame_info->next->frame + SIG_SP_FP_OFFSET;
+#endif
+}
+
+
+#ifdef USE_PROC_FS	/* Target dependent support for /proc */
+
+#include <sys/procfs.h>
+
+/*  The /proc interface divides the target machine's register set up into
+    two different sets, the general register set (gregset) and the floating
+    point register set (fpregset).  For each set, there is an ioctl to get
+    the current register set and another ioctl to set the current values.
+
+    The actual structure passed through the ioctl interface is, of course,
+    naturally machine dependent, and is different for each set of registers.
+    For the m68k for example, the general register set is typically defined
+    by:
+
+	typedef int gregset_t[18];
+
+	#define	R_D0	0
+	...
+	#define	R_PS	17
+
+    and the floating point set by:
+
+    	typedef	struct fpregset {
+	  int	f_pcr;
+	  int	f_psr;
+	  int	f_fpiaddr;
+	  int	f_fpregs[8][3];		(8 regs, 96 bits each)
+	} fpregset_t;
+
+    These routines provide the packing and unpacking of gregset_t and
+    fpregset_t formatted data.
+
+ */
+
+/* Atari SVR4 has R_SR but not R_PS */
+
+#if !defined (R_PS) && defined (R_SR)
+#define R_PS R_SR
+#endif
+
+/*  Given a pointer to a general register set in /proc format (gregset_t *),
+    unpack the register contents and supply them as gdb's idea of the current
+    register values. */
+
+void
+supply_gregset (gregsetp)
+gregset_t *gregsetp;
+{
+  register int regi;
+  register greg_t *regp = (greg_t *) gregsetp;
+
+  for (regi = 0 ; regi < R_PC ; regi++)
+    {
+      supply_register (regi, (char *) (regp + regi));
+    }
+  supply_register (PS_REGNUM, (char *) (regp + R_PS));
+  supply_register (PC_REGNUM, (char *) (regp + R_PC));
+}
+
+void
+fill_gregset (gregsetp, regno)
+gregset_t *gregsetp;
+int regno;
+{
+  register int regi;
+  register greg_t *regp = (greg_t *) gregsetp;
+  extern char registers[];
+
+  for (regi = 0 ; regi < R_PC ; regi++)
+    {
+      if ((regno == -1) || (regno == regi))
+	{
+	  *(regp + regi) = *(int *) &registers[REGISTER_BYTE (regi)];
+	}
+    }
+  if ((regno == -1) || (regno == PS_REGNUM))
+    {
+      *(regp + R_PS) = *(int *) &registers[REGISTER_BYTE (PS_REGNUM)];
+    }
+  if ((regno == -1) || (regno == PC_REGNUM))
+    {
+      *(regp + R_PC) = *(int *) &registers[REGISTER_BYTE (PC_REGNUM)];
+    }
+}
+
+#if defined (FP0_REGNUM)
+
+/*  Given a pointer to a floating point register set in /proc format
+    (fpregset_t *), unpack the register contents and supply them as gdb's
+    idea of the current floating point register values. */
+
+void 
+supply_fpregset (fpregsetp)
+fpregset_t *fpregsetp;
+{
+  register int regi;
+  char *from;
+  
+  for (regi = FP0_REGNUM ; regi < FPC_REGNUM ; regi++)
+    {
+      from = (char *) &(fpregsetp -> f_fpregs[regi-FP0_REGNUM][0]);
+      supply_register (regi, from);
+    }
+  supply_register (FPC_REGNUM, (char *) &(fpregsetp -> f_pcr));
+  supply_register (FPS_REGNUM, (char *) &(fpregsetp -> f_psr));
+  supply_register (FPI_REGNUM, (char *) &(fpregsetp -> f_fpiaddr));
+}
+
+/*  Given a pointer to a floating point register set in /proc format
+    (fpregset_t *), update the register specified by REGNO from gdb's idea
+    of the current floating point register set.  If REGNO is -1, update
+    them all. */
+
+void
+fill_fpregset (fpregsetp, regno)
+fpregset_t *fpregsetp;
+int regno;
+{
+  int regi;
+  char *to;
+  char *from;
+  extern char registers[];
+
+  for (regi = FP0_REGNUM ; regi < FPC_REGNUM ; regi++)
+    {
+      if ((regno == -1) || (regno == regi))
+	{
+	  from = (char *) &registers[REGISTER_BYTE (regi)];
+	  to = (char *) &(fpregsetp -> f_fpregs[regi-FP0_REGNUM][0]);
+	  memcpy (to, from, REGISTER_RAW_SIZE (regi));
+	}
+    }
+  if ((regno == -1) || (regno == FPC_REGNUM))
+    {
+      fpregsetp -> f_pcr = *(int *) &registers[REGISTER_BYTE (FPC_REGNUM)];
+    }
+  if ((regno == -1) || (regno == FPS_REGNUM))
+    {
+      fpregsetp -> f_psr = *(int *) &registers[REGISTER_BYTE (FPS_REGNUM)];
+    }
+  if ((regno == -1) || (regno == FPI_REGNUM))
+    {
+      fpregsetp -> f_fpiaddr = *(int *) &registers[REGISTER_BYTE (FPI_REGNUM)];
+    }
+}
+
+#endif	/* defined (FP0_REGNUM) */
+
+#endif  /* USE_PROC_FS */
+
+#ifdef GET_LONGJMP_TARGET
+/* Figure out where the longjmp will land.  Slurp the args out of the stack.
+   We expect the first arg to be a pointer to the jmp_buf structure from which
+   we extract the pc (JB_PC) that we will land at.  The pc is copied into PC.
+   This routine returns true on success. */
+
+int
+get_longjmp_target(pc)
+     CORE_ADDR *pc;
+{
+  char buf[TARGET_PTR_BIT / TARGET_CHAR_BIT];
+  CORE_ADDR sp, jb_addr;
+
+  sp = read_register(SP_REGNUM);
+
+  if (target_read_memory (sp + SP_ARG0, /* Offset of first arg on stack */
+			  buf,
+			  TARGET_PTR_BIT / TARGET_CHAR_BIT))
+    return 0;
+
+  jb_addr = extract_address (buf, TARGET_PTR_BIT / TARGET_CHAR_BIT);
+
+  if (target_read_memory (jb_addr + JB_PC * JB_ELEMENT_SIZE, buf,
+			  TARGET_PTR_BIT / TARGET_CHAR_BIT))
+    return 0;
+
+  *pc = extract_address (buf, TARGET_PTR_BIT / TARGET_CHAR_BIT);
+
+  return 1;
+}
+#endif /* GET_LONGJMP_TARGET */
+
+/* Immediately after a function call, return the saved pc before the frame
+   is setup.  For sun3's, we check for the common case of being inside of a
+   system call, and if so, we know that Sun pushes the call # on the stack
+   prior to doing the trap. */
+
+CORE_ADDR
+m68k_saved_pc_after_call(frame)
+     struct frame_info *frame;
+{
+#ifdef SYSCALL_TRAP
+  int op;
+
+  op = read_memory_integer (frame->pc - SYSCALL_TRAP_OFFSET, 2);
+
+  if (op == SYSCALL_TRAP)
+    return read_memory_integer (read_register (SP_REGNUM) + 4, 4);
+  else
+#endif /* SYSCALL_TRAP */
+    return read_memory_integer (read_register (SP_REGNUM), 4);
+}
+
+void
+_initialize_m68k_tdep ()
+{
+  tm_print_insn = print_insn_m68k;
+}