opcodes/s390-dis.c

   1 /* s390-dis.c -- Disassemble S390 instructions
   2    Copyright (C) 2000, 2001 Free Software Foundation, Inc.
   3    Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com).
   4
   5    This file is part of GDB, GAS and the GNU binutils.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  20    02111-1307, USA.  */
  21
  22 #include <stdio.h>
  23 #include "ansidecl.h"
  24 #include "sysdep.h"
  25 #include "dis-asm.h"
  26 #include "opcode/s390.h"
  27
  28 static int init_flag = 0;
  29 static int opc_index[256];
  30 static int current_arch_mask = 0;
  31
  32 /* Set up index table for first opcode byte */
  33 static void
  34 init_disasm(info)
  35     struct disassemble_info *info ATTRIBUTE_UNUSED;
  36 {
  37   const struct s390_opcode *opcode;
  38   const struct s390_opcode *opcode_end;
  39
  40   memset(opc_index, 0, sizeof(opc_index));
  41   opcode_end = s390_opcodes + s390_num_opcodes;
  42   for (opcode = s390_opcodes; opcode < opcode_end; opcode++) {
  43     opc_index[(int) opcode->opcode[0]] = opcode - s390_opcodes;
  44     while ((opcode < opcode_end) &&
  45            (opcode[1].opcode[0] == opcode->opcode[0]))
  46       opcode++;
  47   }
  48   switch (info->mach) {
  49   case bfd_mach_s390_esa:
  50     current_arch_mask = 1 << S390_OPCODE_ESA;
  51     break;
  52   case bfd_mach_s390_esame:
  53     current_arch_mask = 1 << S390_OPCODE_ESAME;
  54     break;
  55   default:
  56     abort();
  57   }
  58   init_flag = 1;
  59 }
  60
  61 /* Extracts an operand value from an instruction.  */
  62
  63 static inline unsigned int
  64 s390_extract_operand (insn, operand)
  65      unsigned char *insn;
  66      const struct s390_operand *operand;
  67 {
  68   unsigned int val;
  69   int bits;
  70
  71   /* extract fragments of the operand byte for byte */
  72   insn += operand->shift/8;
  73   bits = (operand->shift & 7) + operand->bits;
  74   val = 0;
  75   do {
  76     val <<= 8;
  77     val |= (unsigned int) *insn++;
  78     bits -= 8;
  79   } while (bits > 0);
  80   val >>= -bits;
  81   val &= ((1U << (operand->bits-1))<<1) - 1;
  82
  83   /* sign extend value if the operand is signed or pc relative */
  84   if ((operand->flags & (S390_OPERAND_SIGNED|S390_OPERAND_PCREL)) &&
  85       (val & (1U << (operand->bits-1))))
  86     val |= (-1U << (operand->bits-1))<<1;
  87
  88   /* double value if the operand is pc relative */
  89   if (operand->flags & S390_OPERAND_PCREL)
  90     val <<= 1;
  91
  92   /* length x in an instructions has real length x+1 */
  93   if (operand->flags & S390_OPERAND_LENGTH)
  94     val++;
  95   return val;
  96 }
  97
  98 /* Print a S390 instruction.  */
  99
 100 int
 101 print_insn_s390 (memaddr, info)
 102      bfd_vma memaddr;
 103      struct disassemble_info *info;
 104 {
 105   bfd_byte buffer[6];
 106   const struct s390_opcode *opcode;
 107   const struct s390_opcode *opcode_end;
 108   unsigned int value;
 109   int status, opsize, bufsize;
 110   char separator;
 111
 112   if (init_flag == 0)
 113     init_disasm(info);
 114
 115   /* The output looks better if we put 6 bytes on a line.  */
 116   info->bytes_per_line = 6;
 117
 118   /* Every S390 instruction is max 6 bytes long.  */
 119   memset(buffer, 0, 6);
 120   status = (*info->read_memory_func) (memaddr, buffer, 6, info);
 121   if (status != 0) {
 122     for (bufsize = 0; bufsize < 6; bufsize++)
 123       if ((*info->read_memory_func) (memaddr, buffer, bufsize+1, info) != 0)
 124         break;
 125     if (bufsize <= 0) {
 126       (*info->memory_error_func) (status, memaddr, info);
 127       return -1;
 128     }
 129     /* Opsize calculation looks strange but it works
 130        00xxxxxx -> 2 bytes, 01xxxxxx/10xxxxxx -> 4 bytes,
 131        11xxxxxx -> 6 bytes.  */
 132     opsize = ((((buffer[0]>>6)+1)>>1)+1)<<1;
 133     status = opsize > bufsize;
 134   } else {
 135     bufsize = 6;
