diff --git a/src/cmd/6g/gg.h b/src/cmd/6g/gg.h
index 6ba975bad26..ce5f6c86cd7 100644
--- a/src/cmd/6g/gg.h
+++ b/src/cmd/6g/gg.h
@@ -42,23 +42,6 @@ struct	Prog
 	void*	reg;		// pointer to containing Reg struct
 };
 
-typedef	struct	Magic Magic;
-struct	Magic
-{
-	int	w;	// input for both - width
-	int	s;	// output for both - shift
-	int	bad;	// output for both - unexpected failure
-
-	// magic multiplier for signed literal divisors
-	int64	sd;	// input - literal divisor
-	int64	sm;	// output - multiplier
-
-	// magic multiplier for unsigned literal divisors
-	uint64	ud;	// input - literal divisor
-	uint64	um;	// output - multiplier
-	int	ua;	// output - adder
-};
-
 EXTERN	Biobuf*	bout;
 EXTERN	int32	dynloc;
 EXTERN	uchar	reg[D_NONE];
@@ -142,10 +125,6 @@ void	sudoclean(void);
 int	sudoaddable(int, Node*, Addr*);
 void	afunclit(Addr*);
 void	datagostring(Strlit*, Addr*);
-int	powtwo(Node*);
-Type*	tounsigned(Type*);
-void	smagic(Magic*);
-void	umagic(Magic*);
 
 /*
  * obj.c
diff --git a/src/cmd/6g/ggen.c b/src/cmd/6g/ggen.c
index a3723738f55..2a61ca4e6b0 100644
--- a/src/cmd/6g/ggen.c
+++ b/src/cmd/6g/ggen.c
@@ -563,7 +563,7 @@ restx(Node *x, Node *oldx)
 void
 cgen_div(int op, Node *nl, Node *nr, Node *res)
 {
-	Node ax, dx, cx, oldax, olddx, oldcx;
+	Node ax, dx, oldax, olddx;
 	Node n1, n2, n3, savl, savr;
 	int n, w, s;
 	Magic m;
@@ -697,16 +697,11 @@ divbymul:
 		umagic(&m);
 		if(m.bad)
 			break;
-		if(m.ua != 0) {
-			// todo fixup
-			break;
-		}
 		if(op == OMOD)
 			goto longmod;
 
 		savex(D_AX, &ax, &oldax, res, nl->type);
 		savex(D_DX, &dx, &olddx, res, nl->type);
-		savex(D_CX, &cx, &oldcx, res, nl->type);
 
 		regalloc(&n1, nl->type, N);
 		cgen(nl, &n1);				// num -> reg(n1)
@@ -716,15 +711,24 @@ divbymul:
 
 		gins(optoas(OHMUL, nl->type), &n1, N);	// imul reg
 
-		nodconst(&n2, nl->type, m.s);
-		gins(optoas(ORSH, nl->type), &n2, &dx);	// shift dx
+		if(m.ua) {
+			// need to add numerator accounting for overflow
+			gins(optoas(OADD, nl->type), &n1, &dx);
+			nodconst(&n2, nl->type, 1);
+			gins(optoas(ORRC, nl->type), &n2, &dx);
+			nodconst(&n2, nl->type, m.s-1);
+			gins(optoas(ORSH, nl->type), &n2, &dx);
+		} else {
+			nodconst(&n2, nl->type, m.s);
+			gins(optoas(ORSH, nl->type), &n2, &dx);	// shift dx
+		}
+
 
 		regfree(&n1);
 		gmove(&dx, res);
 
 		restx(&ax, &oldax);
 		restx(&dx, &olddx);
-		restx(&cx, &oldcx);
 		return;
 
 	case TINT16:
@@ -735,16 +739,11 @@ divbymul:
 		smagic(&m);
 		if(m.bad)
 			break;
-		if(m.sm < 0) {
-			// todo fixup
-			break;
-		}
 		if(op == OMOD)
 			goto longmod;
 
 		savex(D_AX, &ax, &oldax, res, nl->type);
 		savex(D_DX, &dx, &olddx, res, nl->type);
-		savex(D_CX, &cx, &oldcx, res, nl->type);
 
 		regalloc(&n1, nl->type, N);
 		cgen(nl, &n1);				// num -> reg(n1)
@@ -754,6 +753,11 @@ divbymul:
 
 		gins(optoas(OHMUL, nl->type), &n1, N);	// imul reg
 
+		if(m.sm < 0) {
+			// need to add numerator
+			gins(optoas(OADD, nl->type), &n1, &dx);
+		}
+
 		nodconst(&n2, nl->type, m.s);
 		gins(optoas(ORSH, nl->type), &n2, &dx);	// shift dx
 
