diff --git a/src/cmd/gc/Makefile b/src/cmd/gc/Makefile
index e3adaef769c..9c3f2e977e9 100644
--- a/src/cmd/gc/Makefile
+++ b/src/cmd/gc/Makefile
@@ -22,7 +22,9 @@ OFILES=\
 	export.$O\
 	walk.$O\
 	const.$O\
-	mparith.$O\
+	mparith1.$O\
+	mparith2.$O\
+	mparith3.$O\
 	sysimport.$O\
 	compat.$O\
 
diff --git a/src/cmd/gc/const.c b/src/cmd/gc/const.c
index fff0e0c4a35..2188178a697 100644
--- a/src/cmd/gc/const.c
+++ b/src/cmd/gc/const.c
@@ -323,16 +323,7 @@ evconst(Node *n)
 			goto settrue;
 		goto setfalse;
 	}
-	*n = *nl;
-
-	// second half of dance
-	if(wl == Wlitint) {
-		n->val.u.xval = xval;
-	} else
-	if(wl == Wlitfloat) {
-		n->val.u.fval = fval;
-	}
-	return;
+	goto ret;
 
 settrue:
 	*n = *booltrue;
@@ -343,6 +334,15 @@ setfalse:
 	return;
 
 unary:
+	if(wl == Wlitint) {
+		xval = mal(sizeof(*xval));
+		mpmovefixfix(xval, nl->val.u.xval);
+	} else
+	if(wl == Wlitfloat) {
+		fval = mal(sizeof(*fval));
+		mpmovefltflt(fval, nl->val.u.fval);
+	}
+
 	switch(TUP(n->op, wl)) {
 	default:
 		yyerror("illegal combination of literals %O %d", n->op, wl);
@@ -351,16 +351,16 @@ unary:
 	case TUP(OPLUS, Wlitint):
 		break;
 	case TUP(OMINUS, Wlitint):
-		mpnegfix(nl->val.u.xval);
+		mpnegfix(xval);
 		break;
 	case TUP(OCOM, Wlitint):
-		mpcomfix(nl->val.u.xval);
+		mpcomfix(xval);
 		break;
 
 	case TUP(OPLUS, Wlitfloat):
 		break;
 	case TUP(OMINUS, Wlitfloat):
-		mpnegflt(nl->val.u.fval);
+		mpnegflt(fval);
 		break;
 
 	case TUP(ONOT, Wlitbool):
@@ -368,7 +368,17 @@ unary:
 			goto settrue;
 		goto setfalse;
 	}
+
+ret:
 	*n = *nl;
+
+	// second half of dance
+	if(wl == Wlitint) {
+		n->val.u.xval = xval;
+	} else
+	if(wl == Wlitfloat) {
+		n->val.u.fval = fval;
+	}
 }
 
 void
diff --git a/src/cmd/gc/go.h b/src/cmd/gc/go.h
index 636856e1990..af50d48bd36 100644
--- a/src/cmd/gc/go.h
+++ b/src/cmd/gc/go.h
@@ -78,8 +78,6 @@ typedef	struct	Mpflt	Mpflt;
 struct	Mpflt
 {
 	double	val;
-	long	a[Mpprec];
-	uchar	neg;
 	uchar	ovf;
 };
 
@@ -471,46 +469,54 @@ void	ungetc(int);
 void	mkpackage(char*);
 
