diff --git a/lcode.c b/lcode.c
index ad0c05d2..1c1517bf 100644
--- a/lcode.c
+++ b/lcode.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lcode.c,v 1.72 2001/06/08 12:29:27 roberto Exp roberto $
+** $Id: lcode.c,v 1.73 2001/06/08 19:00:57 roberto Exp roberto $
 ** Code generator for Lua
 ** See Copyright Notice in lua.h
 */
@@ -69,8 +69,8 @@ int luaK_jump (FuncState *fs) {
 }
 
 
-static int luaK_condjump (FuncState *fs, OpCode op, int B, int C) {
-  luaK_codeABC(fs, op, NO_REG, B, C);
+static int luaK_condjump (FuncState *fs, OpCode op, int A, int B, int C) {
+  luaK_codeABC(fs, op, A, B, C);
   return luaK_codeAsBc(fs, OP_CJMP, 0, NO_JUMP);
 }
 
@@ -261,12 +261,11 @@ static int number_constant (FuncState *fs, lua_Number r) {
 
 void luaK_setcallreturns (FuncState *fs, expdesc *e, int nresults) {
   if (e->k == VCALL) {  /* expression is an open function call? */
-    int a = GETARG_A(getcode(fs, e));
-    int c = (nresults == LUA_MULTRET) ? NO_REG : a + nresults;
-    SETARG_C(getcode(fs, e), c);
+    if (nresults == LUA_MULTRET) nresults = NO_REG;
+    SETARG_C(getcode(fs, e), nresults);
     if (nresults == 1) {  /* `regular' expression? */
       e->k = VNONRELOC;
-      e->u.i.info = a;
+      e->u.i.info = GETARG_A(getcode(fs, e));
     }
   }
 }
@@ -499,13 +498,13 @@ static int jumponcond (FuncState *fs, expdesc *e, OpCode op) {
     if (GET_OPCODE(ie) == OP_NOT) {
       op = invertoperator(op);
       fs->pc--;  /* remove previous OP_NOT */
-      return luaK_condjump(fs, op, GETARG_B(ie), 0);
+      return luaK_condjump(fs, op, NO_REG, GETARG_B(ie), 0);
     }
     /* else go through */
   }
   discharge2anyreg(fs, e);
   freeexp(fs, e);
-  return luaK_condjump(fs, op, e->u.i.info, 0);
+  return luaK_condjump(fs, op, NO_REG, e->u.i.info, 0);
 }
 
 
@@ -748,7 +747,7 @@ void luaK_posfix (FuncState *fs, BinOpr op, expdesc *e1, expdesc *e2) {
         e1->k = VRELOCABLE;
       }
       else {  /* jump */
-        e1->u.i.info = luaK_condjump(fs, opc, o1, o2);
+        e1->u.i.info = luaK_condjump(fs, opc, o1, 0, o2);
         e1->k = VJMP;
       }
     }
diff --git a/ldebug.c b/ldebug.c
index 62372fca..27494a4e 100644
--- a/ldebug.c
+++ b/ldebug.c
@@ -1,5 +1,5 @@
 /*
-** $Id: ldebug.c,v 1.80 2001/06/08 12:29:27 roberto Exp roberto $
+** $Id: ldebug.c,v 1.81 2001/06/08 19:00:57 roberto Exp roberto $
 ** Debug Interface
 ** See Copyright Notice in lua.h
 */
@@ -349,6 +349,7 @@ static Instruction luaG_symbexec (const Proto *pt, int lastpc, int reg) {
     int a = GETARG_A(i);
     int b = 0;
     int c = 0;
+    checkreg(pt, a);
     switch (getOpMode(op)) {
       case iABC: {
         b = GETARG_B(i);
@@ -370,7 +371,6 @@ static Instruction luaG_symbexec (const Proto *pt, int lastpc, int reg) {
         break;
       }
     }
-    if (testOpMode(op, OpModeAreg)) checkreg(pt, a);
     if (testOpMode(op, OpModesetA)) {
       if (a == reg) last = pc;  /* change register `a' */
     }
@@ -414,20 +414,20 @@ static Instruction luaG_symbexec (const Proto *pt, int lastpc, int reg) {
         break;
       }
       case OP_CALL: {
-        if (b == NO_REG) b = pt->maxstacksize;
+        if (b != NO_REG) {
+          checkreg(pt, a+b);
+        }
         if (c == NO_REG) {
           check(checkopenop(pt->code[pc+1]));
-          c = 1;
         }
-        check(b > a);
-        checkreg(pt, b-1);
-        checkreg(pt, c-1);
+        else if (c != 0)
+          checkreg(pt, a+c-1);
         if (reg >= a) last = pc;  /* affect all registers above base */
         break;
       }
       case OP_RETURN: {
-        if (b == NO_REG) b = pt->maxstacksize;
-        checkreg(pt, b-1);
+        if (b != NO_REG && b != 0)
+          checkreg(pt, a+b-1);
         break;
       }
       case OP_FORPREP:
@@ -566,49 +566,49 @@ void luaG_ordererror (lua_State *L, const TObject *p1, const TObject *p2) {
 
