osfmk/ppc/db_disasm.c

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*
  26  * @OSF_COPYRIGHT@
  27  */
  28
  29 /*
  30  * Instruction disassembler.
  31  */
  32
  33 #include <mach/boolean.h>
  34 #include <machine/db_machdep.h>
  35
  36 #include <ddb/db_access.h>
  37 #include <ddb/db_sym.h>
  38 #include <ddb/db_output.h>
  39
  40 #include <kern/task.h>
  41 #include <kern/misc_protos.h>
  42
  43 #include "ppc_disasm.h"
  44
  45 db_addr_t       db_disasm_pc, db_disasm_symaddr;
  46 boolean_t       db_disasm_print_symaddr;
  47
  48 /*
  49  * Disassemble instruction at 'loc'.  'altfmt' specifies an
  50  * (optional) alternate format.  Return address of start of
  51  * next instruction.
  52  */
  53 db_addr_t
  54 db_disasm(
  55         db_addr_t       loc,
  56         boolean_t       altfmt,
  57         task_t          task)
  58 {
  59         int inst;
  60         char *p;
  61
  62         inst = db_get_task_value(loc, 4, FALSE, task);
  63         db_disasm_pc = loc;
  64         db_disasm_print_symaddr = FALSE;
  65         p = in(inst);
  66         db_printf("%s", p);
  67         if (db_disasm_print_symaddr) {
  68                 db_printf(" <");
  69                 db_task_printsym(db_disasm_symaddr, DB_STGY_ANY, task);
  70                 db_printf(">");
  71         }
  72         dis_done();
  73         return (loc+4);
  74 }
  75
  76 /*
  77  * Given four bytes of instruction (stored as an int, not an
  78  * array of characters), compute if the instruction reads
  79  * memory.
  80  */
  81 int
  82 db_inst_load(
  83         unsigned long insw)
  84 {
  85 #if 1
  86         db_printf("db_inst_load: coming soon in a debugger near you!\n");
  87         return 0;
  88 #else
  89         unsigned char insb, bits;
  90
  91         insb = insw & 0xff;
  92         insw >>= 8;
  93         bits = db_ldstrtab[insb];
  94         if (!(bits & DBLS_LOAD))
  95                 return (0);
  96         while (1) {
  97                 switch (bits & DBLS_MODS) {
  98                 case 0:
  99                         return (1);
 100                 case DBLS_MODRM:
 101                         insb = insw & 0xff;
 102                         return ((insb & 0xc0) != 0xc0);
 103                 case DBLS_SECOND|DBLS_MODRM:
 104                         insb = insw & 0xff;
 105                         return ((insb & 0xc0) != 0xc0 ? 2 : 0);
 106                 case DBLS_SECOND:
 107                         return (2);
 108                 case DBLS_ESCAPE:
 109                         insb = insw & 0xff;
 110                         insw >>= 8;
 111                         bits = db_ldstrtab0f[insb];
 112                         break;
 113                 case DBLS_SWREG:
 114                         return (db_inst_swreg(TRUE, insw, insb));
 115                 default:
 116                         panic ("db_inst_load: unknown mod bits");
 117                 }
 118         }
 119 #endif
 120 }
 121
 122 /*
 123  * Given four bytes of instruction (stored as an int, not an
 124  * array of characters), compute if the instruction writes
 125  * memory.
 126  */
 127 int
 128 db_inst_store(
 129         unsigned long insw)
 130 {
 131 #if 1
 132         db_printf("db_inst_store: coming soon in a debugger near you!\n");
 133         return 0;
 134 #else
 135         unsigned char insb, bits;
 136
 137         insb = insw & 0xff;
 138         insw >>= 8;
 139         bits = db_ldstrtab[insb];
 140         if (!(bits & DBLS_STORE))
 141                 return (0);
 142         while (1) {
 143                 switch (bits & DBLS_MODS) {
 144                 case 0:
 145                         return (1);
 146                 case DBLS_MODRM:
 147                         insb = insw & 0xff;
 148                         return ((insb & 0xc0) != 0xc0);
 149                 case DBLS_SECOND|DBLS_MODRM:
 150                         insb = insw & 0xff;
 151                         return ((insb & 0xc0) != 0xc0 ? 2 : 0);
 152                 case DBLS_SECOND:
 153                         return (2);
 154                 case DBLS_ESCAPE:
 155                         insb = insw & 0xff;
 156                         insw >>= 8;
 157                         bits = db_ldstrtab0f[insb];
 158                         break;
 159                 case DBLS_SWREG:
 160                         return (db_inst_swreg(FALSE, insw, insb));
 161                 default:
 162                         panic ("db_inst_store: unknown mod bits");
 163                 }
 164         }
 165 #endif
 166 }
 167
 168 /*
 169  * Extra routines for the automatically generated disassembler
 170  */
 171 char *
 172 hex(
 173         bits n)
 174 {
 175         char *p;
 176
 177         if (n < 10)
 178                 return dec(n);
 179         p = dis_alloc(11);
 180         sprintf(p, "0x%lx", n);
 181         return p;
 182 }
 183
 184 char *
 185 dec(
 186         bits n)
 187 {
 188         char *p = dis_alloc(11);
 189         sprintf(p, "%lu", n);
 190         return p;
 191 }
 192
 193 char *
 194 brdispl(
 195         bits displ,
 196         bits nbits)
 197 {
 198         int sign, extended;
 199
 200         sign = 1 << (nbits - 1);
 201         extended = (displ & sign ? displ - (sign << 1) : displ);
 202         db_disasm_symaddr = db_disasm_pc + (extended << 2);
 203         db_disasm_print_symaddr = TRUE;
 204         return hex(extended << 2);
 205 }
 206
 207 char *
 208 mbz(
 209         bits n)
 210 {
 211         return n ? "[reserved bits not zero]" : "";
 212 }
 213
 214 size_t db_disasm_string_size = 0;
 215 #define DB_DISASM_STRING_MAXSIZE        4096
 216 char db_disasm_string[DB_DISASM_STRING_MAXSIZE];
 217
 218 void *db_disasm_malloc(size_t size);    /* forward */
 219 void *
 220 db_disasm_malloc(
 221         size_t size)
 222 {
 223         void * new_buf;
 224
 225         if (db_disasm_string_size + size <= DB_DISASM_STRING_MAXSIZE) {
 226                 new_buf = (void *) (db_disasm_string + db_disasm_string_size);
 227                 db_disasm_string_size += size;
 228                 return new_buf;
 229         }
 230         db_printf("db_disasm_malloc(size=%d) failed: %d left !\n",
 231                   size,
 232                   DB_DISASM_STRING_MAXSIZE - db_disasm_string_size);
 233         return (void *) 0;
 234 }