1221 lines
34 KiB
C
1221 lines
34 KiB
C
/* Target-dependent code for GDB, the GNU debugger.
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Copyright 1986, 1987, 1989, 1991, 1992, 1993, 1994, 1995
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Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
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#include "defs.h"
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#include "frame.h"
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#include "inferior.h"
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#include "symtab.h"
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#include "target.h"
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#include "gdbcore.h"
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#include "xcoffsolib.h"
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#include <a.out.h>
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extern struct obstack frame_cache_obstack;
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extern int errno;
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/* Nonzero if we just simulated a single step break. */
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int one_stepped;
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/* Breakpoint shadows for the single step instructions will be kept here. */
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static struct sstep_breaks {
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/* Address, or 0 if this is not in use. */
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CORE_ADDR address;
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/* Shadow contents. */
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char data[4];
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} stepBreaks[2];
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/* Static function prototypes */
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static CORE_ADDR
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find_toc_address PARAMS ((CORE_ADDR pc));
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static CORE_ADDR
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branch_dest PARAMS ((int opcode, int instr, CORE_ADDR pc, CORE_ADDR safety));
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static void
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frame_get_cache_fsr PARAMS ((struct frame_info *fi,
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struct aix_framedata *fdatap));
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/*
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* Calculate the destination of a branch/jump. Return -1 if not a branch.
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*/
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static CORE_ADDR
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branch_dest (opcode, instr, pc, safety)
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int opcode;
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int instr;
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CORE_ADDR pc;
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CORE_ADDR safety;
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{
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register long offset;
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CORE_ADDR dest;
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int immediate;
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int absolute;
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int ext_op;
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absolute = (int) ((instr >> 1) & 1);
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switch (opcode) {
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case 18 :
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immediate = ((instr & ~3) << 6) >> 6; /* br unconditional */
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if (absolute)
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dest = immediate;
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else
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dest = pc + immediate;
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break;
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case 16 :
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immediate = ((instr & ~3) << 16) >> 16; /* br conditional */
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if (absolute)
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dest = immediate;
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else
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dest = pc + immediate;
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break;
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case 19 :
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ext_op = (instr>>1) & 0x3ff;
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if (ext_op == 16) /* br conditional register */
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dest = read_register (LR_REGNUM) & ~3;
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else if (ext_op == 528) /* br cond to count reg */
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{
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dest = read_register (CTR_REGNUM) & ~3;
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/* If we are about to execute a system call, dest is something
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like 0x22fc or 0x3b00. Upon completion the system call
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will return to the address in the link register. */
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if (dest < TEXT_SEGMENT_BASE)
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dest = read_register (LR_REGNUM) & ~3;
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}
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else return -1;
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break;
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default: return -1;
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}
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return (dest < TEXT_SEGMENT_BASE) ? safety : dest;
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}
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/* AIX does not support PT_STEP. Simulate it. */
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void
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single_step (signal)
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int signal;
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{
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#define INSNLEN(OPCODE) 4
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static char breakp[] = BREAKPOINT;
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int ii, insn;
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CORE_ADDR loc;
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CORE_ADDR breaks[2];
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int opcode;
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if (!one_stepped) {
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loc = read_pc ();
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insn = read_memory_integer (loc, 4);
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breaks[0] = loc + INSNLEN(insn);
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opcode = insn >> 26;
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breaks[1] = branch_dest (opcode, insn, loc, breaks[0]);
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/* Don't put two breakpoints on the same address. */
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if (breaks[1] == breaks[0])
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breaks[1] = -1;
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stepBreaks[1].address = 0;
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for (ii=0; ii < 2; ++ii) {
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/* ignore invalid breakpoint. */
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if ( breaks[ii] == -1)
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continue;
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read_memory (breaks[ii], stepBreaks[ii].data, 4);
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write_memory (breaks[ii], breakp, 4);
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stepBreaks[ii].address = breaks[ii];
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}
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one_stepped = 1;
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} else {
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/* remove step breakpoints. */
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for (ii=0; ii < 2; ++ii)
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if (stepBreaks[ii].address != 0)
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write_memory
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(stepBreaks[ii].address, stepBreaks[ii].data, 4);
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one_stepped = 0;
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}
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errno = 0; /* FIXME, don't ignore errors! */
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/* What errors? {read,write}_memory call error(). */
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}
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/* return pc value after skipping a function prologue. */
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skip_prologue (pc)
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CORE_ADDR pc;
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{
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char buf[4];
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unsigned int tmp;
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unsigned long op;
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if (target_read_memory (pc, buf, 4))
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return pc; /* Can't access it -- assume no prologue. */
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op = extract_unsigned_integer (buf, 4);
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/* Assume that subsequent fetches can fail with low probability. */
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if (op == 0x7c0802a6) { /* mflr r0 */
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pc += 4;
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op = read_memory_integer (pc, 4);
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}
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if ((op & 0xfc00003e) == 0x7c000026) { /* mfcr Rx */
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pc += 4;
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op = read_memory_integer (pc, 4);
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}
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if ((op & 0xfc000000) == 0x48000000) { /* bl foo, to save fprs??? */
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pc += 4;
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op = read_memory_integer (pc, 4);
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/* At this point, make sure this is not a trampoline function
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(a function that simply calls another functions, and nothing else).
