Initial revision

1 files changed, 679 insertions, 0 deletions

diff --git a/gdb/mips-tdep.c b/gdb/mips-tdep.c
new file mode 100644
index 0000000..abdd206
--- /dev/null
+++ b/gdb/mips-tdep.c
@@ -0,0 +1,679 @@
+/* Work with core dump and executable files, for GDB on MIPS. 
+   This code would be in core.c if it weren't machine-dependent. */
+
+/* Low level interface to ptrace, for GDB when running under Unix.
+   Copyright (C) 1988, 1989, 1990  Free Software Foundation, Inc.
+   Contributed by Alessandro Forin(af@cs.cmu.edu) at CMU
+   and by Per Bothner(bothner@cs.wisc.edu) at U.Wisconsin.
+
+This file is part of GDB.
+
+GDB 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 1, or (at your option)
+any later version.
+
+GDB 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 GDB; see the file COPYING.  If not, write to
+the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+/* FIXME: Can a MIPS porter/tester determine which of these include
+   files we still need?   -- gnu@cygnus.com */
+#include <stdio.h>
+#include <mips/inst.h>
+#include "defs.h"
+#include "param.h"
+#include "frame.h"
+#include "inferior.h"
+#include "symtab.h"
+#include "value.h"
+#include "gdbcmd.h"
+
+#ifdef USG
+#include <sys/types.h>
+#endif
+
+#include <sys/param.h>
+#include <sys/dir.h>
+#include <signal.h>
+#include <sys/ioctl.h>
+
+#include "gdbcore.h"
+
+#ifndef	MIPSMAGIC
+#ifdef MIPSEL
+#define MIPSMAGIC	MIPSELMAGIC
+#else
+#define MIPSMAGIC	MIPSEBMAGIC
+#endif
+#endif
+
+#define VM_MIN_ADDRESS (unsigned)0x400000
+
+#include <sys/user.h>		/* After a.out.h  */
+#include <sys/file.h>
+#include <sys/stat.h>
+
+
+#define PROC_LOW_ADDR(proc) ((proc)->adr) /* least address */
+#define PROC_HIGH_ADDR(proc) ((proc)->pad2) /* upper address bound */
+#define PROC_FRAME_OFFSET(proc) ((proc)->framesize)
+#define PROC_FRAME_REG(proc) ((proc)->framereg)
+#define PROC_REG_MASK(proc) ((proc)->regmask)
+#define PROC_FREG_MASK(proc) ((proc)->fregmask)
+#define PROC_REG_OFFSET(proc) ((proc)->regoffset)
+#define PROC_FREG_OFFSET(proc) ((proc)->fregoffset)
+#define PROC_PC_REG(proc) ((proc)->pcreg)
+#define PROC_SYMBOL(proc) (*(struct symbol**)&(proc)->isym)
+#define _PROC_MAGIC_ 0x0F0F0F0F
+#define PROC_DESC_IS_DUMMY(proc) ((proc)->isym == _PROC_MAGIC_)
+#define SET_PROC_DESC_IS_DUMMY(proc) ((proc)->isym = _PROC_MAGIC_)
+
+struct linked_proc_info
+{
+  struct mips_extra_func_info info;
+  struct linked_proc_info *next;
+} * linked_proc_desc_table = NULL;
+
+
+#define READ_FRAME_REG(fi, regno) read_next_frame_reg((fi)->next, regno)
+
+int
+read_next_frame_reg(fi, regno)
+     FRAME fi;
+     int regno;
+{
+#define SIGFRAME_BASE   sizeof(struct sigcontext)
+#define SIGFRAME_PC_OFF (-SIGFRAME_BASE+ 2*sizeof(int))
+#define SIGFRAME_SP_OFF (-SIGFRAME_BASE+32*sizeof(int))
+#define SIGFRAME_RA_OFF (-SIGFRAME_BASE+34*sizeof(int))
+  for (; fi; fi = fi->next)
+      if (in_sigtramp(fi->pc, 0)) {
+	  /* No idea if this code works. --PB. */
+	  int offset;
+	  if (regno == PC_REGNUM) offset = SIGFRAME_PC_OFF;
+	  else if (regno == RA_REGNUM) offset = SIGFRAME_RA_OFF;
+	  else if (regno == SP_REGNUM) offset = SIGFRAME_SP_OFF;
+	  else return 0;
+	  return read_memory_integer(fi->frame + offset, 4);
+      }
+      else if (regno == SP_REGNUM) return fi->frame;
+      else if (fi->saved_regs->regs[regno])
+	return read_memory_integer(fi->saved_regs->regs[regno], 4);
+  return read_register(regno);
+}
+
+int
+mips_frame_saved_pc(frame)
+     FRAME frame;
+{
+  mips_extra_func_info_t proc_desc = (mips_extra_func_info_t)frame->proc_desc;
+  int pcreg = proc_desc ? PROC_PC_REG(proc_desc) : RA_REGNUM;
+  if (proc_desc && PROC_DESC_IS_DUMMY(proc_desc))
+      return read_memory_integer(frame->frame - 4, 4);
+#if 0
+  /* If in the procedure prologue, RA_REGNUM might not have been saved yet.
