text: /*
  ** $Id: lcode.c,v 2.25.1.3 2007/12/28 15:32:23 roberto Exp $
  ** Code generator for Lua
  ** See Copyright Notice in lua.h
  */
  
  
  #include <stdlib.h>
  
  #define lcode_c
  #define LUA_CORE
  
  #include "lua.h"
  
  #include "lcode.h"
  #include "ldebug.h"
  #include "ldo.h"
  #include "lgc.h"
  #include "llex.h"
  #include "lmem.h"
  #include "lobject.h"
  #include "lopcodes.h"
  #include "lparser.h"
  #include "ltable.h"
  
  
  #define hasjumps(e)	((e)->t != (e)->f)
  
  
  static int isnumeral(expdesc* e) {
  	return (e->k == VKNUM && e->t == NO_JUMP && e->f == NO_JUMP);
  }
  
  
  void luaK_nil(FuncState* fs, int from, int n) {
  	Instruction* previous;
  	if (fs->pc > fs->lasttarget) {  /* no jumps to current position? */
  		if (fs->pc == 0) {  /* function start? */
  			if (from >= fs->nactvar)
  				return;  /* positions are already clean */
  		}
  		else {
  			previous = &fs->f->code[fs->pc - 1];
  			if (GET_OPCODE(*previous) == OP_LOADNIL && !G(fs->L)->convert) {
  				int pfrom = GETARG_A(*previous);
  				int pto = GETARG_B(*previous);
  				if (pfrom <= from && from <= pto + 1) {  /* can connect both? */
  					if (from + n - 1 > pto)
  						SETARG_B(*previous, from + n - 1);
  					return;
  				}
  			}
  		}
  	}
  	luaK_codeABC(fs, OP_LOADNIL, from, from + n - 1, 0);  /* else no optimization */
  }
  
  
  int luaK_jump(FuncState* fs) {
  	int jpc = fs->jpc;  /* save list of jumps to here */
  	int j;
  	fs->jpc = NO_JUMP;
  	j = luaK_codeAsBx(fs, OP_JMP, 0, NO_JUMP);
  	luaK_concat(fs, &j, jpc);  /* keep them on hold */
  	return j;
  }
  
  
  void luaK_ret(FuncState* fs, int first, int nret) {
  	luaK_codeABC(fs, OP_RETURN, first, nret + 1, 0);
  }
  
  
  static int condjump(FuncState* fs, OpCode op, int A, int B, int C) {
  	luaK_codeABC(fs, op, A, B, C);
  	return luaK_jump(fs);
  }
  
  
  static void fixjump(FuncState* fs, int pc, int dest) {
  	Instruction* jmp = &fs->f->code[pc];
  	int offset = dest - (pc + 1);
  	lua_assert(dest != NO_JUMP);
  	if (GET_OPCODE(*jmp) == OP_FORPREP || GET_OPCODE(*jmp) == OP_FORLOOP || GET_OPCODE(*jmp) == OP_TFORLOOP) {
  		if (abs(offset) > 32000)
  			luaX_syntaxerror(fs->ls, "for control structure too long");
  	}
  	if (abs(offset) > MAXARG_sBx)
  		luaX_syntaxerror(fs->ls, "control structure too long");
  	if (GETARG_A(*jmp) == 5)
  		SETARG_sBx(*jmp, offset - 1);
  	else
  		SETARG_sBx(*jmp, offset);
  }
  
  
  /*
  ** returns current `pc' and marks it as a jump target (to avoid wrong
  ** optimizations with consecutive instructions not in the same basic block).
  */
  int luaK_getlabel(FuncState* fs) {
  	fs->lasttarget = fs->pc;
  	return fs->pc;
  }
  
