/* 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(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 (lessequal(L, RKB(i), RKC(i)) == GETARG_A(i))            dojump(L, pc, GETARG_sBx(*pc));        )        pc++;        continue;      }      case OP_TEST: {        if (l_isfalse(ra) != GETARG_C(i))          dojump(L, pc, GETARG_sBx(*pc));        pc++;        continue;      }      case OP_TESTSET: {        TValue *rb = RB(i);        if (l_isfalse(rb) != GETARG_C(i)) {          setobjs2s(L, ra, rb);          dojump(L, pc, GETARG_sBx(*pc));        }        pc++;        continue;      }      case OP_CALL: {        int b = GETARG_B(i);        int nresults = GETARG_C(i) - 1;        if (b != 0) L->top = ra+b;  /* else previous instruction set top */        L->savedpc = pc;        switch (luaD_precall(L, ra, nresults)) {          case PCRLUA: {            nexeccalls++;            goto reentry;  /* restart luaV_execute over new Lua function */          }          case PCRC: {            /* it was a C function (`precall' called it); adjust results */            if (nresults >= 0) L->top = L->ci->top;            base = L->base;            continue;          }          default: {            return;  /* yield */          }        }      }      case OP_TAILCALL: {        int b = GETARG_B(i);        if (b != 0) L->top = ra+b;  /* else previous instruction set top */        L->savedpc = pc;        lua_assert(GETARG_C(i) - 1 == LUA_MULTRET);        switch (luaD_precall(L, ra, LUA_MULTRET)) {          case PCRLUA: {            /* tail call: put new frame in place of previous one */            CallInfo *ci = L->ci - 1;  /* previous frame */            int aux;            StkId func = ci->func;            StkId pfunc = (ci+1)->func;  /* previous function index */            if (L->openupval) luaF_close(L, ci->base);            L->base = ci->base = ci->func + ((ci+1)->base - pfunc);            for (aux = 0; pfunc+aux < L->top; aux++)  /* move frame down */              setobjs2s(L, func+aux, pfunc+aux);            ci->top = L->top = func+aux;  /* correct top */            lua_assert(L->top == L->base + clvalue(func)->l.p->maxstacksize);            ci->savedpc = L->savedpc;            ci->tailcalls++;  /* one more call lost */            L->ci--;  /* remove new frame */            goto reentry;          }          case PCRC: {  /* it was a C function (`precall' called it) */            base = L->base;            continue;          }          default: {            return;  /* yield */          }        }      }      case OP_RETURN: {        int b = GETARG_B(i);        if (b != 0) L->top = ra+b-1;        if (L->openupval) luaF_close(L, base);        L->savedpc = pc;        b = luaD_poscall(L, ra);        if (--nexeccalls == 0)  /* was previous function running `here'? */          return;  /* no: return */        else {  /* yes: continue its execution */          if (b) L->top = L->ci->top;          lua_assert(isLua(L->ci));          lua_assert(GET_OPCODE(*((L->ci)->savedpc - 1)) == OP_CALL);          goto reentry;        }      }      case OP_FORLOOP: {        lua_Number step = nvalue(ra+2);        lua_Number idx = luai_numadd(nvalue(ra), step); /* increment index */        lua_Number limit = nvalue(ra+1);        if (luai_numlt(0, step) ? luai_numle(idx, limit)                                : luai_numle(limit, idx)) {          dojump(L, pc, GETARG_sBx(i));  /* jump back */          setnvalue(ra, idx);  /* update internal index... */          setnvalue(ra+3, idx);  /* ...and external index */        }        continue;      }      case OP_FORPREP: {        const TValue *init = ra;        const TValue *plimit = ra+1;        const TValue *pstep = ra+2;        L->savedpc = pc;  /* next steps may throw errors */        if (!tonumber(init, ra))          luaG_runerror(L, LUA_QL("for") " initial value must be a number");        else if (!tonumber(plimit, ra+1))          luaG_runerror(L, LUA_QL("for") " limit must be a number");        else if (!tonumber(pstep, ra+2))          luaG_runerror(L, LUA_QL("for") " step must be a number");        setnvalue(ra, luai_numsub(nvalue(ra), nvalue(pstep)));        dojump(L, pc, GETARG_sBx(i));        continue;      }      case OP_TFORLOOP: {        StkId cb = ra + 3;  /* call base */        setobjs2s(L, cb+2, ra+2);        setobjs2s(L, cb+1, ra+1);        setobjs2s(L, cb, ra);        L->top = cb+3;  /* func. + 2 args (state and index) */        Protect(luaD_call(L, cb, GETARG_C(i)));        L->top = L->ci->top;        cb = RA(i) + 3;  /* previous call may change the stack */        if (!ttisnil(cb)) {  /* continue loop? */          setobjs2s(L, cb-1, cb);  /* save control variable */          dojump(L, pc, GETARG_sBx(*pc));  /* jump back */        }        pc++;        continue;      }      case OP_SETLIST: {        int n = GETARG_B(i);        int c = GETARG_C(i);        int last;        Table *h;        if (n == 0) {          n = cast_int(L->top - ra) - 1;          L->top = L->ci->top;        }        if (c == 0) c = cast_int(*pc++);        runtime_check(L, ttistable(ra));        h = hvalue(ra);        last = ((c-1)*LFIELDS_PER_FLUSH) + n;        if (last > h->sizearray)  /* needs more space? */          luaH_resizearray(L, h, last);  /* pre-alloc it at once */        for (; n > 0; n--) {          TValue *val = ra+n;          setobj2t(L, luaH_setnum(L, h, last--), val);          luaC_barriert(L, h, val);        }        continue;      }      case OP_CLOSE: {        luaF_close(L, ra);        continue;      }      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->env);        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(L, ra, ncl);        Protect(luaC_checkGC(L));        continue;      }      case OP_VARARG: {        int b = GETARG_B(i) - 1;        int j;        CallInfo *ci = L->ci;        int n = cast_int(ci->base - ci->func) - cl->p->numparams - 1;        if (b == LUA_MULTRET) {          Protect(luaD_checkstack(L, n));          ra = RA(i);  /* previous call may change the stack */          b = n;          L->top = ra + n;        }        for (j = 0; j < b; j++) {          if (j < n) {            setobjs2s(L, ra + j, ci->base - n + j);          }          else {            setnilvalue(ra + j);          }        }        continue;      }    }  }}