From ee7c64efe50830eac7ec441ef457e7e8c88e7613 Mon Sep 17 00:00:00 2001
From: Russ Cox <rsc@golang.org>
Date: Wed, 6 Jan 2010 18:18:07 -0800
Subject: [PATCH] 8c: only refer to extern register variables in MOVL
 instructions

R=ken2
https://golang.org/cl/183136
---
 src/cmd/8c/cgen.c | 6 ++++++
 src/cmd/8c/sgen.c | 3 ++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/cmd/8c/cgen.c b/src/cmd/8c/cgen.c
index 0d147b02fa..edb29ad8c7 100644
--- a/src/cmd/8c/cgen.c
+++ b/src/cmd/8c/cgen.c
@@ -55,6 +55,12 @@ cgen(Node *n, Node *nn)
 	l = n->left;
 	r = n->right;
 	o = n->op;
+
+	if(n->op == OEXREG || (nn != Z && nn->op == OEXREG)) {
+		gmove(n, nn);
+		return;
+	}
+
 	if(n->addable >= INDEXED) {
 		if(nn == Z) {
 			switch(o) {
diff --git a/src/cmd/8c/sgen.c b/src/cmd/8c/sgen.c
index c143c9a800..c4f91987ca 100644
--- a/src/cmd/8c/sgen.c
+++ b/src/cmd/8c/sgen.c
@@ -98,6 +98,7 @@ indexshift(Node *n)
  *		(20) * (X) ==> 7	multiplier in indexing
  *		(X,7) + (13,1) ==> 8	adder in indexing (addresses)
  *		(8) ==> &9(OINDEX)	index, almost addressable
+ *		100					extern register
  *
  *	calculate complexity (number of registers)
  */
@@ -125,7 +126,7 @@ xcom(Node *n)
 		break;
 
 	case OEXREG:
-		n->addable = 10;
+		n->addable = 0;
 		break;
 
 	case OREGISTER: