utils/disassembler/arm/main.c

   1 #include <stdio.h>
   2 #include <string.h>
   3 #include <stdlib.h>
   4 #include <stdint.h>
   5
   6 #define ULONG  uint32_t
   7 #define USHORT uint16_t
   8 #define UCHAR  uint8_t
   9
  10 ULONG isdata[1000000]; /* each bit defines one byte as: code=0, data=1 */
  11
  12 extern void dis_asm(ULONG off, ULONG val, char *stg);
  13
  14 int static inline le2int(unsigned char* buf)
  15 {
  16    int32_t res = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
  17
  18    return res;
  19 }
  20
  21 int main(int argc, char **argv)
  22 {
  23   FILE   *in, *out;
  24   char   *ptr, stg[256];
  25   unsigned char buf[4];
  26   ULONG  pos, sz, val, loop;
  27   int    offset, offset1;
  28   USHORT regid;
  29
  30   if(argc == 1 || strcmp(argv[1], "--help") == 0)
  31   { printf("Usage: arm_disass [input file]\n");
  32     printf(" disassembles input file to 'disasm.txt'\n");
  33     exit(-1);
  34   }
  35
  36   in = fopen(argv[1], "rb");
  37   if(in == NULL)
  38   { printf("Cannot open %s", argv[1]);
  39     exit(-1);
  40   }
  41
  42   out = fopen("disasm.txt", "w");
  43   if(out == NULL) exit(-1);
  44
  45   fseek(in, 0, SEEK_END);
  46   sz = ftell(in);
  47
  48   /* first loop only sets data/code tags */
  49   for(loop=0; loop<2; loop++)
  50   {
  51     for(pos=0; pos<sz; pos+=4)
  52     {
  53       /* clear disassembler string start */
  54       memset(stg, 0, 40);
  55       /* read next code dword */
  56       fseek(in, pos, SEEK_SET);
  57       fread(buf, 1, 4, in);
  58
  59       val = le2int(buf);
  60
  61       /* check for data tag set: if 1 byte out of 4 is marked => assume data */
  62       if((isdata[pos>>5] & (0xf << (pos & 31))) || (val & 0xffff0000) == 0)
  63       {
  64         sprintf(stg, "%6x:      %08x", pos, val);
  65       }
  66       else
  67       {
  68         dis_asm(pos, val, stg);
  69
  70         /* check for instant mov operation */
  71         if(memcmp(stg+17, "mov ", 4) == 0 && (ptr=strstr(stg, "0x")) != NULL)
  72         {
  73           regid = *(USHORT*)(stg+22);
  74
  75           sscanf(ptr+2, "%x", &offset);
  76           if(ptr[-1] == '-')
  77             offset = -offset;
  78         }
  79         else
  80         /* check for add/sub operation */
  81         if((ptr=strstr(stg, "0x")) != NULL
  82          && (memcmp(stg+17, "add ", 4) == 0 || memcmp(stg+17, "sub ", 4) == 0))
  83         {
  84           if(regid == *(USHORT*)(stg+22) && regid == *(USHORT*)(stg+26))
  85           {
  86             sscanf(ptr+2, "%x", &offset1);
  87             if(ptr[-1] == '-')
  88               offset1 = -offset1;
  89
  90             if(memcmp(stg+17, "add ", 4) == 0) offset += offset1;
  91             else                               offset -= offset1;
  92
  93             /* add result to disassembler string */
  94             sprintf(stg+strlen(stg), " <- 0x%x", offset);
  95           }
  96           else
  97             regid = 0;
  98         }
  99         else
 100           regid = 0;
 101
 102         /* check for const data */
 103         if(memcmp(stg+26, "[pc, ", 5) == 0 && (ptr=strstr(stg, "0x")) != NULL)
 104         {
 105           sscanf(ptr+2, "%x", &offset);
 106           if(ptr[-1] == '-')
 107             offset = -offset;
 108
 109           /* add data tag */
 110           isdata[(pos+offset+8)>>5] |= 1 << ((pos+offset+8) & 31);
 111
 112           /* add const data to disassembler string */
 113           fseek(in, pos+offset+8, SEEK_SET);
 114           fread(&buf, 1, 4, in);
 115           offset = le2int(buf);
 116
 117           sprintf(stg+strlen(stg), " <- 0x%x", offset);
 118         }
 119       }
 120
 121       /* remove trailing spaces */
 122       while(stg[strlen(stg)-1] == 32)
 123         stg[strlen(stg)-1] = 0;
 124
 125       if(loop == 1)
 126         fprintf(out, "%s\n", stg);
 127     }
 128   }
 129
 130   fclose(in);
 131   return 0;
 132 }