lopcodes.h

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/*
** $Id: lopcodes.h,v 1.149.1.1 2017/04/19 17:20:42 roberto Exp $
** Opcodes for Lua virtual machine
** See Copyright Notice in lua.h
*/
 
#ifndef lopcodes_h
#define lopcodes_h
 
#include "llimits.h"
 
 
/*===========================================================================
  We assume that instructions are unsigned numbers.
  All instructions have an opcode in the first 6 bits.
  Instructions can have the following fields:
        'A' : 8 bits
        'B' : 9 bits
        'C' : 9 bits
        'Ax' : 26 bits ('A', 'B', and 'C' together)
        'Bx' : 18 bits ('B' and 'C' together)
        'sBx' : signed Bx
 
  A signed argument is represented in excess K; that is, the number
  value is the unsigned value minus K. K is exactly the maximum value
  for that argument (so that -max is represented by 0, and +max is
  represented by 2*max), which is half the maximum for the corresponding
  unsigned argument.
===========================================================================*/
 
 
enum OpMode {iABC, iABx, iAsBx, iAx};  /* basic instruction format */
 
 
/*
** size and position of opcode arguments.
*/
#define SIZE_C          9
#define SIZE_B          9
#define SIZE_Bx         (SIZE_C + SIZE_B)
#define SIZE_A          8
#define SIZE_Ax         (SIZE_C + SIZE_B + SIZE_A)
 
#define SIZE_OP         6
 
#define POS_OP          0
#define POS_A           (POS_OP + SIZE_OP)
#define POS_C           (POS_A + SIZE_A)
#define POS_B           (POS_C + SIZE_C)
#define POS_Bx          POS_C
#define POS_Ax          POS_A
 
 
/*
** limits for opcode arguments.
** we use (signed) int to manipulate most arguments,
** so they must fit in LUAI_BITSINT-1 bits (-1 for sign)
*/
#if SIZE_Bx < LUAI_BITSINT-1
#define MAXARG_Bx        ((1<<SIZE_Bx)-1)
#define MAXARG_sBx        (MAXARG_Bx>>1)         /* 'sBx' is signed */
#else
#define MAXARG_Bx        MAX_INT
#define MAXARG_sBx        MAX_INT
#endif
 
#if SIZE_Ax < LUAI_BITSINT-1
#define MAXARG_Ax       ((1<<SIZE_Ax)-1)
#else
#define MAXARG_Ax       MAX_INT
#endif
 
 
#define MAXARG_A        ((1<<SIZE_A)-1)
#define MAXARG_B        ((1<<SIZE_B)-1)
#define MAXARG_C        ((1<<SIZE_C)-1)
 
 
/* creates a mask with 'n' 1 bits at position 'p' */
#define MASK1(n,p)      ((~((~(Instruction)0)<<(n)))<<(p))
 
/* creates a mask with 'n' 0 bits at position 'p' */
#define MASK0(n,p)      (~MASK1(n,p))
 
/*
** the following macros help to manipulate instructions
*/
 
#define GET_OPCODE(i)   (cast(OpCode, ((i)>>POS_OP) & MASK1(SIZE_OP,0)))
#define SET_OPCODE(i,o) ((i) = (((i)&MASK0(SIZE_OP,POS_OP)) | \
                ((cast(Instruction, o)<<POS_OP)&MASK1(SIZE_OP,POS_OP))))
 
#define getarg(i,pos,size)      (cast(int, ((i)>>pos) & MASK1(size,0)))
#define setarg(i,v,pos,size)    ((i) = (((i)&MASK0(size,pos)) | \
                ((cast(Instruction, v)<<pos)&MASK1(size,pos))))
 
#define GETARG_A(i)     getarg(i, POS_A, SIZE_A)
#define SETARG_A(i,v)   setarg(i, v, POS_A, SIZE_A)
 
#define GETARG_B(i)     getarg(i, POS_B, SIZE_B)
#define SETARG_B(i,v)   setarg(i, v, POS_B, SIZE_B)
 
#define GETARG_C(i)     getarg(i, POS_C, SIZE_C)
#define SETARG_C(i,v)   setarg(i, v, POS_C, SIZE_C)
 
#define GETARG_Bx(i)    getarg(i, POS_Bx, SIZE_Bx)
#define SETARG_Bx(i,v)  setarg(i, v, POS_Bx, SIZE_Bx)
 
#define GETARG_Ax(i)    getarg(i, POS_Ax, SIZE_Ax)
#define SETARG_Ax(i,v)  setarg(i, v, POS_Ax, SIZE_Ax)
 