  
  
  static int getjump(FuncState* fs, int pc) {
  	int offset = GETARG_sBx(fs->f->code[pc]);
  	if (offset == NO_JUMP)  /* point to itself represents end of list */
  		return NO_JUMP;  /* end of list */
  	else
  		if (GETARG_A(fs->f->code[pc]) == 5)
  			return (pc + 2) + offset;  /* turn offset into absolute position */
  	return (pc + 1) + offset;  /* turn offset into absolute position */
  }
  
  
  static Instruction* getjumpcontrol(FuncState* fs, int pc) {
  	Instruction* pi = &fs->f->code[pc];
  	if (pc >= 1 && testTMode(GET_OPCODE(*(pi - 1))))
  		return pi - 1;
  	else
  		return pi;
  }
  
  
  /*
  ** check whether list has any jump that do not produce a value
  ** (or produce an inverted value)
  */
  static int need_value(FuncState* fs, int list) {
  	for (; list != NO_JUMP; list = getjump(fs, list)) {
  		Instruction i = *getjumpcontrol(fs, list);
  		if (GET_OPCODE(i) != OP_TESTSET) return 1;
  	}
  	return 0;  /* not found */
  }
  
  
  static int patchtestreg(FuncState* fs, int node, int reg) {
  	Instruction* i = getjumpcontrol(fs, node);
  	if (GET_OPCODE(*i) != OP_TESTSET)
  		return 0;  /* cannot patch other instructions */
  	if (reg != NO_REG && reg != GETARG_B(*i))
  		SETARG_A(*i, reg);
  	else  /* no register to put value or register already has the value */
  		*i = CREATE_ABC(OP_TEST, GETARG_B(*i), 0, GETARG_C(*i));
  
  	return 1;
  }
  
  
  static void removevalues(FuncState* fs, int list) {
  	for (; list != NO_JUMP; list = getjump(fs, list))
  		patchtestreg(fs, list, NO_REG);
  }
  
  
  static void patchlistaux(FuncState* fs, int list, int vtarget, int reg,
  	int dtarget) {
  	while (list != NO_JUMP) {
  		int next = getjump(fs, list);
  		if (patchtestreg(fs, list, reg))
  			fixjump(fs, list, vtarget);
  		else
  			fixjump(fs, list, dtarget);  /* jump to default target */
  		list = next;
  	}
  }
  
  
  static void dischargejpc(FuncState* fs) {
  	patchlistaux(fs, fs->jpc, fs->pc, NO_REG, fs->pc);
  	fs->jpc = NO_JUMP;
  }
  
  
  void luaK_patchlist(FuncState* fs, int list, int target) {
  	if (target == fs->pc)
  		luaK_patchtohere(fs, list);
  	else {
  		lua_assert(target < fs->pc);
  		patchlistaux(fs, list, target, NO_REG, target);
  	}
  }
  
  
  void luaK_patchtohere(FuncState* fs, int list) {
  	luaK_getlabel(fs);
  	luaK_concat(fs, &fs->jpc, list);
  }
  
  
  void luaK_concat(FuncState* fs, int* l1, int l2) {
  	if (l2 == NO_JUMP) return;
  	else if (*l1 == NO_JUMP)
  		*l1 = l2;
  	else {
  		int list = *l1;
  		int next;
  		while ((next = getjump(fs, list)) != NO_JUMP)  /* find last element */
  			list = next;
  		fixjump(fs, list, l2);
  	}
  }
  
  
  void luaK_checkstack(FuncState* fs, int n) {
  	int newstack = fs->freereg + n;
  	if (newstack > fs->f->maxstacksize) {
  		if (newstack >= MAXSTACK)
  			luaX_syntaxerror(fs->ls, "function or expression too complex");
  		fs->f->maxstacksize = cast_byte(newstack);
  	}
  }
  
  
  void luaK_reserveregs(FuncState* fs, int n) {
  	luaK_checkstack(fs, n);
  	fs->freereg += n;
  }
  
  
  static void freereg(FuncState* fs, int reg) {
  	if (!ISK(reg) && reg >= fs->nactvar) {
  		fs->freereg--;
  		lua_assert(reg == fs->freereg);
  	}
  }
  