 
 #define opmode(t,a,b,c,sa,k,m) (((t)<<OpModeT) | \
-   ((a)<<OpModeAreg) | ((b)<<OpModeBreg) | ((c)<<OpModeCreg) | \
+   ((b)<<OpModeBreg) | ((c)<<OpModeCreg) | \
    ((sa)<<OpModesetA) | ((k)<<OpModeK) | (m))
 
 
 const lu_byte luaG_opmodes[] = {
-/*       T A B C sA K mode		   opcode    */
-  opmode(0,1,1,0, 1,0,iABC),		/* OP_MOVE */
-  opmode(0,1,0,0, 1,1,iABc),		/* OP_LOADK */
-  opmode(0,1,0,0, 1,0,iAsBc),		/* OP_LOADINT */
-  opmode(0,1,1,0, 1,0,iABC),		/* OP_LOADNIL */
-  opmode(0,1,0,0, 1,0,iABc),		/* OP_LOADUPVAL */
-  opmode(0,1,0,0, 1,1,iABc),		/* OP_GETGLOBAL */
-  opmode(0,1,1,1, 1,0,iABC),		/* OP_GETTABLE */
-  opmode(0,1,0,0, 0,1,iABc),		/* OP_SETGLOBAL */
-  opmode(0,1,1,1, 0,0,iABC),		/* OP_SETTABLE */
-  opmode(0,1,0,0, 1,0,iABc),		/* OP_NEWTABLE */
-  opmode(0,1,1,1, 1,0,iABC),		/* OP_SELF */
-  opmode(0,1,1,1, 1,0,iABC),		/* OP_ADD */
-  opmode(0,1,1,1, 1,0,iABC),		/* OP_SUB */
-  opmode(0,1,1,1, 1,0,iABC),		/* OP_MUL */
-  opmode(0,1,1,1, 1,0,iABC),		/* OP_DIV */
-  opmode(0,1,1,1, 1,0,iABC),		/* OP_POW */
-  opmode(0,1,1,0, 1,0,iABC),		/* OP_UNM */
-  opmode(0,1,1,0, 1,0,iABC),		/* OP_NOT */
-  opmode(0,1,1,1, 1,0,iABC),		/* OP_CONCAT */
-  opmode(0,0,0,0, 0,0,iAsBc),		/* OP_JMP */
-  opmode(0,0,0,0, 0,0,iAsBc),		/* OP_CJMP */
-  opmode(1,0,1,1, 0,0,iABC),		/* OP_TESTEQ */
-  opmode(1,0,1,1, 0,0,iABC),		/* OP_TESTNE */
-  opmode(1,0,1,1, 0,0,iABC),		/* OP_TESTLT */
-  opmode(1,0,1,1, 0,0,iABC),		/* OP_TESTLE */
-  opmode(1,0,1,1, 0,0,iABC),		/* OP_TESTGT */
-  opmode(1,0,1,1, 0,0,iABC),		/* OP_TESTGE */
-  opmode(1,1,1,0, 1,0,iABC),		/* OP_TESTT */
-  opmode(1,1,1,0, 1,0,iABC),		/* OP_TESTF */
-  opmode(0,1,0,0, 1,0,iAsBc),		/* OP_NILJMP */
-  opmode(0,1,0,0, 0,0,iABC),		/* OP_CALL */
-  opmode(0,1,0,0, 0,0,iABC),		/* OP_RETURN */
-  opmode(0,1,0,0, 0,0,iAsBc),		/* OP_FORPREP */
-  opmode(0,1,0,0, 0,0,iAsBc),		/* OP_FORLOOP */
+/*       T J B C sA K mode		   opcode    */
+  opmode(0,0,1,0, 1,0,iABC),		/* OP_MOVE */
+  opmode(0,0,0,0, 1,1,iABc),		/* OP_LOADK */
+  opmode(0,0,0,0, 1,0,iAsBc),		/* OP_LOADINT */
+  opmode(0,0,1,0, 1,0,iABC),		/* OP_LOADNIL */
+  opmode(0,0,0,0, 1,0,iABc),		/* OP_LOADUPVAL */
+  opmode(0,0,0,0, 1,1,iABc),		/* OP_GETGLOBAL */
+  opmode(0,0,1,1, 1,0,iABC),		/* OP_GETTABLE */
+  opmode(0,0,0,0, 0,1,iABc),		/* OP_SETGLOBAL */
+  opmode(0,0,1,1, 0,0,iABC),		/* OP_SETTABLE */
+  opmode(0,0,0,0, 1,0,iABc),		/* OP_NEWTABLE */
+  opmode(0,0,1,1, 1,0,iABC),		/* OP_SELF */
+  opmode(0,0,1,1, 1,0,iABC),		/* OP_ADD */
+  opmode(0,0,1,1, 1,0,iABC),		/* OP_SUB */
