1/*	$NetBSD$	*/
2
3/*
4** Id: lopcodes.h,v 1.125.1.1 2007/12/27 13:02:25 roberto Exp
5** Opcodes for Lua virtual machine
6** See Copyright Notice in lua.h
7*/
8
9#ifndef lopcodes_h
10#define lopcodes_h
11
12#include "llimits.h"
13
14
15/*===========================================================================
16  We assume that instructions are unsigned numbers.
17  All instructions have an opcode in the first 6 bits.
18  Instructions can have the following fields:
19	`A' : 8 bits
20	`B' : 9 bits
21	`C' : 9 bits
22	`Bx' : 18 bits (`B' and `C' together)
23	`sBx' : signed Bx
24
25  A signed argument is represented in excess K; that is, the number
26  value is the unsigned value minus K. K is exactly the maximum value
27  for that argument (so that -max is represented by 0, and +max is
28  represented by 2*max), which is half the maximum for the corresponding
29  unsigned argument.
30===========================================================================*/
31
32
33enum OpMode {iABC, iABx, iAsBx};  /* basic instruction format */
34
35
36/*
37** size and position of opcode arguments.
38*/
39#define SIZE_C		9
40#define SIZE_B		9
41#define SIZE_Bx		(SIZE_C + SIZE_B)
42#define SIZE_A		8
43
44#define SIZE_OP		6
45
46#define POS_OP		0
47#define POS_A		(POS_OP + SIZE_OP)
48#define POS_C		(POS_A + SIZE_A)
49#define POS_B		(POS_C + SIZE_C)
50#define POS_Bx		POS_C
51
52
53/*
54** limits for opcode arguments.
55** we use (signed) int to manipulate most arguments,
56** so they must fit in LUAI_BITSINT-1 bits (-1 for sign)
57*/
58#if SIZE_Bx < LUAI_BITSINT-1
59#define MAXARG_Bx        ((1<<SIZE_Bx)-1)
60#define MAXARG_sBx        (MAXARG_Bx>>1)         /* `sBx' is signed */
61#else
62#define MAXARG_Bx        MAX_INT
63#define MAXARG_sBx        MAX_INT
64#endif
65
66
67#define MAXARG_A        ((1<<SIZE_A)-1)
68#define MAXARG_B        ((1<<SIZE_B)-1)
69#define MAXARG_C        ((1<<SIZE_C)-1)
70
71
72/* creates a mask with `n' 1 bits at position `p' */
73#define MASK1(n,p)	((~((~(Instruction)0)<<n))<<p)
74
75/* creates a mask with `n' 0 bits at position `p' */
76#define MASK0(n,p)	(~MASK1(n,p))
77
78/*
79** the following macros help to manipulate instructions
80*/
81
82#define GET_OPCODE(i)	(cast(OpCode, ((i)>>POS_OP) & MASK1(SIZE_OP,0)))
83#define SET_OPCODE(i,o)	((i) = (((i)&MASK0(SIZE_OP,POS_OP)) | \
84		((cast(Instruction, o)<<POS_OP)&MASK1(SIZE_OP,POS_OP))))
85
86#define GETARG_A(i)	(cast(int, ((i)>>POS_A) & MASK1(SIZE_A,0)))
87#define SETARG_A(i,u)	((i) = (((i)&MASK0(SIZE_A,POS_A)) | \
88		((cast(Instruction, u)<<POS_A)&MASK1(SIZE_A,POS_A))))
89
90#define GETARG_B(i)	(cast(int, ((i)>>POS_B) & MASK1(SIZE_B,0)))
91#define SETARG_B(i,b)	((i) = (((i)&MASK0(SIZE_B,POS_B)) | \
92		((cast(Instruction, b)<<POS_B)&MASK1(SIZE_B,POS_B))))
93
94#define GETARG_C(i)	(cast(int, ((i)>>POS_C) & MASK1(SIZE_C,0)))
95#define SETARG_C(i,b)	((i) = (((i)&MASK0(SIZE_C,POS_C)) | \
96		((cast(Instruction, b)<<POS_C)&MASK1(SIZE_C,POS_C))))