  
  void freeexp(FuncState* fs, expdesc* e) {
  	if (e->k == VNONRELOC)
  		freereg(fs, e->u.s.info);
  }
  
  
  static int addk(FuncState* fs, TValue* k, TValue* v) {
  	lua_State* L = fs->L;
  	TValue* idx = luaH_set(L, fs->h, k);
  	Proto* f = fs->f;
  	int oldsize = f->sizek;
  	if (ttisnumber(idx)) {
  		lua_assert(luaO_rawequalObj(&fs->f->k[cast_int(nvalue(idx))], v));
  		return cast_int(nvalue(idx));
  	}
  	else {  /* constant not found; create a new entry */
  		setnvalue(idx, cast_num(fs->nk));
  		luaM_growvector(L, f->k, fs->nk, f->sizek, TValue,
  			MAXARG_Bx, "constant table overflow");
  		while (oldsize < f->sizek) setnilvalue(&f->k[oldsize++]);
  		setobj(L, &f->k[fs->nk], v);
  		luaC_barrier(L, f, v);
  		return fs->nk++;
  	}
  }
  
  
  int luaK_stringK(FuncState* fs, TString* s) {
  	TValue o;
  	setsvalue(fs->L, &o, s);
  	return addk(fs, &o, &o);
  }
  
  
  int luaK_numberK(FuncState* fs, lua_Number r) {
  	TValue o;
  	setnvalue(&o, r);
  	return addk(fs, &o, &o);
  }
  
  
  static int boolK(FuncState* fs, int b) {
  	TValue o;
  	setbvalue(&o, b);
  	return addk(fs, &o, &o);
  }
  
  
  static int nilK(FuncState* fs) {
  	TValue k, v;
  	setnilvalue(&v);
  	/* cannot use nil as key; instead use table itself to represent nil */
  	sethvalue(fs->L, &k, fs->h);
  	return addk(fs, &k, &v);
  }
  
  
  void luaK_setreturns(FuncState* fs, expdesc* e, int nresults) {
  	if (e->k == VCALL) {  /* expression is an open function call? */
  		SETARG_C(getcode(fs, e), nresults + 1);
  	}
  	else if (e->k == VVARARG) {
  		SETARG_B(getcode(fs, e), nresults + 1);
  		SETARG_A(getcode(fs, e), fs->freereg);
  		luaK_reserveregs(fs, 1);
  	}
  }
  
  
  void luaK_setoneret(FuncState* fs, expdesc* e) {
  	if (e->k == VCALL) {  /* expression is an open function call? */
  		e->k = VNONRELOC;
  		e->u.s.info = GETARG_A(getcode(fs, e));
  	}
  	else if (e->k == VVARARG) {
  		SETARG_B(getcode(fs, e), 2);
  		e->k = VRELOCABLE;  /* can relocate its simple result */
  	}
  }
  
  
  void luaK_dischargevars(FuncState* fs, expdesc* e) {
  	switch (e->k) {
  	case VLOCAL: {
  		e->k = VNONRELOC;
  		break;
  	}
  	case VUPVAL: {
  		e->u.s.info = luaK_codeABC(fs, OP_GETUPVAL, 0, e->u.s.info, 0);
  		e->k = VRELOCABLE;
  		break;
  	}
  	case VGLOBAL: {
  		e->u.s.info = luaK_codeABx(fs, OP_GETGLOBAL, 0, e->u.s.info);
  		e->k = VRELOCABLE;
  		break;
  	}
  	case VINDEXED: {
  		freereg(fs, e->u.s.aux);
  		freereg(fs, e->u.s.info);
  		e->u.s.info = luaK_codeABC(fs, OP_GETTABLE, 0, e->u.s.info, e->u.s.aux);
  		e->k = VRELOCABLE;
  		break;
  	}
  	case VVARARG:
  	case VCALL: {
  		luaK_setoneret(fs, e);
  		break;
  	}
  	default: break;  /* there is one value available (somewhere) */
  	}
  }
  