+  opmode(0,0,1,1, 1,0,iABC),		/* OP_MUL */
+  opmode(0,0,1,1, 1,0,iABC),		/* OP_DIV */
+  opmode(0,0,1,1, 1,0,iABC),		/* OP_POW */
+  opmode(0,0,1,0, 1,0,iABC),		/* OP_UNM */
+  opmode(0,0,1,0, 1,0,iABC),		/* OP_NOT */
+  opmode(0,0,1,1, 1,0,iABC),		/* OP_CONCAT */
+  opmode(0,1,0,0, 0,0,iAsBc),		/* OP_JMP */
+  opmode(0,1,0,0, 0,0,iAsBc),		/* OP_CJMP */
+  opmode(1,0,0,1, 0,0,iABC),		/* OP_TESTEQ */
+  opmode(1,0,0,1, 0,0,iABC),		/* OP_TESTNE */
+  opmode(1,0,0,1, 0,0,iABC),		/* OP_TESTLT */
+  opmode(1,0,0,1, 0,0,iABC),		/* OP_TESTLE */
+  opmode(1,0,0,1, 0,0,iABC),		/* OP_TESTGT */
+  opmode(1,0,0,1, 0,0,iABC),		/* OP_TESTGE */
+  opmode(1,0,1,0, 1,0,iABC),		/* OP_TESTT */
+  opmode(1,0,1,0, 1,0,iABC),		/* OP_TESTF */
+  opmode(0,0,0,0, 1,0,iAsBc),		/* OP_NILJMP */
+  opmode(0,0,0,0, 0,0,iABC),		/* OP_CALL */
+  opmode(0,0,0,0, 0,0,iABC),		/* OP_RETURN */
+  opmode(0,0,0,0, 0,0,iAsBc),		/* OP_FORPREP */
+  opmode(0,0,0,0, 0,0,iAsBc),		/* OP_FORLOOP */
   opmode(0,1,0,0, 0,0,iAsBc),		/* OP_TFORPREP */
   opmode(0,1,0,0, 0,0,iAsBc),		/* OP_TFORLOOP */
-  opmode(0,1,0,0, 0,0,iABc),		/* OP_SETLIST */
-  opmode(0,1,0,0, 0,0,iABc),		/* OP_SETLIST0 */
-  opmode(0,1,0,0, 0,0,iABc)		/* OP_CLOSURE */
+  opmode(0,0,0,0, 0,0,iABc),		/* OP_SETLIST */
+  opmode(0,0,0,0, 0,0,iABc),		/* OP_SETLIST0 */
+  opmode(0,0,0,0, 0,0,iABc)		/* OP_CLOSURE */
 };
diff --git a/ldebug.h b/ldebug.h
index c48681f1..678ef1ce 100644
--- a/ldebug.h
+++ b/ldebug.h
@@ -1,5 +1,5 @@
 /*
-** $Id: ldebug.h,v 1.12 2001/06/05 18:17:01 roberto Exp roberto $
+** $Id: ldebug.h,v 1.13 2001/06/06 17:50:36 roberto Exp roberto $
 ** Auxiliary functions from Debug Interface module
 ** See Copyright Notice in lua.h
 */
@@ -18,8 +18,7 @@ enum OpMode {iABC, iABc, iAsBc};  /* basic instruction format */
 ** masks for instruction properties
 */
 enum OpModeMask {
-  OpModeAreg = 2,	/* A is a register */
-  OpModeBreg,		/* B is a register */
+  OpModeBreg = 2,	/* B is a register */
   OpModeCreg,		/* C is a register/constant */
   OpModesetA,		/* instruction set register A */
   OpModeK,		/* Bc is a constant */
diff --git a/lopcodes.h b/lopcodes.h
index bbca12d9..45674257 100644
--- a/lopcodes.h
+++ b/lopcodes.h
@@ -1,5 +1,5 @@
 /*
-** $Id: lopcodes.h,v 1.73 2001/06/05 18:17:01 roberto Exp roberto $
+** $Id: lopcodes.h,v 1.74 2001/06/08 19:00:57 roberto Exp roberto $
 ** Opcodes for Lua virtual machine
 ** See Copyright Notice in lua.h
 */
@@ -153,20 +153,20 @@ OP_CONCAT,/*	A B C	R(A) := R(B).. ... ..R(C)			*/
 OP_JMP,/*	sBc	PC += sBc					*/
 OP_CJMP,/*	sBc	if test then PC += sBc		(see (1))	*/
 
