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354 lines
9.7 KiB
C
354 lines
9.7 KiB
C
/* s390-dis.c -- Disassemble S390 instructions
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Copyright (C) 2000-2016 Free Software Foundation, Inc.
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Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com).
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This file is part of the GNU opcodes library.
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This library 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 3, or (at your option)
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any later version.
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It is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
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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 file; see the file COPYING. If not, write to the
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Free Software Foundation, 51 Franklin Street - Fifth Floor, Boston,
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MA 02110-1301, USA. */
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#include "sysdep.h"
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#include <stdio.h>
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#include "ansidecl.h"
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#include "dis-asm.h"
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#include "opintl.h"
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#include "opcode/s390.h"
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static int init_flag = 0;
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static int opc_index[256];
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static int current_arch_mask = 0;
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/* Set up index table for first opcode byte. */
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static void
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init_disasm (struct disassemble_info *info)
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{
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int i;
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const char *p;
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memset (opc_index, 0, sizeof (opc_index));
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/* Reverse order, such that each opc_index ends up pointing to the
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first matching entry instead of the last. */
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for (i = s390_num_opcodes; i--; )
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opc_index[s390_opcodes[i].opcode[0]] = i;
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for (p = info->disassembler_options; p != NULL; )
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{
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if (CONST_STRNEQ (p, "esa"))
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current_arch_mask = 1 << S390_OPCODE_ESA;
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else if (CONST_STRNEQ (p, "zarch"))
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current_arch_mask = 1 << S390_OPCODE_ZARCH;
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else
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fprintf (stderr, "Unknown S/390 disassembler option: %s\n", p);
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p = strchr (p, ',');
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if (p != NULL)
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p++;
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}
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if (!current_arch_mask)
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current_arch_mask = 1 << S390_OPCODE_ZARCH;
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init_flag = 1;
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}
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/* Derive the length of an instruction from its first byte. */
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static inline int
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s390_insn_length (const bfd_byte *buffer)
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{
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/* 00xxxxxx -> 2, 01xxxxxx/10xxxxxx -> 4, 11xxxxxx -> 6. */
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return ((buffer[0] >> 6) + 3) & ~1U;
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}
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/* Match the instruction in BUFFER against the given OPCODE, excluding
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the first byte. */
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static inline int
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s390_insn_matches_opcode (const bfd_byte *buffer,
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const struct s390_opcode *opcode)
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{
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return (buffer[1] & opcode->mask[1]) == opcode->opcode[1]
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&& (buffer[2] & opcode->mask[2]) == opcode->opcode[2]
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&& (buffer[3] & opcode->mask[3]) == opcode->opcode[3]
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&& (buffer[4] & opcode->mask[4]) == opcode->opcode[4]
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&& (buffer[5] & opcode->mask[5]) == opcode->opcode[5];
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}
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union operand_value
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{
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int i;
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unsigned int u;
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};
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/* Extracts an operand value from an instruction. */
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/* We do not perform the shift operation for larl-type address
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operands here since that would lead to an overflow of the 32 bit
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integer value. Instead the shift operation is done when printing
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the operand. */
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static inline union operand_value
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s390_extract_operand (const bfd_byte *insn,
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const struct s390_operand *operand)
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{
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union operand_value ret;
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unsigned int val;
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int bits;
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const bfd_byte *orig_insn = insn;
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/* Extract fragments of the operand byte for byte. */
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insn += operand->shift / 8;
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bits = (operand->shift & 7) + operand->bits;
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val = 0;
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do
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{
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val <<= 8;
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val |= (unsigned int) *insn++;
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bits -= 8;
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}
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while (bits > 0);
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val >>= -bits;
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val &= ((1U << (operand->bits - 1)) << 1) - 1;
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/* Check for special long displacement case. */
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if (operand->bits == 20 && operand->shift == 20)
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val = (val & 0xff) << 12 | (val & 0xfff00) >> 8;
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/* Sign extend value if the operand is signed or pc relative. Avoid
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integer overflows. */
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if (operand->flags & (S390_OPERAND_SIGNED | S390_OPERAND_PCREL))
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{
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unsigned int m = 1U << (operand->bits - 1);
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if (val >= m)
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ret.i = (int) (val - m) - 1 - (int) (m - 1U);
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else
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ret.i = (int) val;
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}
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else if (operand->flags & S390_OPERAND_LENGTH)
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/* Length x in an instruction has real length x + 1. */
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ret.u = val + 1;
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else if (operand->flags & S390_OPERAND_VR)
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{
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/* Extract the extra bits for a vector register operand stored
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in the RXB field. */
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unsigned vr = operand->shift == 32 ? 3
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: (unsigned) operand->shift / 4 - 2;
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ret.u = val | ((orig_insn[4] & (1 << (3 - vr))) << (vr + 1));
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}
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else
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ret.u = val;
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return ret;
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}
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/* Print the S390 instruction in BUFFER, assuming that it matches the
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given OPCODE. */
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static void
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s390_print_insn_with_opcode (bfd_vma memaddr,
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struct disassemble_info *info,
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const bfd_byte *buffer,
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const struct s390_opcode *opcode)
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{
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const unsigned char *opindex;
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char separator;
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/* Mnemonic. */
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info->fprintf_func (info->stream, "%s", opcode->name);
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/* Operands. */
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separator = '\t';
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for (opindex = opcode->operands; *opindex != 0; opindex++)
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{
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const struct s390_operand *operand = s390_operands + *opindex;
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union operand_value val = s390_extract_operand (buffer, operand);
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unsigned long flags = operand->flags;
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if ((flags & S390_OPERAND_INDEX) && val.u == 0)
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continue;
