1/*
2** $Id: lopcodes.h,v 1.142 2011/07/15 12:50:29 roberto Exp $
3** Opcodes for Lua virtual machine
4** See Copyright Notice in lua.h
5*/
6
7#ifndef lopcodes_h
8#define lopcodes_h
9
10#include "llimits.h"
11
12
13/*===========================================================================
14  We assume that instructions are unsigned numbers.
15  All instructions have an opcode in the first 6 bits.
16  Instructions can have the following fields:
17	`A' : 8 bits
18	`B' : 9 bits
19	`C' : 9 bits
20	'Ax' : 26 bits ('A', 'B', and 'C' together)
21	`Bx' : 18 bits (`B' and `C' together)
22	`sBx' : signed Bx
23
24  A signed argument is represented in excess K; that is, the number
25  value is the unsigned value minus K. K is exactly the maximum value
26  for that argument (so that -max is represented by 0, and +max is
27  represented by 2*max), which is half the maximum for the corresponding
28  unsigned argument.
29===========================================================================*/
30
31
32enum OpMode {iABC, iABx, iAsBx, iAx};  /* basic instruction format */
33
34
35/*
36** size and position of opcode arguments.
37*/
38#define SIZE_C		9
39#define SIZE_B		9
40#define SIZE_Bx		(SIZE_C + SIZE_B)
41#define SIZE_A		8
42#define SIZE_Ax		(SIZE_C + SIZE_B + SIZE_A)
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#define POS_Ax		POS_A
52
53
54/*
55** limits for opcode arguments.
56** we use (signed) int to manipulate most arguments,
57** so they must fit in LUAI_BITSINT-1 bits (-1 for sign)
58*/
59#if SIZE_Bx < LUAI_BITSINT-1
60#define MAXARG_Bx        ((1<<SIZE_Bx)-1)
61#define MAXARG_sBx        (MAXARG_Bx>>1)         /* `sBx' is signed */
62#else
63#define MAXARG_Bx        MAX_INT
64#define MAXARG_sBx        MAX_INT
65#endif
66
67#if SIZE_Ax < LUAI_BITSINT-1
68#define MAXARG_Ax	((1<<SIZE_Ax)-1)
69#else
70#define MAXARG_Ax	MAX_INT
71#endif
72
73
74#define MAXARG_A        ((1<<SIZE_A)-1)
75#define MAXARG_B        ((1<<SIZE_B)-1)
76#define MAXARG_C        ((1<<SIZE_C)-1)
77
78
79/* creates a mask with `n' 1 bits at position `p' */
80#define MASK1(n,p)	((~((~(Instruction)0)<<(n)))<<(p))
81
82/* creates a mask with `n' 0 bits at position `p' */
83#define MASK0(n,p)	(~MASK1(n,p))
84
85/*
86** the following macros help to manipulate instructions
87*/
88
89#define GET_OPCODE(i)	(cast(OpCode, ((i)>>POS_OP) & MASK1(SIZE_OP,0)))
90#define SET_OPCODE(i,o)	((i) = (((i)&MASK0(SIZE_OP,POS_OP)) | \
91		((cast(Instruction, o)<<POS_OP)&MASK1(SIZE_OP,POS_OP))))
92
93#define getarg(i,pos,size)	(cast(int, ((i)>>pos) & MASK1(size,0)))
94#define setarg(i,v,pos,size)	((i) = (((i)&MASK0(size,pos)) | \
95                ((cast(Instruction, v)<<pos)&MASK1(size,pos))))
96
97#define GETARG_A(i)	getarg(i, POS_A, SIZE_A)
98#define SETARG_A(i,v)	setarg(i, v, POS_A, SIZE_A)
99
100#define GETARG_B(i)	getarg(i, POS_B, SIZE_B)
101#define SETARG_B(i,v)	setarg(i, v, POS_B, SIZE_B)
102
103#define GETARG_C(i)	getarg(i, POS_C, SIZE_C)
104#define SETARG_C(i,v)	setarg(i, v, POS_C, SIZE_C)
105
106#define GETARG_Bx(i)	getarg(i, POS_Bx, SIZE_Bx)
