liblua/lopcodes.h

   1 /*
   2 ** $Id: lopcodes.h,v 1.142 2011/07/15 12:50:29 roberto Exp $
   3 ** Opcodes for Lua virtual machine
   4 ** See Copyright Notice in lua.h
   5 */
   6
   7 #ifndef lopcodes_h
   8 #define lopcodes_h
   9
  10 #include "llimits.h"
  11
  12
  13 /*===========================================================================
  14   We assume that instructions are unsigned numbers.
  15   All instructions have an opcode in the first 6 bits.
  16   Instructions can have the following fields:
  17         `A' : 8 bits
  18         `B' : 9 bits
  19         `C' : 9 bits
  20         'Ax' : 26 bits ('A', 'B', and 'C' together)
  21         `Bx' : 18 bits (`B' and `C' together)
  22         `sBx' : signed Bx
  23
  24   A signed argument is represented in excess K; that is, the number
  25   value is the unsigned value minus K. K is exactly the maximum value
  26   for that argument (so that -max is represented by 0, and +max is
  27   represented by 2*max), which is half the maximum for the corresponding
  28   unsigned argument.
  29 ===========================================================================*/
  30
  31
  32 enum OpMode {iABC, iABx, iAsBx, iAx};  /* basic instruction format */
  33
  34
  35 /*
  36 ** size and position of opcode arguments.
  37 */
  38 #define SIZE_C          9
  39 #define SIZE_B          9
  40 #define SIZE_Bx         (SIZE_C + SIZE_B)
  41 #define SIZE_A          8
  42 #define SIZE_Ax         (SIZE_C + SIZE_B + SIZE_A)
  43
  44 #define SIZE_OP         6
  45
  46 #define POS_OP          0
  47 #define POS_A           (POS_OP + SIZE_OP)
  48 #define POS_C           (POS_A + SIZE_A)
  49 #define POS_B           (POS_C + SIZE_C)
  50 #define POS_Bx          POS_C
  51 #define POS_Ax          POS_A
  52
  53
  54 /*
  55 ** limits for opcode arguments.
  56 ** we use (signed) int to manipulate most arguments,
  57 ** so they must fit in LUAI_BITSINT-1 bits (-1 for sign)
  58 */
  59 #if SIZE_Bx < LUAI_BITSINT-1
  60 #define MAXARG_Bx        ((1<<SIZE_Bx)-1)
  61 #define MAXARG_sBx        (MAXARG_Bx>>1)         /* `sBx' is signed */
  62 #else
  63 #define MAXARG_Bx        MAX_INT
  64 #define MAXARG_sBx        MAX_INT
  65 #endif
  66
  67 #if SIZE_Ax < LUAI_BITSINT-1
  68 #define MAXARG_Ax       ((1<<SIZE_Ax)-1)
  69 #else
  70 #define MAXARG_Ax       MAX_INT
  71 #endif
  72
  73
  74 #define MAXARG_A        ((1<<SIZE_A)-1)
  75 #define MAXARG_B        ((1<<SIZE_B)-1)
  76 #define MAXARG_C        ((1<<SIZE_C)-1)
  77
  78
  79 /* creates a mask with `n' 1 bits at position `p' */
  80 #define MASK1(n,p)      ((~((~(Instruction)0)<<(n)))<<(p))
  81
  82 /* creates a mask with `n' 0 bits at position `p' */
  83 #define MASK0(n,p)      (~MASK1(n,p))
  84
  85 /*
  86 ** the following macros help to manipulate instructions
  87 */
  88
  89 #define GET_OPCODE(i)   (cast(OpCode, ((i)>>POS_OP) & MASK1(SIZE_OP,0)))
  90 #define SET_OPCODE(i,o) ((i) = (((i)&MASK0(SIZE_OP,POS_OP)) | \
  91                 ((cast(Instruction, o)<<POS_OP)&MASK1(SIZE_OP,POS_OP))))
  92
  93 #define getarg(i,pos,size)      (cast(int, ((i)>>pos) & MASK1(size,0)))
  94 #define setarg(i,v,pos,size)    ((i) = (((i)&MASK0(size,pos)) | \
  95                 ((cast(Instruction, v)<<pos)&MASK1(size,pos))))
  96
  97 #define GETARG_A(i)     getarg(i, POS_A, SIZE_A)
  98 #define SETARG_A(i,v)   setarg(i, v, POS_A, SIZE_A)
  99
 100 #define GETARG_B(i)     getarg(i, POS_B, SIZE_B)
 101 #define SETARG_B(i,v)   setarg(i, v, POS_B, SIZE_B)
 102
 103 #define GETARG_C(i)     getarg(i, POS_C, SIZE_C)
 104 #define SETARG_C(i,v)   setarg(i, v, POS_C, SIZE_C)
 105
 106 #define GETARG_Bx(i)    getarg(i, POS_Bx, SIZE_Bx)
 107 #define SETARG_Bx(i,v)  setarg(i, v, POS_Bx, SIZE_Bx)
