diff --git a/src/cmd/5g/galign.c b/src/cmd/5g/galign.c
index 9a367797aa..6f1e957d05 100644
--- a/src/cmd/5g/galign.c
+++ b/src/cmd/5g/galign.c
@@ -29,8 +29,11 @@ betypeinit(void)
 
 	zprog.link = P;
 	zprog.as = AGOK;
+	zprog.scond = C_SCOND_NONE;
+	zprog.reg = NREG;
 	zprog.from.type = D_NONE;
 	zprog.from.index = D_NONE;
+	zprog.from.reg = NREG;
 	zprog.from.scale = 0;
 	zprog.to = zprog.from;
 
diff --git a/src/cmd/5g/ggen.c b/src/cmd/5g/ggen.c
index 9a73480a71..0e9d469259 100644
--- a/src/cmd/5g/ggen.c
+++ b/src/cmd/5g/ggen.c
@@ -84,6 +84,7 @@ compile(Node *fn)
 
 	// fill in argument size
 	ptxt->to.type = D_CONST2;
+	ptxt->reg = 0; // flags
 	ptxt->to.offset2 = rnd(curfn->type->argwid, maxround);
 
 	// fill in final stack size
diff --git a/src/cmd/5g/gobj.c b/src/cmd/5g/gobj.c
index 6f2c94b2b0..4531e116fa 100644
--- a/src/cmd/5g/gobj.c
+++ b/src/cmd/5g/gobj.c
@@ -64,8 +64,8 @@ zhist(Biobuf *b, int line, vlong offset)
 	Addr a;
 
 	Bputc(b, AHISTORY);
-	Bputc(b, 0);
-	Bputc(b, 0);
+	Bputc(b, C_SCOND_NONE);
+	Bputc(b, NREG);
 	Bputc(b, line);
 	Bputc(b, line>>8);
 	Bputc(b, line>>16);
@@ -89,8 +89,8 @@ zaddr(Biobuf *b, Addr *a, int s)
 
 	switch(a->type) {
 	case D_STATIC:
-	case D_EXTERN:
 	case D_AUTO:
+	case D_EXTERN:
 	case D_PARAM:
 		Bputc(b, D_OREG);
 		Bputc(b, a->reg);
@@ -112,8 +112,6 @@ zaddr(Biobuf *b, Addr *a, int s)
 	case D_REG:
 	case D_FREG:
 	case D_PSR:
-	case D_EXTERN:
-	case D_PARAM:
 		break;
 
 	case D_CONST2:
@@ -128,6 +126,8 @@ zaddr(Biobuf *b, Addr *a, int s)
 	case D_SHIFT:
 	case D_STATIC:
 	case D_AUTO:
+	case D_EXTERN:
+	case D_PARAM:
 		l = a->offset;
 		Bputc(b, l);
 		Bputc(b, l>>8);
diff --git a/src/cmd/5g/gsubr.c b/src/cmd/5g/gsubr.c
index fe83abbb2b..48eaa16021 100644
--- a/src/cmd/5g/gsubr.c
+++ b/src/cmd/5g/gsubr.c
@@ -34,10 +34,14 @@ void
 clearp(Prog *p)
 {
 	p->as = AEND;
+	p->reg = NREG;
+	p->scond = C_SCOND_NONE;
 	p->from.type = D_NONE;
 	p->from.index = D_NONE;
+	p->from.reg = NREG;
 	p->to.type = D_NONE;
 	p->to.index = D_NONE;
+	p->to.reg = NREG;
 	p->loc = pcloc;
 	pcloc++;
 }
diff --git a/src/cmd/5g/list.c b/src/cmd/5g/list.c
index ab8256ca51..b46188a73f 100644
--- a/src/cmd/5g/list.c
+++ b/src/cmd/5g/list.c
@@ -38,7 +38,6 @@ listinit(void)
 	fmtinstall('A', Aconv);		// as
 	fmtinstall('P', Pconv);		// Prog*
 	fmtinstall('D', Dconv);		// Addr*
-	fmtinstall('R', Rconv);		// reg
 	fmtinstall('Y', Yconv);		// sconst
 }
 
@@ -80,21 +79,13 @@ Dconv(Fmt *fp)
 
 	a = va_arg(fp->args, Addr*);
 	i = a->type;
-	// TODO(kaib): Add back
-//	if(i >= D_INDIR) {
-//		if(a->offset)
-//			snprint(str, sizeof(str), "%d(%R)", a->offset, i-D_INDIR);
-//		else
-//			snprint(str, sizeof(str), "(%R)", i-D_INDIR);
-//		goto brk;
-//	}
 	switch(i) {
 
 	default:
-		if(a->offset)
-			snprint(str, sizeof(str), "$%d,%R", a->offset, i);
+		if(a->type == D_OREG)
+			snprint(str, sizeof(str), "$%d(R%d)", a->offset, a->reg);
 		else
-			snprint(str, sizeof(str), "%R", i);
+			snprint(str, sizeof(str), "R%d", a->reg);
 		break;
 
 	case D_NONE:
@@ -149,50 +140,10 @@ Dconv(Fmt *fp)
 //		a->type = D_ADDR;
 //		goto conv;
 	}
-brk:
-	if(a->index != D_NONE) {
-		snprint(s, sizeof(s), "(%R*%d)", (int)a->index, (int)a->scale);
-		strcat(str, s);
-	}
 conv:
 	return fmtstrcpy(fp, str);
 }
 
-static	char*	regstr[] =
-{
-	"R0",
-	"R1",
-	"R2",
-	"R3",
-	"R4",
-	"R5",
-	"R6",
-	"R7",
-	"R8",
-	"R9",
-	"R10",
-	"R11",
-	"R12",
-	"R13",
-	"R14",
-	"R15",
-	"NONE",
-};
-
-int
-Rconv(Fmt *fp)
-{
-	char str[STRINGSZ];
-	int r;
-
-	r = va_arg(fp->args, int);
-	if(r < 0 || r >= nelem(regstr) || regstr[r] == nil) {
-		snprint(str, sizeof(str), "BAD_R(%d)", r);
-		return fmtstrcpy(fp, str);
-	}
-	return fmtstrcpy(fp, regstr[r]);
-}
-
 int
 Aconv(Fmt *fp)
 {
diff --git a/src/cmd/5l/5.out.h b/src/cmd/5l/5.out.h
index 45f30fa5d5..29dd4d3679 100644
--- a/src/cmd/5l/5.out.h
+++ b/src/cmd/5l/5.out.h
@@ -200,7 +200,8 @@ enum	as
 #define C_SCOND_LT	11
 #define C_SCOND_GT	12
 #define C_SCOND_LE	13
-#define C_SCOND_N	15
+#define C_SCOND_NONE	14
+#define C_SCOND_NV	15
 
 /* type/name */
 #define	D_GOK	0
diff --git a/src/cmd/5l/span.c b/src/cmd/5l/span.c
index 4ca8e01f74..bf7bd34a48 100644
--- a/src/cmd/5l/span.c
+++ b/src/cmd/5l/span.c
@@ -864,8 +864,8 @@ oplook(Prog *p)
 			p->optab = (o-otab)+1;
 			return o;
 		}
-	diag("illegal combination %A %d %d %d",
-		p->as, a1, a2, a3);
+	diag("illegal combination %A %d %d %d, %d %d",
+		p->as, a1, a2, a3, p->from.type, p->to.type);
 	prasm(p);
 	if(o == 0)
 		o = otab;