107#define SETARG_Bx(i,v)	setarg(i, v, POS_Bx, SIZE_Bx)
108
109#define GETARG_Ax(i)	getarg(i, POS_Ax, SIZE_Ax)
110#define SETARG_Ax(i,v)	setarg(i, v, POS_Ax, SIZE_Ax)
111
112#define GETARG_sBx(i)	(GETARG_Bx(i)-MAXARG_sBx)
113#define SETARG_sBx(i,b)	SETARG_Bx((i),cast(unsigned int, (b)+MAXARG_sBx))
114
115
116#define CREATE_ABC(o,a,b,c)	((cast(Instruction, o)<<POS_OP) \
117			| (cast(Instruction, a)<<POS_A) \
118			| (cast(Instruction, b)<<POS_B) \
119			| (cast(Instruction, c)<<POS_C))
120
121#define CREATE_ABx(o,a,bc)	((cast(Instruction, o)<<POS_OP) \
122			| (cast(Instruction, a)<<POS_A) \
123			| (cast(Instruction, bc)<<POS_Bx))
124
125#define CREATE_Ax(o,a)		((cast(Instruction, o)<<POS_OP) \
126			| (cast(Instruction, a)<<POS_Ax))
127
128
129/*
130** Macros to operate RK indices
131*/
132
133/* this bit 1 means constant (0 means register) */
134#define BITRK		(1 << (SIZE_B - 1))
135
136/* test whether value is a constant */
137#define ISK(x)		((x) & BITRK)
138
139/* gets the index of the constant */
140#define INDEXK(r)	((int)(r) & ~BITRK)
141
142#define MAXINDEXRK	(BITRK - 1)
143
144/* code a constant index as a RK value */
145#define RKASK(x)	((x) | BITRK)
146
147
148/*
149** invalid register that fits in 8 bits
150*/
151#define NO_REG		MAXARG_A
152
153
154/*
155** R(x) - register
156** Kst(x) - constant (in constant table)
157** RK(x) == if ISK(x) then Kst(INDEXK(x)) else R(x)
158*/
159
160
161/*
162** grep "ORDER OP" if you change these enums
163*/
164
165typedef enum {
166/*----------------------------------------------------------------------
167name		args	description
168------------------------------------------------------------------------*/
169OP_MOVE,/*	A B	R(A) := R(B)					*/
170OP_LOADK,/*	A Bx	R(A) := Kst(Bx)					*/
171OP_LOADKX,/*	A 	R(A) := Kst(extra arg)				*/
172OP_LOADBOOL,/*	A B C	R(A) := (Bool)B; if (C) pc++			*/
173OP_LOADNIL,/*	A B	R(A), R(A+1), ..., R(A+B) := nil		*/
174OP_GETUPVAL,/*	A B	R(A) := UpValue[B]				*/
175
176OP_GETTABUP,/*	A B C	R(A) := UpValue[B][RK(C)]			*/
177OP_GETTABLE,/*	A B C	R(A) := R(B)[RK(C)]				*/
178
179OP_SETTABUP,/*	A B C	UpValue[A][RK(B)] := RK(C)			*/
180OP_SETUPVAL,/*	A B	UpValue[B] := R(A)				*/
181OP_SETTABLE,/*	A B C	R(A)[RK(B)] := RK(C)				*/
182
183OP_NEWTABLE,/*	A B C	R(A) := {} (size = B,C)				*/
184
185OP_SELF,/*	A B C	R(A+1) := R(B); R(A) := R(B)[RK(C)]		*/
186
187OP_ADD,/*	A B C	R(A) := RK(B) + RK(C)				*/
188OP_SUB,/*	A B C	R(A) := RK(B) - RK(C)				*/
189OP_MUL,/*	A B C	R(A) := RK(B) * RK(C)				*/
190OP_DIV,/*	A B C	R(A) := RK(B) / RK(C)				*/
191OP_MOD,/*	A B C	R(A) := RK(B) % RK(C)				*/
192OP_POW,/*	A B C	R(A) := RK(B) ^ RK(C)				*/
193OP_UNM,/*	A B	R(A) := -R(B)					*/
194OP_NOT,/*	A B	R(A) := not R(B)				*/
195OP_LEN,/*	A B	R(A) := length of R(B)				*/
196
197OP_CONCAT,/*	A B C	R(A) := R(B).. ... ..R(C)			*/
198
199OP_JMP,/*	A sBx	pc+=sBx; if (A) close all upvalues >= R(A) + 1	*/
200OP_EQ,/*	A B C	if ((RK(B) == RK(C)) ~= A) then pc++		*/
201OP_LT,/*	A B C	if ((RK(B) <  RK(C)) ~= A) then pc++		*/
