From b304d7f4a8035844cf88f7079f48e6236986a7dd Mon Sep 17 00:00:00 2001
From: Mark Pizzolato <mark@infocomm.com>
Date: Sat, 12 Mar 2016 08:04:44 -0800
Subject: [PATCH] HP3000: Bug fix for byte instruction effective addresses
calculations with negative indexes.
Update from Dave Bryan
---
HP3000/hp3000_cpu.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/HP3000/hp3000_cpu.c b/HP3000/hp3000_cpu.c
index f66c3a8b..0e06cb95 100644
--- a/HP3000/hp3000_cpu.c
+++ b/HP3000/hp3000_cpu.c
@@ -25,6 +25,7 @@
CPU HP 3000 Series III Central Processing Unit
+ 11-Mar-16 JDB Fixed byte EA calculations with negative indexes
22-Dec-15 JDB First release version
01-Apr-15 JDB First successful run of MPE-V/R through account login
11-Dec-12 JDB Created
@@ -2457,10 +2458,10 @@ else { /* otherwise the mod
if ((CIR & LSDX_MASK) == LDD_X /* if the mode */
|| (CIR & LSDX_MASK) == STD_X) /* is double-word indexed */
- displacement = displacement + X * 2; /* then add the doubled index to the displacement */
+ displacement = displacement + X * 2 & DV_MASK; /* then add the doubled index to the displacement */
else if (mode_disp & X_FLAG) /* otherwise if the mode is indexed */
- displacement = displacement + X; /* then add the index to the displacement */
+ displacement = displacement + X & DV_MASK; /* then add the index to the displacement */
if (selector == NULL) /* if a word address is requested */
base = base + displacement; /* then add in the word displacement */