diff --git a/src/cmd/6g/Makefile b/src/cmd/6g/Makefile
index a6d3eb76235..f1e76692ef0 100644
--- a/src/cmd/6g/Makefile
+++ b/src/cmd/6g/Makefile
@@ -19,6 +19,7 @@ OFILES=\
 	galign.$O\
 	ggen.$O\
 	cgen.$O\
+	cplx.$O\
 	gsubr.$O\
 	peep.$O\
 	reg.$O\
diff --git a/src/cmd/6g/cgen.c b/src/cmd/6g/cgen.c
index 483c093c83c..7344fe7102b 100644
--- a/src/cmd/6g/cgen.c
+++ b/src/cmd/6g/cgen.c
@@ -134,6 +134,13 @@ cgen(Node *n, Node *res)
 		goto ret;
 	}
 
+	// complex ops are special.
+	if(iscomplex[n->type->etype] || iscomplex[res->type->etype] ||
+	   n->left != N && iscomplex[n->left->type->etype]) {
+		complexgen(n, res);
+		goto ret;
+	}
+
 	a = optoas(OAS, n->type);
 	if(sudoaddable(a, n, &addr)) {
 		if(res->op == OREGISTER) {
@@ -222,6 +229,7 @@ cgen(Node *n, Node *res)
 		regalloc(&n1, nl->type, res);
 		regalloc(&n2, n->type, &n1);
 		cgen(nl, &n1);
+
 		// if we do the conversion n1 -> n2 here
 		// reusing the register, then gmove won't
 		// have to allocate its own register.
diff --git a/src/cmd/6g/cplx.c b/src/cmd/6g/cplx.c
new file mode 100644
index 00000000000..0a8b999c43b
--- /dev/null
+++ b/src/cmd/6g/cplx.c
@@ -0,0 +1,147 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include "gg.h"
+
+#define	CASE(a,b)	(((a)<<16)|((b)<<0))
+
+/*
+ * generate:
+ *	res = n;
+ * simplifies and calls gmove.
+ */
+void
+complexmove(Node *f, Node *t)
+{
+	int ft, tt;
+	Node n1, n2;
+
+	if(debug['g']) {
+		dump("\ncomplex-f", f);
+		dump("complex-t", t);
+	}
+
+	if(!t->addable)
+		fatal("to no addable");
+
+	ft = cplxsubtype(simsimtype(f->type));
+	tt = cplxsubtype(simsimtype(t->type));
+
+	// copy halfs of complex literal
+	if(f->op == OLITERAL) {
+		// real part
+		nodfconst(&n1, types[ft], &f->val.u.cval->real);
+		n2 = *t;
+		n2.type = types[tt];
+		gmove(&n1, &n2);
+
+		// imag part
+		nodfconst(&n1, types[ft], &f->val.u.cval->imag);
+		n2.xoffset += n2.type->width;
+		gmove(&n1, &n2);
+		return;
+	}
+
+	// make from addable
+	if(!f->addable) {
+		tempname(&n1, f->type);
+		complexgen(f, &n1);
+		f = &n1;
+	}
+
+	// real part
+	n1 = *f;
+	n1.type = types[ft];
+
+	n2 = *t;
+	n2.type = types[tt];
+
+	gmove(&n1, &n2);
+
+	// imag part
+	n1.xoffset += n1.type->width;
+	n2.xoffset += n2.type->width;
+	gmove(&n1, &n2);
+
+}
+
+void
+complexgen(Node *n, Node *res)
+{
+	Node *nl, *nr;
+	Node n1, n2;
+	int tl, tr;
+
+	if(debug['g']) {
+		dump("\ncomplex-n", n);
+		dump("complex-res", res);
+	}
+
+	// perform conversion from n to res
+	tl = simsimtype(res->type);
+	tl = cplxsubtype(tl);
+	tr = simsimtype(n->type);
+	tr = cplxsubtype(tr);
+	if(tl != tr) {
+		tempname(&n1, n->type);
+		complexgen(n, &n1);
+		complexmove(&n1, n);
+		return;
+	}
+
+	nl = n->left;
+	if(nl == N)
+		return;
+
+	nr = n->right;
+	if(nr != N) {
+		// make both sides addable in ullman order
+		if(nl->ullman > nr->ullman) {
+			if(!nl->addable) {
+				tempname(&n1, nl->type);
+				complexgen(nl, &n1);
+				nl = &n1;
+			}
+			if(!nr->addable) {
+				tempname(&n1, nr->type);
+				complexgen(nr, &n2);
+				nr = &n2;
+			}
+		} else {
+			if(!nr->addable) {
+				tempname(&n1, nr->type);
+				complexgen(nr, &n2);
+				nr = &n2;
+			}
+			if(!nl->addable) {
+				tempname(&n1, nl->type);
+				complexgen(nl, &n1);
+				nl = &n1;
+			}
+		}
+	}
+
+	switch(n->op) {
+	default:
+		fatal("opcode %O", n->op);
+		break;
+
+	case OADD:
+	case OSUB:
+	case OMUL:
+	case ODIV:
+		if(nr == N)
+			fatal("");
+		fatal("opcode %O", n->op);
+		break;
+
+	case OMINUS:
+		fatal("opcode %O", n->op);
+		break;
+
+	case OCONV:
+		complexmove(nl, res);
+		break;
+	}
+}
diff --git a/src/cmd/6g/gg.h b/src/cmd/6g/gg.h
index 8d0c3838565..264d01f8510 100644
--- a/src/cmd/6g/gg.h
+++ b/src/cmd/6g/gg.h
@@ -128,6 +128,14 @@ void	sudoclean(void);
 int	sudoaddable(int, Node*, Addr*);
 void	afunclit(Addr*);
 void	datagostring(Strlit*, Addr*);
+int	cplxsubtype(int);
+void	nodfconst(Node*, Type*, Mpflt*);
+
+/*
+ * cplx.c
+ */
+void	complexmove(Node*, Node*);
+void	complexgen(Node*, Node*);
 