  
  static int code_label(FuncState* fs, int A, int b, int jump) {
  	luaK_getlabel(fs);  /* those instructions may be jump targets */
  	return luaK_codeABC(fs, OP_LOADBOOL, A, b, jump);
  }
  
  
  static void discharge2reg(FuncState* fs, expdesc* e, int reg) {
  	luaK_dischargevars(fs, e);
  	switch (e->k) {
  	case VNIL: {
  		luaK_nil(fs, reg, 1);
  		break;
  	}
  	case VFALSE:  case VTRUE: {
  		luaK_codeABC(fs, OP_LOADBOOL, reg, e->k == VTRUE, 0);
  		break;
  	}
  	case VK: {
  		luaK_codeABx(fs, OP_LOADK, reg, e->u.s.info);
  		break;
  	}
  	case VKNUM: {
  		luaK_codeABx(fs, OP_LOADK, reg, luaK_numberK(fs, e->u.nval));
  		break;
  	}
  	case VRELOCABLE: {
  		Instruction* pc = &getcode(fs, e);
  		SETARG_A(*pc, reg);
  		break;
  	}
  	case VNONRELOC: {
  		if (reg != e->u.s.info)
  			luaK_codeABC(fs, OP_MOVE, reg, e->u.s.info, 0);
  		break;
  	}
  	default: {
  		lua_assert(e->k == VVOID || e->k == VJMP);
  		return;  /* nothing to do... */
  	}
  	}
  	e->u.s.info = reg;
  	e->k = VNONRELOC;
  }
  
  
  static void discharge2anyreg(FuncState* fs, expdesc* e) {
  	if (e->k != VNONRELOC) {
  		luaK_reserveregs(fs, 1);
  		discharge2reg(fs, e, fs->freereg - 1);
  	}
  }
  
  
  void exp2reg(FuncState* fs, expdesc* e, int reg) {
  	discharge2reg(fs, e, reg);
  	if (e->k == VJMP)
  		luaK_concat(fs, &e->t, e->u.s.info);  /* put this jump in `t' list */
  	if (hasjumps(e)) {
  		int final;  /* position after whole expression */
  		int p_f = NO_JUMP;  /* position of an eventual LOAD false */
  		int p_t = NO_JUMP;  /* position of an eventual LOAD true */
  		if (need_value(fs, e->t) || need_value(fs, e->f)) {
  			int fj = (e->k == VJMP) ? NO_JUMP : luaK_jump(fs);
  			p_f = code_label(fs, reg, 0, 1);
  			p_t = code_label(fs, reg, 1, 0);
  			luaK_patchtohere(fs, fj);
  		}
  		final = luaK_getlabel(fs);
  		patchlistaux(fs, e->f, final, reg, p_f);
  		patchlistaux(fs, e->t, final, reg, p_t);
  	}
  	e->f = e->t = NO_JUMP;
  	e->u.s.info = reg;
  	e->k = VNONRELOC;
  }
  
  
  void luaK_exp2nextreg(FuncState* fs, expdesc* e) {
  	luaK_dischargevars(fs, e);
  	freeexp(fs, e);
  	luaK_reserveregs(fs, 1);
  	exp2reg(fs, e, fs->freereg - 1);
  }
  
  
  int luaK_exp2anyreg(FuncState* fs, expdesc* e) {
  	luaK_dischargevars(fs, e);
  	if (e->k == VNONRELOC) {
  		if (!hasjumps(e)) return e->u.s.info;  /* exp is already in a register */
  		if (e->u.s.info >= fs->nactvar) {  /* reg. is not a local? */
  			exp2reg(fs, e, e->u.s.info);  /* put value on it */
  			return e->u.s.info;
  		}
  	}
  	luaK_exp2nextreg(fs, e);  /* default */
  	return e->u.s.info;
  }
  
  
  void luaK_exp2val(FuncState* fs, expdesc* e) {
  	if (hasjumps(e))
  		luaK_exp2anyreg(fs, e);
  	else
  		luaK_dischargevars(fs, e);
  }
  
