src/luac/opcode.c

   1 /*
   2 ** $Id: opcode.c,v 1.9 1999/05/25 19:58:55 lhf Exp $
   3 ** opcode information
   4 ** See Copyright Notice in lua.h
   5 */
   6
   7 #include "luac.h"
   8
   9 enum {                                  /* for Opcode.args */
  10  ARGS_NONE,
  11  ARGS_B,
  12  ARGS_W,
  13  ARGS_BB,
  14  ARGS_WB
  15 };
  16
  17 static Opcode Info[]=                   /* ORDER lopcodes.h */
  18 {
  19 #include "opcode.h"
  20 };
  21
  22 static Opcode Fake[]=                   /* ORDER luac.h */
  23 {
  24 { "NOP", NOP, NOP, ARGS_NONE, -1, -1 },
  25 { "STACK", STACK, STACK, ARGS_B, -1, -1 },
  26 { "ARGS", ARGS, ARGS, ARGS_B, -1, -1 },
  27 { "VARARGS", VARARGS, VARARGS, ARGS_B, -1, -1 },
  28 };
  29
  30 #define NOPCODES        (sizeof(Info)/sizeof(Info[0]))
  31
  32 int luaU_opcodeinfo(TProtoFunc* tf, Byte* p, Opcode* I, char* xFILE, int xLINE)
  33 {
  34  Opcode OP;
  35  Byte* code=tf->code;
  36  int op=*p;
  37  int size=1;
  38  if (p==code)                           /* first byte is STACK */
  39  {
  40   OP=Fake[-STACK];
  41   OP.arg=op;
  42  }
  43  else if (p==code+1)                    /* second byte is ARGS or VARARGS */
  44  {
  45   if (op<ZEROVARARG)
  46   {
  47    OP=Fake[-ARGS];
  48    OP.arg=op;
  49   }
  50   else
  51   {
  52    OP=Fake[-VARARGS];
  53    OP.arg=op-ZEROVARARG;
  54   }
  55  }
  56  else if (op==NOP)                      /* NOP is fake */
  57  {
  58   OP=Fake[0];
  59  }
  60  else if (op>=NOPCODES)                 /* cannot happen */
  61  {
  62   luaL_verror("[%s:%d] bad opcode %d at pc=%d" IN,
  63         xFILE,xLINE,op,(int)(p-code),INLOC);
  64   return 0;
  65  }
  66  else                                   /* ordinary opcode */
  67  {
  68   OP=Info[op];
  69   switch (OP.args)
  70   {
  71    case ARGS_NONE:      size=1;
  72     break;
  73    case ARGS_B:         size=2; OP.arg=p[1];
  74     break;
  75    case ARGS_W:         size=3; OP.arg=(p[1]<<8)+p[2];
  76     break;
  77    case ARGS_BB:        size=3; OP.arg=p[1];            OP.arg2=p[2];
  78     break;
  79    case ARGS_WB:        size=4; OP.arg=(p[1]<<8)+p[2];  OP.arg2=p[3];
  80     break;
  81    default:                             /* cannot happen */
  82     luaL_verror("[%s:%d] bad args %d for %s at pc=%d" IN,
  83         __FILE__,__LINE__,OP.args,OP.name,(int)(p-code),INLOC);
  84     break;
  85   }
  86  }
  87  *I=OP;
  88  return size;
  89 }
  90
  91 int luaU_codesize(TProtoFunc* tf)
  92 {
  93  Byte* code=tf->code;
  94  Byte* p=code;
  95  for (;;)
  96  {
  97   Opcode OP;
  98   p+=INFO(tf,p,&OP);
  99   if (OP.op==ENDCODE) break;
 100  }
 101  return p-code;
 102 }