 108
 109 #define GETARG_Ax(i)    getarg(i, POS_Ax, SIZE_Ax)
 110 #define SETARG_Ax(i,v)  setarg(i, v, POS_Ax, SIZE_Ax)
 111
 112 #define GETARG_sBx(i)   (GETARG_Bx(i)-MAXARG_sBx)
 113 #define SETARG_sBx(i,b) SETARG_Bx((i),cast(unsigned int, (b)+MAXARG_sBx))
 114
 115
 116 #define CREATE_ABC(o,a,b,c)     ((cast(Instruction, o)<<POS_OP) \
 117                         | (cast(Instruction, a)<<POS_A) \
 118                         | (cast(Instruction, b)<<POS_B) \
 119                         | (cast(Instruction, c)<<POS_C))
 120
 121 #define CREATE_ABx(o,a,bc)      ((cast(Instruction, o)<<POS_OP) \
 122                         | (cast(Instruction, a)<<POS_A) \
 123                         | (cast(Instruction, bc)<<POS_Bx))
 124
 125 #define CREATE_Ax(o,a)          ((cast(Instruction, o)<<POS_OP) \
 126                         | (cast(Instruction, a)<<POS_Ax))
 127
 128
 129 /*
 130 ** Macros to operate RK indices
 131 */
 132
 133 /* this bit 1 means constant (0 means register) */
 134 #define BITRK           (1 << (SIZE_B - 1))
 135
 136 /* test whether value is a constant */
 137 #define ISK(x)          ((x) & BITRK)
 138
 139 /* gets the index of the constant */
 140 #define INDEXK(r)       ((int)(r) & ~BITRK)
 141
 142 #define MAXINDEXRK      (BITRK - 1)
 143
 144 /* code a constant index as a RK value */
 145 #define RKASK(x)        ((x) | BITRK)
 146
 147
 148 /*
 149 ** invalid register that fits in 8 bits
 150 */
 151 #define NO_REG          MAXARG_A
 152
 153
 154 /*
 155 ** R(x) - register
 156 ** Kst(x) - constant (in constant table)
 157 ** RK(x) == if ISK(x) then Kst(INDEXK(x)) else R(x)
 158 */
 159
 160
 161 /*
 162 ** grep "ORDER OP" if you change these enums
 163 */
 164
 165 typedef enum {
 166 /*----------------------------------------------------------------------
 167 name            args    description
 168 ------------------------------------------------------------------------*/
 169 OP_MOVE,/*      A B     R(A) := R(B)                                    */
 170 OP_LOADK,/*     A Bx    R(A) := Kst(Bx)                                 */
 171 OP_LOADKX,/*    A       R(A) := Kst(extra arg)                          */
 172 OP_LOADBOOL,/*  A B C   R(A) := (Bool)B; if (C) pc++                    */
 173 OP_LOADNIL,/*   A B     R(A), R(A+1), ..., R(A+B) := nil                */
 174 OP_GETUPVAL,/*  A B     R(A) := UpValue[B]                              */
 175
 176 OP_GETTABUP,/*  A B C   R(A) := UpValue[B][RK(C)]                       */
 177 OP_GETTABLE,/*  A B C   R(A) := R(B)[RK(C)]                             */
 178
 179 OP_SETTABUP,/*  A B C   UpValue[A][RK(B)] := RK(C)                      */
 180 OP_SETUPVAL,/*  A B     UpValue[B] := R(A)                              */
 181 OP_SETTABLE,/*  A B C   R(A)[RK(B)] := RK(C)                            */
 182
 183 OP_NEWTABLE,/*  A B C   R(A) := {} (size = B,C)                         */
 184
 185 OP_SELF,/*      A B C   R(A+1) := R(B); R(A) := R(B)[RK(C)]             */
 186
 187 OP_ADD,/*       A B C   R(A) := RK(B) + RK(C)                           */
 188 OP_SUB,/*       A B C   R(A) := RK(B) - RK(C)                           */
 189 OP_MUL,/*       A B C   R(A) := RK(B) * RK(C)                           */
 190 OP_DIV,/*       A B C   R(A) := RK(B) / RK(C)                           */
 191 OP_MOD,/*       A B C   R(A) := RK(B) % RK(C)                           */
 192 OP_POW,/*       A B C   R(A) := RK(B) ^ RK(C)                           */
 193 OP_UNM,/*       A B     R(A) := -R(B)                                   */
 194 OP_NOT,/*       A B     R(A) := not R(B)                                */
 195 OP_LEN,/*       A B     R(A) := length of R(B)                          */
 196
