void luaV_execute (lua_State *L) {
CallInfo *ci = L->ci;
LClosure *cl;
TValue *k;
StkId base;
newframe: /* reentry point when frame changes (call/return) */
lua_assert(ci == L->ci);
cl = clLvalue(ci->func);
k = cl->p->k;
base = ci->u.l.base;
//printf( "s:%p\n", ci->u.l.savedpc );
/* main loop of interpreter */
for (;;) {
Instruction i = *(ci->u.l.savedpc++);
StkId ra;
if ((L->hookmask & (LUA_MASKLINE | LUA_MASKCOUNT)) &&
(--L->hookcount == 0 || L->hookmask & LUA_MASKLINE)) {
Protect(traceexec(L));
}
/* warning!! several calls may realloc the stack and invalidate `ra' */
ra = RA(i);
lua_assert(base == ci->u.l.base);
lua_assert(base <= L->top && L->top < L->stack + L->stacksize);
// 命令出力
//printInst( ci->u.l.savedpc - 1 );
vmdispatch (GET_OPCODE(i)) {
vmcase(OP_MOVE,
setobjs2s(L, ra, RB(i));
)
vmcase(OP_LOADK,
TValue *rb = k + GETARG_Bx(i);
setobj2s(L, ra, rb);
)
vmcase(OP_LOADKX,
TValue *rb;
lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_EXTRAARG);
rb = k + GETARG_Ax(*ci->u.l.savedpc++);
setobj2s(L, ra, rb);
)
void luaV_execute (lua_State *L, int nexeccalls) {
LClosure *cl;
StkId base;
TValue *k;
const Instruction *pc;
reentry: /* entry point */
lua_assert(isLua(L->ci));
pc = L->savedpc;
cl = &clvalue(L->ci->func)->l;
base = L->base;
k = cl->p->k;
/* main loop of interpreter */
for (;;) {
const Instruction i = *pc++;
StkId ra;
if ((L->hookmask & (LUA_MASKLINE | LUA_MASKCOUNT)) &&
(--L->hookcount == 0 || L->hookmask & LUA_MASKLINE)) {
traceexec(L, pc);
if (L->status == LUA_YIELD) { /* did hook yield? */
L->savedpc = pc - 1;
return;
}
base = L->base;
}
/* warning!! several calls may realloc the stack and invalidate `ra' */
ra = RA(i);
lua_assert(base == L->base && L->base == L->ci->base);
lua_assert(base <= L->top && L->top <= L->stack + L->stacksize);
lua_assert(L->top == L->ci->top || luaG_checkopenop(i));
switch (GET_OPCODE(i)) {
case OP_MOVE: {
setobjs2s(L, ra, RB(i));
continue;
}
case OP_LOADK: {
setobj2s(L, ra, KBx(i));
continue;
}
case OP_LOADBOOL: {
setbvalue(ra, GETARG_B(i));
if (GETARG_C(i)) pc++; /* skip next instruction (if C) */
continue;
}
case OP_LOADNIL: {
TValue *rb = RB(i);
do {
setnilvalue(rb--);
} while (rb >= ra);
continue;
}
case OP_GETUPVAL: {
int b = GETARG_B(i);
setobj2s(L, ra, cl->upvals[b]->v);
continue;
}
case OP_GETGLOBAL: {
TValue g;
TValue *rb = KBx(i);
sethvalue(L, &g, cl->env);
lua_assert(ttisstring(rb));
Protect(luaV_gettable(L, &g, rb, ra));
continue;
}
case OP_GETTABLE: {
Protect(luaV_gettable(L, RB(i), RKC(i), ra));
continue;
}
case OP_SETGLOBAL: {
TValue g;
sethvalue(L, &g, cl->env);
lua_assert(ttisstring(KBx(i)));
Protect(luaV_settable(L, &g, KBx(i), ra));
continue;
}
case OP_SETUPVAL: {
UpVal *uv = cl->upvals[GETARG_B(i)];
setobj(L, uv->v, ra);
luaC_barrier(L, uv, ra);
continue;
}
case OP_SETTABLE: {
Protect(luaV_settable(L, ra, RKB(i), RKC(i)));
continue;
}
case OP_NEWTABLE: {
int b = GETARG_B(i);
int c = GETARG_C(i);
sethvalue(L, ra, luaH_new(L, luaO_fb2int(b), luaO_fb2int(c)));
Protect(luaC_checkGC(L));
continue;
}
case OP_SELF: {
StkId rb = RB(i);
setobjs2s(L, ra+1, rb);
Protect(luaV_gettable(L, rb, RKC(i), ra));
continue;
}
case OP_ADD: {
arith_op(luai_numadd, TM_ADD);
continue;
}
case OP_SUB: {
arith_op(luai_numsub, TM_SUB);
continue;
}
case OP_MUL: {
arith_op(luai_nummul, TM_MUL);
continue;
}
case OP_DIV: {
arith_op(luai_numdiv, TM_DIV);
continue;
}
case OP_MOD: {
arith_op(luai_nummod, TM_MOD);
continue;
}
case OP_POW: {
arith_op(luai_numpow, TM_POW);
continue;
}
case OP_UNM: {
TValue *rb = RB(i);
if (ttisnumber(rb)) {
lua_Number nb = nvalue(rb);
setnvalue(ra, luai_numunm(nb));
}
else {
Protect(luaV_arith(L, ra, rb, rb, TM_UNM));
}
continue;
}
case OP_NOT: {
int res = l_isfalse(RB(i)); /* next assignment may change this value */
setbvalue(ra, res);
continue;
}
case OP_LEN: {
const TValue *rb = RB(i);
switch (ttype(rb)) {
case LUA_TTABLE: {
setnvalue(ra, cast_num(luaH_getn(hvalue(rb))));
break;
}
case LUA_TSTRING: {
setnvalue(ra, cast_num(tsvalue(rb)->len));
break;
}
default: { /* try metamethod */
Protect(
if (!call_binTM(L, rb, luaO_nilobject, ra, TM_LEN))
luaG_typeerror(L, rb, "get length of");
)
}
}
continue;
}
case OP_CONCAT: {
int b = GETARG_B(i);
int c = GETARG_C(i);
Protect(luaV_concat(L, c-b+1, c); luaC_checkGC(L));
setobjs2s(L, RA(i), base+b);
continue;
}
case OP_JMP: {
dojump(L, pc, GETARG_sBx(i));
continue;
}
case OP_EQ: {
TValue *rb = RKB(i);
TValue *rc = RKC(i);
Protect(
if (equalobj(L, rb, rc) == GETARG_A(i))
dojump(L, pc, GETARG_sBx(*pc));
)
pc++;
continue;
}
case OP_LT: {
Protect(
if (luaV_lessthan(L, RKB(i), RKC(i)) == GETARG_A(i))
dojump(L, pc, GETARG_sBx(*pc));
)
pc++;
continue;
}
case OP_LE: {
Protect(
if (luaV_lessequal(L, RKB(i), RKC(i)) == GETARG_A(i))
dojump(L, pc, GETARG_sBx(*pc));
)
pc++;
continue;