 /*
- *	mparith.c
+ *	mparith1.c
  */
-void	mpmovefixfix(Mpint *a, Mpint *b);
-void	mpmovefixflt(Mpflt *a, Mpint *b);
-void	mpmovefltfix(Mpint *a, Mpflt *b);
-void	mpmovefltflt(Mpflt *a, Mpflt *b);
-void	mpmovecfix(Mpint *a, vlong v);
-void	mpmovecflt(Mpflt *a, double f);
-
 int	mpcmpfixfix(Mpint *a, Mpint *b);
-int	mpcmpfltflt(Mpflt *a, Mpflt *b);
 int	mpcmpfixc(Mpint *b, vlong c);
-int	mpcmpfltc(Mpint *b, double c);
-int	mptestfixfix(Mpint *a);
-int	mptestfltflt(Mpflt *a);
-
-void	mpaddfixfix(Mpint *a, Mpint *b);
-void	mpaddfltflt(Mpflt *a, Mpflt *b);
+int	mpcmpfltflt(Mpflt *a, Mpflt *b);
+int	mpcmpfltc(Mpflt *b, double c);
 void	mpsubfixfix(Mpint *a, Mpint *b);
 void	mpsubfltflt(Mpflt *a, Mpflt *b);
-void	mpmulfixfix(Mpint *a, Mpint *b);
-void	mpmulfltflt(Mpflt *a, Mpflt *b);
+void	mpaddcfix(Mpint *a, vlong c);
+void	mpaddcflt(Mpflt *a, double c);
+void	mpmulcfix(Mpint *a, vlong c);
+void	mpmulcflt(Mpflt *a, double c);
 void	mpdivfixfix(Mpint *a, Mpint *b);
-void	mpdivfltflt(Mpflt *a, Mpflt *b);
-void	mpnegfix(Mpint *a);
-void	mpnegflt(Mpflt *a);
+void	mpmodfixfix(Mpint *a, Mpint *b);
+void	mpatofix(Mpint *a, char *s);
+void	mpatoflt(Mpflt *a, char *s);
+void	mpmovefltfix(Mpint *a, Mpflt *b);
+void	mpmovefixflt(Mpflt *a, Mpint *b);
 
+/*
+ *	mparith2.c
+ */
+void	mpmovefixfix(Mpint *a, Mpint *b);
+void	mpmovecfix(Mpint *a, vlong v);
+int	mptestfix(Mpint *a);
+void	mpaddfixfix(Mpint *a, Mpint *b);
+void	mpmulfixfix(Mpint *a, Mpint *b);
+void	mpdivmodfixfix(Mpint *q, Mpint *r, Mpint *n, Mpint *d);
+void	mpnegfix(Mpint *a);
 void	mpandfixfix(Mpint *a, Mpint *b);
 void	mplshfixfix(Mpint *a, Mpint *b);
-void	mpmodfixfix(Mpint *a, Mpint *b);
 void	mporfixfix(Mpint *a, Mpint *b);
 void	mprshfixfix(Mpint *a, Mpint *b);
 void	mpxorfixfix(Mpint *a, Mpint *b);
 void	mpcomfix(Mpint *a);
-
-double	mpgetflt(Mpflt *a);
 vlong	mpgetfix(Mpint *a);
 
-void	mpatofix(Mpint *a, char *s);
-void	mpatoflt(Mpflt *a, char *s);
+/*
+ *	mparith3.c
+ */
+void	mpmovefltflt(Mpflt *a, Mpflt *b);
+void	mpmovecflt(Mpflt *a, double f);
+int	mptestflt(Mpflt *a);
+void	mpaddfltflt(Mpflt *a, Mpflt *b);
+void	mpmulfltflt(Mpflt *a, Mpflt *b);
+void	mpdivfltflt(Mpflt *a, Mpflt *b);
+void	mpnegflt(Mpflt *a);
+double	mpgetflt(Mpflt *a);
 
 /*
  *	subr.c
diff --git a/src/cmd/gc/lex.c b/src/cmd/gc/lex.c
index deb61c36a9e..a1859b6e91b 100644
--- a/src/cmd/gc/lex.c
+++ b/src/cmd/gc/lex.c
@@ -1076,11 +1076,11 @@ lexinit(void)
 	mpatofix(minintval[TINT32], "-0x80000000");
 	mpatofix(maxintval[TINT64], "0x7fffffffffffffff");
 	mpatofix(minintval[TINT64], "-0x8000000000000000");
+
 	mpatofix(maxintval[TUINT8], "0xff");
 	mpatofix(maxintval[TUINT16], "0xffff");
 	mpatofix(maxintval[TUINT32], "0xffffffff");
-	mpatofix(maxintval[TUINT64], "0x7fffffffffffffff");
-	mpatofix(minintval[TUINT64], "-0x8000000000000000");
+	mpatofix(maxintval[TUINT64], "0xffffffffffffffff");
 
 	mpatoflt(maxfltval[TFLOAT32], "3.40282347e+38");
 	mpatoflt(minfltval[TFLOAT32], "-3.40282347e+38");