+   * Assume non-leaf functions start with:
+   *	addiu $sp,$sp,-frame_size
+   *	sw $ra,ra_offset($sp)
+   * This if the pc is pointing at either of these instructions,
+   * then $ra hasn't been trashed.
+   * If the pc has advanced beyond these two instructions,
+   * then $ra has been saved.
+   * critical, and much more complex. Handling $ra is enough to get
+   * a stack trace, but some register values with be wrong.
+   */
+  if (frame->proc_desc && frame->pc < PROC_LOW_ADDR(proc_desc) + 8)
+      return read_register(pcreg);
+#endif
+  return read_next_frame_reg(frame, pcreg);
+}
+
+static struct mips_extra_func_info temp_proc_desc;
+static struct frame_saved_regs temp_saved_regs;
+
+CORE_ADDR heuristic_proc_start(pc)
+    CORE_ADDR pc;
+{
+
+    CORE_ADDR start_pc = pc;
+    CORE_ADDR fence = start_pc - 10000;
+    if (fence < VM_MIN_ADDRESS) fence = VM_MIN_ADDRESS;
+    /* search back for previous return */
+    for (start_pc -= 4; ; start_pc -= 4)
+	if (start_pc < fence) return 0; 
+	else if (ABOUT_TO_RETURN(start_pc))
+	    break;
+
+    start_pc += 8; /* skip return, and its delay slot */
+#if 0
+    /* skip nops (usually 1) 0 - is this */
+    while (start_pc < pc && read_memory_integer (start_pc, 4) == 0)
+	start_pc += 4;
+#endif
+    return start_pc;
+}
+
+mips_extra_func_info_t
+heuristic_proc_desc(start_pc, limit_pc, next_frame)
+    CORE_ADDR start_pc, limit_pc;
+    FRAME next_frame;
+{
+    CORE_ADDR sp = next_frame ? next_frame->frame : read_register (SP_REGNUM);
+    CORE_ADDR cur_pc;
+    int frame_size;
+    int has_frame_reg = 0;
+    int reg30; /* Value of $r30. Used by gcc for frame-pointer */
+    unsigned long reg_mask = 0;
+
+    if (start_pc == 0) return NULL;
+    bzero(&temp_proc_desc, sizeof(temp_proc_desc));
+    bzero(&temp_saved_regs, sizeof(struct frame_saved_regs));
+    if (start_pc + 200 < limit_pc) limit_pc = start_pc + 200;
+  restart:
+    frame_size = 0;
+    for (cur_pc = start_pc; cur_pc < limit_pc; cur_pc += 4) {
+	unsigned long word;
+	int status;
+
+	status = read_memory_nobpt (cur_pc, &word, 4); 
+	if (status) memory_error (status, cur_pc); 
+	if ((word & 0xFFFF0000) == 0x27bd0000) /* addiu $sp,$sp,-i */
+	    frame_size += (-word) & 0xFFFF;
+	else if ((word & 0xFFFF0000) == 0x23bd0000) /* addu $sp,$sp,-i */
+	    frame_size += (-word) & 0xFFFF;
+	else if ((word & 0xFFE00000) == 0xafa00000) { /* sw reg,offset($sp) */
+	    int reg = (word & 0x001F0000) >> 16;
+	    reg_mask |= 1 << reg;
+	    temp_saved_regs.regs[reg] = sp + (short)word;
+	}
+	else if ((word & 0xFFFF0000) == 0x27be0000) { /* addiu $30,$sp,size */
+	    if ((unsigned short)word != frame_size)
+		reg30 = sp + (unsigned short)word;
+	    else if (!has_frame_reg) {
+		int alloca_adjust;
+		has_frame_reg = 1;
+		reg30 = read_next_frame_reg(next_frame, 30);
+		alloca_adjust = reg30 - (sp + (unsigned short)word);
+		if (alloca_adjust > 0) {
+		    /* FP > SP + frame_size. This may be because
+		    /* of an alloca or somethings similar.