@@ -761,15 +765,17 @@ divbymul:
 		gins(optoas(ORSH, nl->type), &n2, &n1);	// -1 iff num is neg
 		gins(optoas(OSUB, nl->type), &n1, &dx);	// added
 
-		if(m.sd < 0)
+		if(m.sd < 0) {
+			// this could probably be removed
+			// by factoring it into the multiplier
 			gins(optoas(OMINUS, nl->type), N, &dx);
+		}
 
 		regfree(&n1);
 		gmove(&dx, res);
 
 		restx(&ax, &oldax);
 		restx(&dx, &olddx);
-		restx(&cx, &oldcx);
 		return;
 	}
 	goto longdiv;
diff --git a/src/cmd/6g/gsubr.c b/src/cmd/6g/gsubr.c
index f7c80f50e38..c98642ee0dc 100644
--- a/src/cmd/6g/gsubr.c
+++ b/src/cmd/6g/gsubr.c
@@ -1473,6 +1473,26 @@ optoas(int op, Type *t)
 		a = ASARQ;
 		break;
 
+	case CASE(ORRC, TINT8):
+	case CASE(ORRC, TUINT8):
+		a = ARCRB;
+		break;
+
+	case CASE(ORRC, TINT16):
+	case CASE(ORRC, TUINT16):
+		a = ARCRW;
+		break;
+
+	case CASE(ORRC, TINT32):
+	case CASE(ORRC, TUINT32):
+		a = ARCRL;
+		break;
+
+	case CASE(ORRC, TINT64):
+	case CASE(ORRC, TUINT64):
+		a = ARCRQ;
+		break;
+
 	case CASE(OHMUL, TINT8):
 	case CASE(OMUL, TINT8):
 	case CASE(OMUL, TUINT8):
@@ -1883,252 +1903,3 @@ no:
 	sudoclean();
 	return 0;
 }
-
-int
-powtwo(Node *n)
-{
-	uvlong v, b;
-	int i;
-
-	if(n == N || n->op != OLITERAL || n->type == T)
-		goto no;
-	if(!isint[n->type->etype])
-		goto no;
-
-	v = mpgetfix(n->val.u.xval);
-	b = 1ULL;
-	for(i=0; i<64; i++) {
-		if(b == v)
-			return i;
-		b = b<<1;
-	}
-
-	if(!issigned[n->type->etype])
-		goto no;
-
-	v = -v;
-	b = 1ULL;
-	for(i=0; i<64; i++) {
-		if(b == v)
-			return i+1000;
-		b = b<<1;
-	}
-
-no:
-	return -1;
-}
-
-Type*
-tounsigned(Type *t)
-{
-
-	// this is types[et+1], but not sure
-	// that this relation is immutable
-	switch(t->etype) {
-	default:
-		print("tounsigned: unknown type %T\n", t);
-		t = T;
-		break;
-	case TINT:
-		t = types[TUINT];
-		break;
-	case TINT8:
-		t = types[TUINT8];
-		break;
-	case TINT16:
-		t = types[TUINT16];
-		break;
-	case TINT32:
-		t = types[TUINT32];
-		break;
-	case TINT64:
-		t = types[TUINT64];
-		break;
-	}
-	return t;
-}
-
-void
-smagic(Magic *m)
-{
-	int p;
-	uint64 ad, anc, delta, q1, r1, q2, r2, t;
-	uint64 mask, two31;
-
-	m->bad = 0;
-	switch(m->w) {
-	default:
-		m->bad = 1;
-		return;
-	case 8:
-		mask = 0xffLL;
-		break;
-	case 16:
-		mask = 0xffffLL;
-		break;
-	case 32:
-		mask = 0xffffffffLL;
-		break;
-	case 64:
-		mask = 0xffffffffffffffffLL;
-		break;
-	}
-	two31 = mask ^ (mask>>1);
-
-	p = m->w-1;
-	ad = m->sd;
-	if(m->sd < 0)
-		ad = -m->sd;
-
-	// bad denominators