 /*
  * obj.c
diff --git a/src/cmd/6g/gsubr.c b/src/cmd/6g/gsubr.c
index 5549830e3f1..c58ebb78de5 100644
--- a/src/cmd/6g/gsubr.c
+++ b/src/cmd/6g/gsubr.c
@@ -475,6 +475,11 @@ gmove(Node *f, Node *t)
 	tt = simsimtype(t->type);
 	cvt = t->type;
 
+	if(iscomplex[ft] || iscomplex[tt]) {
+		complexmove(f, t);
+		return;
+	}
+
 	// cannot have two memory operands
 	if(ismem(f) && ismem(t))
 		goto hard;
@@ -490,6 +495,7 @@ gmove(Node *f, Node *t)
 			// float constants come from memory.
 			if(isfloat[tt])
 				goto hard;
+			// complex constants take double move.
 			// 64-bit immediates are really 32-bit sign-extended
 			// unless moving into a register.
 			if(isint[tt]) {
@@ -1973,3 +1979,29 @@ no:
 	sudoclean();
 	return 0;
 }
+
+int
+cplxsubtype(int et)
+{
+	if(et == TCOMPLEX64)
+		return TFLOAT32;
+	if(et == TCOMPLEX128)
+		return TFLOAT64;
+	fatal("cplxsubtype: %E\n", et);
+	return 0;
+}
+
+void
+nodfconst(Node *n, Type *t, Mpflt* fval)
+{
+	memset(n, 0, sizeof(*n));
+	n->op = OLITERAL;
+	n->addable = 1;
+	ullmancalc(n);
+	n->val.u.fval = fval;
+	n->val.ctype = CTFLT;
+	n->type = t;
+
+	if(!isfloat[t->etype])
+		fatal("nodfconst: bad type %T", t);
+}
diff --git a/src/cmd/gc/const.c b/src/cmd/gc/const.c
index f16c52d58cf..0cf6922d7d5 100644
--- a/src/cmd/gc/const.c
+++ b/src/cmd/gc/const.c
@@ -9,8 +9,8 @@ static	Val	tocplx(Val);
 static	Val	toflt(Val);
 static	Val	tostr(Val);
 static	Val	copyval(Val);
-static	void	cmplxmpy(Mpcplx *v, Mpcplx *rv);
-static	void	cmplxdiv(Mpcplx *v, Mpcplx *rv);
+static	void	cmplxmpy(Mpcplx*, Mpcplx*);
+static	void	cmplxdiv(Mpcplx*, Mpcplx*);
 