+		     * Fix sp to "pre-alloca" value, and try again.
+		     */
+		    sp += alloca_adjust;
+		    goto restart;
+		}
+	    }
+	}
+	else if ((word & 0xFFE00000) == 0xafc00000) { /* sw reg,offset($30) */
+	    int reg = (word & 0x001F0000) >> 16;
+	    reg_mask |= 1 << reg;
+	    temp_saved_regs.regs[reg] = reg30 + (short)word;
+	}
+    }
+    if (has_frame_reg) {
+	PROC_FRAME_REG(&temp_proc_desc) = 30;
+	PROC_FRAME_OFFSET(&temp_proc_desc) = 0;
+    }
+    else {
+	PROC_FRAME_REG(&temp_proc_desc) = SP_REGNUM;
+	PROC_FRAME_OFFSET(&temp_proc_desc) = frame_size;
+    }
+    PROC_REG_MASK(&temp_proc_desc) = reg_mask;
+    PROC_PC_REG(&temp_proc_desc) = RA_REGNUM;
+    return &temp_proc_desc;
+}
+
+mips_extra_func_info_t
+find_proc_desc(pc, next_frame)
+    CORE_ADDR pc;
+    FRAME next_frame;
+{
+  mips_extra_func_info_t proc_desc;
+  extern struct block *block_for_pc();
+  struct block   *b = block_for_pc(pc);
+
+  struct symbol *sym =
+      b ? lookup_symbol(".gdbinfo.", b, LABEL_NAMESPACE, 0, NULL) : NULL;
+  if (sym != NULL)
+    {
+	/* IF this is the topmost frame AND
+	 * (this proc does not have debugging information OR
+	 * the PC is in the procedure prologue)
+	 * THEN create a "hueristic" proc_desc (by analyzing
+	 * the actual code) to replace the "official" proc_desc.
+	 */
+	proc_desc = (struct mips_extra_func_info *)sym->value.value;
+	if (next_frame == NULL) {
+	    struct symtab_and_line val;
+	    struct symbol *proc_symbol =
+		PROC_DESC_IS_DUMMY(proc_desc) ? 0 : PROC_SYMBOL(proc_desc);
+	    if (proc_symbol) {
+		val = find_pc_line (BLOCK_START
+				    (SYMBOL_BLOCK_VALUE(proc_symbol)),
+				    0);
+		val.pc = val.end ? val.end : pc;
+	    }
+	    if (!proc_symbol || pc < val.pc) {
+		mips_extra_func_info_t found_heuristic =
+		    heuristic_proc_desc(PROC_LOW_ADDR(proc_desc),
+					pc, next_frame);
+		if (found_heuristic) proc_desc = found_heuristic;
+	    }
+	}
+    }
+  else
+    {
+      register struct linked_proc_info *link;
+      for (link = linked_proc_desc_table; link; link = link->next)
+	  if (PROC_LOW_ADDR(&link->info) <= pc
+	      && PROC_HIGH_ADDR(&link->info) > pc)
+	      return &link->info;
+      proc_desc =
+	  heuristic_proc_desc(heuristic_proc_start(pc), pc, next_frame);
+    }
+  return proc_desc;
+}
+
+mips_extra_func_info_t cached_proc_desc;
+
+FRAME_ADDR mips_frame_chain(frame)
+    FRAME frame;
+{
+    extern CORE_ADDR startup_file_start;	/* From blockframe.c */
+    mips_extra_func_info_t proc_desc;
+    CORE_ADDR saved_pc = FRAME_SAVED_PC(frame);
+    if (startup_file_start)
+      { /* has at least the __start symbol */
+	if (saved_pc == 0 || !outside_startup_file (saved_pc)) return 0;
+      }
+    else
+      { /* This hack depends on the internals of __start. */
+	/* We also assume the breakpoints are *not* inserted */
+        if (read_memory_integer (saved_pc + 8, 4) & 0xFC00003F == 0xD)
+	    return 0;  /* break */
+      }
+    proc_desc = find_proc_desc(saved_pc, frame);
+    if (!proc_desc) return 0;
+    cached_proc_desc = proc_desc;
+    return read_next_frame_reg(frame, PROC_FRAME_REG(proc_desc))
+	+ PROC_FRAME_OFFSET(proc_desc);
+}
+
+void
+init_extra_frame_info(fci)
+     struct frame_info *fci;
+{
+  extern struct obstack frame_cache_obstack;
+  /* Use proc_desc calculated in frame_chain */
+  mips_extra_func_info_t proc_desc = fci->next ? cached_proc_desc :
+      find_proc_desc(fci->pc, fci->next);