-OP_TESTEQ,/*	B C	test := (R(B) == R/K(C))			*/
-OP_TESTNE,/*	B C	test := (R(B) ~= R/K(C))			*/
-OP_TESTLT,/*	B C	test := (R(B) < R/K(C))				*/
-OP_TESTLE,/*	B C	test := (R(B) <= R/K(C))			*/
-OP_TESTGT,/*	B C	test := (R(B) > R/K(C))				*/
-OP_TESTGE,/*	B C	test := (R(B) >= R/K(C))			*/
+OP_TESTEQ,/*	A C	test := (R(A) == R/K(C))			*/
+OP_TESTNE,/*	A C	test := (R(A) ~= R/K(C))			*/
+OP_TESTLT,/*	A C	test := (R(A) < R/K(C))				*/
+OP_TESTLE,/*	A C	test := (R(A) <= R/K(C))			*/
+OP_TESTGT,/*	A C	test := (R(A) > R/K(C))				*/
+OP_TESTGE,/*	A C	test := (R(A) >= R/K(C))			*/
 
 OP_TESTT,/*	A B	test := R(B); if (test) R(A) := R(B)		*/
 OP_TESTF,/*	A B	test := not R(B); if (test) R(A) := nil		*/
 
 OP_NILJMP,/*	A	R(A) := nil; PC++;				*/
 
-OP_CALL,/*	A B C	R(A), ... ,R(C-1) := R(A)(R(A+1), ... ,R(B-1))	*/
-OP_RETURN,/*	A B	return R(A), ... ,R(B-1)	(see (3))	*/
+OP_CALL,/*	A B C	R(A), ... ,R(A+C-1) := R(A)(R(A+1), ... ,R(A+B))*/
+OP_RETURN,/*	A B	return R(A), ... ,R(A+B-1)	(see (3))	*/
 
 OP_FORPREP,/*	A sBc							*/
 OP_FORLOOP,/*	A sBc							*/
@@ -191,10 +191,10 @@ OP_CLOSURE /*	A Bc	R(A) := closure(KPROTO[Bc], R(A), ... ,R(A+n))	*/
       instructions OP_TEST* and OP_CJMP must always occur together.
 