-	if(ad == 0 || ad == 1 || ad == two31) {
-		m->bad = 1;
-		return;
-	}
-
-	t = two31;
-	ad &= mask;
-
-	anc = t - 1 - t%ad;
-	anc &= mask;
-
-	q1 = two31/anc;
-	r1 = two31 - q1*anc;
-	q1 &= mask;
-	r1 &= mask;
-
-	q2 = two31/ad;
-	r2 = two31 - q2*ad;
-	q2 &= mask;
-	r2 &= mask;
-
-	for(;;) {
-		p++;
-		q1 <<= 1;
-		r1 <<= 1;
-		q1 &= mask;
-		r1 &= mask;
-		if(r1 >= anc) {
-			q1++;
-			r1 -= anc;
-			q1 &= mask;
-			r1 &= mask;
-		}
-
-		q2 <<= 1;
-		r2 <<= 1;
-		q2 &= mask;
-		r2 &= mask;
-		if(r2 >= ad) {
-			q2++;
-			r2 -= ad;
-			q2 &= mask;
-			r2 &= mask;
-		}
-
-		delta = ad - r2;
-		delta &= mask;
-		if(q1 < delta || (q1 == delta && r1 == 0)) {
-			continue;
-		}
-		break;
-	}
-
-	m->sm = q2+1;
-	if(m->sm & two31)
-		m->sm |= ~mask;
-	m->s = p-m->w;
-}
-
-void
-umagic(Magic *m)
-{
-	int p;
-	uint64 nc, delta, q1, r1, q2, r2;
-	uint64 mask, two31;
-
-	m->bad = 0;
-	m->ua = 0;
-
-	switch(m->w) {
-	default:
-		m->bad = 1;
-		return;
-	case 8:
-		mask = 0xffLL;
-		break;
-	case 16:
-		mask = 0xffffLL;
-		break;
-	case 32:
-		mask = 0xffffffffLL;
-		break;
-	case 64:
-		mask = 0xffffffffffffffffLL;
-		break;
-	}
-	two31 = mask ^ (mask>>1);
-
-	m->ud &= mask;
-	if(m->ud == 0 || m->ud == two31) {
-		m->bad = 1;
-		return;
-	}
-	nc = mask - (-m->ud&mask)%m->ud;
-	p = m->w-1;
-
-	q1 = two31/nc;
-	r1 = two31 - q1*nc;
-	q1 &= mask;
-	r1 &= mask;
-
-	q2 = (two31-1) / m->ud;
-	r2 = (two31-1) - q2*m->ud;
-	q2 &= mask;
-	r2 &= mask;
-
-	for(;;) {
-		p++;
-		if(r1 >= nc-r1) {
-			q1 <<= 1;
-			q1++;
-			r1 <<= 1;
-			r1 -= nc;
-		} else {
-			q1 <<= 1;
-			r1 <<= 1;
-		}
-		q1 &= mask;
-		r1 &= mask;
-		if(r2+1 >= m->ud-r2) {
-			if(q2 >= two31-1) {
-				m->ua = 1;
-			}
-			q2 <<= 1;
-			q2++;
-			r2 <<= 1;
-			r2++;
-			r2 -= m->ud;
-		} else {
-			if(q2 >= two31) {
-				m->ua = 1;
-			}
-			q2 <<= 1;
-			r2 <<= 1;
-			r2++;
-		}
-		q2 &= mask;
-		r2 &= mask;
-
-		delta = m->ud - 1 - r2;
-		delta &= mask;
-
-		if(p < m->w+m->w)
-		if(q1 < delta || (q1 == delta && r1 == 0)) {
-			continue;
-		}
-		break;
-	}
-	m->um = q2+1;
-	m->s = p-m->w;
-}
diff --git a/src/cmd/6g/peep.c b/src/cmd/6g/peep.c
index 4cfdf59e0de..4432203f2f5 100644
--- a/src/cmd/6g/peep.c
+++ b/src/cmd/6g/peep.c
@@ -390,6 +390,14 @@ subprop(Reg *r0)
 		case AMULQ:
 		case AMULW:
 
+		case ARCLB:
+		case ARCLL:
+		case ARCLQ:
+		case ARCLW:
+		case ARCRB:
+		case ARCRL:
+		case ARCRQ:
+		case ARCRW:
 		case AROLB:
 		case AROLL:
 		case AROLQ:
@@ -652,6 +660,14 @@ copyu(Prog *p, Adr *v, Adr *s)
 		}
 		goto caseread;
 
