text: /*
  ** $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)
  */
  
  
  #if 0
  /*
  ** grep "ORDER OP" if you change these enums
  */
  
  typedef enum {
    OP_ADD,/* A B C R(A) := RK(B) + RK(C)       */  // by c0i
    OP_CALL,/*  A B C R(A), ... ,R(A+C-2) := R(A)(R(A+1), ... ,R(A+B-1)) */ // by c0i
  
  /*----------------------------------------------------------------------
  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)				*/ // by c0i
  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)) */  // by c0i
  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;
  #else
  #include "lopcodes2.h"
  #endif
  
  #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
  