}
/*
** Executes the given Lua function. Parameters are between [base,top).
** Returns n such that the the results are between [n,top).
*/
StkId luaV_execute (lua_State *L, const Closure *cl, StkId base) {
const Proto *const tf = cl->f.l;
StkId top; /* keep top local, for performance */
const Instruction *pc = tf->code;
TString **const kstr = tf->kstr;
const lua_Hook linehook = L->linehook;
infovalue(base-1)->pc = &pc;
luaD_checkstack(L, tf->maxstacksize+EXTRA_STACK);
if (tf->is_vararg) /* varargs? */
adjust_varargs(L, base, tf->numparams);
else
luaD_adjusttop(L, base, tf->numparams);
top = L->top;
/* main loop of interpreter */
for (;;) {
const Instruction i = *pc++;
if (linehook)
traceexec(L, base, top, linehook);
switch (GET_OPCODE(i)) {
case OP_END: {
L->top = top;
return top;
}
case OP_RETURN: {
L->top = top;
return base+GETARG_U(i);
}
case OP_CALL: {
int nres = GETARG_B(i);
if (nres == MULT_RET) nres = LUA_MULTRET;
L->top = top;
luaD_call(L, base+GETARG_A(i), nres);
top = L->top;
break;
}
case OP_TAILCALL: {
L->top = top;
luaD_call(L, base+GETARG_A(i), LUA_MULTRET);
return base+GETARG_B(i);
}
case OP_PUSHNIL: {
int n = GETARG_U(i);
LUA_ASSERT(n>0, "invalid argument");
do {
ttype(top++) = LUA_TNIL;
} while (--n > 0);
break;
}
case OP_POP: {
top -= GETARG_U(i);
break;
}
case OP_PUSHINT: {
ttype(top) = LUA_TNUMBER;
nvalue(top) = (Number)GETARG_S(i);
top++;
break;
}
case OP_PUSHSTRING: {
ttype(top) = LUA_TSTRING;
tsvalue(top) = kstr[GETARG_U(i)];
top++;
break;
}
case OP_PUSHNUM: {
ttype(top) = LUA_TNUMBER;
nvalue(top) = tf->knum[GETARG_U(i)];
top++;
break;
}
case OP_PUSHNEGNUM: {
ttype(top) = LUA_TNUMBER;
nvalue(top) = -tf->knum[GETARG_U(i)];
top++;
break;
}
case OP_PUSHUPVALUE: {
*top++ = cl->upvalue[GETARG_U(i)];
break;
}
case OP_GETLOCAL: {
*top++ = *(base+GETARG_U(i));
break;
}
case OP_GETGLOBAL: {
L->top = top;
*top = *luaV_getglobal(L, kstr[GETARG_U(i)]);
top++;
break;
}
case OP_GETTABLE: {
L->top = top;
top--;
*(top-1) = *luaV_gettable(L, top-1);
break;
}
case OP_GETDOTTED: {
ttype(top) = LUA_TSTRING;
tsvalue(top) = kstr[GETARG_U(i)];
L->top = top+1;
*(top-1) = *luaV_gettable(L, top-1);
break;
}
case OP_GETINDEXED: {
*top = *(base+GETARG_U(i));
L->top = top+1;
*(top-1) = *luaV_gettable(L, top-1);
break;
}
case OP_PUSHSELF: {
TObject receiver;
receiver = *(top-1);
ttype(top) = LUA_TSTRING;
tsvalue(top++) = kstr[GETARG_U(i)];
L->top = top;
*(top-2) = *luaV_gettable(L, top-2);
*(top-1) = receiver;
break;
}
case OP_CREATETABLE: {
L->top = top;
luaC_checkGC(L);
hvalue(top) = luaH_new(L, GETARG_U(i));
ttype(top) = LUA_TTABLE;
top++;
break;
}
case OP_SETLOCAL: {
*(base+GETARG_U(i)) = *(--top);
break;
}
case OP_SETGLOBAL: {
L->top = top;
luaV_setglobal(L, kstr[GETARG_U(i)]);
top--;
break;
}
case OP_SETTABLE: {
StkId t = top-GETARG_A(i);
L->top = top;
luaV_settable(L, t, t+1);
top -= GETARG_B(i); /* pop values */
break;
}
case OP_SETLIST: {
int aux = GETARG_A(i) * LFIELDS_PER_FLUSH;
int n = GETARG_B(i);
Hash *arr = hvalue(top-n-1);
L->top = top-n; /* final value of `top' (in case of errors) */
for (; n; n--)
*luaH_setint(L, arr, n+aux) = *(--top);
break;
}
case OP_SETMAP: {
int n = GETARG_U(i);
StkId finaltop = top-2*n;
Hash *arr = hvalue(finaltop-1);
L->top = finaltop; /* final value of `top' (in case of errors) */
for (; n; n--) {
top-=2;
*luaH_set(L, arr, top) = *(top+1);
}
break;
}
case OP_ADD: {
if (tonumber(top-2) || tonumber(top-1))
call_arith(L, top, TM_ADD);
else
nvalue(top-2) += nvalue(top-1);
top--;
break;
}
case OP_ADDI: {
if (tonumber(top-1)) {
ttype(top) = LUA_TNUMBER;
nvalue(top) = (Number)GETARG_S(i);
call_arith(L, top+1, TM_ADD);
}
else
nvalue(top-1) += (Number)GETARG_S(i);
break;
}
case OP_SUB: {
if (tonumber(top-2) || tonumber(top-1))
call_arith(L, top, TM_SUB);
else
nvalue(top-2) -= nvalue(top-1);
top--;
break;
}
case OP_MULT: {
if (tonumber(top-2) || tonumber(top-1))
call_arith(L, top, TM_MUL);
else
nvalue(top-2) *= nvalue(top-1);
top--;
break;
}
case OP_DIV: {
if (tonumber(top-2) || tonumber(top-1))
call_arith(L, top, TM_DIV);
else
nvalue(top-2) /= nvalue(top-1);
top--;
break;
}
case OP_POW: {
if (!call_binTM(L, top, TM_POW))
lua_error(L, "undefined operation");
top--;
break;
}
case OP_CONCAT: {
int n = GETARG_U(i);
luaV_strconc(L, n, top);
top -= n-1;
L->top = top;
luaC_checkGC(L);
break;
}
case OP_MINUS: {
if (tonumber(top-1)) {
ttype(top) = LUA_TNIL;
call_arith(L, top+1, TM_UNM);
}
else
nvalue(top-1) = -nvalue(top-1);
break;
}
case OP_NOT: {
ttype(top-1) =
(ttype(top-1) == LUA_TNIL) ? LUA_TNUMBER : LUA_TNIL;
nvalue(top-1) = 1;
break;
}
case OP_JMPNE: {
top -= 2;
if (!luaO_equalObj(top, top+1)) dojump(pc, i);
break;
}
case OP_JMPEQ: {
top -= 2;
if (luaO_equalObj(top, top+1)) dojump(pc, i);
break;
}
case OP_JMPLT: {
top -= 2;
if (luaV_lessthan(L, top, top+1, top+2)) dojump(pc, i);
break;
}
case OP_JMPLE: { /* a <= b === !(b<a) */
top -= 2;
if (!luaV_lessthan(L, top+1, top, top+2)) dojump(pc, i);
break;
}
case OP_JMPGT: { /* a > b === (b<a) */
top -= 2;
if (luaV_lessthan(L, top+1, top, top+2)) dojump(pc, i);
break;
}
case OP_JMPGE: { /* a >= b === !(a<b) */
top -= 2;
if (!luaV_lessthan(L, top, top+1, top+2)) dojump(pc, i);
break;
}
case OP_JMPT: {
if (ttype(--top) != LUA_TNIL) dojump(pc, i);
break;
}
case OP_JMPF: {
if (ttype(--top) == LUA_TNIL) dojump(pc, i);
break;
}
case OP_JMPONT: {
if (ttype(top-1) == LUA_TNIL) top--;
else dojump(pc, i);
break;
}
case OP_JMPONF: {
if (ttype(top-1) != LUA_TNIL) top--;
else dojump(pc, i);
break;
}
case OP_JMP: {
dojump(pc, i);
break;
}
case OP_PUSHNILJMP: {
ttype(top++) = LUA_TNIL;
pc++;
break;
}
case OP_FORPREP: {
if (tonumber(top-1))
lua_error(L, "`for' step must be a number");
if (tonumber(top-2))
lua_error(L, "`for' limit must be a number");
if (tonumber(top-3))
lua_error(L, "`for' initial value must be a number");
if (nvalue(top-1) > 0 ?