   (2) In OP_CALL, if (B == NO_REG) then B = top. C is the number of returns,
-      and can be NO_REG. OP_CALL always set "top" to last_result+1, so
-      next open instruction (OP_CALL, OP_RETURN, OP_SETLIST) may use "top".
+      and can be NO_REG. OP_CALL can set `top' to last_result+1, so
+      next open instruction (OP_CALL, OP_RETURN, OP_SETLIST) may use `top'.
 
-  (3) In OP_RETURN, if (B == NO_REG) then B = top.
+  (3) In OP_RETURN, if (B == NO_REG) then return up to `top'
 ===========================================================================*/
 
 
diff --git a/lparser.c b/lparser.c
index 8dff5638..b077c324 100644
--- a/lparser.c
+++ b/lparser.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lparser.c,v 1.146 2001/06/08 12:29:27 roberto Exp roberto $
+** $Id: lparser.c,v 1.147 2001/06/08 19:00:57 roberto Exp roberto $
 ** LL(1) Parser and code generator for Lua
 ** See Copyright Notice in lua.h
 */
@@ -415,7 +415,7 @@ static int explist1 (LexState *ls, expdesc *v) {
 static void funcargs (LexState *ls, expdesc *f) {
   FuncState *fs = ls->fs;
   expdesc args;
-  int base, top;
+  int base, nparams;
   switch (ls->t.token) {
     case l_c('('): {  /* funcargs -> `(' [ explist1 ] `)' */
       int line = ls->linenumber;
@@ -446,13 +446,13 @@ static void funcargs (LexState *ls, expdesc *f) {
   lua_assert(f->k == VNONRELOC);
   base = f->u.i.info;  /* base register for call */
   if (args.k == VCALL)
-    top = NO_REG;  /* open call */
+    nparams = NO_REG;  /* open call */
   else {
     if (args.k != VVOID)
       luaK_exp2nextreg(fs, &args);  /* close last argument */
-    top = fs->freereg;
+    nparams = fs->freereg - (base+1);
   }
-  init_exp(f, VCALL, luaK_codeABC(fs, OP_CALL, base, top, base+1));
+  init_exp(f, VCALL, luaK_codeABC(fs, OP_CALL, base, nparams, 1));
   fs->freereg = base+1;  /* call remove function and arguments and leaves
                             (unless changed) one result */
 }
@@ -1091,31 +1091,31 @@ static void retstat (LexState *ls) {
   /* stat -> RETURN explist */
   FuncState *fs = ls->fs;
   expdesc e;
-  int first, last1;  /* registers with returned values */
+  int first, nret;  /* registers with returned values */
   next(ls);  /* skip RETURN */
   if (block_follow(ls->t.token) || ls->t.token == l_c(';'))
-    first = last1 = 0;  /* return no values */
+    first = nret = 0;  /* return no values */
   else {
     int n = explist1(ls, &e);  /* optional return values */
     if (e.k == VCALL) {
       luaK_setcallreturns(fs, &e, LUA_MULTRET);
       first = fs->nactloc;
-      last1 = NO_REG;  /* return all values */
+      nret = NO_REG;  /* return all values */
     }
     else {
       if (n == 1) {  /* only one value? */
         luaK_exp2anyreg(fs, &e);
         first = e.u.i.info;
-        last1 = first+1;  /* return only this value */
+        nret = 1;  /* return only this value */
       }
       else {
         luaK_exp2nextreg(fs, &e);  /* values must go to the `stack' */
         first = fs->nactloc;
-        last1 = fs->freereg;  /* return all `active' values */
+        nret = fs->freereg - first;  /* return all `active' values */
       }
     }
   }
-  luaK_codeABC(fs, OP_RETURN, first, last1, 0);
+  luaK_codeABC(fs, OP_RETURN, first, nret, 0);
   fs->freereg = fs->nactloc;  /* removes all temp values */
 }
 