+	case ARCLB:
+	case ARCLL:
+	case ARCLQ:
+	case ARCLW:
+	case ARCRB:
+	case ARCRL:
+	case ARCRQ:
+	case ARCRW:
 	case AROLB:
 	case AROLL:
 	case AROLQ:
diff --git a/src/cmd/6g/reg.c b/src/cmd/6g/reg.c
index daad3f12504..f9704f202b1 100644
--- a/src/cmd/6g/reg.c
+++ b/src/cmd/6g/reg.c
@@ -298,6 +298,14 @@ regopt(Prog *firstp)
 		case ASARL:
 		case ASARQ:
 		case ASARW:
+		case ARCLB:
+		case ARCLL:
+		case ARCLQ:
+		case ARCLW:
+		case ARCRB:
+		case ARCRL:
+		case ARCRQ:
+		case ARCRW:
 		case AROLB:
 		case AROLL:
 		case AROLQ:
diff --git a/src/cmd/gc/go.h b/src/cmd/gc/go.h
index c0c4354b875..73deb98263a 100644
--- a/src/cmd/gc/go.h
+++ b/src/cmd/gc/go.h
@@ -343,7 +343,8 @@ enum
 	OKEY, OPARAM,
 	OLEN,
 	OMAKE, OMAKECHAN, OMAKEMAP, OMAKESLICE,
-	OMUL, ODIV, OMOD, OLSH, ORSH, OHMUL, OAND, OANDNOT,
+	OHMUL, ORRC, OLRC,	// high-mul and rotate-carry
+	OMUL, ODIV, OMOD, OLSH, ORSH, OAND, OANDNOT,
 	ONEW,
 	ONOT, OCOM, OPLUS, OMINUS,
 	OOROR,
@@ -542,6 +543,27 @@ struct Idir
 	char*	dir;
 };
 
+/*
+ * argument passing to/from
+ * smagic and umagic
+ */
+typedef	struct	Magic Magic;
+struct	Magic
+{
+	int	w;	// input for both - width
+	int	s;	// output for both - shift
+	int	bad;	// output for both - unexpected failure
+
+	// magic multiplier for signed literal divisors
+	int64	sd;	// input - literal divisor
+	int64	sm;	// output - multiplier
+
+	// magic multiplier for unsigned literal divisors
+	uint64	ud;	// input - literal divisor
+	uint64	um;	// output - multiplier
+	int	ua;	// output - adder
+};
+
 /*
  * note this is the runtime representation
  * of the compilers arrays.
@@ -856,6 +878,11 @@ void	genwrapper(Type*, Type*, Sym*);
 
 int	simsimtype(Type*);
 
+int	powtwo(Node*);
+Type*	tounsigned(Type*);
+void	smagic(Magic*);
+void	umagic(Magic*);
+
 /*
  *	dcl.c
  */
diff --git a/src/cmd/gc/subr.c b/src/cmd/gc/subr.c
index e6ddaf63fca..d4ee33d8726 100644
--- a/src/cmd/gc/subr.c
+++ b/src/cmd/gc/subr.c
@@ -3019,3 +3019,270 @@ resumecheckwidth(void)
 	}
 }
 
