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/* Print DEC PDP-11 instructions.
Copyright (C) 2001-2022 Free Software Foundation, Inc.
This file is part of the GNU opcodes library.
This library 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 3, or (at your option)
any later version.
It 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., 51 Franklin Street - Fifth Floor, Boston,
MA 02110-1301, USA. */
#include "sysdep.h"
#include "disassemble.h"
#include "opcode/pdp11.h"
#define AFTER_INSTRUCTION "\t"
#define OPERAND_SEPARATOR ", "
#define JUMP 0x1000 /* Flag that this operand is used in a jump. */
#define FPRINTF (*info->fprintf_func)
#define F info->stream
/* Sign-extend a 16-bit number in an int. */
#define sign_extend(x) ((((x) & 0xffff) ^ 0x8000) - 0x8000)
static int
read_word (bfd_vma memaddr, int *word, disassemble_info *info)
{
int status;
bfd_byte x[2];
status = (*info->read_memory_func) (memaddr, x, 2, info);
if (status != 0)
return -1;
*word = x[1] << 8 | x[0];
return 0;
}
static void
print_signed_octal (int n, disassemble_info *info)
{
if (n < 0)
FPRINTF (F, "-%o", -n);
else
FPRINTF (F, "%o", n);
}
static void
print_reg (int reg, disassemble_info *info)
{
/* Mask off the addressing mode, if any. */
reg &= 7;
switch (reg)
{
case 0: case 1: case 2: case 3: case 4: case 5:
FPRINTF (F, "r%d", reg); break;
case 6: FPRINTF (F, "sp"); break;
case 7: FPRINTF (F, "pc"); break;
default: ; /* error */
}
}
static void
print_freg (int freg, disassemble_info *info)
{
FPRINTF (F, "fr%d", freg);
}
static int
print_operand (bfd_vma *memaddr, int code, disassemble_info *info)
{
int mode = (code >> 3) & 7;
int reg = code & 7;
int disp;
switch (mode)
{
case 0:
print_reg (reg, info);
break;
case 1:
FPRINTF (F, "(");
print_reg (reg, info);
FPRINTF (F, ")");
break;
case 2:
if (reg == 7)
{
int data;
if (read_word (*memaddr, &data, info) < 0)
return -1;
FPRINTF (F, "$");
print_signed_octal (sign_extend (data), info);
*memaddr += 2;
}
else
{
FPRINTF (F, "(");
print_reg (reg, info);
FPRINTF (F, ")+");
}
break;
case 3:
if (reg == 7)
{
int address;
if (read_word (*memaddr, &address, info) < 0)
return -1;
FPRINTF (F, "*$%o", address);
*memaddr += 2;
}
else
{
FPRINTF (F, "*(");
print_reg (reg, info);
FPRINTF (F, ")+");
}
break;
case 4:
FPRINTF (F, "-(");
print_reg (reg, info);
FPRINTF (F, ")");
break;
case 5:
FPRINTF (F, "*-(");
print_reg (reg, info);
FPRINTF (F, ")");
break;
case 6:
case 7:
if (read_word (*memaddr, &disp, info) < 0)
return -1;
*memaddr += 2;
if (reg == 7)
{
bfd_vma address = *memaddr + sign_extend (disp);
if (mode == 7)
FPRINTF (F, "*");
if (!(code & JUMP))
FPRINTF (F, "$");
(*info->print_address_func) (address, info);
}
else
{
if (mode == 7)
FPRINTF (F, "*");
print_signed_octal (sign_extend (disp), info);
FPRINTF (F, "(");
print_reg (reg, info);
FPRINTF (F, ")");
}
break;
}
return 0;
}
static int
print_foperand (bfd_vma *memaddr, int code, disassemble_info *info)
{
int mode = (code >> 3) & 7;
int reg = code & 7;
if (mode == 0)
print_freg (reg, info);
else
return print_operand (memaddr, code, info);
return 0;
}
/* Print the PDP-11 instruction at address MEMADDR in debugged memory,
on INFO->STREAM. Returns length of the instruction, in bytes. */
int
print_insn_pdp11 (bfd_vma memaddr, disassemble_info *info)
{
bfd_vma start_memaddr = memaddr;
int opcode;
int src, dst;
int i;
info->bytes_per_line = 6;
info->bytes_per_chunk = 2;
info->display_endian = BFD_ENDIAN_LITTLE;
if (read_word (memaddr, &opcode, info) != 0)
return -1;
memaddr += 2;
src = (opcode >> 6) & 0x3f;
dst = opcode & 0x3f;
for (i = 0; i < pdp11_num_opcodes; i++)
{