+  fci->saved_regs = (struct frame_saved_regs*)
+    obstack_alloc (&frame_cache_obstack, sizeof(struct frame_saved_regs));
+  bzero(fci->saved_regs, sizeof(struct frame_saved_regs));
+  fci->proc_desc =
+      proc_desc == &temp_proc_desc ? (char*)NULL : (char*)proc_desc;
+  if (proc_desc)
+    {
+      int ireg;
+      CORE_ADDR reg_position;
+      unsigned long mask;
+      /* r0 bit means kernel trap */
+      int kernel_trap = PROC_REG_MASK(proc_desc) & 1;
+
+      /* Fixup frame-pointer - only needed for top frame */
+      /* This may not be quite right, if procedure has a real frame register */
+      if (fci->pc == PROC_LOW_ADDR(proc_desc))
+	  fci->frame = read_register (SP_REGNUM);
+      else
+	  fci->frame = READ_FRAME_REG(fci, PROC_FRAME_REG(proc_desc))
+	      + PROC_FRAME_OFFSET(proc_desc);
+
+      if (proc_desc == &temp_proc_desc)
+	  *fci->saved_regs = temp_saved_regs;
+      else
+      {
+	  /* find which general-purpose registers were saved */
+	  reg_position = fci->frame + PROC_REG_OFFSET(proc_desc);
+	  mask = kernel_trap ? 0xFFFFFFFF : PROC_REG_MASK(proc_desc);
+	  for (ireg= 31; mask; --ireg, mask <<= 1)
+	      if (mask & 0x80000000)
+	      {
+		  fci->saved_regs->regs[ireg] = reg_position;
+		  reg_position -= 4;
+	      }
+	  /* find which floating-point registers were saved */
+	  reg_position = fci->frame + PROC_FREG_OFFSET(proc_desc);
+	  /* The freg_offset points to where the first *double* register is saved.
+	   * So skip to the high-order word. */
+	  reg_position += 4;
+	  mask = kernel_trap ? 0xFFFFFFFF : PROC_FREG_MASK(proc_desc);
+	  for (ireg = 31; mask; --ireg, mask <<= 1)
+	      if (mask & 0x80000000)
+	      {
+		  fci->saved_regs->regs[32+ireg] = reg_position;
+		  reg_position -= 4;
+	      }
+      }
+
+      /* hack: if argument regs are saved, guess these contain args */
+      if ((PROC_REG_MASK(proc_desc) & 0xF0) == 0) fci->num_args = -1;
+      else if ((PROC_REG_MASK(proc_desc) & 0x80) == 0) fci->num_args = 4;
+      else if ((PROC_REG_MASK(proc_desc) & 0x40) == 0) fci->num_args = 3;
+      else if ((PROC_REG_MASK(proc_desc) & 0x20) == 0) fci->num_args = 2;
+      else if ((PROC_REG_MASK(proc_desc) & 0x10) == 0) fci->num_args = 1;
+
+      fci->saved_regs->regs[PC_REGNUM] = fci->saved_regs->regs[RA_REGNUM];
+    }
+  if (fci->next == 0)
+      supply_register(FP_REGNUM, &fci->frame);
+}
+
+
+CORE_ADDR mips_push_arguments(nargs, args, sp, struct_return, struct_addr)
+  int nargs;
+  value *args;
+  CORE_ADDR sp;
+  int struct_return;
+  CORE_ADDR struct_addr;
+{
+  CORE_ADDR buf;
+  register i;
+  int accumulate_size = struct_return ? 4 : 0;
+  struct mips_arg { char *contents; int len; int offset; };
+  struct mips_arg *mips_args =
+      (struct mips_arg*)alloca(nargs * sizeof(struct mips_arg));
+  register struct mips_arg *m_arg;
+  for (i = 0, m_arg = mips_args; i < nargs; i++, m_arg++) {
+    extern value value_arg_coerce();
+    value arg = value_arg_coerce (args[i]);
+    m_arg->len = TYPE_LENGTH (VALUE_TYPE (arg));
+    /* This entire mips-specific routine is because doubles must be aligned
+     * on 8-byte boundaries. It still isn't quite right, because MIPS decided
+     * to align 'struct {int a, b}' on 4-byte boundaries (even though this
+     * breaks their varargs implementation...). A correct solution
+     * requires an simulation of gcc's 'alignof' (and use of 'alignof'
+     * in stdarg.h/varargs.h).