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if ((flags & S390_OPERAND_BASE) &&
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val.u == 0 && separator == '(')
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{
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separator = ',';
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continue;
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}
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/* For instructions with a last optional operand don't print it
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if zero. */
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if ((opcode->flags & S390_INSTR_FLAG_OPTPARM)
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&& val.u == 0
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&& opindex[1] == 0)
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break;
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if (flags & S390_OPERAND_GPR)
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info->fprintf_func (info->stream, "%c%%r%u", separator, val.u);
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else if (flags & S390_OPERAND_FPR)
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info->fprintf_func (info->stream, "%c%%f%u", separator, val.u);
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else if (flags & S390_OPERAND_VR)
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info->fprintf_func (info->stream, "%c%%v%i", separator, val.u);
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else if (flags & S390_OPERAND_AR)
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info->fprintf_func (info->stream, "%c%%a%u", separator, val.u);
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else if (flags & S390_OPERAND_CR)
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info->fprintf_func (info->stream, "%c%%c%u", separator, val.u);
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else if (flags & S390_OPERAND_PCREL)
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{
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info->fprintf_func (info->stream, "%c", separator);
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info->print_address_func (memaddr + val.i + val.i, info);
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}
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else if (flags & S390_OPERAND_SIGNED)
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info->fprintf_func (info->stream, "%c%i", separator, val.i);
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else
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{
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if (flags & S390_OPERAND_OR1)
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val.u &= ~1;
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if (flags & S390_OPERAND_OR2)
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val.u &= ~2;
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if (flags & S390_OPERAND_OR8)
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val.u &= ~8;
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if ((opcode->flags & S390_INSTR_FLAG_OPTPARM)
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&& val.u == 0
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&& opindex[1] == 0)
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break;
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info->fprintf_func (info->stream, "%c%u", separator, val.u);
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}
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if (flags & S390_OPERAND_DISP)
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separator = '(';
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else if (flags & S390_OPERAND_BASE)
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{
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info->fprintf_func (info->stream, ")");
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separator = ',';
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}
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else
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separator = ',';
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}
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}
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/* Check whether opcode A's mask is more specific than that of B. */
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static int
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opcode_mask_more_specific (const struct s390_opcode *a,
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const struct s390_opcode *b)
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{
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return (((int) a->mask[0] + a->mask[1] + a->mask[2]
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+ a->mask[3] + a->mask[4] + a->mask[5])
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> ((int) b->mask[0] + b->mask[1] + b->mask[2]
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+ b->mask[3] + b->mask[4] + b->mask[5]));
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}
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/* Print a S390 instruction. */
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int
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print_insn_s390 (bfd_vma memaddr, struct disassemble_info *info)
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{
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bfd_byte buffer[6];
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const struct s390_opcode *opcode = NULL;
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unsigned int value;
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int status, opsize, bufsize;
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if (init_flag == 0)
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init_disasm (info);
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/* The output looks better if we put 6 bytes on a line. */
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info->bytes_per_line = 6;
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/* Every S390 instruction is max 6 bytes long. */
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memset (buffer, 0, 6);
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status = info->read_memory_func (memaddr, buffer, 6, info);
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if (status != 0)
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{
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for (bufsize = 0; bufsize < 6; bufsize++)
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if (info->read_memory_func (memaddr, buffer, bufsize + 1, info) != 0)
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break;
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if (bufsize <= 0)
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{
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info->memory_error_func (status, memaddr, info);
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return -1;
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}
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opsize = s390_insn_length (buffer);
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status = opsize > bufsize;
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}
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else
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{
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bufsize = 6;
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opsize = s390_insn_length (buffer);
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}
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if (status == 0)
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{
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const struct s390_opcode *op;
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/* Find the "best match" in the opcode table. */
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for (op = s390_opcodes + opc_index[buffer[0]];
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op != s390_opcodes + s390_num_opcodes
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&& op->opcode[0] == buffer[0];
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op++)
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{
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if ((op->modes & current_arch_mask)
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&& s390_insn_matches_opcode (buffer, op)
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&& (opcode == NULL
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|| opcode_mask_more_specific (op, opcode)))
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opcode = op;
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}
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}
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if (opcode != NULL)
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{
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/* The instruction is valid. Print it and return its size. */
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s390_print_insn_with_opcode (memaddr, info, buffer, opcode);
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return opsize;
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}
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/* Fall back to hex print. */
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if (bufsize >= 4)
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{
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value = (unsigned int) buffer[0];
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value = (value << 8) + (unsigned int) buffer[1];
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value = (value << 8) + (unsigned int) buffer[2];
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value = (value << 8) + (unsigned int) buffer[3];
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info->fprintf_func (info->stream, ".long\t0x%08x", value);
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return 4;
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}
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else if (bufsize >= 2)
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{
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value = (unsigned int) buffer[0];
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value = (value << 8) + (unsigned int) buffer[1];
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info->fprintf_func (info->stream, ".short\t0x%04x", value);
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return 2;
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}
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else
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{
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value = (unsigned int) buffer[0];
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info->fprintf_func (info->stream, ".byte\t0x%02x", value);
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return 1;
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}
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}
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void
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print_s390_disassembler_options (FILE *stream)
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{
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fprintf (stream, _("\n\
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The following S/390 specific disassembler options are supported for use\n\
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with the -M switch (multiple options should be separated by commas):\n"));
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fprintf (stream, _(" esa Disassemble in ESA architecture mode\n"));
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fprintf (stream, _(" zarch Disassemble in z/Architecture mode\n"));
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}
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