202OP_LE,/*	A B C	if ((RK(B) <= RK(C)) ~= A) then pc++		*/
203
204OP_TEST,/*	A C	if not (R(A) <=> C) then pc++			*/
205OP_TESTSET,/*	A B C	if (R(B) <=> C) then R(A) := R(B) else pc++	*/
206
207OP_CALL,/*	A B C	R(A), ... ,R(A+C-2) := R(A)(R(A+1), ... ,R(A+B-1)) */
208OP_TAILCALL,/*	A B C	return R(A)(R(A+1), ... ,R(A+B-1))		*/
209OP_RETURN,/*	A B	return R(A), ... ,R(A+B-2)	(see note)	*/
210
211OP_FORLOOP,/*	A sBx	R(A)+=R(A+2);
212			if R(A) <?= R(A+1) then { pc+=sBx; R(A+3)=R(A) }*/
213OP_FORPREP,/*	A sBx	R(A)-=R(A+2); pc+=sBx				*/
214
215OP_TFORCALL,/*	A C	R(A+3), ... ,R(A+2+C) := R(A)(R(A+1), R(A+2));	*/
216OP_TFORLOOP,/*	A sBx	if R(A+1) ~= nil then { R(A)=R(A+1); pc += sBx }*/
217
218OP_SETLIST,/*	A B C	R(A)[(C-1)*FPF+i] := R(A+i), 1 <= i <= B	*/
219
220OP_CLOSURE,/*	A Bx	R(A) := closure(KPROTO[Bx])			*/
221
222OP_VARARG,/*	A B	R(A), R(A+1), ..., R(A+B-2) = vararg		*/
223
224OP_EXTRAARG/*	Ax	extra (larger) argument for previous opcode	*/
225} OpCode;
226
227
228#define NUM_OPCODES	(cast(int, OP_EXTRAARG) + 1)
229
230
231
232/*===========================================================================
233  Notes:
234  (*) In OP_CALL, if (B == 0) then B = top. If (C == 0), then `top' is
235  set to last_result+1, so next open instruction (OP_CALL, OP_RETURN,
236  OP_SETLIST) may use `top'.
237
238  (*) In OP_VARARG, if (B == 0) then use actual number of varargs and
239  set top (like in OP_CALL with C == 0).
240
241  (*) In OP_RETURN, if (B == 0) then return up to `top'.
242
243  (*) In OP_SETLIST, if (B == 0) then B = `top'; if (C == 0) then next
244  'instruction' is EXTRAARG(real C).
245
246  (*) In OP_LOADKX, the next 'instruction' is always EXTRAARG.
247
248  (*) For comparisons, A specifies what condition the test should accept
249  (true or false).
250
251  (*) All `skips' (pc++) assume that next instruction is a jump.
252
253===========================================================================*/
254
255
256/*
257** masks for instruction properties. The format is:
258** bits 0-1: op mode
259** bits 2-3: C arg mode
260** bits 4-5: B arg mode
261** bit 6: instruction set register A
262** bit 7: operator is a test (next instruction must be a jump)
263*/
264
265enum OpArgMask {
266  OpArgN,  /* argument is not used */
267  OpArgU,  /* argument is used */
268  OpArgR,  /* argument is a register or a jump offset */
269  OpArgK   /* argument is a constant or register/constant */
270};
271
272LUAI_DDEC const lu_byte luaP_opmodes[NUM_OPCODES];
273
274#define getOpMode(m)	(cast(enum OpMode, luaP_opmodes[m] & 3))
275#define getBMode(m)	(cast(enum OpArgMask, (luaP_opmodes[m] >> 4) & 3))
276#define getCMode(m)	(cast(enum OpArgMask, (luaP_opmodes[m] >> 2) & 3))
277#define testAMode(m)	(luaP_opmodes[m] & (1 << 6))
278#define testTMode(m)	(luaP_opmodes[m] & (1 << 7))
279
280
281LUAI_DDEC const char *const luaP_opnames[NUM_OPCODES+1];  /* opcode names */
282
283
284/* number of list items to accumulate before a SETLIST instruction */
285#define LFIELDS_PER_FLUSH	50
286
287
288#endif
289