From 261dbbbe81c74bbb815c48a788d2452802fc699b Mon Sep 17 00:00:00 2001
From: Vince Weaver <vincent.weaver@maine.edu>
Date: Mon, 2 Jul 2018 11:20:30 -0400
Subject: [PATCH] hgr: actual hgr now works.  N flag on CMP is a but unexpected

---
 gr-sim/hgr-sim.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/gr-sim/hgr-sim.c b/gr-sim/hgr-sim.c
index b7d2a0a4..49f390b6 100644
--- a/gr-sim/hgr-sim.c
+++ b/gr-sim/hgr-sim.c
@@ -5,9 +5,12 @@
 #include "6502_emulate.h"
 
 static void color_shift(void) {
+
 	// F47E
-	a=a<<1;
-	if (a>=0xc0) goto done_color_shift;
+	asl();
+	cmp(0xc0);
+
+	if (!n) goto done_color_shift;
 
 	a=ram[HGR_BITS];
 	a=a^0x7f;
@@ -120,7 +123,10 @@ static void hposn(void) {
 	// F438
 	a=x;
 	if (y==0) {
+		c=0;
 		goto hposn_2;
+	} else {
+		c=1;
 	}
 	y=35;
 	adc(4);
@@ -136,8 +142,7 @@ hposn_2:
 					// MSKTBL=F5B8
 	ram[HMASK]=a;
 	a=y;
-	c=a&1;
-	a=a>>1;
+	lsr();
 	a=ram[HGR_COLOR];
 	ram[HGR_BITS]=a;
 	if (c) color_shift();