+/*
+ * return power of 2 of the constant
+ * operand. -1 if it is not a power of 2.
+ * 1000+ if it is a -(power of 2)
+ */
+int
+powtwo(Node *n)
+{
+	uvlong v, b;
+	int i;
+
+	if(n == N || n->op != OLITERAL || n->type == T)
+		goto no;
+	if(!isint[n->type->etype])
+		goto no;
+
+	v = mpgetfix(n->val.u.xval);
+	b = 1ULL;
+	for(i=0; i<64; i++) {
+		if(b == v)
+			return i;
+		b = b<<1;
+	}
+
+	if(!issigned[n->type->etype])
+		goto no;
+
+	v = -v;
+	b = 1ULL;
+	for(i=0; i<64; i++) {
+		if(b == v)
+			return i+1000;
+		b = b<<1;
+	}
+
+no:
+	return -1;
+}
+
+/*
+ * return the unsigned type for
+ * a signed integer type.
+ * returns T if input is not a
+ * signed integer type.
+ */
+Type*
+tounsigned(Type *t)
+{
+
+	// this is types[et+1], but not sure
+	// that this relation is immutable
+	switch(t->etype) {
+	default:
+		print("tounsigned: unknown type %T\n", t);
+		t = T;
+		break;
+	case TINT:
+		t = types[TUINT];
+		break;
+	case TINT8:
+		t = types[TUINT8];
+		break;
+	case TINT16:
+		t = types[TUINT16];
+		break;
+	case TINT32:
+		t = types[TUINT32];
+		break;
+	case TINT64:
+		t = types[TUINT64];
+		break;
+	}
+	return t;
+}
+
+/*
+ * magic number for signed division
+ * see hacker's delight chapter 10
+ */
+void
+smagic(Magic *m)
+{
+	int p;
+	uint64 ad, anc, delta, q1, r1, q2, r2, t;
+	uint64 mask, two31;
+
+	m->bad = 0;
+	switch(m->w) {
+	default:
+		m->bad = 1;
+		return;
+	case 8:
+		mask = 0xffLL;
+		break;
+	case 16:
+		mask = 0xffffLL;
+		break;
+	case 32:
+		mask = 0xffffffffLL;
+		break;
+	case 64:
+		mask = 0xffffffffffffffffLL;
+		break;
+	}
+	two31 = mask ^ (mask>>1);
+
+	p = m->w-1;
+	ad = m->sd;
+	if(m->sd < 0)
+		ad = -m->sd;
+
+	// bad denominators
+	if(ad == 0 || ad == 1 || ad == two31) {
+		m->bad = 1;
+		return;
+	}
+
+	t = two31;
+	ad &= mask;
+
+	anc = t - 1 - t%ad;
+	anc &= mask;
+
+	q1 = two31/anc;
+	r1 = two31 - q1*anc;
+	q1 &= mask;
+	r1 &= mask;
+
+	q2 = two31/ad;
+	r2 = two31 - q2*ad;
+	q2 &= mask;
+	r2 &= mask;
+
+	for(;;) {
+		p++;
+		q1 <<= 1;
+		r1 <<= 1;
+		q1 &= mask;
+		r1 &= mask;
+		if(r1 >= anc) {
+			q1++;
+			r1 -= anc;
+			q1 &= mask;
+			r1 &= mask;
+		}
+
+		q2 <<= 1;
+		r2 <<= 1;
+		q2 &= mask;
+		r2 &= mask;
+		if(r2 >= ad) {
+			q2++;
+			r2 -= ad;
+			q2 &= mask;
+			r2 &= mask;
+		}
+
+		delta = ad - r2;
+		delta &= mask;
+		if(q1 < delta || (q1 == delta && r1 == 0)) {
+			continue;
+		}
+		break;
+	}
+
+	m->sm = q2+1;
+	if(m->sm & two31)
+		m->sm |= ~mask;
+	m->s = p-m->w;
+}
+
+/*
+ * magic number for unsigned division
+ * see hacker's delight chapter 10
+ */
+void
+umagic(Magic *m)
+{
+	int p;
+	uint64 nc, delta, q1, r1, q2, r2;
+	uint64 mask, two31;
+
+	m->bad = 0;
+	m->ua = 0;
+
+	switch(m->w) {
+	default:
+		m->bad = 1;
+		return;
+	case 8:
+		mask = 0xffLL;
+		break;
+	case 16:
+		mask = 0xffffLL;
+		break;
+	case 32:
+		mask = 0xffffffffLL;
+		break;
+	case 64:
+		mask = 0xffffffffffffffffLL;
+		break;
+	}
+	two31 = mask ^ (mask>>1);
+
+	m->ud &= mask;
+	if(m->ud == 0 || m->ud == two31) {
+		m->bad = 1;
+		return;
+	}
+	nc = mask - (-m->ud&mask)%m->ud;
+	p = m->w-1;
+
+	q1 = two31/nc;
+	r1 = two31 - q1*nc;
+	q1 &= mask;
+	r1 &= mask;
+
+	q2 = (two31-1) / m->ud;
+	r2 = (two31-1) - q2*m->ud;
+	q2 &= mask;
+	r2 &= mask;
+
+	for(;;) {
+		p++;
+		if(r1 >= nc-r1) {
+			q1 <<= 1;
+			q1++;
+			r1 <<= 1;
+			r1 -= nc;
+		} else {
+			q1 <<= 1;
+			r1 <<= 1;
+		}
+		q1 &= mask;
+		r1 &= mask;
+		if(r2+1 >= m->ud-r2) {
+			if(q2 >= two31-1) {
+				m->ua = 1;
+			}
+			q2 <<= 1;
+			q2++;
+			r2 <<= 1;
+			r2++;
+			r2 -= m->ud;
+		} else {
+			if(q2 >= two31) {
+				m->ua = 1;
+			}
+			q2 <<= 1;
+			r2 <<= 1;
+			r2++;
+		}
+		q2 &= mask;
+		r2 &= mask;
+
+		delta = m->ud - 1 - r2;
+		delta &= mask;
+
+		if(p < m->w+m->w)
+		if(q1 < delta || (q1 == delta && r1 == 0)) {
+			continue;
+		}
+		break;
+	}
+	m->um = q2+1;
+	m->s = p-m->w;
+}