+     */
+    if (m_arg->len > 4) accumulate_size = (accumulate_size + 7) & -8;
+    m_arg->offset = accumulate_size;
+    accumulate_size = (accumulate_size + m_arg->len + 3) & -4;
+    m_arg->contents = VALUE_CONTENTS(arg);
+  }
+  accumulate_size = (accumulate_size + 7) & (-8);
+  if (accumulate_size < 16) accumulate_size = 16; 
+  sp -= accumulate_size;
+  for (i = nargs; m_arg--, --i >= 0; )
+    write_memory(sp + m_arg->offset, m_arg->contents, m_arg->len);
+  if (struct_return) {
+    buf = struct_addr;
+    write_memory(sp, &buf, sizeof(CORE_ADDR));
+}
+  return sp;
+}
+
+/* MASK(i,j) == (1<<i) + (1<<(i+1)) + ... + (1<<j)). Assume i<=j<31. */
+#define MASK(i,j) ((1 << (j)+1)-1 ^ (1 << (i))-1)
+
+void
+mips_push_dummy_frame()
+{
+  int ireg;
+  struct linked_proc_info *link = (struct linked_proc_info*)
+      xmalloc(sizeof(struct linked_proc_info));
+  mips_extra_func_info_t proc_desc = &link->info;
+  CORE_ADDR sp = read_register (SP_REGNUM);
+  CORE_ADDR save_address;
+  REGISTER_TYPE buffer;
+  link->next = linked_proc_desc_table;
+  linked_proc_desc_table = link;
+#define PUSH_FP_REGNUM 16 /* must be a register preserved across calls */
+#define GEN_REG_SAVE_MASK MASK(1,16)|MASK(24,28)|(1<<31)
+#define GEN_REG_SAVE_COUNT 22
+#define FLOAT_REG_SAVE_MASK MASK(0,19)
+#define FLOAT_REG_SAVE_COUNT 20
+#define SPECIAL_REG_SAVE_COUNT 4
+  /*
+   * The registers we must save are all those not preserved across
+   * procedure calls. Dest_Reg (see tm-mips.h) must also be saved.
+   * In addition, we must save the PC, and PUSH_FP_REGNUM.
+   * (Ideally, we should also save MDLO/-HI and FP Control/Status reg.)
+   *
+   * Dummy frame layout:
+   *  (high memory)
+   * 	Saved PC
+   *	Saved MMHI, MMLO, FPC_CSR
+   *	Saved R31
+   *	Saved R28
+   *	...
+   *	Saved R1
+   *    Saved D18 (i.e. F19, F18)
+   *    ...