  
  int luaK_exp2RK(FuncState* fs, expdesc* e) {
  	luaK_exp2val(fs, e);
  	switch (e->k) {
  	case VKNUM:
  	case VTRUE:
  	case VFALSE:
  	case VNIL: {
  		if (fs->nk <= MAXINDEXRK && !G(fs->L)->convert) {  /* constant fit in RK operand? */
  			e->u.s.info = (e->k == VNIL) ? nilK(fs) :
  				(e->k == VKNUM) ? luaK_numberK(fs, e->u.nval) :
  				boolK(fs, (e->k == VTRUE));
  			e->k = VK;
  			return RKASK(e->u.s.info);
  		}
  		else break;
  	}
  	case VK: {
  		if (e->u.s.info <= MAXINDEXRK && !G(fs->L)->convert)  /* constant fit in argC? */
  			return RKASK(e->u.s.info);
  		else break;
  	}
  	default: break;
  	}
  	/* not a constant in the right range: put it in a register */
  	return luaK_exp2anyreg(fs, e);
  }
  
  
  void luaK_storevar(FuncState* fs, expdesc* var, expdesc* ex) {
  	switch (var->k) {
  	case VLOCAL: {
  		freeexp(fs, ex);
  		exp2reg(fs, ex, var->u.s.info);
  		return;
  	}
  	case VUPVAL: {
  		int e = luaK_exp2anyreg(fs, ex);
  		luaK_codeABC(fs, OP_SETUPVAL, e, var->u.s.info, 0);
  		break;
  	}
  	case VGLOBAL: {
  		int e = luaK_exp2anyreg(fs, ex);
  		luaK_codeABx(fs, OP_SETGLOBAL, e, var->u.s.info);
  		break;
  	}
  	case VINDEXED: {
  		int e = luaK_exp2RK(fs, ex);
  		luaK_codeABC(fs, OP_SETTABLE, var->u.s.info, var->u.s.aux, e);
  		break;
  	}
  	default: {
  		lua_assert(0);  /* invalid var kind to store */
  		break;
  	}
  	}
  	freeexp(fs, ex);
  }
  
  
  void luaK_self(FuncState* fs, expdesc* e, expdesc* key) {
  	if (!G(fs->L)->convert) {
  		int func;
  		luaK_exp2anyreg(fs, e);
  		freeexp(fs, e);
  		func = fs->freereg;
  		luaK_reserveregs(fs, 2);
  		luaK_codeABC(fs, OP_SELF, func, e->u.s.info, luaK_exp2RK(fs, key));
  		freeexp(fs, key);
  		e->u.s.info = func;
  		e->k = VNONRELOC;
  	}
  	else {
  		int func;
  		luaK_exp2anyreg(fs, e);
  		luaK_reserveregs(fs, 2);
  		freeexp(fs, e);
  	}
  }
  
  
  static void invertjump(FuncState* fs, expdesc* e) {
  	Instruction* pc = getjumpcontrol(fs, e->u.s.info);
  	lua_assert(testTMode(GET_OPCODE(*pc)) && GET_OPCODE(*pc) != OP_TESTSET &&
  		GET_OPCODE(*pc) != OP_TEST);
  	SETARG_A(*pc, !(GETARG_A(*pc)));
  }
  
  
  static int jumponcond(FuncState* fs, expdesc* e, int cond) {
  	if (e->k == VRELOCABLE) {
  		Instruction ie = getcode(fs, e);
  		if (GET_OPCODE(ie) == OP_NOT) {
  			fs->pc--;  /* remove previous OP_NOT */
  			return condjump(fs, OP_TEST, GETARG_B(ie), 0, !cond);
  		}
  		/* else go through */
  	}
  	discharge2anyreg(fs, e);
  	freeexp(fs, e);
  	return condjump(fs, OP_TESTSET, NO_REG, e->u.s.info, cond);
  }
  
