/*

 ** $Id: lopcodes.h,v 1.125.1.1 2007/12/27 13:02:25 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

 	`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};  /* 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_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

 

 

 /*

 ** 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

 

 

 #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_A(i)	(cast(int, ((i)>>POS_A) & MASK1(SIZE_A,0)))

 #define SETARG_A(i,u)	((i) = (((i)&MASK0(SIZE_A,POS_A)) | \

 		((cast(Instruction, u)<<POS_A)&MASK1(SIZE_A,POS_A))))

 

 #define GETARG_B(i)	(cast(int, ((i)>>POS_B) & MASK1(SIZE_B,0)))

 #define SETARG_B(i,b)	((i) = (((i)&MASK0(SIZE_B,POS_B)) | \

 		((cast(Instruction, b)<<POS_B)&MASK1(SIZE_B,POS_B))))

 

 #define GETARG_C(i)	(cast(int, ((i)>>POS_C) & MASK1(SIZE_C,0)))

 #define SETARG_C(i,b)	((i) = (((i)&MASK0(SIZE_C,POS_C)) | \

 		((cast(Instruction, b)<<POS_C)&MASK1(SIZE_C,POS_C))))

 

 #define GETARG_Bx(i)	(cast(int, ((i)>>POS_Bx) & MASK1(SIZE_Bx,0)))

 #define SETARG_Bx(i,b)	((i) = (((i)&MASK0(SIZE_Bx,POS_Bx)) | \

 		((cast(Instruction, b)<<POS_Bx)&MASK1(SIZE_Bx,POS_Bx))))

 

 #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))

 

 

 /*

 ** 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)

 

 #define MAXINDEXRK	(BITRK - 1)

 

 /* 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_LOADBOOL,/*	A B C	R(A) := (Bool)B; if (C) pc++			*/

 OP_LOADNIL,/*	A B	R(A) := ... := R(B) := nil			*/

 OP_GETUPVAL,/*	A B	R(A) := UpValue[B]				*/

 

 OP_GETGLOBAL,/*	A Bx	R(A) := Gbl[Kst(Bx)]				*/

 OP_GETTABLE,/*	A B C	R(A) := R(B)[RK(C)]				*/

 

 OP_SETGLOBAL,/*	A Bx	Gbl[Kst(Bx)] := R(A)				*/

 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_DIV,/*	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_UNM,/*	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,/*	sBx	pc+=sBx					*/

 

 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_TFORLOOP,/*	A C	R(A+3), ... ,R(A+2+C) := R(A)(R(A+1), R(A+2)); 

                         if R(A+3) ~= nil then R(A+2)=R(A+3) else pc++	*/ 

 OP_SETLIST,/*	A B C	R(A)[(C-1)*FPF+i] := R(A+i), 1 <= i <= B	*/

 

 OP_CLOSE,/*	A 	close all variables in the stack up to (>=) R(A)*/

 OP_CLOSURE,/*	A Bx	R(A) := closure(KPROTO[Bx], R(A), ... ,R(A+n))	*/

 

 OP_VARARG/*	A B	R(A), R(A+1), ..., R(A+B-1) = vararg		*/

 } OpCode;

 

 

 #define NUM_OPCODES	(cast(int, OP_VARARG) + 1)

 

 

 

 /*===========================================================================

   Notes:

   (*) In OP_CALL, if (B == 0) then B = top. C is the number of returns - 1,

       and can be 0: OP_CALL then sets `top' 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 real C

 

   (*) 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

 */  

 

 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_DATA 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_DATA 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