+   *    Saved D0 (i.e. F1, F0)
+   *	CALL_DUMMY (subroutine stub; see m-mips.h)
+   *	Parameter build area (not yet implemented)
+   *  (low memory)
+   */
+  PROC_REG_MASK(proc_desc) = GEN_REG_SAVE_MASK;
+  PROC_FREG_MASK(proc_desc) = FLOAT_REG_SAVE_MASK;
+  PROC_REG_OFFSET(proc_desc) = /* offset of (Saved R31) from FP */
+      -sizeof(long) - 4 * SPECIAL_REG_SAVE_COUNT;
+  PROC_FREG_OFFSET(proc_desc) = /* offset of (Saved D18) from FP */
+      -sizeof(double) - 4 * (SPECIAL_REG_SAVE_COUNT + GEN_REG_SAVE_COUNT);
+  /* save general registers */
+  save_address = sp + PROC_REG_OFFSET(proc_desc);
+  for (ireg = 32; --ireg >= 0; )
+    if (PROC_REG_MASK(proc_desc) & (1 << ireg))
+      {
+	buffer = read_register (ireg);
+	write_memory (save_address, &buffer, sizeof(REGISTER_TYPE));
+	save_address -= 4;
+      }
+  /* save floating-points registers */
+  save_address = sp + PROC_FREG_OFFSET(proc_desc);
+  for (ireg = 32; --ireg >= 0; )
+    if (PROC_FREG_MASK(proc_desc) & (1 << ireg))
+      {
+	buffer = read_register (ireg);
+	write_memory (save_address, &buffer, 4);
+	save_address -= 4;
+      }
+  write_register (PUSH_FP_REGNUM, sp);
+  PROC_FRAME_REG(proc_desc) = PUSH_FP_REGNUM;
+  PROC_FRAME_OFFSET(proc_desc) = 0;
+  buffer = read_register (PC_REGNUM);
+  write_memory (sp - 4, &buffer, sizeof(REGISTER_TYPE));
+  buffer = read_register (HI_REGNUM);
+  write_memory (sp - 8, &buffer, sizeof(REGISTER_TYPE));
+  buffer = read_register (LO_REGNUM);
+  write_memory (sp - 12, &buffer, sizeof(REGISTER_TYPE));
+  buffer = read_register (FCRCS_REGNUM);
+  write_memory (sp - 16, &buffer, sizeof(REGISTER_TYPE));
+  sp -= 4 * (GEN_REG_SAVE_COUNT+FLOAT_REG_SAVE_COUNT+SPECIAL_REG_SAVE_COUNT);
+  write_register (SP_REGNUM, sp);
+  PROC_LOW_ADDR(proc_desc) = sp - CALL_DUMMY_SIZE + CALL_DUMMY_START_OFFSET;
+  PROC_HIGH_ADDR(proc_desc) = sp;
+  SET_PROC_DESC_IS_DUMMY(proc_desc);
+  PROC_PC_REG(proc_desc) = RA_REGNUM;
+}
+
+void
+mips_pop_frame()
+{ register int regnum;
+  FRAME frame = get_current_frame ();
+  CORE_ADDR new_sp = frame->frame;
+  mips_extra_func_info_t proc_desc = (mips_extra_func_info_t)frame->proc_desc;
+  if (PROC_DESC_IS_DUMMY(proc_desc))
+    {
+      struct linked_proc_info **ptr = &linked_proc_desc_table;;
+      for (; &ptr[0]->info != proc_desc; ptr = &ptr[0]->next )
+	  if (ptr[0] == NULL) abort();
+      *ptr = ptr[0]->next;
+      free (ptr[0]);
+      write_register (HI_REGNUM, read_memory_integer(new_sp - 8, 4));
+      write_register (LO_REGNUM, read_memory_integer(new_sp - 12, 4));
+      write_register (FCRCS_REGNUM, read_memory_integer(new_sp - 16, 4));
+    }
+  write_register (PC_REGNUM, FRAME_SAVED_PC(frame));
+  if (frame->proc_desc) {
+    for (regnum = 32; --regnum >= 0; )
+      if (PROC_REG_MASK(proc_desc) & (1 << regnum))
+	write_register (regnum,
+		  read_memory_integer (frame->saved_regs->regs[regnum], 4));
+    for (regnum = 64; --regnum >= 32; )
+      if (PROC_FREG_MASK(proc_desc) & (1 << regnum))
+	write_register (regnum,
+		  read_memory_integer (frame->saved_regs->regs[regnum], 4));
+  }
+  write_register (SP_REGNUM, new_sp);
+  flush_cached_frames ();
+  set_current_frame (create_new_frame (new_sp, read_pc ()));
+}
+
+static mips_print_register(regnum, all)
+     int regnum, all;
+{
+      unsigned char raw_buffer[8];
+      REGISTER_TYPE val;
+
+      read_relative_register_raw_bytes (regnum, raw_buffer);
+
+      if (!(regnum & 1) && regnum >= FP0_REGNUM && regnum < FP0_REGNUM+32) {
+	  read_relative_register_raw_bytes (regnum+1, raw_buffer+4);
+	  printf_filtered ("(d%d: ", regnum&31);
+	  val_print (builtin_type_double, raw_buffer, 0,
