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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