nvalue(top-3) > nvalue(top-2) :
nvalue(top-3) < nvalue(top-2)) { /* `empty' loop? */
top -= 3; /* remove control variables */
dojump(pc, i); /* jump to loop end */
}
break;
}
case OP_FORLOOP: {
LUA_ASSERT(ttype(top-1) == LUA_TNUMBER, "invalid step");
LUA_ASSERT(ttype(top-2) == LUA_TNUMBER, "invalid limit");
if (ttype(top-3) != LUA_TNUMBER)
lua_error(L, "`for' index must be a number");
nvalue(top-3) += nvalue(top-1); /* increment index */
if (nvalue(top-1) > 0 ?
nvalue(top-3) > nvalue(top-2) :
nvalue(top-3) < nvalue(top-2))
top -= 3; /* end loop: remove control variables */
else
dojump(pc, i); /* repeat loop */
break;
}
case OP_LFORPREP: {
Node *node;
if (ttype(top-1) != LUA_TTABLE)
lua_error(L, "`for' table must be a table");
node = luaH_next(L, hvalue(top-1), &luaO_nilobject);
if (node == NULL) { /* `empty' loop? */
top--; /* remove table */
dojump(pc, i); /* jump to loop end */
}
else {
top += 2; /* index,value */
*(top-2) = *key(node);
*(top-1) = *val(node);
}
break;
}
case OP_LFORLOOP: {
Node *node;
LUA_ASSERT(ttype(top-3) == LUA_TTABLE, "invalid table");
node = luaH_next(L, hvalue(top-3), top-2);
if (node == NULL) /* end loop? */
top -= 3; /* remove table, key, and value */
else {
*(top-2) = *key(node);
*(top-1) = *val(node);
dojump(pc, i); /* repeat loop */
}
break;
}
case OP_CLOSURE: {
L->top = top;
luaV_Lclosure(L, tf->kproto[GETARG_A(i)], GETARG_B(i));
top = L->top;
luaC_checkGC(L);
break;
}
}
}
}
StkId luaV_execute (lua_State *L) {
LClosure *cl;
TObject *k;
const Instruction *pc;
callentry: /* entry point when calling new functions */
L->ci->u.l.pc = &pc;
if (L->hookmask & LUA_MASKCALL)
luaD_callhook(L, LUA_HOOKCALL, -1);
retentry: /* entry point when returning to old functions */
lua_assert(L->ci->state == CI_SAVEDPC ||
L->ci->state == (CI_SAVEDPC | CI_CALLING));
L->ci->state = CI_HASFRAME; /* activate frame */
pc = L->ci->u.l.savedpc;
cl = &clvalue(L->base - 1)->l;
k = cl->p->k;
/* main loop of interpreter */
for (;;) {
const Instruction i = *pc++;
StkId base, ra;
if ((L->hookmask & (LUA_MASKLINE | LUA_MASKCOUNT)) &&
(--L->hookcount == 0 || L->hookmask & LUA_MASKLINE)) {
traceexec(L);
if (L->ci->state & CI_YIELD) { /* did hook yield? */
L->ci->u.l.savedpc = pc - 1;
L->ci->state = CI_YIELD | CI_SAVEDPC;
return NULL;
}
}
/* warning!! several calls may realloc the stack and invalidate `ra' */
base = L->base;
ra = RA(i);
lua_assert(L->ci->state & CI_HASFRAME);
lua_assert(base == L->ci->base);
lua_assert(L->top <= L->stack + L->stacksize && L->top >= base);
lua_assert(L->top == L->ci->top ||
GET_OPCODE(i) == OP_CALL || GET_OPCODE(i) == OP_TAILCALL ||
GET_OPCODE(i) == OP_RETURN || GET_OPCODE(i) == OP_SETLISTO);
switch (GET_OPCODE(i)) {
case OP_MOVE: {
setobjs2s(ra, RB(i));
break;
}
case OP_LOADK: {
setobj2s(ra, KBx(i));
break;
}
case OP_LOADBOOL: {
setbvalue(ra, GETARG_B(i));
if (GETARG_C(i)) pc++; /* skip next instruction (if C) */
break;
}
case OP_LOADNIL: {
TObject *rb = RB(i);
do {
setnilvalue(rb--);
} while (rb >= ra);
break;
}
case OP_GETUPVAL: {
int b = GETARG_B(i);
setobj2s(ra, cl->upvals[b]->v);
break;
}
case OP_GETGLOBAL: {
TObject *rb = KBx(i);
const TObject *v;
lua_assert(ttisstring(rb) && ttistable(&cl->g));
v = luaH_getstr(hvalue(&cl->g), tsvalue(rb));
if (!ttisnil(v)) { setobj2s(ra, v); }
else
setobj2s(XRA(i), luaV_index(L, &cl->g, rb, 0));
break;
}
case OP_GETTABLE: {
StkId rb = RB(i);
TObject *rc = RKC(i);
if (ttistable(rb)) {
const TObject *v = luaH_get(hvalue(rb), rc);
if (!ttisnil(v)) { setobj2s(ra, v); }
else
setobj2s(XRA(i), luaV_index(L, rb, rc, 0));
}
else
setobj2s(XRA(i), luaV_getnotable(L, rb, rc, 0));
break;
}
case OP_SETGLOBAL: {
lua_assert(ttisstring(KBx(i)) && ttistable(&cl->g));
luaV_settable(L, &cl->g, KBx(i), ra);
break;
}
case OP_SETUPVAL: {
int b = GETARG_B(i);
setobj(cl->upvals[b]->v, ra); /* write barrier */
break;
}
case OP_SETTABLE: {
luaV_settable(L, ra, RKB(i), RKC(i));
break;
}
case OP_NEWTABLE: {
int b = GETARG_B(i);
b = fb2int(b);
sethvalue(ra, luaH_new(L, b, GETARG_C(i)));
luaC_checkGC(L);
break;
}
case OP_SELF: {
StkId rb = RB(i);
TObject *rc = RKC(i);
runtime_check(L, ttisstring(rc));
setobjs2s(ra+1, rb);
if (ttistable(rb)) {
const TObject *v = luaH_getstr(hvalue(rb), tsvalue(rc));
if (!ttisnil(v)) { setobj2s(ra, v); }
else
setobj2s(XRA(i), luaV_index(L, rb, rc, 0));
}
else
setobj2s(XRA(i), luaV_getnotable(L, rb, rc, 0));
break;
}
case OP_ADD: {
TObject *rb = RKB(i);
TObject *rc = RKC(i);
if (ttisnumber(rb) && ttisnumber(rc)) {
setnvalue(ra, nvalue(rb) + nvalue(rc));
}
else
Arith(L, ra, rb, rc, TM_ADD);
break;
}
case OP_SUB: {
TObject *rb = RKB(i);
TObject *rc = RKC(i);
if (ttisnumber(rb) && ttisnumber(rc)) {
setnvalue(ra, nvalue(rb) - nvalue(rc));
}
else
Arith(L, ra, rb, rc, TM_SUB);
break;
}
case OP_MUL: {
TObject *rb = RKB(i);
TObject *rc = RKC(i);
if (ttisnumber(rb) && ttisnumber(rc)) {
setnvalue(ra, nvalue(rb) * nvalue(rc));
}
else
Arith(L, ra, rb, rc, TM_MUL);
break;
}
case OP_DIV: {
TObject *rb = RKB(i);
TObject *rc = RKC(i);
if (ttisnumber(rb) && ttisnumber(rc)) {