 197 OP_CONCAT,/*    A B C   R(A) := R(B).. ... ..R(C)                       */
 198
 199 OP_JMP,/*       A sBx   pc+=sBx; if (A) close all upvalues >= R(A) + 1  */
 200 OP_EQ,/*        A B C   if ((RK(B) == RK(C)) ~= A) then pc++            */
 201 OP_LT,/*        A B C   if ((RK(B) <  RK(C)) ~= A) then pc++            */
 202 OP_LE,/*        A B C   if ((RK(B) <= RK(C)) ~= A) then pc++            */
 203
 204 OP_TEST,/*      A C     if not (R(A) <=> C) then pc++                   */
 205 OP_TESTSET,/*   A B C   if (R(B) <=> C) then R(A) := R(B) else pc++     */
 206
 207 OP_CALL,/*      A B C   R(A), ... ,R(A+C-2) := R(A)(R(A+1), ... ,R(A+B-1)) */
 208 OP_TAILCALL,/*  A B C   return R(A)(R(A+1), ... ,R(A+B-1))              */
 209 OP_RETURN,/*    A B     return R(A), ... ,R(A+B-2)      (see note)      */
 210
 211 OP_FORLOOP,/*   A sBx   R(A)+=R(A+2);
 212                         if R(A) <?= R(A+1) then { pc+=sBx; R(A+3)=R(A) }*/
 213 OP_FORPREP,/*   A sBx   R(A)-=R(A+2); pc+=sBx                           */
 214
 215 OP_TFORCALL,/*  A C     R(A+3), ... ,R(A+2+C) := R(A)(R(A+1), R(A+2));  */
 216 OP_TFORLOOP,/*  A sBx   if R(A+1) ~= nil then { R(A)=R(A+1); pc += sBx }*/
 217
 218 OP_SETLIST,/*   A B C   R(A)[(C-1)*FPF+i] := R(A+i), 1 <= i <= B        */
 219
 220 OP_CLOSURE,/*   A Bx    R(A) := closure(KPROTO[Bx])                     */
 221
 222 OP_VARARG,/*    A B     R(A), R(A+1), ..., R(A+B-2) = vararg            */
 223
 224 OP_EXTRAARG/*   Ax      extra (larger) argument for previous opcode     */
 225 } OpCode;
 226
 227
 228 #define NUM_OPCODES     (cast(int, OP_EXTRAARG) + 1)
 229
 230
 231
 232 /*===========================================================================
 233   Notes:
 234   (*) In OP_CALL, if (B == 0) then B = top. If (C == 0), then `top' is
 235   set to last_result+1, so next open instruction (OP_CALL, OP_RETURN,
 236   OP_SETLIST) may use `top'.
 237
 238   (*) In OP_VARARG, if (B == 0) then use actual number of varargs and
 239   set top (like in OP_CALL with C == 0).
 240
 241   (*) In OP_RETURN, if (B == 0) then return up to `top'.
 242
 243   (*) In OP_SETLIST, if (B == 0) then B = `top'; if (C == 0) then next
 244   'instruction' is EXTRAARG(real C).
 245
 246   (*) In OP_LOADKX, the next 'instruction' is always EXTRAARG.
 247
 248   (*) For comparisons, A specifies what condition the test should accept
 249   (true or false).
 250
 251   (*) All `skips' (pc++) assume that next instruction is a jump.
 252
 253 ===========================================================================*/
 254
 255
 256 /*
 257 ** masks for instruction properties. The format is:
 258 ** bits 0-1: op mode
 259 ** bits 2-3: C arg mode
 260 ** bits 4-5: B arg mode
 261 ** bit 6: instruction set register A
 262 ** bit 7: operator is a test (next instruction must be a jump)
 263 */
 264
 265 enum OpArgMask {
 266   OpArgN,  /* argument is not used */
 267   OpArgU,  /* argument is used */
 268   OpArgR,  /* argument is a register or a jump offset */
 269   OpArgK   /* argument is a constant or register/constant */
 270 };
 271
 272 LUAI_DDEC const lu_byte luaP_opmodes[NUM_OPCODES];
 273
 274 #define getOpMode(m)    (cast(enum OpMode, luaP_opmodes[m] & 3))
 275 #define getBMode(m)     (cast(enum OpArgMask, (luaP_opmodes[m] >> 4) & 3))
 276 #define getCMode(m)     (cast(enum OpArgMask, (luaP_opmodes[m] >> 2) & 3))
 277 #define testAMode(m)    (luaP_opmodes[m] & (1 << 6))
 278 #define testTMode(m)    (luaP_opmodes[m] & (1 << 7))
 279
 280
 281 LUAI_DDEC const char *const luaP_opnames[NUM_OPCODES+1];  /* opcode names */
 282
 283
 284 /* number of list items to accumulate before a SETLIST instruction */
 285 #define LFIELDS_PER_FLUSH       50
 286
 287
 288 #endif