6c: copy all of packed structs in OAS

code assumed struct was aligned to atleast LONG.
For packed structs we need to copy the reaminder as well.
Repro:

typedef struct {
	char	a;
	char	b;
	short	c;
	short	d;
	char	e;
	char	f;
	char	g;
	char	h;
} A;

void
main(int argc, char **argv)
{
	A a1, a2;

	a2.a = 1;
	a2.b = 2;
	a2.c = 3;
	a2.d = 4;
	a2.e = 5;
	a2.f = 6;
	a2.g = 7;
	a2.h = 8;

	a1 = a2;
	print("%d %d %d %d %d %d %d %d\n", a1.a, a1.b, a1.c, a1.d, a1.e, a1.f, a1.g, a1.h);
}

1 files changed, 8 insertions, 1 deletions

diff --git a/sys/src/cmd/6c/cgen.c b/sys/src/cmd/6c/cgen.c
index 05b285946..b87c14a60 100644
--- a/sys/src/cmd/6c/cgen.c
+++ b/sys/src/cmd/6c/cgen.c
@@ -1400,7 +1400,7 @@ sugen(Node *n, Node *nn, long w)
 	Prog *p1;
 	Node nod0, nod1, nod2, nod3, nod4, *l, *r;
 	Type *t;
-	int v, c, mt, mo;
+	int v, c, mt, mo, re;
 	vlong o0, o1;
 
 	if(n == Z || n->type == T)
@@ -1683,6 +1683,7 @@ copy:
 		}
 		o0 = n->xoffset;
 		o1 = nn->xoffset;
+		re = w % ewidth[mt];
 		w /= ewidth[mt];
 		while(--w >= 0) {
 			gins(mo, n, &nod0);
@@ -1690,6 +1691,12 @@ copy:
 			n->xoffset += ewidth[mt];
 			nn->xoffset += ewidth[mt];
 		}
+		while(--re >= 0) {
+			gins(AMOVB, n, &nod0);
+			gins(AMOVB, &nod0, nn);
+			n->xoffset += 1;
+			nn->xoffset += 1;
+		}
 		n->xoffset = o0;
 		nn->xoffset = o1;
 		if(nn == &nod2)