diff --git a/lvm.c b/lvm.c
index 64df3762..5cadb252 100644
--- a/lvm.c
+++ b/lvm.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lvm.c,v 1.182 2001/06/08 19:00:57 roberto Exp roberto $
+** $Id: lvm.c,v 1.183 2001/06/08 19:20:02 roberto Exp roberto $
 ** Lua virtual machine
 ** See Copyright Notice in lua.h
 */
@@ -488,37 +488,37 @@ StkId luaV_execute (lua_State *L, const Closure *cl, StkId base) {
       }
       case OP_TESTEQ: {
         lua_assert(GET_OPCODE(*pc) == OP_CJMP);
-        if (luaO_equalObj(RB(i), RKC(i))) dojump(pc, *pc);
+        if (luaO_equalObj(ra, RKC(i))) dojump(pc, *pc);
         pc++;
         break;
       }
       case OP_TESTNE: {
         lua_assert(GET_OPCODE(*pc) == OP_CJMP);
-        if (!luaO_equalObj(RB(i), RKC(i))) dojump(pc, *pc);
+        if (!luaO_equalObj(ra, RKC(i))) dojump(pc, *pc);
         pc++;
         break;
       }
       case OP_TESTLT: {
         lua_assert(GET_OPCODE(*pc) == OP_CJMP);
-        if (luaV_lessthan(L, RB(i), RKC(i))) dojump(pc, *pc);
+        if (luaV_lessthan(L, ra, RKC(i))) dojump(pc, *pc);
         pc++;
         break;
       }
       case OP_TESTLE: {  /* b <= c  ===  !(c<b) */
         lua_assert(GET_OPCODE(*pc) == OP_CJMP);
-        if (!luaV_lessthan(L, RKC(i), RB(i))) dojump(pc, *pc);
+        if (!luaV_lessthan(L, RKC(i), ra)) dojump(pc, *pc);
         pc++;
         break;
       }
       case OP_TESTGT: {  /* b > c  ===  (c<b) */
         lua_assert(GET_OPCODE(*pc) == OP_CJMP);
-        if (luaV_lessthan(L, RKC(i), RB(i))) dojump(pc, *pc);
+        if (luaV_lessthan(L, RKC(i), ra)) dojump(pc, *pc);
         pc++;
         break;
       }
       case OP_TESTGE: {  /* b >= c  === !(b<c) */
         lua_assert(GET_OPCODE(*pc) == OP_CJMP);
-        if (!luaV_lessthan(L, RB(i), RKC(i))) dojump(pc, *pc);
+        if (!luaV_lessthan(L, ra, RKC(i))) dojump(pc, *pc);
         pc++;
         break;
       }
@@ -550,11 +550,11 @@ StkId luaV_execute (lua_State *L, const Closure *cl, StkId base) {
         int c;
         int b = GETARG_B(i);
         if (b != NO_REG)
-          L->top = base+b;
+          L->top = ra+b+1;
         luaD_call(L, ra);
         c = GETARG_C(i);
         if (c != NO_REG) {
-          while (L->top < base+c) setnilvalue(L->top++);
+          while (L->top < ra+c) setnilvalue(L->top++);
           L->top = base + tf->maxstacksize;
         }
         break;
@@ -562,7 +562,7 @@ StkId luaV_execute (lua_State *L, const Closure *cl, StkId base) {
       case OP_RETURN: {
         int b = GETARG_B(i);
         if (b != NO_REG)
-          L->top = base+b;
+          L->top = ra+b;
         return ra;
       }
       case OP_FORPREP: {
@@ -578,10 +578,10 @@ StkId luaV_execute (lua_State *L, const Closure *cl, StkId base) {
         /* go through */
       }
       case OP_FORLOOP: {
-        if (ttype(ra) != LUA_TNUMBER)
-          luaD_error(L, l_s("`for' index must be a number"));
         runtime_check(L, ttype(ra+1) == LUA_TNUMBER &&
                          ttype(ra+2) == LUA_TNUMBER);
+        if (ttype(ra) != LUA_TNUMBER)
+          luaD_error(L, l_s("`for' index must be a number"));
         nvalue(ra) += nvalue(ra+2);  /* increment index */
         if (nvalue(ra+2) > 0 ?
             nvalue(ra) <= nvalue(ra+1) :