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If the next is not a nop, this branch was part of the function
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prologue. */
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if (op == 0x4def7b82 || /* crorc 15, 15, 15 */
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op == 0x0)
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return pc - 4; /* don't skip over this branch */
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}
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if ((op & 0xfc1f0000) == 0xd8010000) { /* stfd Rx,NUM(r1) */
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pc += 4; /* store floating register double */
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op = read_memory_integer (pc, 4);
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}
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if ((op & 0xfc1f0000) == 0xbc010000) { /* stm Rx, NUM(r1) */
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pc += 4;
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op = read_memory_integer (pc, 4);
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}
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while ((op & 0xfc1f0000) == 0x9001 && /* st rx,NUM(r1), rx >= r13 */
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(op & 0x03e00000) >= 0x01a00000) {
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pc += 4;
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op = read_memory_integer (pc, 4);
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}
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if ((op & 0xfc1f0000) == 0x94210000) { /* stu r1,NUM(r1) */
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pc += 4;
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op = read_memory_integer (pc, 4);
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}
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while ((tmp = (op >> 22)) == 0x20f) { /* l r31, ... or */
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pc += 4; /* l r30, ... */
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op = read_memory_integer (pc, 4);
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}
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/* store parameters into stack */
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while(
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(op & 0xfc1f0000) == 0xd8010000 || /* stfd Rx,NUM(r1) */
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(op & 0xfc1f0000) == 0x90010000 || /* st r?, NUM(r1) */
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(op & 0xfc000000) == 0xfc000000 || /* frsp, fp?, .. */
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(op & 0xd0000000) == 0xd0000000) /* stfs, fp?, .. */
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{
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pc += 4; /* store fpr double */
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op = read_memory_integer (pc, 4);
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}
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if (op == 0x603f0000 /* oril r31, r1, 0x0 */
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|| op == 0x7c3f0b78) { /* mr r31, r1 */
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pc += 4; /* this happens if r31 is used as */
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op = read_memory_integer (pc, 4); /* frame ptr. (gcc does that) */
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tmp = 0;
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while ((op >> 16) == (0x907f + tmp)) { /* st r3, NUM(r31) */
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pc += 4; /* st r4, NUM(r31), ... */
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op = read_memory_integer (pc, 4);
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tmp += 0x20;
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}
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}
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#if 0
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/* I have problems with skipping over __main() that I need to address
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* sometime. Previously, I used to use misc_function_vector which
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* didn't work as well as I wanted to be. -MGO */
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/* If the first thing after skipping a prolog is a branch to a function,
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this might be a call to an initializer in main(), introduced by gcc2.
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We'd like to skip over it as well. Fortunately, xlc does some extra
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work before calling a function right after a prologue, thus we can
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single out such gcc2 behaviour. */
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if ((op & 0xfc000001) == 0x48000001) { /* bl foo, an initializer function? */
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op = read_memory_integer (pc+4, 4);
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if (op == 0x4def7b82) { /* cror 0xf, 0xf, 0xf (nop) */
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/* check and see if we are in main. If so, skip over this initializer
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function as well. */
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tmp = find_pc_misc_function (pc);
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if (tmp >= 0 && STREQ (misc_function_vector [tmp].name, "main"))
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return pc + 8;
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}
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}
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#endif /* 0 */
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return pc;
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}
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/*************************************************************************
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Support for creating pushind a dummy frame into the stack, and popping
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frames, etc.
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*************************************************************************/
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/* The total size of dummy frame is 436, which is;
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32 gpr's - 128 bytes
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32 fpr's - 256 "
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7 the rest - 28 "
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and 24 extra bytes for the callee's link area. The last 24 bytes
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for the link area might not be necessary, since it will be taken
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care of by push_arguments(). */
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#define DUMMY_FRAME_SIZE 436
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#define DUMMY_FRAME_ADDR_SIZE 10
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/* Make sure you initialize these in somewhere, in case gdb gives up what it
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was debugging and starts debugging something else. FIXMEibm */
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static int dummy_frame_count = 0;
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static int dummy_frame_size = 0;
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static CORE_ADDR *dummy_frame_addr = 0;
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extern int stop_stack_dummy;
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/* push a dummy frame into stack, save all register. Currently we are saving
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only gpr's and fpr's, which is not good enough! FIXMEmgo */
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void
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push_dummy_frame ()
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{
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/* stack pointer. */
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CORE_ADDR sp;
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/* Same thing, target byte order. */
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char sp_targ[4];
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/* link register. */
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CORE_ADDR pc;
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/* Same thing, target byte order. */
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char pc_targ[4];
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int ii;
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target_fetch_registers (-1);
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if (dummy_frame_count >= dummy_frame_size) {
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dummy_frame_size += DUMMY_FRAME_ADDR_SIZE;
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if (dummy_frame_addr)
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dummy_frame_addr = (CORE_ADDR*) xrealloc
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(dummy_frame_addr, sizeof(CORE_ADDR) * (dummy_frame_size));
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else
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dummy_frame_addr = (CORE_ADDR*)
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xmalloc (sizeof(CORE_ADDR) * (dummy_frame_size));
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}
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sp = read_register(SP_REGNUM);
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pc = read_register(PC_REGNUM);
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store_address (pc_targ, 4, pc);
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dummy_frame_addr [dummy_frame_count++] = sp;
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/* Be careful! If the stack pointer is not decremented first, then kernel
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thinks he is free to use the space underneath it. And kernel actually
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uses that area for IPC purposes when executing ptrace(2) calls. So
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before writing register values into the new frame, decrement and update
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%sp first in order to secure your frame. */
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write_register (SP_REGNUM, sp-DUMMY_FRAME_SIZE);
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/* gdb relies on the state of current_frame. We'd better update it,
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otherwise things like do_registers_info() wouldn't work properly! */
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flush_cached_frames ();
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/* save program counter in link register's space. */
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write_memory (sp+8, pc_targ, 4);
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/* save all floating point and general purpose registers here. */
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/* fpr's, f0..f31 */
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for (ii = 0; ii < 32; ++ii)
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write_memory (sp-8-(ii*8), ®isters[REGISTER_BYTE (31-ii+FP0_REGNUM)], 8);
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/* gpr's r0..r31 */
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for (ii=1; ii <=32; ++ii)
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write_memory (sp-256-(ii*4), ®isters[REGISTER_BYTE (32-ii)], 4);
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/* so far, 32*2 + 32 words = 384 bytes have been written.