97
98#define GETARG_Bx(i)	(cast(int, ((i)>>POS_Bx) & MASK1(SIZE_Bx,0)))
99#define SETARG_Bx(i,b)	((i) = (((i)&MASK0(SIZE_Bx,POS_Bx)) | \
100		((cast(Instruction, b)<<POS_Bx)&MASK1(SIZE_Bx,POS_Bx))))
101
102#define GETARG_sBx(i)	(GETARG_Bx(i)-MAXARG_sBx)
103#define SETARG_sBx(i,b)	SETARG_Bx((i),cast(unsigned int, (b)+MAXARG_sBx))
104
105
106#define CREATE_ABC(o,a,b,c)	((cast(Instruction, o)<<POS_OP) \
107			| (cast(Instruction, a)<<POS_A) \
108			| (cast(Instruction, b)<<POS_B) \
109			| (cast(Instruction, c)<<POS_C))
110
111#define CREATE_ABx(o,a,bc)	((cast(Instruction, o)<<POS_OP) \
112			| (cast(Instruction, a)<<POS_A) \
113			| (cast(Instruction, bc)<<POS_Bx))
114
115
116/*
117** Macros to operate RK indices
118*/
119
120/* this bit 1 means constant (0 means register) */
121#define BITRK		(1 << (SIZE_B - 1))
122
123/* test whether value is a constant */
124#define ISK(x)		((x) & BITRK)
125
126/* gets the index of the constant */
127#define INDEXK(r)	((int)(r) & ~BITRK)
128
129#define MAXINDEXRK	(BITRK - 1)
130
131/* code a constant index as a RK value */
132#define RKASK(x)	((x) | BITRK)
133
134
135/*
136** invalid register that fits in 8 bits
137*/
138#define NO_REG		MAXARG_A
139
140
141/*
142** R(x) - register
143** Kst(x) - constant (in constant table)
144** RK(x) == if ISK(x) then Kst(INDEXK(x)) else R(x)
145*/
146
147
148/*
149** grep "ORDER OP" if you change these enums
150*/
151
152typedef enum {
153/*----------------------------------------------------------------------
154name		args	description
155------------------------------------------------------------------------*/
156OP_MOVE,/*	A B	R(A) := R(B)					*/
157OP_LOADK,/*	A Bx	R(A) := Kst(Bx)					*/
158OP_LOADBOOL,/*	A B C	R(A) := (Bool)B; if (C) pc++			*/
159OP_LOADNIL,/*	A B	R(A) := ... := R(B) := nil			*/
160OP_GETUPVAL,/*	A B	R(A) := UpValue[B]				*/
161
162OP_GETGLOBAL,/*	A Bx	R(A) := Gbl[Kst(Bx)]				*/
163OP_GETTABLE,/*	A B C	R(A) := R(B)[RK(C)]				*/
164
165OP_SETGLOBAL,/*	A Bx	Gbl[Kst(Bx)] := R(A)				*/
166OP_SETUPVAL,/*	A B	UpValue[B] := R(A)				*/
167OP_SETTABLE,/*	A B C	R(A)[RK(B)] := RK(C)				*/
168
169OP_NEWTABLE,/*	A B C	R(A) := {} (size = B,C)				*/
170
171OP_SELF,/*	A B C	R(A+1) := R(B); R(A) := R(B)[RK(C)]		*/
172
173OP_ADD,/*	A B C	R(A) := RK(B) + RK(C)				*/
174OP_SUB,/*	A B C	R(A) := RK(B) - RK(C)				*/
175OP_MUL,/*	A B C	R(A) := RK(B) * RK(C)				*/
176OP_DIV,/*	A B C	R(A) := RK(B) / RK(C)				*/
177OP_MOD,/*	A B C	R(A) := RK(B) % RK(C)				*/
178OP_POW,/*	A B C	R(A) := RK(B) ^ RK(C)				*/
179OP_UNM,/*	A B	R(A) := -R(B)					*/
180OP_NOT,/*	A B	R(A) := not R(B)				*/
181OP_LEN,/*	A B	R(A) := length of R(B)				*/
182
183OP_CONCAT,/*	A B C	R(A) := R(B).. ... ..R(C)			*/
184
185OP_JMP,/*	sBx	pc+=sBx					*/
186
187OP_EQ,/*	A B C	if ((RK(B) == RK(C)) ~= A) then pc++		*/
188OP_LT,/*	A B C	if ((RK(B) <  RK(C)) ~= A) then pc++  		*/
189OP_LE,/*	A B C	if ((RK(B) <= RK(C)) ~= A) then pc++  		*/