setnvalue(ra, nvalue(rb) / nvalue(rc));
}
else
Arith(L, ra, rb, rc, TM_DIV);
break;
}
case OP_POW: {
Arith(L, ra, RKB(i), RKC(i), TM_POW);
break;
}
case OP_UNM: {
const TObject *rb = RB(i);
TObject temp;
if (tonumber(rb, &temp)) {
setnvalue(ra, -nvalue(rb));
}
else {
setnilvalue(&temp);
if (!call_binTM(L, RB(i), &temp, ra, TM_UNM))
luaG_aritherror(L, RB(i), &temp);
}
break;
}
case OP_NOT: {
int res = l_isfalse(RB(i)); /* next assignment may change this value */
setbvalue(ra, res);
break;
}
case OP_CONCAT: {
int b = GETARG_B(i);
int c = GETARG_C(i);
luaV_concat(L, c-b+1, c); /* may change `base' (and `ra') */
base = L->base;
setobjs2s(RA(i), base+b);
luaC_checkGC(L);
break;
}
case OP_JMP: {
dojump(pc, GETARG_sBx(i));
break;
}
case OP_EQ: {
if (equalobj(L, RKB(i), RKC(i)) != GETARG_A(i)) pc++;
else dojump(pc, GETARG_sBx(*pc) + 1);
break;
}
case OP_LT: {
if (luaV_lessthan(L, RKB(i), RKC(i)) != GETARG_A(i)) pc++;
else dojump(pc, GETARG_sBx(*pc) + 1);
break;
}
case OP_LE: {
if (luaV_lessequal(L, RKB(i), RKC(i)) != GETARG_A(i)) pc++;
else dojump(pc, GETARG_sBx(*pc) + 1);
break;
}
case OP_TEST: {
TObject *rb = RB(i);
if (l_isfalse(rb) == GETARG_C(i)) pc++;
else {
setobjs2s(ra, rb);
dojump(pc, GETARG_sBx(*pc) + 1);
}
break;
}
case OP_CALL:
case OP_TAILCALL: {
StkId firstResult;
int b = GETARG_B(i);
int nresults;
if (b != 0) L->top = ra+b; /* else previous instruction set top */
nresults = GETARG_C(i) - 1;
firstResult = luaD_precall(L, ra);
if (firstResult) {
if (firstResult > L->top) { /* yield? */
lua_assert(L->ci->state == (CI_C | CI_YIELD));
(L->ci - 1)->u.l.savedpc = pc;
(L->ci - 1)->state = CI_SAVEDPC;
return NULL;
}
/* it was a C function (`precall' called it); adjust results */
luaD_poscall(L, nresults, firstResult);
if (nresults >= 0) L->top = L->ci->top;
}
else { /* it is a Lua function */
if (GET_OPCODE(i) == OP_CALL) { /* regular call? */
(L->ci-1)->u.l.savedpc = pc; /* save `pc' to return later */
(L->ci-1)->state = (CI_SAVEDPC | CI_CALLING);
}
else { /* tail call: put new frame in place of previous one */
int aux;
base = (L->ci - 1)->base; /* `luaD_precall' may change the stack */
ra = RA(i);
if (L->openupval) luaF_close(L, base);
for (aux = 0; ra+aux < L->top; aux++) /* move frame down */
setobjs2s(base+aux-1, ra+aux);
(L->ci - 1)->top = L->top = base+aux; /* correct top */
lua_assert(L->ci->state & CI_SAVEDPC);
(L->ci - 1)->u.l.savedpc = L->ci->u.l.savedpc;
(L->ci - 1)->u.l.tailcalls++; /* one more call lost */
(L->ci - 1)->state = CI_SAVEDPC;
L->ci--; /* remove new frame */
L->base = L->ci->base;
}
goto callentry;
}
break;
}
case OP_RETURN: {
CallInfo *ci = L->ci - 1; /* previous function frame */
int b = GETARG_B(i);
if (b != 0) L->top = ra+b-1;
lua_assert(L->ci->state & CI_HASFRAME);
if (L->openupval) luaF_close(L, base);
L->ci->state = CI_SAVEDPC; /* deactivate current function */
L->ci->u.l.savedpc = pc;
/* previous function was running `here'? */
if (!(ci->state & CI_CALLING)) {
lua_assert((ci->state & CI_C) || ci->u.l.pc != &pc);
return ra; /* no: return */
}
else { /* yes: continue its execution */
int nresults;
lua_assert(ci->u.l.pc == &pc &&
ttisfunction(ci->base - 1) &&
(ci->state & CI_SAVEDPC));
lua_assert(GET_OPCODE(*(ci->u.l.savedpc - 1)) == OP_CALL);
nresults = GETARG_C(*(ci->u.l.savedpc - 1)) - 1;
luaD_poscall(L, nresults, ra);
if (nresults >= 0) L->top = L->ci->top;
goto retentry;
}
}
case OP_FORLOOP: {
lua_Number step, idx, limit;
const TObject *plimit = ra+1;
const TObject *pstep = ra+2;
if (!ttisnumber(ra))
luaG_runerror(L, "`for' initial value must be a number");
if (!tonumber(plimit, ra+1))
luaG_runerror(L, "`for' limit must be a number");
if (!tonumber(pstep, ra+2))
luaG_runerror(L, "`for' step must be a number");
step = nvalue(pstep);
idx = nvalue(ra) + step; /* increment index */
limit = nvalue(plimit);
if (step > 0 ? idx <= limit : idx >= limit) {
dojump(pc, GETARG_sBx(i)); /* jump back */
chgnvalue(ra, idx); /* update index */
}
break;
}
case OP_TFORLOOP: {
int nvar = GETARG_C(i) + 1;
StkId cb = ra + nvar + 2; /* call base */
setobjs2s(cb, ra);
setobjs2s(cb+1, ra+1);
setobjs2s(cb+2, ra+2);
L->top = cb+3; /* func. + 2 args (state and index) */
luaD_call(L, cb, nvar);
L->top = L->ci->top;
ra = XRA(i) + 2; /* final position of first result */
cb = ra + nvar;
do { /* move results to proper positions */
nvar--;
setobjs2s(ra+nvar, cb+nvar);
} while (nvar > 0);
if (ttisnil(ra)) /* break loop? */
pc++; /* skip jump (break loop) */
else
dojump(pc, GETARG_sBx(*pc) + 1); /* jump back */
break;
}
case OP_TFORPREP: { /* for compatibility only */
if (ttistable(ra)) {
setobjs2s(ra+1, ra);
setobj2s(ra, luaH_getstr(hvalue(gt(L)), luaS_new(L, "next")));
}
dojump(pc, GETARG_sBx(i));
break;
}
case OP_SETLIST:
case OP_SETLISTO: {
int bc;
int n;
Table *h;
runtime_check(L, ttistable(ra));
h = hvalue(ra);
bc = GETARG_Bx(i);
if (GET_OPCODE(i) == OP_SETLIST)
n = (bc&(LFIELDS_PER_FLUSH-1)) + 1;
else {
n = L->top - ra - 1;
L->top = L->ci->top;
}
bc &= ~(LFIELDS_PER_FLUSH-1); /* bc = bc - bc%FPF */
for (; n > 0; n--)
setobj2t(luaH_setnum(L, h, bc+n), ra+n); /* write barrier */