 /*
  * truncate float literal fv to 32-bit or 64-bit precision
@@ -589,6 +589,7 @@ evconst(Node *n)
 	case TUP(OXOR, CTINT):
 		mpxorfixfix(v.u.xval, rv.u.xval);
 		break;
+
 	case TUP(OADD, CTFLT):
 		mpaddfltflt(v.u.fval, rv.u.fval);
 		break;
@@ -619,6 +620,13 @@ evconst(Node *n)
 		cmplxmpy(v.u.cval, rv.u.cval);
 		break;
 	case TUP(ODIV, CTCPLX):
+		if(mpcmpfltc(&rv.u.cval->real, 0) == 0 &&
+		   mpcmpfltc(&rv.u.cval->imag, 0) == 0) {
+			yyerror("complex division by zero");
+			mpmovecflt(&rv.u.cval->real, 1.0);
+			mpmovecflt(&rv.u.cval->imag, 0.0);
+			break;
+		}
 		cmplxdiv(v.u.cval, rv.u.cval);
 		break;
 
@@ -677,6 +685,17 @@ evconst(Node *n)
 			goto settrue;
 		goto setfalse;
 
+	case TUP(OEQ, CTCPLX):
+		if(mpcmpfltflt(&v.u.cval->real, &rv.u.cval->real) == 0 &&
+		   mpcmpfltflt(&v.u.cval->imag, &rv.u.cval->imag) == 0)
+			goto settrue;
+		goto setfalse;
+	case TUP(ONE, CTCPLX):
+		if(mpcmpfltflt(&v.u.cval->real, &rv.u.cval->real) != 0 ||
+		   mpcmpfltflt(&v.u.cval->imag, &rv.u.cval->imag) != 0)
+			goto settrue;
+		goto setfalse;
+
 	case TUP(OEQ, CTSTR):
 		if(cmpslit(nl, nr) == 0)
 			goto settrue;
diff --git a/src/cmd/gc/mparith1.c b/src/cmd/gc/mparith1.c
index 8bf71315208..8110e77b98d 100644
--- a/src/cmd/gc/mparith1.c
+++ b/src/cmd/gc/mparith1.c
@@ -206,7 +206,7 @@ void
 mpatoflt(Mpflt *a, char *as)
 {
 	Mpflt b;
-	int dp, c, f, ef, ex, eb, zer;
+	int dp, c, f, ef, ex, eb;
 	char *s;
 
 	s = as;
@@ -214,7 +214,6 @@ mpatoflt(Mpflt *a, char *as)
 	f = 0;		/* sign */
 	ex = 0;		/* exponent */
 	eb = 0;		/* binary point */
-	zer = 1;	/* zero */
 
 	mpmovecflt(a, 0.0);
 	for(;;) {
@@ -243,8 +242,6 @@ mpatoflt(Mpflt *a, char *as)
 		case '7':
 		case '8':
 		case '9':
-			zer = 0;
-
 		case '0':
 			mpmulcflt(a, 10);
 			mpaddcflt(a, c-'0');
diff --git a/src/cmd/gc/mparith3.c b/src/cmd/gc/mparith3.c
index f97d0b829d6..b9cd4ea8475 100644
--- a/src/cmd/gc/mparith3.c
+++ b/src/cmd/gc/mparith3.c
@@ -53,18 +53,12 @@ mpaddfltflt(Mpflt *a, Mpflt *b)
 		print("\n%F + %F", a, b);
 
 	sa = sigfig(a);
-	sb = sigfig(b);
-
 	if(sa == 0) {
-		if(sb == 0) {
-			// zero
-			a->exp = 0;
-			a->val.neg = 0;
-			return;
-		}
 		mpmovefltflt(a, b);
 		goto out;
 	}
+
+	sb = sigfig(b);
 	if(sb == 0)
 		goto out;
 
@@ -100,15 +94,20 @@ mpmulfltflt(Mpflt *a, Mpflt *b)
 		print("%F\n * %F\n", a, b);
 
 	sa = sigfig(a);
-	sb = sigfig(b);
-
-	if(sa == 0 || sb == 0) {
+	if(sa == 0) {
 		// zero
 		a->exp = 0;
 		a->val.neg = 0;
 		return;
 	}
 
+	sb = sigfig(b);
+	if(sb == 0) {
+		// zero
+		mpmovefltflt(a, b);
+		return;
+	}
+
 	mpmulfract(&a->val, &b->val);
 	a->exp = (a->exp + b->exp) + Mpscale*Mpprec - 1;
 
@@ -126,9 +125,7 @@ mpdivfltflt(Mpflt *a, Mpflt *b)
 	if(Mpdebug)
 		print("%F\n / %F\n", a, b);
 