 136     opsize = ((((buffer[0]>>6)+1)>>1)+1)<<1;
 137   }
 138
 139   if (status == 0) {
 140     /* Find the first match in the opcode table.  */
 141     opcode_end = s390_opcodes + s390_num_opcodes;
 142     for (opcode = s390_opcodes + opc_index[(int) buffer[0]];
 143          (opcode < opcode_end) && (buffer[0] == opcode->opcode[0]);
 144          opcode++) {
 145       const struct s390_operand *operand;
 146       const unsigned char *opindex;
 147
 148       /* check architecture */
 149       if (!(opcode->architecture & current_arch_mask))
 150         continue;
 151       /* check signature of the opcode */
 152       if ((buffer[1] & opcode->mask[1]) != opcode->opcode[1] ||
 153           (buffer[2] & opcode->mask[2]) != opcode->opcode[2] ||
 154           (buffer[3] & opcode->mask[3]) != opcode->opcode[3] ||
 155           (buffer[4] & opcode->mask[4]) != opcode->opcode[4] ||
 156           (buffer[5] & opcode->mask[5]) != opcode->opcode[5])
 157         continue;
 158
 159       /* the instruction is valid */
 160       if (opcode->operands[0] != 0)
 161         (*info->fprintf_func) (info->stream, "%s\t", opcode->name);
 162       else
 163         (*info->fprintf_func) (info->stream, "%s", opcode->name);
 164
 165       /* Extract the operands.  */
 166       separator = 0;
 167       for (opindex = opcode->operands; *opindex != 0; opindex++) {
 168         unsigned int value;
 169
 170         operand = s390_operands + *opindex;
 171         value = s390_extract_operand(buffer, operand);
 172
 173         if ((operand->flags & S390_OPERAND_INDEX) && value == 0)
 174           continue;
 175         if ((operand->flags & S390_OPERAND_BASE) &&
 176             value == 0 && separator == '(') {
 177           separator = ',';
 178           continue;
 179         }
 180
 181         if (separator)
 182           (*info->fprintf_func) (info->stream, "%c", separator);
 183
 184         if (operand->flags & S390_OPERAND_GPR)
 185           (*info->fprintf_func) (info->stream, "%%r%i", value);
 186         else if (operand->flags & S390_OPERAND_FPR)
 187           (*info->fprintf_func) (info->stream, "%%f%i", value);
 188         else if (operand->flags & S390_OPERAND_AR)
 189           (*info->fprintf_func) (info->stream, "%%a%i", value);
 190         else if (operand->flags & S390_OPERAND_CR)
 191           (*info->fprintf_func) (info->stream, "%%c%i", value);
 192         else if (operand->flags & S390_OPERAND_PCREL)
 193           (*info->print_address_func) (memaddr + (int) value, info);
 194         else if (operand->flags & S390_OPERAND_SIGNED)
 195           (*info->fprintf_func) (info->stream, "%i", (int) value);
 196         else
 197           (*info->fprintf_func) (info->stream, "%i", value);
 198
 199         if (operand->flags & S390_OPERAND_DISP) {
 200           separator = '(';
 201         } else if (operand->flags & S390_OPERAND_BASE) {
 202           (*info->fprintf_func) (info->stream, ")");
 203           separator = ',';
 204         } else
 205           separator = ',';
 206       }
 207
 208       /* found instruction, printed it, return its size */
 209       return opsize;
 210     }
 211     /* no matching instruction found, fall through to hex print  */
 212   }
 213
 214   if (bufsize >= 4) {
 215     value = (unsigned int) buffer[0];
 216     value = (value << 8) + (unsigned int) buffer[1];
 217     value = (value << 8) + (unsigned int) buffer[2];
 218     value = (value << 8) + (unsigned int) buffer[3];
 219     (*info->fprintf_func) (info->stream,".long\t0x%08x", value);
 220     return 4;
 221   } else if (bufsize >= 2) {
 222     value = (unsigned int) buffer[0];
 223     value = (value << 8) + (unsigned int) buffer[1];
 224     (*info->fprintf_func) (info->stream,".short\t0x%04x", value);
 225     return 2;
 226   } else {
 227     value = (unsigned int) buffer[0];
 228     (*info->fprintf_func) (info->stream,".byte\t0x%02x", value);
 229     return 1;
 230   }
 231 }