break;
}
case OP_CLOSE: {
luaF_close(L, ra);
break;
}
case OP_CLOSURE: {
Proto *p;
Closure *ncl;
int nup, j;
p = cl->p->p[GETARG_Bx(i)];
nup = p->nups;
ncl = luaF_newLclosure(L, nup, &cl->g);
ncl->l.p = p;
for (j=0; j<nup; j++, pc++) {
if (GET_OPCODE(*pc) == OP_GETUPVAL)
ncl->l.upvals[j] = cl->upvals[GETARG_B(*pc)];
else {
lua_assert(GET_OPCODE(*pc) == OP_MOVE);
ncl->l.upvals[j] = luaF_findupval(L, base + GETARG_B(*pc));
}
}
setclvalue(ra, ncl);
luaC_checkGC(L);
break;
}
}
}
}
static void Arith (lua_State *L, StkId ra, const TValue *rb,
const TValue *rc, TMS op) {
TValue tempb, tempc;
const TValue *b, *c;
#if LUA_REFCOUNT
luarc_newvalue(&tempb);
luarc_newvalue(&tempc);
if ((b = luaV_tonumber(L, rb, &tempb)) != NULL &&
(c = luaV_tonumber(L, rc, &tempc)) != NULL) {
#else
if ((b = luaV_tonumber(rb, &tempb)) != NULL &&
(c = luaV_tonumber(rc, &tempc)) != NULL) {
#endif /* LUA_REFCOUNT */
lua_Number nb = nvalue(b), nc = nvalue(c);
#if LUA_REFCOUNT
luarc_cleanvalue(&tempb);
luarc_cleanvalue(&tempc);
#endif /* LUA_REFCOUNT */
switch (op) {
case TM_ADD: setnvalue(ra, luai_numadd(nb, nc)); break;
case TM_SUB: setnvalue(ra, luai_numsub(nb, nc)); break;
case TM_MUL: setnvalue(ra, luai_nummul(nb, nc)); break;
case TM_DIV: setnvalue(ra, luai_numdiv(nb, nc)); break;
case TM_MOD: setnvalue(ra, luai_nummod(nb, nc)); break;
case TM_POW: setnvalue(ra, luai_numpow(nb, nc)); break;
case TM_UNM: setnvalue(ra, luai_numunm(nb)); break;
default: lua_assert(0); break;
}
}
#if LUA_REFCOUNT
else if (!call_binTM(L, rb, rc, ra, op)) {
luarc_cleanvalue(&tempb);
luarc_cleanvalue(&tempc);
luaG_aritherror(L, rb, rc);
}
#else
else if (!call_binTM(L, rb, rc, ra, op))
luaG_aritherror(L, rb, rc);
#endif /* LUA_REFCOUNT */
}
/*
** some macros for common tasks in `luaV_execute'
*/
#define runtime_check(L, c) { if (!(c)) break; }
#define RA(i) (base+GETARG_A(i))
/* to be used after possible stack reallocation */
#define RB(i) check_exp(getBMode(GET_OPCODE(i)) == OpArgR, base+GETARG_B(i))
#define RC(i) check_exp(getCMode(GET_OPCODE(i)) == OpArgR, base+GETARG_C(i))
#define RKB(i) check_exp(getBMode(GET_OPCODE(i)) == OpArgK, \
ISK(GETARG_B(i)) ? k+INDEXK(GETARG_B(i)) : base+GETARG_B(i))
#define RKC(i) check_exp(getCMode(GET_OPCODE(i)) == OpArgK, \
ISK(GETARG_C(i)) ? k+INDEXK(GETARG_C(i)) : base+GETARG_C(i))
#define KBx(i) check_exp(getBMode(GET_OPCODE(i)) == OpArgK, k+GETARG_Bx(i))
#define dojump(L,pc,i) {(pc) += (i); luai_threadyield(L);}
#define Protect(x) { L->savedpc = pc; {x;}; base = L->base; }
#define arith_op(op,tm) { \
TValue *rb = RKB(i); \
TValue *rc = RKC(i); \
if (ttisnumber(rb) && ttisnumber(rc)) { \
lua_Number nb = nvalue(rb), nc = nvalue(rc); \
setnvalue(ra, op(nb, nc)); \
} \
else \
Protect(Arith(L, ra, rb, rc, tm)); \
}
#if LUA_BITFIELD_OPS
#define bit_op(op) { \
TValue *rb = RKB(i); \
TValue *rc = RKC(i); \
if (ttisnumber(rb) && ttisnumber(rc)) { \
unsigned int nb = (unsigned int)nvalue(rb), nc = (unsigned int)nvalue(rc); \
setnvalue(ra, nb op nc); \
} \
else \
luaG_aritherror(L, rb, rc); \
}
#endif /* LUA_BITFIELD_OPS */
void luaV_execute (lua_State *L, int nexeccalls) {
LClosure *cl;
StkId base;
TValue *k;
const Instruction *pc;
reentry: /* entry point */
lua_assert(isLua(L->ci));
pc = L->savedpc;
cl = &clvalue(L->ci->func)->l;
base = L->base;
k = cl->p->k;
/* main loop of interpreter */
for (;;) {
const Instruction i = *pc++;
StkId ra;
if ((L->hookmask & (LUA_MASKLINE | LUA_MASKCOUNT)) &&
(--L->hookcount == 0 || L->hookmask & LUA_MASKLINE)) {
traceexec(L, pc);
if (L->status == LUA_YIELD) { /* did hook yield? */
L->savedpc = pc - 1;
return;
}
base = L->base;
}
/* warning!! several calls may realloc the stack and invalidate `ra' */
ra = RA(i);
lua_assert(base == L->base && L->base == L->ci->base);
lua_assert(base <= L->top && L->top <= L->stack + L->stacksize);
lua_assert(L->top == L->ci->top || luaG_checkopenop(i));
switch (GET_OPCODE(i)) {
case OP_MOVE: {
setobjs2s(L, ra, RB(i));
continue;
}
case OP_LOADK: {
setobj2s(L, ra, KBx(i));
continue;
}
case OP_LOADBOOL: {
setbvalue(ra, GETARG_B(i));
if (GETARG_C(i)) pc++; /* skip next instruction (if C) */
continue;
}
case OP_LOADNIL: {
TValue *rb = RB(i);
do {
setnilvalue(rb--);
} while (rb >= ra);
continue;
}
case OP_GETUPVAL: {
int b = GETARG_B(i);
setobj2s(L, ra, cl->upvals[b]->v);
continue;
}
case OP_GETGLOBAL: {
TValue g;
TValue *rb = KBx(i);
#if LUA_REFCOUNT
sethvalue2n(L, &g, cl->env);
#else
sethvalue(L, &g, cl->env);
#endif /* LUA_REFCOUNT */
lua_assert(ttisstring(rb));
Protect(luaV_gettable(L, &g, rb, ra));
#if LUA_REFCOUNT
setnilvalue(&g);
#endif /* LUA_REFCOUNT */
continue;
}
case OP_GETTABLE: {
Protect(luaV_gettable(L, RB(i), RKC(i), ra));
continue;
}
case OP_SETGLOBAL: {
TValue g;
#if LUA_REFCOUNT
sethvalue2n(L, &g, cl->env);
#else
sethvalue(L, &g, cl->env);
#endif /* LUA_REFCOUNT */
lua_assert(ttisstring(KBx(i)));
Protect(luaV_settable(L, &g, KBx(i), ra));
#if LUA_REFCOUNT
setnilvalue(&g);
#endif /* LUA_REFCOUNT */
continue;
}
case OP_SETUPVAL: {
UpVal *uv = cl->upvals[GETARG_B(i)];