-	sa = sigfig(a);
 	sb = sigfig(b);
-
 	if(sb == 0) {
 		// zero and ovfl
 		a->exp = 0;
@@ -137,6 +134,8 @@ mpdivfltflt(Mpflt *a, Mpflt *b)
 		yyerror("mpdivfltflt divide by zero");
 		return;
 	}
+
+	sa = sigfig(a);
 	if(sa == 0) {
 		// zero
 		a->exp = 0;
diff --git a/src/cmd/gc/typecheck.c b/src/cmd/gc/typecheck.c
index 2908459fc48..158dee67389 100644
--- a/src/cmd/gc/typecheck.c
+++ b/src/cmd/gc/typecheck.c
@@ -1367,13 +1367,9 @@ checkconv(Type *nt, Type *t, int explicit, int *op, int *et, char *desc)
 		return 1;
 	}
 
-	// simple fix-float
-	if(isint[t->etype] || isfloat[t->etype])
-	if(isint[nt->etype] || isfloat[nt->etype])
-		return 1;
-
-	// between versions of complex
-	if(iscomplex[t->etype] || iscomplex[nt->etype])
+	// simple fix-float-complex
+	if(isint[t->etype] || isfloat[t->etype] || iscomplex[t->etype])
+	if(isint[nt->etype] || isfloat[nt->etype] || iscomplex[nt->etype])
 		return 1;
 
 	// to string
diff --git a/src/cmd/gc/walk.c b/src/cmd/gc/walk.c
index 5113094304c..e902600ba0e 100644
--- a/src/cmd/gc/walk.c
+++ b/src/cmd/gc/walk.c
@@ -1727,7 +1727,7 @@ walkprint(Node *nn, NodeList **init, int defer)
 				on = syslook("printfloat", 0);
 		} else if(iscomplex[et]) {
 			if(defer) {
-				fmtprint(&fmt, "%%f");
+				fmtprint(&fmt, "%%C");
 				t = types[TCOMPLEX128];
 			} else
 				on = syslook("printcomplex", 0);
diff --git a/src/pkg/runtime/print.c b/src/pkg/runtime/print.c
index 1214fed51d4..d721f395356 100644
--- a/src/pkg/runtime/print.c
+++ b/src/pkg/runtime/print.c
@@ -118,6 +118,9 @@ vprintf(int8 *s, byte *arg)
 		case 'f':
 			·printfloat(*(float64*)arg);
 			break;
+		case 'C':
+			·printcomplex(*(Complex128*)arg);
+			break;
 		case 'i':
 			·printiface(*(Iface*)arg);
 			break;
@@ -258,6 +261,16 @@ void
 	write(fd, buf, n+7);
 }
 
+void
+·printcomplex(Complex128 v)
+{
+	write(fd, "(", 1);
+	·printfloat(v.real);
+	write(fd, ",", 1);
+	·printfloat(v.imag);
+	write(fd, "i)", 2);
+}
+
 void
 ·printuint(uint64 v)
 {
diff --git a/src/pkg/runtime/runtime.h b/src/pkg/runtime/runtime.h
index b361bacc1e8..194503ec8a3 100644
--- a/src/pkg/runtime/runtime.h
+++ b/src/pkg/runtime/runtime.h
@@ -59,11 +59,13 @@ typedef	struct	SigTab		SigTab;
 typedef	struct	MCache		MCache;
 typedef	struct	Iface		Iface;
 typedef	struct	Itab		Itab;
-typedef	struct	Eface	Eface;
+typedef	struct	Eface		Eface;
 typedef	struct	Type		Type;
 typedef	struct	Defer		Defer;
 typedef	struct	hash		Hmap;
 typedef	struct	Hchan		Hchan;
+typedef	struct	Complex64	Complex64;
+typedef	struct	Complex128	Complex128;
 
 /*
  * per-cpu declaration.
@@ -145,6 +147,16 @@ struct Eface
 	Type*	type;
 	void*	data;
 };
+struct Complex64
+{
+	float32	real;
+	float32	imag;
+};
+struct Complex128
+{
+	float64	real;
+	float64	imag;
+};
 
 struct	Slice
 {				// must not move anything
@@ -460,6 +472,7 @@ void	notewakeup(Note*);
 #define runtime_printpointer ·printpointer
 #define runtime_printstring ·printstring
 #define runtime_printuint ·printuint
+#define runtime_printcomplex ·printcomplex
 #define runtime_setcallerpc ·setcallerpc
 #endif
 
@@ -492,6 +505,7 @@ void	runtime_printpointer(void*);
 void	runtime_printuint(uint64);
 void	runtime_printhex(uint64);
 void	runtime_printslice(Slice);
+void	runtime_printcomplex(Complex128);
 void	·panicl(int32);
 
 /*