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arm-pinsn.c
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C/C++ Source or Header
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1992-09-11
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7KB
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272 lines
/* Print ARM instructions for GDB, the GNU debugger.
Copyright (C) 1986, 1989 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., 675 Mass Ave, Cambridge, MA 02139, USA. */
#include <stdio.h>
#include <ctype.h>
#include <assert.h>
#include "defs.h"
#include "param.h"
#include "symtab.h"
#include "arm-opcode.h"
extern char *reg_names[];
static char *shift_names[] = {
"lsl", "lsr", "asr", "ror",
};
static char *cond_names[] = {
"eq", "ne", "cs", "cc", "mi", "pl", "vs", "vc",
"hi", "ls", "ge", "lt", "gt", "le", "", "nv"
};
static char float_precision[] = "sdep";
static char float_rounding[] = " pmz";
static float float_immed[] = { 0.0, 1.0, 2.0, 3.0, 4.0, 5.0, 0.5, 10.0 };
static void print_ldr_str_offset();
static void print_ldc_stc_offset();
static long immediate_value();
/* Print the ARM instruction at address MEMADDR in debugged memory,
on STREAM. Returns length of the instruction, in bytes. */
int
print_insn (memaddr, stream)
CORE_ADDR memaddr;
FILE *stream;
{
unsigned long ins;
register struct opcode *op;
register char *p;
register int i, c;
int s, e, val;
ins = read_memory_integer(memaddr, 4);
for (i = 0, op = opcodes; i < N_OPCODES; i++, op++)
if ((ins & op->mask) == op->value) break;
assert(i != N_OPCODES);
for (p = op->assembler; *p;) {
c = *p++;
if (c == '%') {
s = e = 0;
while (isdigit(*p))
s = s*10 + (*p++ - '0');
if (*p == '-') {
p++;
while (isdigit(*p))
e = e*10 + (*p++ - '0');
} else
e = s;
assert(s >= 0 && s <= 31 && e >= 0 && e <= 31);
val = (ins >> s) & ((1 << (e + 1 - s)) - 1);
switch (*p++) {
case '%' :
putc('%', stream);
break;
case 'd' :
fprintf(stream, "%d", val);
break;
case 'x' :
fprintf(stream, "%x", val);
break;
case 'r' :
assert(val >= 0 && val <= 15);
fprintf(stream, "%s", reg_names[val]);
break;
case 'c' :
fprintf(stream, "%s", cond_names[ins >> 28]);
break;
case '\'' :
assert(*p);
c = *p++;
if (val)
putc(c, stream);
break;
case '`' :
assert(*p);
c = *p++;
if (!val)
putc(c, stream);
break;
case '?' :
assert(*p);
c = *p++;
assert(*p);
if (val)
p++;
else
c = *p++;
putc(c, stream);
break;
case 'p' :
if (((ins >> 12) & 0xf) == 0xf)
putc('p', stream);
break;
case 'o' :
if (ins & (1<<25)) {
int immed = immediate_value(ins & 0xfff);
fprintf (stream, "#%d (0x%x)", immed, immed);
} else {
int operand2 = ins & 0xfff;
/* in operand2 :
bits 0-3 are the base register
bits 5-6 are the shift (0=lsl, 1=lsr, 2=asr, 3=ror)
if bit 4 is zero then bits 7-11 are an immediate shift count
else bit 7 must be zero and bits 8-11 are the register
to be used as a shift count.
Note: no shift at all is encoded as "reg lsl #0" */
fprintf (stream, "%s", reg_names[operand2 & 0xf]);
if (operand2 & 0xff0) {
/* ror #0 is really rrx (rotate right extend) */
if ((operand2 & 0xff0) == 0x060)
fprintf (stream, ", rrx");
else {
fprintf (stream, ", %s ",
shift_names[(operand2 >> 5) & 3]);
if (operand2 & (1<<4)) /* register shift */
fprintf (stream, "%s",
reg_names[operand2 >> 8]);
else /* immediate shift */
fprintf (stream, "#%d",
operand2 >> 7);
}
}
}
break;
case 'a' :
fprintf (stream, "[%s", reg_names[(ins >> 16) & 0xf]);
if (ins & (1<<24)) {
fprintf (stream, ", ");
print_ldr_str_offset (ins, stream);
putc (']', stream);
if (ins & (1<<21)) putc('!', stream);
/* If it is a pc relative load, then it is probably
a constant so print it */
if (((ins >> 16) & 0xf) == 15 &&
(ins & (1<<25)) == 0 &&
(ins & (1<<20))) {
int addr = memaddr + 8 +
(ins & 0xfff) * ((ins & (1<<23)) ? 1 : -1);
fprintf (stream, " (contents=");
print_address (read_memory_integer(addr, 4), stream);
fprintf (stream, ")");
}
} else {
fprintf (stream, "]," );
print_ldr_str_offset (ins, stream);
}
break;
case 'b' :
print_address (memaddr + 8 + (((int)ins << 8) >> 6), stream);
break;
case 'A' :
fprintf (stream, "[%s", reg_names[(ins >> 16) & 0xf]);
if (ins & (1<<24)) {
fprintf (stream, ", ");
print_ldc_stc_offset (ins, stream);
putc(']', stream);
if (ins & (1<<21))
putc('!', stream);
} else {
fprintf (stream, "], ");
print_ldc_stc_offset (ins, stream);
}
break;
case 'm' :
{
int regnum, first = 1;
putc('{', stream);
for (regnum = 0; regnum < 16; regnum++)
if (ins & (1<<regnum)) {
if (!first)
putc (',', stream);
first = 0;
fprintf (stream, "%s", reg_names[regnum]);
}
putc('}', stream);
}
break;
case 'P' :
val = ((ins >> 18) & 2) | ((ins >> 7) & 1);
putc(float_precision[val], stream);
break;
case 'Q' :
val = ((ins >> 21) & 2) | ((ins >> 15) & 1);
putc(float_precision[val], stream);
break;
case 'R' :
val = ((ins >> 5) & 3);
if (val) putc(float_rounding[val], stream);
break;
case 'f' :
assert(val >= 0 && val <= 15);
if (val > 7)
fprintf (stream, "#%3.1f", float_immed[val - 8]);
else
fprintf (stream, "f%d", val);
break;
default:
abort();
}
} else
putc(c, stream);
}
return 4;
}
static long
immediate_value(operand)
int operand;
{
int val = operand & 0xff;
int shift = 2*(operand >> 8);
/* immediate value is (val ror shift) */
return (val >> shift) | (val << (32 - shift));
}
static void
print_ldr_str_offset(ins, stream)
unsigned long ins;
FILE *stream;
{
if ((ins & (1<<25)) == 0)
fprintf (stream, "#%d",
(ins & 0xfff) * ((ins & (1<<23)) ? 1 : -1));
else {
fprintf (stream, "%s%s", reg_names[ins & 0xf],
(ins & (1<<23)) ? "" : "-");
if (ins & 0xff0)
fprintf (stream, ", %s #%d",
shift_names[(ins >> 5) & 3],
(ins >> 7) & 0x1f);
}
}
static void
print_ldc_stc_offset(ins, stream)
unsigned long ins;
FILE *stream;
{
fprintf (stream, "#%d",
4 * (ins & 0xff) * ((ins & (1<<23)) ? 1 : -1));
}