#define GETARG_sBx(i)   (GETARG_Bx(i)-MAXARG_sBx)
#define SETARG_sBx(i,b) SETARG_Bx((i),cast(unsigned int, (b)+MAXARG_sBx))
 
 
#define CREATE_ABC(o,a,b,c)     ((cast(Instruction, o)<<POS_OP) \
                        | (cast(Instruction, a)<<POS_A) \
                        | (cast(Instruction, b)<<POS_B) \
                        | (cast(Instruction, c)<<POS_C))
 
#define CREATE_ABx(o,a,bc)      ((cast(Instruction, o)<<POS_OP) \
                        | (cast(Instruction, a)<<POS_A) \
                        | (cast(Instruction, bc)<<POS_Bx))
 
#define CREATE_Ax(o,a)          ((cast(Instruction, o)<<POS_OP) \
                        | (cast(Instruction, a)<<POS_Ax))
 
 
/*
** Macros to operate RK indices
*/
 
/* this bit 1 means constant (0 means register) */
#define BITRK           (1 << (SIZE_B - 1))
 
/* test whether value is a constant */
#define ISK(x)          ((x) & BITRK)
 
/* gets the index of the constant */
#define INDEXK(r)       ((int)(r) & ~BITRK)
 
#if !defined(MAXINDEXRK)  /* (for debugging only) */
#define MAXINDEXRK      (BITRK - 1)
#endif
 
/* code a constant index as a RK value */
#define RKASK(x)        ((x) | BITRK)
 
 
/*
** invalid register that fits in 8 bits
*/
#define NO_REG          MAXARG_A
 
 
/*
** R(x) - register
** Kst(x) - constant (in constant table)
** RK(x) == if ISK(x) then Kst(INDEXK(x)) else R(x)
*/
 
 
/*
** grep "ORDER OP" if you change these enums
*/
 
typedef enum {
/*----------------------------------------------------------------------
name            args    description
------------------------------------------------------------------------*/
OP_MOVE,/*      A B     R(A) := R(B)                                    */
OP_LOADK,/*     A Bx    R(A) := Kst(Bx)                                 */
OP_LOADKX,/*    A       R(A) := Kst(extra arg)                          */
OP_LOADBOOL,/*  A B C   R(A) := (Bool)B; if (C) pc++                    */
OP_LOADNIL,/*   A B     R(A), R(A+1), ..., R(A+B) := nil                */
OP_GETUPVAL,/*  A B     R(A) := UpValue[B]                              */
 
OP_GETTABUP,/*  A B C   R(A) := UpValue[B][RK(C)]                       */
OP_GETTABLE,/*  A B C   R(A) := R(B)[RK(C)]                             */
 
OP_SETTABUP,/*  A B C   UpValue[A][RK(B)] := RK(C)                      */
OP_SETUPVAL,/*  A B     UpValue[B] := R(A)                              */
OP_SETTABLE,/*  A B C   R(A)[RK(B)] := RK(C)                            */
 
OP_NEWTABLE,/*  A B C   R(A) := {} (size = B,C)                         */
 
OP_SELF,/*      A B C   R(A+1) := R(B); R(A) := R(B)[RK(C)]             */
 
OP_ADD,/*       A B C   R(A) := RK(B) + RK(C)                           */
OP_SUB,/*       A B C   R(A) := RK(B) - RK(C)                           */
OP_MUL,/*       A B C   R(A) := RK(B) * RK(C)                           */
OP_MOD,/*       A B C   R(A) := RK(B) % RK(C)                           */
OP_POW,/*       A B C   R(A) := RK(B) ^ RK(C)                           */
OP_DIV,/*       A B C   R(A) := RK(B) / RK(C)                           */
OP_IDIV,/*      A B C   R(A) := RK(B) // RK(C)                          */
OP_BAND,/*      A B C   R(A) := RK(B) & RK(C)                           */
OP_BOR,/*       A B C   R(A) := RK(B) | RK(C)                           */
OP_BXOR,/*      A B C   R(A) := RK(B) ~ RK(C)                           */
OP_SHL,/*       A B C   R(A) := RK(B) << RK(C)                          */
OP_SHR,/*       A B C   R(A) := RK(B) >> RK(C)                          */
OP_UNM,/*       A B     R(A) := -R(B)                                   */
OP_BNOT,/*      A B     R(A) := ~R(B)                                   */
OP_NOT,/*       A B     R(A) := not R(B)                                */
OP_LEN,/*       A B     R(A) := length of R(B)                          */
 