setobj(L, uv->v, ra);
luaC_barrier(L, uv, ra);
continue;
}
case OP_SETTABLE: {
Protect(luaV_settable(L, ra, RKB(i), RKC(i)));
continue;
}
case OP_NEWTABLE: {
int b = GETARG_B(i);
int c = GETARG_C(i);
sethvalue(L, ra, luaH_new(L, luaO_fb2int(b), luaO_fb2int(c)));
Protect(luaC_checkGC(L));
continue;
}
case OP_SELF: {
StkId rb = RB(i);
setobjs2s(L, ra+1, rb);
Protect(luaV_gettable(L, rb, RKC(i), ra));
continue;
}
case OP_ADD: {
arith_op(luai_numadd, TM_ADD);
continue;
}
case OP_SUB: {
arith_op(luai_numsub, TM_SUB);
continue;
}
case OP_MUL: {
arith_op(luai_nummul, TM_MUL);
continue;
}
case OP_DIV: {
arith_op(luai_numdiv, TM_DIV);
continue;
}
case OP_MOD: {
arith_op(luai_nummod, TM_MOD);
continue;
}
case OP_POW: {
arith_op(luai_numpow, TM_POW);
continue;
}
case OP_UNM: {
TValue *rb = RB(i);
if (ttisnumber(rb)) {
lua_Number nb = nvalue(rb);
setnvalue(ra, luai_numunm(nb));
}
else {
Protect(Arith(L, ra, rb, rb, TM_UNM));
}
continue;
}
case OP_NOT: {
int res = l_isfalse(RB(i)); /* next assignment may change this value */
setbvalue(ra, res);
continue;
}
#if LUA_BITFIELD_OPS
case OP_BAND: {
bit_op(&);
continue;
}
case OP_BOR: {
bit_op(|);
continue;
}
case OP_BXOR: {
bit_op(^);
continue;
}
case OP_BSHL: {
bit_op(<<);
continue;
}
case OP_BSHR: {
bit_op(>>);
continue;
}
#endif /* LUA_BITFIELD_OPS */
case OP_LEN: {
const TValue *rb = RB(i);
switch (ttype(rb)) {
case LUA_TTABLE: {
setnvalue(ra, cast_num(luaH_getn(hvalue(rb))));
break;
}
case LUA_TSTRING: {
setnvalue(ra, cast_num(tsvalue(rb)->len));
break;
}
#if LUA_WIDESTRING
case LUA_TWSTRING: {
setnvalue(ra, cast_num(tsvalue(rb)->len));
break;
}
#endif /* LUA_WIDESTRING */
default: { /* try metamethod */
Protect(
if (!call_binTM(L, rb, luaO_nilobject, ra, TM_LEN))
luaG_typeerror(L, rb, "get length of");
)
}
}
continue;
}
case OP_CONCAT: {
int b = GETARG_B(i);
int c = GETARG_C(i);
Protect(luaV_concat(L, c-b+1, c); luaC_checkGC(L));
setobjs2s(L, RA(i), base+b);
continue;
}
case OP_JMP: {
dojump(L, pc, GETARG_sBx(i));
continue;
}
case OP_EQ: {
TValue *rb = RKB(i);
TValue *rc = RKC(i);
Protect(
if (equalobj(L, rb, rc) == GETARG_A(i))
dojump(L, pc, GETARG_sBx(*pc));
)
pc++;
continue;
}
case OP_LT: {
Protect(
if (luaV_lessthan(L, RKB(i), RKC(i)) == GETARG_A(i))
dojump(L, pc, GETARG_sBx(*pc));
)
pc++;
continue;
}
case OP_LE: {
Protect(
if (lessequal(L, RKB(i), RKC(i)) == GETARG_A(i))
dojump(L, pc, GETARG_sBx(*pc));
)
pc++;
continue;
}
// 已经准备好了lua函数的调用环境，开始逐句执行lua函数的指令
void luaV_execute (lua_State *L, int nexeccalls) {
LClosure *cl;
StkId base;
TValue *k;
const Instruction *pc;
reentry: /* entry point */
pc = L->savedpc; //这时候已经保存了lua函数的第一个指令位置
cl = &clvalue(L->ci->func)->l;
base = L->base;
k = cl->p->k;
/* main loop of interpreter */
for (;;) {
const Instruction i = *pc++;
StkId ra;
if ((L->hookmask & (LUA_MASKLINE | LUA_MASKCOUNT)) &&
(--L->hookcount == 0 || L->hookmask & LUA_MASKLINE)) {
traceexec(L, pc);
if (L->status == LUA_YIELD) { /* did hook yield? */
L->savedpc = pc - 1;
return;
}
base = L->base;
}
/* warning!! several calls may realloc the stack and invalidate `ra' */
ra = RA(i);
lua_assert(base == L->base && L->base == L->ci->base);
lua_assert(base <= L->top && L->top <= L->stack + L->stacksize);
lua_assert(L->top == L->ci->top || luaG_checkopenop(i));
// 阅读说明：
// 每lua的一个函数在编译器会生成这个函数的信息：函数引用到的upvalue，函数固定参数
// 数量，是否含有可变参数，指令序列等等，这些都记录在Proto结构体中。
// 可以通过 luac -o tmp <luafile> | luac -l tmp 来函数对应的字节码以及Proto信息
// 例如以下lua代码：
// -- t.lua
// local x, y, z
// x = x*y + y*z + x*z - (x*x + y*y + z*z)
// 得到以下输出：
// main <t.lua:0,0> (12 instructions, 48 bytes at 0074B6A0)
// 0 + params, 6 slots, 0 upvalues, 3 locals, 0 constants, 0 functions
// 1[2] MUL 3 0 1
// 2[2] MUL 4 1 2
// 3[2] ADD 3 3 4
// 4[2] MUL 4 0 2
// 5[2] ADD 3 3 4
// 6[2] MUL 4 0 0
// 7[2] MUL 5 1 1
// 8[2] ADD 4 4 5
// 9[2] MUL 5 2 2
// 10[2] ADD 4 4 5
// 11[2] SUB 0 3 4
// 12[2] RETURN 0 1
// 从输出可以得到的信息包括：
// 1 生成了多少个Proto
// 2 Proto对应的lua源代码在哪里 (<t.lua:0,0>)
// 3 Proto中的sizecode (12 instructions, 48 bytes at 0074B6A0)
// 4 Proto中的固定参数数量numparams (0 + params，这里的0)
// 5 Proto是否有可变参数is_vararg (0 + params，这里的+表示带有可变参数，没有可变参数就是 0 params)
// 6 Proto中在栈上用到的临时变量总数maxstacksize (6 slots，表示local变量+计算中辅助用的临时变量=6个)
// 7 Proto中用到的upvalue数量nups (0 upvalues，表示用到了0个upvalue)
// 8 Proto中用到的local变量数量sizelocvars (3 locals，刚好t.lua用到了x,y,z三个local变量)
// 9 Proto中用到的字面常量数量sizek (0 constants)
// 10 Proto中用到的Closure数量sizep (0 functions)
// 11 Proto中生成的字节码指令内容code，每条指令包括：
// a 指令下标
// b 指令在源代码中对应的行号
// c 指令opcode
// d 指令参数
//
// PS：第6条和第8条，由于计算一条表达式需要用到的辅助临时变量数目是不定的，但是是可以通过
// 分析一条表达式的AST来确定最少需要几个临时变量（后续遍历+逆波兰式拟真）。
// PS：lua是会对表达式进行常量计算优化的！例如 x = x + 5*60*60*1000，只有一个常量18000000
// PS：函数执行的时候需要用到“一段”参数栈上的空间，也就是第6条所谓的临时变量。这一段空间的
// 范围由L->base开始，到L->top结束。通过相对L->base的下标来标识具体的变量是哪个。一般来说，
// 固定参数的函数，L->base指向第一个固定参数，而L->base-1指向当前正在运行的函数；而可变参数
// 的函数，L->base和当前正在运行的函数中间，保存有全部的传入参数。
switch (GET_OPCODE(i)) {
// 功能：用一个已有的变量创建一个新的变量
// 将一个 lua_TValue设置成另一个lua_TValue的样子
// iABC: A待创建变量在参数栈索引，B参数栈已有lua变量的索引。
case OP_MOVE: {
// local x, y -----> 记录 index(x) = 0, index(y) = 1
// x = ...