+		     stdout, 0, 1, 0, Val_pretty_default);
+	  printf_filtered ("); ", regnum&31);
+      }
+      fputs_filtered (reg_names[regnum], stdout);
+#ifndef NUMERIC_REG_NAMES
+      if (regnum < 32)
+	  printf_filtered ("(r%d): ", regnum);
+      else
+#endif
+	  printf_filtered (": ");
+
+      /* If virtual format is floating, print it that way.  */
+      if (TYPE_CODE (REGISTER_VIRTUAL_TYPE (regnum)) == TYPE_CODE_FLT
+	  && ! INVALID_FLOAT (raw_buffer, REGISTER_VIRTUAL_SIZE(regnum))) {
+	  val_print (REGISTER_VIRTUAL_TYPE (regnum), raw_buffer, 0,
+		     stdout, 0, 1, 0, Val_pretty_default);
+      }
+      /* Else print as integer in hex.  */
+      else
+	{
+	  long val;
+
+	  bcopy (raw_buffer, &val, sizeof (long));
+	  if (val == 0)
+	    printf_filtered ("0");
+	  else if (all)
+	    printf_filtered ("0x%x", val);
+	  else
+	    printf_filtered ("0x%x=%d", val, val);
+	}
+}
+
+mips_do_registers_info(regnum)
+     int regnum;
+{
+  if (regnum != -1) {
+      mips_print_register (regnum, 0);
+      printf_filtered ("\n");
+  }
+  else {
+      for (regnum = 0; regnum < NUM_REGS; ) {
+	  mips_print_register (regnum, 1);
+	  regnum++;
+	  if ((regnum & 3) == 0 || regnum == NUM_REGS)
+	      printf_filtered (";\n");
+	  else
+	      printf_filtered ("; ");
+      }
+  }
+}
+/* Return number of args passed to a frame. described by FIP.
+   Can return -1, meaning no way to tell.  */
+
+mips_frame_num_args(fip)
+	FRAME fip;
+{
+#if 0
+	struct chain_info_t *p;
+
+	p = mips_find_cached_frame(FRAME_FP(fip));
+	if (p->valid)
+		return p->the_info.numargs;
+#endif
+	return -1;
+}
+
+
+/* Bad floats: Returns 0 if P points to a valid IEEE floating point number,
+   1 if P points to a denormalized number or a NaN. LEN says whether this is
+   a single-precision or double-precision float */
+#define SINGLE_EXP_BITS  8
+#define DOUBLE_EXP_BITS 11
+int
+isa_NAN(p, len)
+     int *p, len;
+{
+  int exponent;
+  if (len == 4)
+    {
+      exponent = *p;
+      exponent = exponent << 1 >> (32 - SINGLE_EXP_BITS - 1);
+      return ((exponent == -1) || (! exponent && *p));
+    }
+  else if (len == 8)
+    {
+      exponent = *(p+1);
+      exponent = exponent << 1 >> (32 - DOUBLE_EXP_BITS - 1);
+      return ((exponent == -1) || (! exponent && *p * *(p+1)));
+    }
+  else return 1;
+}
+
+/* To skip prologues, I use this predicate. Returns either PC
+   itself if the code at PC does not look like a function prologue,
+   PC+4 if it does (our caller does not need anything more fancy). */
+
+CORE_ADDR mips_skip_prologue(pc)
+     CORE_ADDR pc;
+{
+    struct symbol *f;
+    struct block *b;
+    unsigned long inst;
+
+    /* For -g modules and most functions anyways the
+       first instruction adjusts the stack. */
+    inst = read_memory_integer(pc, 4);
+    if ((inst & 0xffff0000) == 0x27bd0000)
+	return pc + 4;
+
+    /* Well, it looks like a frameless. Let's make sure.
+       Note that we are not called on the current PC,
+       but on the function`s start PC, and I have definitely
+       seen optimized code that adjusts the SP quite later */
+    b = block_for_pc(pc);
+    if (!b) return pc;
+
+    f = lookup_symbol(".gdbinfo.", b, LABEL_NAMESPACE, 0, NULL);
+    if (!f) return pc;
+    /* Ideally, I would like to use the adjusted info
+       from mips_frame_info(), but for all practical
+       purposes it will not matter (and it would require
+       a different definition of SKIP_PROLOGUE())
+
+       Actually, it would not hurt to skip the storing
+       of arguments on the stack as well. */
+    if (((struct mips_extra_func_info *)f->value.value)->framesize)
+	return pc + 4;
+
+    return pc;
+}