osfmk/ppc/db_disasm.c

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * @OSF_COPYRIGHT@
  24  */
  25
  26 /*
  27  * Instruction disassembler.
  28  */
  29
  30 #include <mach/boolean.h>
  31 #include <machine/db_machdep.h>
  32
  33 #include <ddb/db_access.h>
  34 #include <ddb/db_sym.h>
  35 #include <ddb/db_output.h>
  36
  37 #include <kern/task.h>
  38 #include <kern/misc_protos.h>
  39
  40 #include "ppc_disasm.h"
  41
  42 db_addr_t       db_disasm_pc, db_disasm_symaddr;
  43 boolean_t       db_disasm_print_symaddr;
  44
  45 /*
  46  * Disassemble instruction at 'loc'.  'altfmt' specifies an
  47  * (optional) alternate format.  Return address of start of
  48  * next instruction.
  49  */
  50 db_addr_t
  51 db_disasm(
  52         db_addr_t       loc,
  53         boolean_t       altfmt,
  54         task_t          task)
  55 {
  56         int inst;
  57         char *p;
  58
  59         inst = db_get_task_value(loc, 4, FALSE, task);
  60         db_disasm_pc = loc;
  61         db_disasm_print_symaddr = FALSE;
  62         p = in(inst);
  63         db_printf("%s", p);
  64         if (db_disasm_print_symaddr) {
  65                 db_printf(" <");
  66                 db_task_printsym(db_disasm_symaddr, DB_STGY_ANY, task);
  67                 db_printf(">");
  68         }
  69         dis_done();
  70         return (loc+4);
  71 }
  72
  73 /*
  74  * Given four bytes of instruction (stored as an int, not an
  75  * array of characters), compute if the instruction reads
  76  * memory.
  77  */
  78 int
  79 db_inst_load(
  80         unsigned long insw)
  81 {
  82 #if 1
  83         db_printf("db_inst_load: coming soon in a debugger near you!\n");
  84         return 0;
  85 #else
  86         unsigned char insb, bits;
  87
  88         insb = insw & 0xff;
  89         insw >>= 8;
  90         bits = db_ldstrtab[insb];
  91         if (!(bits & DBLS_LOAD))
  92                 return (0);
  93         while (1) {
  94                 switch (bits & DBLS_MODS) {
  95                 case 0:
  96                         return (1);
  97                 case DBLS_MODRM:
  98                         insb = insw & 0xff;
  99                         return ((insb & 0xc0) != 0xc0);
 100                 case DBLS_SECOND|DBLS_MODRM:
 101                         insb = insw & 0xff;
 102                         return ((insb & 0xc0) != 0xc0 ? 2 : 0);
 103                 case DBLS_SECOND:
 104                         return (2);
 105                 case DBLS_ESCAPE:
 106                         insb = insw & 0xff;
 107                         insw >>= 8;
 108                         bits = db_ldstrtab0f[insb];
 109                         break;
 110                 case DBLS_SWREG:
 111                         return (db_inst_swreg(TRUE, insw, insb));
 112                 default:
 113                         panic ("db_inst_load: unknown mod bits");
 114                 }
 115         }
 116 #endif
 117 }
 118
 119 /*
 120  * Given four bytes of instruction (stored as an int, not an
 121  * array of characters), compute if the instruction writes
 122  * memory.
 123  */
 124 int
 125 db_inst_store(
 126         unsigned long insw)
 127 {
 128 #if 1
 129         db_printf("db_inst_store: coming soon in a debugger near you!\n");
 130         return 0;
 131 #else
 132         unsigned char insb, bits;
 133
 134         insb = insw & 0xff;
 135         insw >>= 8;
 136         bits = db_ldstrtab[insb];
 137         if (!(bits & DBLS_STORE))
 138                 return (0);
 139         while (1) {
 140                 switch (bits & DBLS_MODS) {
 141                 case 0:
 142                         return (1);
 143                 case DBLS_MODRM:
 144                         insb = insw & 0xff;
 145                         return ((insb & 0xc0) != 0xc0);
 146                 case DBLS_SECOND|DBLS_MODRM:
 147                         insb = insw & 0xff;
 148                         return ((insb & 0xc0) != 0xc0 ? 2 : 0);
 149                 case DBLS_SECOND:
 150                         return (2);
 151                 case DBLS_ESCAPE:
 152                         insb = insw & 0xff;
 153                         insw >>= 8;
 154                         bits = db_ldstrtab0f[insb];
 155                         break;
 156                 case DBLS_SWREG:
 157                         return (db_inst_swreg(FALSE, insw, insb));
 158                 default:
 159                         panic ("db_inst_store: unknown mod bits");
 160                 }
 161         }
 162 #endif
 163 }
 164
 165 /*
 166  * Extra routines for the automatically generated disassembler
 167  */
 168 char *
 169 hex(
 170         bits n)
 171 {
 172         char *p;
 173
 174         if (n < 10)
 175                 return dec(n);
 176         p = dis_alloc(11);
 177         sprintf(p, "0x%lx", n);
 178         return p;
 179 }
 180
 181 char *
 182 dec(
 183         bits n)
 184 {
 185         char *p = dis_alloc(11);
 186         sprintf(p, "%lu", n);
 187         return p;
 188 }
 189
 190 char *
 191 brdispl(
 192         bits displ,
 193         bits nbits)
 194 {
 195         int sign, extended;
 196
 197         sign = 1 << (nbits - 1);
 198         extended = (displ & sign ? displ - (sign << 1) : displ);
 199         db_disasm_symaddr = db_disasm_pc + (extended << 2);
 200         db_disasm_print_symaddr = TRUE;
 201         return hex(extended << 2);
 202 }
 203
 204 char *
 205 mbz(
 206         bits n)
 207 {
 208         return n ? "[reserved bits not zero]" : "";
 209 }
 210
 211 size_t db_disasm_string_size = 0;
 212 #define DB_DISASM_STRING_MAXSIZE        4096
 213 char db_disasm_string[DB_DISASM_STRING_MAXSIZE];
 214
 215 void *db_disasm_malloc(size_t size);    /* forward */
 216 void *
 217 db_disasm_malloc(
 218         size_t size)
 219 {
 220         void * new_buf;
 221
 222         if (db_disasm_string_size + size <= DB_DISASM_STRING_MAXSIZE) {
 223                 new_buf = (void *) (db_disasm_string + db_disasm_string_size);
 224                 db_disasm_string_size += size;
 225                 return new_buf;
 226         }
 227         db_printf("db_disasm_malloc(size=%d) failed: %d left !\n",
 228                   size,
 229                   DB_DISASM_STRING_MAXSIZE - db_disasm_string_size);
 230         return (void *) 0;
 231 }