// .....
// y = x -----> OP_MOVE: 1, 0
setobjs2s(L, ra, RB(i));
continue;
}
// 功能：用一个常量来创建一个新的变量
// 从常量池（保存在Proto类型中）中保存的常量赋值给栈上的变量
// iABx: A待创建变量在参数栈索引，Bx常量在常量池的索引
case OP_LOADK: {
// local x = 9 -----> 记录 index(x) = 0, index(constval(9)) = 1
// >----> OP_LOADK: 0, 1
setobj2s(L, ra, KBx(i));
continue;
}
// 功能：用一个布尔值来创建一个新的变量
// iABC: A待创建变量在参数栈索引，B布尔值，C通常是0
case OP_LOADBOOL: {
// 注意，local c = true这种，true就不作为一个常量放到k里面
// 而是作为字面值放到参数B里面了！所以不需要KB(i)！
// local a = false -----> 记录 index(a) = 0
// >----> OP_LOADBOOL 0 0 0
// local b = true -----> 记录 index(b) = 1
// >----> OP_LOADBOOL 1 1 0
setbvalue(ra, GETARG_B(i));
if (GETARG_C(i)) pc++; /* skip next instruction (if C) */
continue;
}
// 功能：用nil来初始化一个到多个变量
// 类似于bzero，这个指令会把一段内存中的变量置为nil
// iABC: A第一个要置nil的变量参数栈索引，B最后一个要置nil的变量参数栈索引
case OP_LOADNIL: {
// local a, b, c, d, e, f, g = 1, 2, 3, 4 -----> index(a~g) = 0~6
// >----> OP_LOADNIL 4 6
TValue *rb = RB(i);
do {
setnilvalue(rb--);
} while (rb >= ra);
continue;
}
// 功能：用upvalue来创建一个新的变量
// 所谓的“创建”操作，其实创建的不是副本而是引用
// iABC: A待创建变量在参数栈索引，B当前函数的upvalue表的索引
case OP_GETUPVAL: {
// local x = {}
// ... -- do something to x
// function f() local a = x[1] end -----> 记录index(a) = 0, index(upval(x)) = 1
// >----> OP_GETUPVAL 0 1
int b = GETARG_B(i);
setobj2s(L, ra, cl->upvals[b]->v);
continue;
}
// 功能：从全局表中取某个key的值来创建一个新的变量
// iABx：A待创建变量在参数栈索引，Bxkey对应的常量在常量池的索引
case OP_GETGLOBAL: {
// local a = dofile ------> 记录 index(a) = 0, index(constval("dofile")) = 1
// >-----> OP_GETGLOBAL 0 1
TValue g;
TValue *rb = KBx(i);
sethvalue(L, &g, cl->env);
lua_assert(ttisstring(rb));
Protect(luaV_gettable(L, &g, rb, ra));
continue;
}
// 功能：从某个table中取某个key的值来创建一个新的变量
// iABC：A待创建变量在参数栈索引，B要取出key的table变量在参数栈的索引，Ckey对应的参数栈下标或者常量池下标
case OP_GETTABLE: {
// local a = hello["world"] -----> 记录 index(a) = 0, index(hello) = 1 index(constval("world")) = 0
// >----> OP_GETTABLE 0 1 0|BITRK
Protect(luaV_gettable(L, RB(i), RKC(i), ra));
continue;
}
// 功能：将参数栈上变量设置到全局表中
// iABx：A要写入全局表的变量在栈上的索引，Bx写入到全局表的key在常量池中的下标
case OP_SETGLOBAL: {
// 假设我要替换 bit库
// local mybit = {}
// mybit.band = ...
// mybit.bor = ...
// mybit.bxor = ...
// ...
// bit = mybit -----> 记录 index(mybit) = 0, index(constval("bit")) = 1
// >----> OP_SETGLOBAL 0 1
TValue g;
sethvalue(L, &g, cl->env);
lua_assert(ttisstring(KBx(i)));
Protect(luaV_settable(L, &g, KBx(i), ra));
continue;
}
// 功能：修改upvalue的值
// iABC：A要写入upvalue的变量在参数栈上的索引，B待写入的upvalue在upvalue表的索引
case OP_SETUPVAL: {
// local a = 5
// function p()
// a = "hello" -----> 记录 index(upval(a)) = 0, index(constval("hello")) = 1
// >----> OP_SETUPVAL 0 1
// end
UpVal *uv = cl->upvals[GETARG_B(i)];
setobj(L, uv->v, ra);
luaC_barrier(L, uv, ra);
continue;
}
// 功能：修改某个table对应的key
// iABC：A要写入table变量在参数栈的索引，B要写入的key的变量的栈索引或者常量索引，C要写入的value的变量索引或者常量索引
case OP_SETTABLE: {
// local a = {}
// a[5] = 3
Protect(luaV_settable(L, ra, RKB(i), RKC(i)));
continue;
}
// 功能：在栈上创建一个table变量
// iABC：A存放table变量的参数栈索引，B创建的table变量的数组容量，C创建的table变量的字典容量
case OP_NEWTABLE: {
// local a = {} -----> index(a) = 0
// >----> OP_NEWTABLE 0 szArray szHash
int b = GETARG_B(i);
int c = GETARG_C(i);
sethvalue(L, ra, luaH_new(L, luaO_fb2int(b), luaO_fb2int(c)));
Protect(luaC_checkGC(L)); // 注意，创建table可能会引起GC
continue;
}
// 功能：把self.method和self放到参数栈上相邻的两个位置。
// 为成员方法调用的语法糖提供支持
// iABC：A存放self.method的参数栈索引，B存放self的参数栈索引，C需要从self中调用的方法对应的变量索引或者常量索引
// 执行完成后，栈上内容为： ... -> self.method -> self -> ...