#define OP pdp11_opcodes[i]
if ((opcode & OP.mask) == OP.opcode)
switch (OP.type)
{
case PDP11_OPCODE_NO_OPS:
FPRINTF (F, "%s", OP.name);
goto done;
case PDP11_OPCODE_REG:
FPRINTF (F, "%s", OP.name);
FPRINTF (F, AFTER_INSTRUCTION);
print_reg (dst, info);
goto done;
case PDP11_OPCODE_OP:
FPRINTF (F, "%s", OP.name);
FPRINTF (F, AFTER_INSTRUCTION);
if (strcmp (OP.name, "jmp") == 0)
dst |= JUMP;
if (print_operand (&memaddr, dst, info) < 0)
return -1;
goto done;
case PDP11_OPCODE_FOP:
FPRINTF (F, "%s", OP.name);
FPRINTF (F, AFTER_INSTRUCTION);
if (strcmp (OP.name, "jmp") == 0)
dst |= JUMP;
if (print_foperand (&memaddr, dst, info) < 0)
return -1;
goto done;
case PDP11_OPCODE_REG_OP:
FPRINTF (F, "%s", OP.name);
FPRINTF (F, AFTER_INSTRUCTION);
print_reg (src, info);
FPRINTF (F, OPERAND_SEPARATOR);
if (strcmp (OP.name, "jsr") == 0)
dst |= JUMP;
if (print_operand (&memaddr, dst, info) < 0)
return -1;
goto done;
case PDP11_OPCODE_REG_OP_REV:
FPRINTF (F, "%s", OP.name);
FPRINTF (F, AFTER_INSTRUCTION);
if (print_operand (&memaddr, dst, info) < 0)
return -1;
FPRINTF (F, OPERAND_SEPARATOR);
print_reg (src, info);
goto done;
case PDP11_OPCODE_AC_FOP:
{
int ac = (opcode & 0xe0) >> 6;
FPRINTF (F, "%s", OP.name);
FPRINTF (F, AFTER_INSTRUCTION);
print_freg (ac, info);
FPRINTF (F, OPERAND_SEPARATOR);
if (print_foperand (&memaddr, dst, info) < 0)
return -1;
goto done;
}
case PDP11_OPCODE_FOP_AC:
{
int ac = (opcode & 0xe0) >> 6;
FPRINTF (F, "%s", OP.name);
FPRINTF (F, AFTER_INSTRUCTION);
if (print_foperand (&memaddr, dst, info) < 0)
return -1;
FPRINTF (F, OPERAND_SEPARATOR);
print_freg (ac, info);
goto done;
}
case PDP11_OPCODE_AC_OP:
{
int ac = (opcode & 0xe0) >> 6;
FPRINTF (F, "%s", OP.name);
FPRINTF (F, AFTER_INSTRUCTION);
print_freg (ac, info);
FPRINTF (F, OPERAND_SEPARATOR);
if (print_operand (&memaddr, dst, info) < 0)
return -1;
goto done;
}
case PDP11_OPCODE_OP_AC:
{
int ac = (opcode & 0xe0) >> 6;
FPRINTF (F, "%s", OP.name);
FPRINTF (F, AFTER_INSTRUCTION);
if (print_operand (&memaddr, dst, info) < 0)
return -1;
FPRINTF (F, OPERAND_SEPARATOR);
print_freg (ac, info);
goto done;
}
case PDP11_OPCODE_OP_OP:
FPRINTF (F, "%s", OP.name);
FPRINTF (F, AFTER_INSTRUCTION);
if (print_operand (&memaddr, src, info) < 0)
return -1;
FPRINTF (F, OPERAND_SEPARATOR);
if (print_operand (&memaddr, dst, info) < 0)
return -1;
goto done;
case PDP11_OPCODE_DISPL:
{
int displ = (opcode & 0xff) << 8;
bfd_vma address = memaddr + (sign_extend (displ) >> 7);
FPRINTF (F, "%s", OP.name);
FPRINTF (F, AFTER_INSTRUCTION);
(*info->print_address_func) (address, info);
goto done;
}
case PDP11_OPCODE_REG_DISPL:
{
int displ = (opcode & 0x3f) << 10;
bfd_vma address = memaddr - (displ >> 9);
FPRINTF (F, "%s", OP.name);
FPRINTF (F, AFTER_INSTRUCTION);
print_reg (src, info);
FPRINTF (F, OPERAND_SEPARATOR);
(*info->print_address_func) (address, info);
goto done;
}
case PDP11_OPCODE_IMM8:
{
int code = opcode & 0xff;
FPRINTF (F, "%s", OP.name);
FPRINTF (F, AFTER_INSTRUCTION);
FPRINTF (F, "%o", code);
goto done;
}
case PDP11_OPCODE_IMM6:
{
int code = opcode & 0x3f;
FPRINTF (F, "%s", OP.name);
FPRINTF (F, AFTER_INSTRUCTION);
FPRINTF (F, "%o", code);
goto done;
}
case PDP11_OPCODE_IMM3:
{
int code = opcode & 7;
FPRINTF (F, "%s", OP.name);
FPRINTF (F, AFTER_INSTRUCTION);
FPRINTF (F, "%o", code);
goto done;
}
case PDP11_OPCODE_ILLEGAL:
{
FPRINTF (F, ".word");
FPRINTF (F, AFTER_INSTRUCTION);
FPRINTF (F, "%o", opcode);
goto done;
}
default:
/* TODO: is this a proper way of signalling an error? */
FPRINTF (F, "<internal error: unrecognized instruction type>");
return -1;
}
#undef OP
}
done:
return memaddr - start_memaddr;
}
|
