From 2ff1cc5a0c8bf68cbc7d21871097742b281bf3ee Mon Sep 17 00:00:00 2001
From: Donn Seeley <donn@ucbvax.Berkeley.EDU>
Date: Fri, 11 Dec 1987 06:55:45 -0800
Subject: [PATCH] utah rcsid 1.13 87/05/02 15:50:50: Add ZI feature -- generate
 result of bitfield assignment without using a shift.

SCCS-vsn: old/pcc/ccom.tahoe/local2.c 1.22
---
 usr/src/old/pcc/ccom.tahoe/local2.c | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/usr/src/old/pcc/ccom.tahoe/local2.c b/usr/src/old/pcc/ccom.tahoe/local2.c
index 43fc3bf8c3..382b2b08b8 100644
--- a/usr/src/old/pcc/ccom.tahoe/local2.c
+++ b/usr/src/old/pcc/ccom.tahoe/local2.c
@@ -1,5 +1,5 @@
 #ifndef lint
-static char sccsid[] = "@(#)local2.c	1.21 (Berkeley) %G%";
+static char sccsid[] = "@(#)local2.c	1.22 (Berkeley) %G%";
 #endif
 
 # include "pass2.h"
@@ -316,6 +316,25 @@ zzzcode( p, c ) register NODE *p; {
 		printf(ACONFMT, (p->in.right->tn.lval&((1<<fldsz)-1))<<fldshf);
 		return;
 
+	case 'I':	/* produce value of bitfield assignment */
+			/* avoid shifts -- shifts are SLOW on this machine */
+		{
+			register NODE *r = p->in.right;
+			if(r->in.op == ICON && r->tn.name[0] == '\0') {
+				putstr("movl\t");
+				printf(ACONFMT, r->tn.lval & ((1<<fldsz)-1));
+				}
+			else {
+				putstr("andl3\t");
+				printf(ACONFMT, (1 << fldsz) - 1);
+				putchar(',');
+				adrput(r);
+				}
+			putchar(',');
+			adrput(resc);
+			break;
+			}
+
 	case 'H':	/* opcode for shift */
 		if(p->in.op == LS || p->in.op == ASG LS)
 			putstr("shll");
-- 
2.20.1