  
  void luaK_goiftrue(FuncState* fs, expdesc* e) {
  	int pc;  /* pc of last jump */
  	luaK_dischargevars(fs, e);
  	switch (e->k) {
  	case VK: case VKNUM: case VTRUE: {
  		pc = NO_JUMP;  /* always true; do nothing */
  		break;
  	}
  	case VFALSE: {
  		pc = luaK_jump(fs);  /* always jump */
  		break;
  	}
  	case VJMP: {
  		invertjump(fs, e);
  		pc = e->u.s.info;
  		break;
  	}
  	default: {
  		pc = jumponcond(fs, e, 0);
  		break;
  	}
  	}
  	luaK_concat(fs, &e->f, pc);  /* insert last jump in `f' list */
  	luaK_patchtohere(fs, e->t);
  	e->t = NO_JUMP;
  }
  
  
  static void luaK_goiffalse(FuncState* fs, expdesc* e) {
  	int pc;  /* pc of last jump */
  	luaK_dischargevars(fs, e);
  	switch (e->k) {
  	case VNIL: case VFALSE: {
  		pc = NO_JUMP;  /* always false; do nothing */
  		break;
  	}
  	case VTRUE: {
  		pc = luaK_jump(fs);  /* always jump */
  		break;
  	}
  	case VJMP: {
  		pc = e->u.s.info;
  		break;
  	}
  	default: {
  		pc = jumponcond(fs, e, 1);
  		break;
  	}
  	}
  	luaK_concat(fs, &e->t, pc);  /* insert last jump in `t' list */
  	luaK_patchtohere(fs, e->f);
  	e->f = NO_JUMP;
  }
  
  
  static void codenot(FuncState* fs, expdesc* e) {
  	luaK_dischargevars(fs, e);
  	switch (e->k) {
  	case VNIL: case VFALSE: {
  		e->k = VTRUE;
  		break;
  	}
  	case VK: case VKNUM: case VTRUE: {
  		e->k = VFALSE;
  		break;
  	}
  	case VJMP: {
  		invertjump(fs, e);
  		break;
  	}
  	case VRELOCABLE:
  	case VNONRELOC: {
  		discharge2anyreg(fs, e);
  		freeexp(fs, e);
  		e->u.s.info = luaK_codeABC(fs, OP_NOT, 0, e->u.s.info, 0);
  		e->k = VRELOCABLE;
  		break;
  	}
  	default: {
  		lua_assert(0);  /* cannot happen */
  		break;
  	}
  	}
  	/* interchange true and false lists */
  	{ int temp = e->f; e->f = e->t; e->t = temp; }
  	removevalues(fs, e->f);
  	removevalues(fs, e->t);
  }
  
  
  void luaK_indexed(FuncState* fs, expdesc* t, expdesc* k) {
  	t->u.s.aux = luaK_exp2RK(fs, k);
  	t->k = VINDEXED;
  }
  
  
  static int constfolding(OpCode op, expdesc* e1, expdesc* e2) {
  	lua_Number v1, v2, r;
  	if (!isnumeral(e1) || !isnumeral(e2)) return 0;
  	v1 = e1->u.nval;
  	v2 = e2->u.nval;
  	switch (op) {
  	case OP_ADD: r = luai_numadd(v1, v2); break;
  	case OP_SUB: r = luai_numsub(v1, v2); break;
  	case OP_MUL: r = luai_nummul(v1, v2); break;
  	case OP_DIV:
  		if (v2 == 0) return 0;  /* do not attempt to divide by 0 */
  		r = luai_numdiv(v1, v2); break;
  	case OP_MOD:
  		if (v2 == 0) return 0;  /* do not attempt to divide by 0 */
  		r = luai_nummod(v1, v2); break;
  	case OP_POW: r = luai_numpow(v1, v2); break;
  	case OP_UNM: r = luai_numunm(v1); break;
  	case OP_LEN: return 0;  /* no constant folding for 'len' */
  	default: lua_assert(0); r = 0; break;
  	}
  	if (luai_numisnan(r)) return 0;  /* do not attempt to produce NaN */
  	e1->u.nval = r;
  	return 1;
  }
  