// ^
// RA
// 当然，OP_SELF之后能看到OP_CALL的身影
case OP_SELF: {
// CCNode:create() -> index(constants("CCNode")) = 1, index(constants("create")) = 2
// -> OP_GETGLOBAL 0 1
// -> OP_SELF 0 0 2
// -> OP_CALL 0 2 1
StkId rb = RB(i);
setobjs2s(L, ra+1, rb);
Protect(luaV_gettable(L, rb, RKC(i), ra));
continue;
}
//---------------------------------------------------------------------------运算符指令
// 功能：实现二元运算符：+, -, *, /, %, ^
// iABC：A存放运算结果的参数栈索引，B存放第一操作数的参数栈索引，C存放第二操作数的参数栈索引
case OP_ADD: {
// local a, b, c = ... -----> index(a) = 0, index(b) = 1, index(c) = 2
// a = b + c -----> OP_ADD 0 1|BITRK 2|BITRK
// a = 1 + b -----> index(constval(1)) = 0
// >----> OP_ADD 0 0 1|BITRK
// a = 1 + 100 -----> index(constval(1)) = 0, index(constval(100)) = 1
// >----> OP_ADD 0 0 1
arith_op(luai_numadd, TM_ADD);
continue;
}
case OP_SUB: {
// see OP_ADD
arith_op(luai_numsub, TM_SUB);
continue;
}
case OP_MUL: {
// see OP_ADD
arith_op(luai_nummul, TM_MUL);
continue;
}
case OP_DIV: {
// see OP_ADD
arith_op(luai_numdiv, TM_DIV);
continue;
}
case OP_MOD: {
// 这个很特殊！由于lua没有整数，所以mod可不是%这个运算符！
// 这里定义 mod(x, y) => (x - floor(x/y)*y)
// see OP_ADD
arith_op(luai_nummod, TM_MOD);
continue;
}
case OP_POW: {
// see OP_ADD
arith_op(luai_numpow, TM_POW);
continue;
}
// 功能：实现一元运算符 -, not, #
// iABC：A存放运算结果的参数栈索引，B存放操作数的参数栈索引
case OP_UNM: {
// local a = -b -----> index(a) = 1, index(b) = 2
// >----> OP_UNM 1 2
TValue *rb = RB(i);
if (ttisnumber(rb)) {
lua_Number nb = nvalue(rb);
setnvalue(ra, luai_numunm(nb));
}
else {
Protect(Arith(L, ra, rb, rb, TM_UNM));
}
continue;
}
case OP_NOT: {
// local a = not b -----> index(a) = 1, index(b) = 2
// >----> OP_NOT 1 2
// 那local a = not true呢？人家编译期就给你处理好了
int res = l_isfalse(RB(i)); /* next assignment may change this value */
setbvalue(ra, res);
continue;
}
case OP_LEN: {
// local a = #b -----> index(a) = 1, index(b) = 2
// >----> OP_LEN 1 2
const TValue *rb = RB(i);
switch (ttype(rb)) {
case LUA_TTABLE: {
setnvalue(ra, cast_num(luaH_getn(hvalue(rb))));
break;
}
case LUA_TSTRING: {
setnvalue(ra, cast_num(tsvalue(rb)->len));
break;
}
default: { /* try metamethod */
Protect(
if (!call_binTM(L, rb, luaO_nilobject, ra, TM_LEN))
luaG_typeerror(L, rb, "get length of");
)
}
}
continue;
}
// 功能：实现字符串拼接运算符 ..
// iABC：A拼接后存放结果的参数栈索引，B第一个要拼接的变量的参数栈索引，C最后一个要拼接的变量的参数栈索引
// 要执行这个指令，对参数栈有特殊要求：
// ... -> string1 -> string2 ... -> stringN -> ...
// ^ ^
// RB RC
case OP_CONCAT: {
// 类似OP_LOADNIL，只不过，这次范围是[rb,rc]，loadnil是[ra,rb]
// local b, c, d, a = "hello", "world", "!"
// a = b .. c .. d -----> index(a) = 4, index(b~d) = 1~3
// >----> OP_CONCAT 4 1 3
// 问题是如果b~d不能保证是连续的怎么办？答案是一个个MOVE上去在OP_CONCAT...
int b = GETARG_B(i);
int c = GETARG_C(i);
Protect(luaV_concat(L, c-b+1, c); luaC_checkGC(L));
setobjs2s(L, RA(i), base+b);
continue;
}
//---------------------------------------------------------------------------跳转指令
// 功能：无条件跳转
// iAsBx：A不使用，sBx跳转偏移
// 一般这个语句不单独出现，都是在一些条件控制中和其他的条件跳转指令配合使用的。
case OP_JMP: {
// 无条件跳转指令。由于跳转偏移总是有正向和反向之分的，所以需要用到
// 负数。那就只能用iAsBx类型的指令了。而sBx是有长度限制的！
// 所以，如果生成的指令很多，超过了sBx的长度限制，可能就会编译失败
dojump(L, pc, GETARG_sBx(i));
continue;
}
// 功能：检查两个变量是否相等，满足预期则跳转。配合OP_JMP使用。
// iABC：A纯数字，对比较结果的预期，满足预期则跳转，B参数1的索引，C参数2的索引
case OP_EQ: {
// if a == b then -----> index(a) = 1, index(b) = 2
// >----> 这里将生成两行指令：
// >----> OP_EQ 0 1 2 // 用0，因为成立的话跳过，不成立才执行
// >----> OP_JMP N // N 表示then ... end中间的指令数量
// >----> ... // Instructions between "then" and "end"
TValue *rb = RKB(i);
TValue *rc = RKC(i);
Protect(
if (equalobj(L, rb, rc) == GETARG_A(i))
dojump(L, pc, GETARG_sBx(*pc));
)
pc++;
continue;
}
// 功能：检查两个变量是否小于，满足预期则跳转。配合OP_JMP使用。
// iABC：A纯数字，对比较结果的预期，满足预期则跳转，B参数1的索引，C参数2的索引
case OP_LT: {
// if a < b then -----> index(a) = 1, index(b) = 2
// >----> 这里将生成两行指令：
// >----> OP_LT 0 1 2 // 用0，因为成立的话跳过，不成立才执行
// >----> OP_JMP N // N 表示then ... end中间的指令数量
// >----> ... // Instructions between "then" and "end"
Protect(
if (luaV_lessthan(L, RKB(i), RKC(i)) == GETARG_A(i))
dojump(L, pc, GETARG_sBx(*pc));
)
pc++;
continue;
}
// 功能：检查两个变量是否小于等于，满足预期则跳转。配合OP_JMP使用。
// iABC：A纯数字，对比较结果的预期，满足预期则跳转，B参数1的索引，C参数2的索引
case OP_LE: {
// if a <= b then -----> index(a) = 1, index(b) = 2
// >----> 这里将生成两行指令：
// >----> OP_LE 0 1 2 // 用0，因为成立的话跳过，不成立才执行
// >----> OP_JMP N // N 表示then ... end中间的指令数量
// >----> ... // Instructions between "then" and "end"
Protect(
if (lessequal(L, RKB(i), RKC(i)) == GETARG_A(i))
dojump(L, pc, GETARG_sBx(*pc));
)
pc++;
continue;
}