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7 extra registers in our register set: pc, ps, cnd, lr, cnt, xer, mq */
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for (ii=1; ii <= (LAST_SP_REGNUM-FIRST_SP_REGNUM+1); ++ii) {
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write_memory (sp-384-(ii*4),
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®isters[REGISTER_BYTE (FPLAST_REGNUM + ii)], 4);
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}
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/* Save sp or so called back chain right here. */
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store_address (sp_targ, 4, sp);
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write_memory (sp-DUMMY_FRAME_SIZE, sp_targ, 4);
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sp -= DUMMY_FRAME_SIZE;
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/* And finally, this is the back chain. */
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write_memory (sp+8, pc_targ, 4);
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}
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/* Pop a dummy frame.
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In rs6000 when we push a dummy frame, we save all of the registers. This
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is usually done before user calls a function explicitly.
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After a dummy frame is pushed, some instructions are copied into stack,
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and stack pointer is decremented even more. Since we don't have a frame
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pointer to get back to the parent frame of the dummy, we start having
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trouble poping it. Therefore, we keep a dummy frame stack, keeping
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addresses of dummy frames as such. When poping happens and when we
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detect that was a dummy frame, we pop it back to its parent by using
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dummy frame stack (`dummy_frame_addr' array).
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FIXME: This whole concept is broken. You should be able to detect
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a dummy stack frame *on the user's stack itself*. When you do,
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then you know the format of that stack frame -- including its
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saved SP register! There should *not* be a separate stack in the
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GDB process that keeps track of these dummy frames! -- gnu@cygnus.com Aug92
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*/
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pop_dummy_frame ()
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{
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CORE_ADDR sp, pc;
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int ii;
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sp = dummy_frame_addr [--dummy_frame_count];
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/* restore all fpr's. */
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for (ii = 1; ii <= 32; ++ii)
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read_memory (sp-(ii*8), ®isters[REGISTER_BYTE (32-ii+FP0_REGNUM)], 8);
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|
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/* restore all gpr's */
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for (ii=1; ii <= 32; ++ii) {
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read_memory (sp-256-(ii*4), ®isters[REGISTER_BYTE (32-ii)], 4);
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}
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||
|
||
/* restore the rest of the registers. */
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for (ii=1; ii <=(LAST_SP_REGNUM-FIRST_SP_REGNUM+1); ++ii)
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read_memory (sp-384-(ii*4),
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®isters[REGISTER_BYTE (FPLAST_REGNUM + ii)], 4);
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read_memory (sp-(DUMMY_FRAME_SIZE-8),
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®isters [REGISTER_BYTE(PC_REGNUM)], 4);
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||
|
||
/* when a dummy frame was being pushed, we had to decrement %sp first, in
|
||
order to secure astack space. Thus, saved %sp (or %r1) value, is not the
|
||
one we should restore. Change it with the one we need. */
|
||
|
||
*(int*)®isters [REGISTER_BYTE(FP_REGNUM)] = sp;
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||
|
||
/* Now we can restore all registers. */
|
||
|
||
target_store_registers (-1);
|
||
pc = read_pc ();
|
||
flush_cached_frames ();
|
||
}
|
||
|
||
|
||
/* pop the innermost frame, go back to the caller. */
|
||
|
||
void
|
||
pop_frame ()
|
||
{
|
||
CORE_ADDR pc, lr, sp, prev_sp; /* %pc, %lr, %sp */
|
||
struct aix_framedata fdata;
|
||
struct frame_info *frame = get_current_frame ();
|
||
int addr, ii;
|
||
|
||
pc = read_pc ();
|
||
sp = FRAME_FP (frame);
|
||
|
||
if (stop_stack_dummy && dummy_frame_count) {
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pop_dummy_frame ();
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||
return;
|
||
}
|
||
|
||
/* Make sure that all registers are valid. */
|
||
read_register_bytes (0, NULL, REGISTER_BYTES);
|
||
|
||
/* figure out previous %pc value. If the function is frameless, it is
|
||
still in the link register, otherwise walk the frames and retrieve the
|
||
saved %pc value in the previous frame. */
|
||
|
||
addr = get_pc_function_start (frame->pc) + FUNCTION_START_OFFSET;
|
||
function_frame_info (addr, &fdata);
|
||
|
||
if (fdata.frameless)
|
||
prev_sp = sp;
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||
else
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||
prev_sp = read_memory_integer (sp, 4);
|
||
if (fdata.nosavedpc)
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||
lr = read_register (LR_REGNUM);
|
||
else
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||
lr = read_memory_integer (prev_sp+8, 4);
|
||
|
||
/* reset %pc value. */
|
||
write_register (PC_REGNUM, lr);
|
||
|
||
/* reset register values if any was saved earlier. */
|
||
addr = prev_sp - fdata.offset;
|
||
|
||
if (fdata.saved_gpr != -1)
|
||
for (ii = fdata.saved_gpr; ii <= 31; ++ii) {
|
||
read_memory (addr, ®isters [REGISTER_BYTE (ii)], 4);
|
||
addr += 4;
|
||
}
|
||
|
||
if (fdata.saved_fpr != -1)
|
||
for (ii = fdata.saved_fpr; ii <= 31; ++ii) {
|
||
read_memory (addr, ®isters [REGISTER_BYTE (ii+FP0_REGNUM)], 8);
|
||
addr += 8;
|
||
}
|
||
|
||
write_register (SP_REGNUM, prev_sp);
|
||
target_store_registers (-1);
|
||
flush_cached_frames ();
|
||
}
|
||
|
||
/* fixup the call sequence of a dummy function, with the real function address.