  
  static void codearith(FuncState* fs, OpCode op, expdesc* e1, expdesc* e2) {
  	if (constfolding(op, e1, e2))
  		return;
  	else {
  		int o2 = (op != OP_UNM && op != OP_LEN) ? luaK_exp2RK(fs, e2) : 0;
  		int o1 = luaK_exp2RK(fs, e1);
  		if (o1 > o2) {
  			freeexp(fs, e1);
  			freeexp(fs, e2);
  		}
  		else {
  			freeexp(fs, e2);
  			freeexp(fs, e1);
  		}
  		e1->u.s.info = luaK_codeABC(fs, op, 0, o1, o2);
  		e1->k = VRELOCABLE;
  	}
  }
  
  
  static void codecomp(FuncState* fs, OpCode op, int cond, expdesc* e1,
  	expdesc* e2) {
  
  	int o1 = luaK_exp2RK(fs, e1);
  	int o2 = luaK_exp2RK(fs, e2);
  	freeexp(fs, e2);
  	freeexp(fs, e1);
  	if (cond == 0 && op != OP_EQ) {
  		int temp;  /* exchange args to replace by `<' or `<=' */
  		temp = o1; o1 = o2; o2 = temp;  /* o1 <==> o2 */
  		cond = 1;
  	}
  	e1->u.s.info = condjump(fs, op, cond, o1, o2);
  	e1->k = VJMP;
  }
  
  
  void luaK_prefix(FuncState* fs, UnOpr op, expdesc* e) {
  	expdesc e2;
  	e2.t = e2.f = NO_JUMP; e2.k = VKNUM; e2.u.nval = 0;
  	switch (op) {
  	case OPR_MINUS: {
  		if (!isnumeral(e))
  			luaK_exp2anyreg(fs, e);  /* cannot operate on non-numeric constants */
  		codearith(fs, OP_UNM, e, &e2);
  		break;
  	}
  	case OPR_NOT: codenot(fs, e); break;
  	case OPR_LEN: {
  		luaK_exp2anyreg(fs, e);  /* cannot operate on constants */
  		codearith(fs, OP_LEN, e, &e2);
  		break;
  	}
  	default: lua_assert(0);
  	}
  }
  
  
  void luaK_infix(FuncState* fs, BinOpr op, expdesc* v) {
  	switch (op) {
  	case OPR_AND: {
  		luaK_goiftrue(fs, v);
  		break;
  	}
  	case OPR_OR: {
  		luaK_goiffalse(fs, v);
  		break;
  	}
  	case OPR_CONCAT: {
  		luaK_exp2nextreg(fs, v);  /* operand must be on the `stack' */
  		break;
  	}
  	case OPR_ADD: case OPR_SUB: case OPR_MUL: case OPR_DIV:
  	case OPR_MOD: case OPR_POW: {
  		if (!isnumeral(v)) luaK_exp2RK(fs, v);
  		break;
  	}
  	default: {
  		luaK_exp2RK(fs, v);
  		break;
  	}
  	}
  }
  
