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