|
||
its argumets will be passed by gdb. */
|
||
|
||
void
|
||
fix_call_dummy(dummyname, pc, fun, nargs, type)
|
||
char *dummyname;
|
||
CORE_ADDR pc;
|
||
CORE_ADDR fun;
|
||
int nargs; /* not used */
|
||
int type; /* not used */
|
||
{
|
||
#define TOC_ADDR_OFFSET 20
|
||
#define TARGET_ADDR_OFFSET 28
|
||
|
||
int ii;
|
||
CORE_ADDR target_addr;
|
||
CORE_ADDR tocvalue;
|
||
|
||
target_addr = fun;
|
||
tocvalue = find_toc_address (target_addr);
|
||
|
||
ii = *(int*)((char*)dummyname + TOC_ADDR_OFFSET);
|
||
ii = (ii & 0xffff0000) | (tocvalue >> 16);
|
||
*(int*)((char*)dummyname + TOC_ADDR_OFFSET) = ii;
|
||
|
||
ii = *(int*)((char*)dummyname + TOC_ADDR_OFFSET+4);
|
||
ii = (ii & 0xffff0000) | (tocvalue & 0x0000ffff);
|
||
*(int*)((char*)dummyname + TOC_ADDR_OFFSET+4) = ii;
|
||
|
||
ii = *(int*)((char*)dummyname + TARGET_ADDR_OFFSET);
|
||
ii = (ii & 0xffff0000) | (target_addr >> 16);
|
||
*(int*)((char*)dummyname + TARGET_ADDR_OFFSET) = ii;
|
||
|
||
ii = *(int*)((char*)dummyname + TARGET_ADDR_OFFSET+4);
|
||
ii = (ii & 0xffff0000) | (target_addr & 0x0000ffff);
|
||
*(int*)((char*)dummyname + TARGET_ADDR_OFFSET+4) = ii;
|
||
}
|
||
|
||
|
||
/* return information about a function frame.
|
||
in struct aix_frameinfo fdata:
|
||
- frameless is TRUE, if function does not have a frame.
|
||
- nosavedpc is TRUE, if function does not save %pc value in its frame.
|
||
- offset is the number of bytes used in the frame to save registers.
|
||
- saved_gpr is the number of the first saved gpr.
|
||
- saved_fpr is the number of the first saved fpr.
|
||
- alloca_reg is the number of the register used for alloca() handling.
|
||
Otherwise -1.
|
||
*/
|
||
void
|
||
function_frame_info (pc, fdata)
|
||
CORE_ADDR pc;
|
||
struct aix_framedata *fdata;
|
||
{
|
||
unsigned int tmp;
|
||
register unsigned int op;
|
||
char buf[4];
|
||
|
||
fdata->offset = 0;
|
||
fdata->saved_gpr = fdata->saved_fpr = fdata->alloca_reg = -1;
|
||
fdata->frameless = 1;
|
||
|
||
/* Do not error out if we can't access the instructions. */
|
||
if (target_read_memory (pc, buf, 4))
|
||
return;
|
||
op = extract_unsigned_integer (buf, 4);
|
||
if (op == 0x7c0802a6) { /* mflr r0 */
|
||
pc += 4;
|
||
op = read_memory_integer (pc, 4);
|
||
fdata->nosavedpc = 0;
|
||
fdata->frameless = 0;
|
||
}
|
||
else /* else, pc is not saved */
|
||
fdata->nosavedpc = 1;
|
||
|
||
if ((op & 0xfc00003e) == 0x7c000026) { /* mfcr Rx */
|
||
pc += 4;
|
||
op = read_memory_integer (pc, 4);
|
||
fdata->frameless = 0;
|
||
}
|
||
|
||
if ((op & 0xfc000000) == 0x48000000) { /* bl foo, to save fprs??? */
|
||
pc += 4;
|
||
op = read_memory_integer (pc, 4);
|
||
/* At this point, make sure this is not a trampoline function
|
||
(a function that simply calls another functions, and nothing else).
|
||
If the next is not a nop, this branch was part of the function
|
||
prologue. */
|
||
|
||
if (op == 0x4def7b82 || /* crorc 15, 15, 15 */
|
||
op == 0x0)
|
||
return; /* prologue is over */
|
||
fdata->frameless = 0;
|
||
}
|
||
|
||
if ((op & 0xfc1f0000) == 0xd8010000) { /* stfd Rx,NUM(r1) */
|
||
pc += 4; /* store floating register double */
|
||
op = read_memory_integer (pc, 4);
|
||
fdata->frameless = 0;
|
||
}
|
||
|
||
if ((op & 0xfc1f0000) == 0xbc010000) { /* stm Rx, NUM(r1) */
|
||
int tmp2;
|
||
fdata->saved_gpr = (op >> 21) & 0x1f;
|
||
tmp2 = op & 0xffff;
|
||
if (tmp2 > 0x7fff)
|
||
tmp2 = (~0 &~ 0xffff) | tmp2;
|
||
|
||
if (tmp2 < 0) {
|
||
tmp2 = tmp2 * -1;
|
||
fdata->saved_fpr = (tmp2 - ((32 - fdata->saved_gpr) * 4)) / 8;
|
||
if ( fdata->saved_fpr > 0)
|
||
fdata->saved_fpr = 32 - fdata->saved_fpr;
|
||
else
|
||
fdata->saved_fpr = -1;