  
  void luaK_posfix(FuncState* fs, BinOpr op, expdesc* e1, expdesc* e2) {
  	switch (op) {
  	case OPR_AND: {
  		lua_assert(e1->t == NO_JUMP);  /* list must be closed */
  		luaK_dischargevars(fs, e2);
  		luaK_concat(fs, &e2->f, e1->f);
  		*e1 = *e2;
  		break;
  	}
  	case OPR_OR: {
  		lua_assert(e1->f == NO_JUMP);  /* list must be closed */
  		luaK_dischargevars(fs, e2);
  		luaK_concat(fs, &e2->t, e1->t);
  		*e1 = *e2;
  		break;
  	}
  	case OPR_CONCAT: {
  		luaK_exp2val(fs, e2);
  		if (e2->k == VRELOCABLE && GET_OPCODE(getcode(fs, e2)) == OP_CONCAT) {
  			lua_assert(e1->u.s.info == GETARG_B(getcode(fs, e2)) - 1);
  			freeexp(fs, e1);
  			SETARG_B(getcode(fs, e2), e1->u.s.info);
  			e1->k = VRELOCABLE; e1->u.s.info = e2->u.s.info;
  		}
  		else {
  			luaK_exp2nextreg(fs, e2);  /* operand must be on the 'stack' */
  			codearith(fs, OP_CONCAT, e1, e2);
  		}
  		break;
  	}
  	case OPR_ADD: codearith(fs, OP_ADD, e1, e2); break;
  	case OPR_SUB: codearith(fs, OP_SUB, e1, e2); break;
  	case OPR_MUL: codearith(fs, OP_MUL, e1, e2); break;
  	case OPR_DIV: codearith(fs, OP_DIV, e1, e2); break;
  	case OPR_MOD: codearith(fs, OP_MOD, e1, e2); break;
  	case OPR_POW: codearith(fs, OP_POW, e1, e2); break;
  	case OPR_EQ: codecomp(fs, OP_EQ, 1, e1, e2); break;
  	case OPR_NE: codecomp(fs, OP_EQ, 0, e1, e2); break;
  	case OPR_LT: codecomp(fs, OP_LT, 1, e1, e2); break;
  	case OPR_LE: codecomp(fs, OP_LE, 1, e1, e2); break;
  	case OPR_GT: codecomp(fs, OP_LT, 0, e1, e2); break;
  	case OPR_GE: codecomp(fs, OP_LE, 0, e1, e2); break;
  	default: lua_assert(0);
  	}
  }
  
  
  void luaK_fixline(FuncState* fs, int line) {
  	fs->f->lineinfo[fs->pc - 1] = line;
  }
  
  
  static int luaK_code(FuncState* fs, Instruction i, int line) {
  	Proto* f = fs->f;
  	dischargejpc(fs);  /* `pc' will change */
  					   /* put new instruction in code array */
  	luaM_growvector(fs->L, f->code, fs->pc, f->sizecode, Instruction,
  		MAX_INT, "code size overflow");
  	f->code[fs->pc] = i;
  	/* save corresponding line information */
  	luaM_growvector(fs->L, f->lineinfo, fs->pc, f->sizelineinfo, int,
  		MAX_INT, "code size overflow");
  	f->lineinfo[fs->pc] = line;
  	return fs->pc++;
  }
  
  
  int luaK_codeABC(FuncState* fs, OpCode o, int a, int b, int c) {
  	lua_assert(getOpMode(o) == iABC);
  	lua_assert(getBMode(o) != OpArgN || b == 0);
  	lua_assert(getCMode(o) != OpArgN || c == 0);
  	return luaK_code(fs, CREATE_ABC(o, a, b, c), fs->ls->lastline);
  }
  
  
  int luaK_codeABx(FuncState* fs, OpCode o, int a, unsigned int bc) {
  	lua_assert(getOpMode(o) == iABx || getOpMode(o) == iAsBx);
  	lua_assert(getCMode(o) == OpArgN);
  	return luaK_code(fs, CREATE_ABx(o, a, bc), fs->ls->lastline);
  }
  
  
  void luaK_setlist(FuncState* fs, int base, int nelems, int tostore) {
  	int c = (nelems - 1) / LFIELDS_PER_FLUSH + 1;
  	int b = (tostore == LUA_MULTRET) ? 0 : tostore;
  	lua_assert(tostore != 0);
  	if (c <= MAXARG_C)
  		luaK_codeABC(fs, OP_SETLIST, base, b, c);
  	else {
  		luaK_codeABC(fs, OP_SETLIST, base, b, 0);
  		luaK_code(fs, cast(Instruction, c), fs->ls->lastline);
  	}
  	fs->freereg = base + 1;  /* free registers with list values */
  }
  
  