190
191OP_TEST,/*	A C	if not (R(A) <=> C) then pc++			*/
192OP_TESTSET,/*	A B C	if (R(B) <=> C) then R(A) := R(B) else pc++	*/
193
194OP_CALL,/*	A B C	R(A), ... ,R(A+C-2) := R(A)(R(A+1), ... ,R(A+B-1)) */
195OP_TAILCALL,/*	A B C	return R(A)(R(A+1), ... ,R(A+B-1))		*/
196OP_RETURN,/*	A B	return R(A), ... ,R(A+B-2)	(see note)	*/
197
198OP_FORLOOP,/*	A sBx	R(A)+=R(A+2);
199			if R(A) <?= R(A+1) then { pc+=sBx; R(A+3)=R(A) }*/
200OP_FORPREP,/*	A sBx	R(A)-=R(A+2); pc+=sBx				*/
201
202OP_TFORLOOP,/*	A C	R(A+3), ... ,R(A+2+C) := R(A)(R(A+1), R(A+2));
203                        if R(A+3) ~= nil then R(A+2)=R(A+3) else pc++	*/
204OP_SETLIST,/*	A B C	R(A)[(C-1)*FPF+i] := R(A+i), 1 <= i <= B	*/
205
206OP_CLOSE,/*	A 	close all variables in the stack up to (>=) R(A)*/
207OP_CLOSURE,/*	A Bx	R(A) := closure(KPROTO[Bx], R(A), ... ,R(A+n))	*/
208
209OP_VARARG/*	A B	R(A), R(A+1), ..., R(A+B-1) = vararg		*/
210} OpCode;
211
212
213#define NUM_OPCODES	(cast(int, OP_VARARG) + 1)
214
215
216
217/*===========================================================================
218  Notes:
219  (*) In OP_CALL, if (B == 0) then B = top. C is the number of returns - 1,
220      and can be 0: OP_CALL then sets `top' to last_result+1, so
221      next open instruction (OP_CALL, OP_RETURN, OP_SETLIST) may use `top'.
222
223  (*) In OP_VARARG, if (B == 0) then use actual number of varargs and
224      set top (like in OP_CALL with C == 0).
225
226  (*) In OP_RETURN, if (B == 0) then return up to `top'
227
228  (*) In OP_SETLIST, if (B == 0) then B = `top';
229      if (C == 0) then next `instruction' is real C
230
231  (*) For comparisons, A specifies what condition the test should accept
232      (true or false).
233
234  (*) All `skips' (pc++) assume that next instruction is a jump
235===========================================================================*/
236
237
238/*
239** masks for instruction properties. The format is:
240** bits 0-1: op mode
241** bits 2-3: C arg mode
242** bits 4-5: B arg mode
243** bit 6: instruction set register A
244** bit 7: operator is a test
245*/
246
247enum OpArgMask {
248  OpArgN,  /* argument is not used */
249  OpArgU,  /* argument is used */
250  OpArgR,  /* argument is a register or a jump offset */
251  OpArgK   /* argument is a constant or register/constant */
252};
253
254LUAI_DATA const lu_byte luaP_opmodes[NUM_OPCODES];
255
256#define getOpMode(m)	(cast(enum OpMode, luaP_opmodes[m] & 3))
257#define getBMode(m)	(cast(enum OpArgMask, (luaP_opmodes[m] >> 4) & 3))
258#define getCMode(m)	(cast(enum OpArgMask, (luaP_opmodes[m] >> 2) & 3))
259#define testAMode(m)	(luaP_opmodes[m] & (1 << 6))
260#define testTMode(m)	(luaP_opmodes[m] & (1 << 7))
261
262
263LUAI_DATA const char *const luaP_opnames[NUM_OPCODES+1];  /* opcode names */
264
265
266/* number of list items to accumulate before a SETLIST instruction */
267#define LFIELDS_PER_FLUSH	50
268
269
270#endif
271