OP_CONCAT,/*    A B C   R(A) := R(B).. ... ..R(C)                       */
 
OP_JMP,/*       A sBx   pc+=sBx; if (A) close all upvalues >= R(A - 1)  */
OP_EQ,/*        A B C   if ((RK(B) == RK(C)) ~= A) then pc++            */
OP_LT,/*        A B C   if ((RK(B) <  RK(C)) ~= A) then pc++            */
OP_LE,/*        A B C   if ((RK(B) <= RK(C)) ~= A) then pc++            */
 
OP_TEST,/*      A C     if not (R(A) <=> C) then pc++                   */
OP_TESTSET,/*   A B C   if (R(B) <=> C) then R(A) := R(B) else pc++     */
 
OP_CALL,/*      A B C   R(A), ... ,R(A+C-2) := R(A)(R(A+1), ... ,R(A+B-1)) */
OP_TAILCALL,/*  A B C   return R(A)(R(A+1), ... ,R(A+B-1))              */
OP_RETURN,/*    A B     return R(A), ... ,R(A+B-2)      (see note)      */
 
OP_FORLOOP,/*   A sBx   R(A)+=R(A+2);
                        if R(A) <?= R(A+1) then { pc+=sBx; R(A+3)=R(A) }*/
OP_FORPREP,/*   A sBx   R(A)-=R(A+2); pc+=sBx                           */
 
OP_TFORCALL,/*  A C     R(A+3), ... ,R(A+2+C) := R(A)(R(A+1), R(A+2));  */
OP_TFORLOOP,/*  A sBx   if R(A+1) ~= nil then { R(A)=R(A+1); pc += sBx }*/
 
OP_SETLIST,/*   A B C   R(A)[(C-1)*FPF+i] := R(A+i), 1 <= i <= B        */
 
OP_CLOSURE,/*   A Bx    R(A) := closure(KPROTO[Bx])                     */
 
OP_VARARG,/*    A B     R(A), R(A+1), ..., R(A+B-2) = vararg            */
 
OP_EXTRAARG/*   Ax      extra (larger) argument for previous opcode     */
} OpCode;
 
 
#define NUM_OPCODES     (cast(int, OP_EXTRAARG) + 1)
 
 
 
/*===========================================================================
  Notes:
  (*) In OP_CALL, if (B == 0) then B = top. If (C == 0), then 'top' is
  set to last_result+1, so next open instruction (OP_CALL, OP_RETURN,
  OP_SETLIST) may use 'top'.
 
  (*) In OP_VARARG, if (B == 0) then use actual number of varargs and
  set top (like in OP_CALL with C == 0).
 
  (*) In OP_RETURN, if (B == 0) then return up to 'top'.
 
  (*) In OP_SETLIST, if (B == 0) then B = 'top'; if (C == 0) then next
  'instruction' is EXTRAARG(real C).
 
  (*) In OP_LOADKX, the next 'instruction' is always EXTRAARG.
 
  (*) For comparisons, A specifies what condition the test should accept
  (true or false).
 
  (*) All 'skips' (pc++) assume that next instruction is a jump.
 
===========================================================================*/
 
 
/*
** masks for instruction properties. The format is:
** bits 0-1: op mode
** bits 2-3: C arg mode
** bits 4-5: B arg mode
** bit 6: instruction set register A
** bit 7: operator is a test (next instruction must be a jump)
*/
 
enum OpArgMask {
  OpArgN,  /* argument is not used */
  OpArgU,  /* argument is used */
  OpArgR,  /* argument is a register or a jump offset */
  OpArgK   /* argument is a constant or register/constant */
};
 
LUAI_DDEC const lu_byte luaP_opmodes[NUM_OPCODES];
 
#define getOpMode(m)    (cast(enum OpMode, luaP_opmodes[m] & 3))
#define getBMode(m)     (cast(enum OpArgMask, (luaP_opmodes[m] >> 4) & 3))
#define getCMode(m)     (cast(enum OpArgMask, (luaP_opmodes[m] >> 2) & 3))
#define testAMode(m)    (luaP_opmodes[m] & (1 << 6))
#define testTMode(m)    (luaP_opmodes[m] & (1 << 7))
 
 
LUAI_DDEC const char *const luaP_opnames[NUM_OPCODES+1];  /* opcode names */
 
 
/* number of list items to accumulate before a SETLIST instruction */
#define LFIELDS_PER_FLUSH       50
 
 
#endif