|
||
}
|
||
fdata->offset = tmp2;
|
||
pc += 4;
|
||
op = read_memory_integer (pc, 4);
|
||
fdata->frameless = 0;
|
||
}
|
||
|
||
while (((tmp = op >> 16) == 0x9001) || /* st r0, NUM(r1) */
|
||
(tmp == 0x9421) || /* stu r1, NUM(r1) */
|
||
(tmp == 0x93e1)) /* st r31, NUM(r1) */
|
||
{
|
||
int tmp2;
|
||
|
||
/* gcc takes a short cut and uses this instruction to save r31 only. */
|
||
|
||
if (tmp == 0x93e1) {
|
||
if (fdata->offset)
|
||
/* fatal ("Unrecognized prolog."); */
|
||
printf_unfiltered ("Unrecognized prolog!\n");
|
||
|
||
fdata->saved_gpr = 31;
|
||
tmp2 = op & 0xffff;
|
||
if (tmp2 > 0x7fff) {
|
||
tmp2 = - ((~0 &~ 0xffff) | tmp2);
|
||
fdata->saved_fpr = (tmp2 - ((32 - 31) * 4)) / 8;
|
||
if ( fdata->saved_fpr > 0)
|
||
fdata->saved_fpr = 32 - fdata->saved_fpr;
|
||
else
|
||
fdata->saved_fpr = -1;
|
||
}
|
||
fdata->offset = tmp2;
|
||
}
|
||
pc += 4;
|
||
op = read_memory_integer (pc, 4);
|
||
fdata->frameless = 0;
|
||
}
|
||
|
||
while ((tmp = (op >> 22)) == 0x20f) { /* l r31, ... or */
|
||
pc += 4; /* l r30, ... */
|
||
op = read_memory_integer (pc, 4);
|
||
fdata->frameless = 0;
|
||
}
|
||
|
||
/* store parameters into stack */
|
||
while(
|
||
(op & 0xfc1f0000) == 0xd8010000 || /* stfd Rx,NUM(r1) */
|
||
(op & 0xfc1f0000) == 0x90010000 || /* st r?, NUM(r1) */
|
||
(op & 0xfc000000) == 0xfc000000 || /* frsp, fp?, .. */
|
||
(op & 0xd0000000) == 0xd0000000) /* stfs, fp?, .. */
|
||
{
|
||
pc += 4; /* store fpr double */
|
||
op = read_memory_integer (pc, 4);
|
||
fdata->frameless = 0;
|
||
}
|
||
|
||
if (op == 0x603f0000 /* oril r31, r1, 0x0 */
|
||
|| op == 0x7c3f0b78) /* mr r31, r1 */
|
||
{
|
||
fdata->alloca_reg = 31;
|
||
fdata->frameless = 0;
|
||
}
|
||
}
|
||
|
||
|
||
/* Pass the arguments in either registers, or in the stack. In RS6000, the first
|
||
eight words of the argument list (that might be less than eight parameters if
|
||
some parameters occupy more than one word) are passed in r3..r11 registers.
|
||
float and double parameters are passed in fpr's, in addition to that. Rest of
|
||
the parameters if any are passed in user stack. There might be cases in which
|
||
half of the parameter is copied into registers, the other half is pushed into
|
||
stack.
|
||
|
||
If the function is returning a structure, then the return address is passed
|
||
in r3, then the first 7 words of the parametes can be passed in registers,
|
||
starting from r4. */
|
||
|
||
CORE_ADDR
|
||
push_arguments (nargs, args, sp, struct_return, struct_addr)
|
||
int nargs;
|
||
value_ptr *args;
|
||
CORE_ADDR sp;
|
||
int struct_return;
|
||
CORE_ADDR struct_addr;
|
||
{
|
||
int ii, len;
|
||
int argno; /* current argument number */
|
||
int argbytes; /* current argument byte */
|
||
char tmp_buffer [50];
|
||
value_ptr arg;
|
||
int f_argno = 0; /* current floating point argno */
|
||
|
||
CORE_ADDR saved_sp, pc;
|
||
|
||
if ( dummy_frame_count <= 0)
|
||
printf_unfiltered ("FATAL ERROR -push_arguments()! frame not found!!\n");
|
||
|
||
/* The first eight words of ther arguments are passed in registers. Copy
|
||
them appropriately.
|
||
|
||
If the function is returning a `struct', then the first word (which
|
||
will be passed in r3) is used for struct return address. In that
|
||
case we should advance one word and start from r4 register to copy
|
||
parameters. */
|
||
|
||
ii = struct_return ? 1 : 0;
|
||
|
||
for (argno=0, argbytes=0; argno < nargs && ii<8; ++ii) {
|
||
|
||
arg = args[argno];
|
||
len = TYPE_LENGTH (VALUE_TYPE (arg));
|
||
|
||
if (TYPE_CODE (VALUE_TYPE (arg)) == TYPE_CODE_FLT) {
|
||
|
||
/* floating point arguments are passed in fpr's, as well as gpr's.
