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+/*
+** $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
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