|
||
There are 13 fpr's reserved for passing parameters. At this point
|
||
there is no way we would run out of them. */
|
||
|
||
if (len > 8)
|
||
printf_unfiltered (
|
||
"Fatal Error: a floating point parameter #%d with a size > 8 is found!\n", argno);
|
||
|
||
memcpy (®isters[REGISTER_BYTE(FP0_REGNUM + 1 + f_argno)], VALUE_CONTENTS (arg),
|
||
len);
|
||
++f_argno;
|
||
}
|
||
|
||
if (len > 4) {
|
||
|
||
/* Argument takes more than one register. */
|
||
while (argbytes < len) {
|
||
|
||
*(int*)®isters[REGISTER_BYTE(ii+3)] = 0;
|
||
memcpy (®isters[REGISTER_BYTE(ii+3)],
|
||
((char*)VALUE_CONTENTS (arg))+argbytes,
|
||
(len - argbytes) > 4 ? 4 : len - argbytes);
|
||
++ii, argbytes += 4;
|
||
|
||
if (ii >= 8)
|
||
goto ran_out_of_registers_for_arguments;
|
||
}
|
||
argbytes = 0;
|
||
--ii;
|
||
}
|
||
else { /* Argument can fit in one register. No problem. */
|
||
*(int*)®isters[REGISTER_BYTE(ii+3)] = 0;
|
||
memcpy (®isters[REGISTER_BYTE(ii+3)], VALUE_CONTENTS (arg), len);
|
||
}
|
||
++argno;
|
||
}
|
||
|
||
ran_out_of_registers_for_arguments:
|
||
|
||
/* location for 8 parameters are always reserved. */
|
||
sp -= 4 * 8;
|
||
|
||
/* another six words for back chain, TOC register, link register, etc. */
|
||
sp -= 24;
|
||
|
||
/* if there are more arguments, allocate space for them in
|
||
the stack, then push them starting from the ninth one. */
|
||
|
||
if ((argno < nargs) || argbytes) {
|
||
int space = 0, jj;
|
||
value_ptr val;
|
||
|
||
if (argbytes) {
|
||
space += ((len - argbytes + 3) & -4);
|
||
jj = argno + 1;
|
||
}
|
||
else
|
||
jj = argno;
|
||
|
||
for (; jj < nargs; ++jj) {
|
||
val = args[jj];
|
||
space += ((TYPE_LENGTH (VALUE_TYPE (val))) + 3) & -4;
|
||
}
|
||
|
||
/* add location required for the rest of the parameters */
|
||
space = (space + 7) & -8;
|
||
sp -= space;
|
||
|
||
/* This is another instance we need to be concerned about securing our
|
||
stack space. If we write anything underneath %sp (r1), we might conflict
|
||
with the kernel who thinks he is free to use this area. So, update %sp
|
||
first before doing anything else. */
|
||
|
||
write_register (SP_REGNUM, sp);
|
||
|
||
/* if the last argument copied into the registers didn't fit there
|
||
completely, push the rest of it into stack. */
|
||
|
||
if (argbytes) {
|
||
write_memory (
|
||
sp+24+(ii*4), ((char*)VALUE_CONTENTS (arg))+argbytes, len - argbytes);
|
||
++argno;
|
||
ii += ((len - argbytes + 3) & -4) / 4;
|
||
}
|
||
|
||
/* push the rest of the arguments into stack. */
|
||
for (; argno < nargs; ++argno) {
|
||
|
||
arg = args[argno];
|
||
len = TYPE_LENGTH (VALUE_TYPE (arg));
|
||
|
||
|
||
/* float types should be passed in fpr's, as well as in the stack. */
|
||
if (TYPE_CODE (VALUE_TYPE (arg)) == TYPE_CODE_FLT && f_argno < 13) {
|
||
|
||
if (len > 8)
|
||
printf_unfiltered (
|
||
"Fatal Error: a floating point parameter #%d with a size > 8 is found!\n", argno);
|
||
|
||
memcpy (®isters[REGISTER_BYTE(FP0_REGNUM + 1 + f_argno)], VALUE_CONTENTS (arg),
|
||
len);
|
||
++f_argno;
|
||
}
|
||
|
||
write_memory (sp+24+(ii*4), (char *) VALUE_CONTENTS (arg), len);
|
||
ii += ((len + 3) & -4) / 4;
|
||
}
|
||
}
|
||
else
|
||
/* Secure stack areas first, before doing anything else. */
|
||
write_register (SP_REGNUM, sp);
|
||
|
||
saved_sp = dummy_frame_addr [dummy_frame_count - 1];
|
||
read_memory (saved_sp, tmp_buffer, 24);
|
||
write_memory (sp, tmp_buffer, 24);
|
||
|
||
/* set back chain properly */
|
||
store_address (tmp_buffer, 4, saved_sp);
|
||
write_memory (sp, tmp_buffer, 4);
|
||
|
||
target_store_registers (-1);
|
||
return sp;
|
||
}
|
||
|
||
/* a given return value in `regbuf' with a type `valtype', extract and copy its
|
||
value into `valbuf' */
|
||
|
||
void
|
||
extract_return_value (valtype, regbuf, valbuf)
|
||
struct type *valtype;
|
||
char regbuf[REGISTER_BYTES];
|
||
char *valbuf;
|
||
{
|
||
|
||
if (TYPE_CODE (valtype) == TYPE_CODE_FLT) {
|
||
|
||
double dd; float ff;
|
||
/* floats and doubles are returned in fpr1. fpr's have a size of 8 bytes.
|
||
We need to truncate the return value into float size (4 byte) if
|
||
necessary. */
|
||
|
||
if (TYPE_LENGTH (valtype) > 4) /* this is a double */
|
||
memcpy (valbuf, ®buf[REGISTER_BYTE (FP0_REGNUM + 1)],
|
||
TYPE_LENGTH (valtype));
|
||
else { /* float */
|
||
memcpy (&dd, ®buf[REGISTER_BYTE (FP0_REGNUM + 1)], 8);
|
||
ff = (float)dd;
|
||
memcpy (valbuf, &ff, sizeof(float));
|
||
}
|
||
}
|
||
else
|
||
/* return value is copied starting from r3. */
|
||
memcpy (valbuf, ®buf[REGISTER_BYTE (3)], TYPE_LENGTH (valtype));
|
||
}
|
||
|
||
|
||
/* keep structure return address in this variable.
|
||
FIXME: This is a horrid kludge which should not be allowed to continue
|
||
living. This only allows a single nested call to a structure-returning
|
||
function. Come on, guys! -- gnu@cygnus.com, Aug 92 */
|
||
|
||
CORE_ADDR rs6000_struct_return_address;
|
||
|
||
|
||
/* Indirect function calls use a piece of trampoline code to do context
|
||
switching, i.e. to set the new TOC table. Skip such code if we are on
|
||
its first instruction (as when we have single-stepped to here).
|
||
Also skip shared library trampoline code (which is different from
|
||
indirect function call trampolines).
|
||
Result is desired PC to step until, or NULL if we are not in
|
||
trampoline code. */
|
||
|
||
CORE_ADDR
|
||
skip_trampoline_code (pc)
|
||
CORE_ADDR pc;
|
||
{
|
||
register unsigned int ii, op;
|
||
CORE_ADDR solib_target_pc;
|
||
|
||
static unsigned trampoline_code[] = {
|
||
0x800b0000, /* l r0,0x0(r11) */
|
||
0x90410014, /* st r2,0x14(r1) */
|
||
0x7c0903a6, /* mtctr r0 */
|
||
0x804b0004, /* l r2,0x4(r11) */
|
||
0x816b0008, /* l r11,0x8(r11) */
|
||
0x4e800420, /* bctr */
|
||
0x4e800020, /* br */
|
||
0
|
||
};
|
||
|
||
/* If pc is in a shared library trampoline, return its target. */
|
||
solib_target_pc = find_solib_trampoline_target (pc);
|
||
if (solib_target_pc)
|
||
return solib_target_pc;
|
||
|
||
for (ii=0; trampoline_code[ii]; ++ii) {
|
||
op = read_memory_integer (pc + (ii*4), 4);
|
||
if (op != trampoline_code [ii])
|
||
return 0;
|
||
}
|
||
ii = read_register (11); /* r11 holds destination addr */
|
||
pc = read_memory_integer (ii, 4); /* (r11) value */
|
||
return pc;
|
||
}
|
||
|
||
|
||
/* Determines whether the function FI has a frame on the stack or not.
|
||
Called from the FRAMELESS_FUNCTION_INVOCATION macro in tm.h with a
|
||
second argument of 0, and from the FRAME_SAVED_PC macro with a
|
||
second argument of 1. */
|
||
|
||
int
|
||
frameless_function_invocation (fi, pcsaved)
|
||
struct frame_info *fi;
|
||
int pcsaved;
|
||
{
|
||
CORE_ADDR func_start;
|
||
struct aix_framedata fdata;
|
||
|
||
if (fi->next != NULL)
|
||
/* Don't even think about framelessness except on the innermost frame. */
|
||
/* FIXME: Can also be frameless if fi->next->signal_handler_caller (if
|
||
a signal happens while executing in a frameless function). */
|
||
return 0;
|
||
|
||
func_start = get_pc_function_start (fi->pc) + FUNCTION_START_OFFSET;
|
||
|
||
/* If we failed to find the start of the function, it is a mistake
|
||
to inspect the instructions. */
|
||
|
||
if (!func_start)
|
||
return 0;
|
||
|
||
function_frame_info (func_start, &fdata);
|
||
return pcsaved ? fdata.nosavedpc : fdata.frameless;
|
||
}
|
||
|
||
|
||
/* If saved registers of frame FI are not known yet, read and cache them.
|
||
&FDATAP contains aix_framedata; TDATAP can be NULL,
|
||
in which case the framedata are read. */
|
||
|
||
static void
|
||
frame_get_cache_fsr (fi, fdatap)
|
||
struct frame_info *fi;
|
||
struct aix_framedata *fdatap;
|
||
{
|
||
int ii;
|
||
CORE_ADDR frame_addr;
|
||
struct aix_framedata work_fdata;
|
||
|
||
if (fi->cache_fsr)
|
||
return;
|
||
|
||
if (fdatap == NULL) {
|
||
fdatap = &work_fdata;
|
||
function_frame_info (get_pc_function_start (fi->pc), fdatap);
|
||
}
|
||
|
||
fi->cache_fsr = (struct frame_saved_regs *)
|
||
obstack_alloc (&frame_cache_obstack, sizeof (struct frame_saved_regs));
|
||
memset (fi->cache_fsr, '\0', sizeof (struct frame_saved_regs));
|
||
|
||
if (fi->prev && fi->prev->frame)
|
||
frame_addr = fi->prev->frame;
|
||
else
|
||
frame_addr = read_memory_integer (fi->frame, 4);
|
||
|
||
/* if != -1, fdatap->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 (fdatap->saved_fpr >= 0) {
|
||
for (ii=31; ii >= fdatap->saved_fpr; --ii)
|
||
fi->cache_fsr->regs [FP0_REGNUM + ii] = frame_addr - ((32 - ii) * 8);
|
||
frame_addr -= (32 - fdatap->saved_fpr) * 8;
|
||
}
|
||
|
||
/* if != -1, fdatap->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 (fdatap->saved_gpr >= 0)
|
||
for (ii=31; ii >= fdatap->saved_gpr; --ii)
|
||
fi->cache_fsr->regs [ii] = frame_addr - ((32 - ii) * 4);
|
||
}
|
||
|
||
/* Return the address of a frame. This is the inital %sp value when the frame
|
||
was first allocated. For functions calling alloca(), it might be saved in
|
||
an alloca register. */
|
||
|
||
CORE_ADDR
|
||
frame_initial_stack_address (fi)
|
||
struct frame_info *fi;
|
||
{
|
||
CORE_ADDR tmpaddr;
|
||
struct aix_framedata fdata;
|
||
struct frame_info *callee_fi;
|
||
|
||
/* if the initial stack pointer (frame address) of this frame is known,
|
||
just return it. */
|
||
|
||
if (fi->initial_sp)
|
||
return fi->initial_sp;
|
||
|
||
/* find out if this function is using an alloca register.. */
|
||
|
||
function_frame_info (get_pc_function_start (fi->pc), &fdata);
|
||
|
||
/* if saved registers of this frame are not known yet, read and cache them. */
|
||
|
||
if (!fi->cache_fsr)
|
||
frame_get_cache_fsr (fi, &fdata);
|
||
|
||
/* If no alloca register used, then fi->frame is the value of the %sp for
|
||
this frame, and it is good enough. */
|
||
|
||
if (fdata.alloca_reg < 0) {
|
||
fi->initial_sp = fi->frame;
|
||
return fi->initial_sp;
|
||
}
|
||
|
||
/* This function has an alloca register. If this is the top-most frame
|
||
(with the lowest address), the value in alloca register is good. */
|
||
|
||
if (!fi->next)
|
||
return fi->initial_sp = read_register (fdata.alloca_reg);
|
||
|
||
/* Otherwise, this is a caller frame. Callee has usually already saved
|
||
registers, but there are exceptions (such as when the callee
|
||
has no parameters). Find the address in which caller's alloca
|
||
register is saved. */
|
||
|
||
for (callee_fi = fi->next; callee_fi; callee_fi = callee_fi->next) {
|
||
|
||
if (!callee_fi->cache_fsr)
|
||
frame_get_cache_fsr (callee_fi, NULL);
|
||
|
||
/* this is the address in which alloca register is saved. */
|
||
|
||
tmpaddr = callee_fi->cache_fsr->regs [fdata.alloca_reg];
|
||
if (tmpaddr) {
|
||
fi->initial_sp = read_memory_integer (tmpaddr, 4);
|
||
return fi->initial_sp;
|
||
}
|
||
|
||
/* Go look into deeper levels of the frame chain to see if any one of
|
||
the callees has saved alloca register. */
|
||
}
|
||
|
||
/* If alloca register was not saved, by the callee (or any of its callees)
|
||
then the value in the register is still good. */
|
||
|
||
return fi->initial_sp = read_register (fdata.alloca_reg);
|
||
}
|
||
|
||
CORE_ADDR
|
||
rs6000_frame_chain (thisframe)
|
||
struct frame_info *thisframe;
|
||
{
|
||
CORE_ADDR fp;
|
||
if (inside_entry_file ((thisframe)->pc))
|
||
return 0;
|
||
if (thisframe->signal_handler_caller)
|
||
fp = read_memory_integer (thisframe->frame + SIG_FRAME_FP_OFFSET, 4);
|
||
else
|
||
fp = read_memory_integer ((thisframe)->frame, 4);
|
||
|
||
return fp;
|
||
}
|
||
|
||
/* Keep an array of load segment information and their TOC table addresses.
|
||
This info will be useful when calling a shared library function by hand. */
|
||
|
||
struct loadinfo {
|
||
CORE_ADDR textorg, dataorg;
|
||
unsigned long toc_offset;
|
||
};
|
||
|
||
#define LOADINFOLEN 10
|
||
|
||
static struct loadinfo *loadinfo = NULL;
|
||
static int loadinfolen = 0;
|
||
static int loadinfotocindex = 0;
|
||
static int loadinfotextindex = 0;
|
||
|
||
|
||
void
|
||
xcoff_init_loadinfo ()
|
||
{
|
||
loadinfotocindex = 0;
|
||
loadinfotextindex = 0;
|
||
|
||
if (loadinfolen == 0) {
|
||
loadinfo = (struct loadinfo *)
|
||
xmalloc (sizeof (struct loadinfo) * LOADINFOLEN);
|
||
loadinfolen = LOADINFOLEN;
|
||
}
|
||
}
|
||
|
||
|
||
/* FIXME -- this is never called! */
|
||
void
|
||
free_loadinfo ()
|
||
{
|
||
if (loadinfo)
|
||
free (loadinfo);
|
||
loadinfo = NULL;
|
||
loadinfolen = 0;
|
||
loadinfotocindex = 0;
|
||
loadinfotextindex = 0;
|
||
}
|
||
|
||
/* this is called from xcoffread.c */
|
||
|
||
void
|
||
xcoff_add_toc_to_loadinfo (unsigned long tocoff)
|
||
{
|
||
while (loadinfotocindex >= loadinfolen) {
|
||
loadinfolen += LOADINFOLEN;
|
||
loadinfo = (struct loadinfo *)
|
||
xrealloc (loadinfo, sizeof(struct loadinfo) * loadinfolen);
|
||
}
|
||
loadinfo [loadinfotocindex++].toc_offset = tocoff;
|
||
}
|
||
|
||
void
|
||
add_text_to_loadinfo (textaddr, dataaddr)
|
||
CORE_ADDR textaddr;
|
||
CORE_ADDR dataaddr;
|
||
{
|
||
while (loadinfotextindex >= loadinfolen) {
|
||
loadinfolen += LOADINFOLEN;
|
||
loadinfo = (struct loadinfo *)
|
||
xrealloc (loadinfo, sizeof(struct loadinfo) * loadinfolen);
|
||
}
|
||
loadinfo [loadinfotextindex].textorg = textaddr;
|
||
loadinfo [loadinfotextindex].dataorg = dataaddr;
|
||
++loadinfotextindex;
|
||
}
|
||
|
||
|
||
/* FIXME: This assumes that the "textorg" and "dataorg" elements
|
||
of a member of this array are correlated with the "toc_offset"
|
||
element of the same member. But they are sequentially assigned in wildly
|
||
different places, and probably there is no correlation. FIXME! */
|
||
|
||
static CORE_ADDR
|
||
find_toc_address (pc)
|
||
CORE_ADDR pc;
|
||
{
|
||
int ii, toc_entry, tocbase = 0;
|
||
|
||
for (ii=0; ii < loadinfotextindex; ++ii)
|
||
if (pc > loadinfo[ii].textorg && loadinfo[ii].textorg > tocbase) {
|
||
toc_entry = ii;
|
||
tocbase = loadinfo[ii].textorg;
|
||
}
|
||
|
||
return loadinfo[toc_entry].dataorg + loadinfo[toc_entry].toc_offset;
|
||
}
|
||
|
||
void
|
||
_initialize_rs6000_tdep ()
|
||
{
|
||
/* FIXME, this should not be decided via ifdef. */
|
||
#ifdef GDB_TARGET_POWERPC
|
||
tm_print_insn = print_insn_big_powerpc;
|
||
#else
|
||
tm_print_insn = print_insn_rs6000;
|
||
#endif
|
||
}
|