From 9946025bd5f18d216eadf5abb6a6d75e9f007bc2 Mon Sep 17 00:00:00 2001
From: Mike Pavone <pavone@retrodev.com>
Date: Fri, 3 May 2013 21:09:48 -0700
Subject: Fix bank register update

---
 zruntime.S | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

(limited to 'zruntime.S')

diff --git a/zruntime.S b/zruntime.S
index 07953d8..6731a6f 100644
--- a/zruntime.S
+++ b/zruntime.S
@@ -68,7 +68,7 @@ z80_read_byte_noinc:
 	cmp $0x8000, %r13w
 	jae z80_read_bank
 	/* TODO: Bank reg, YM-2612, PSG/VDP */
-	mov $FF, $r13b
+	mov $0xFF, %r13b
 	ret
 z80_read_ram:
 	and $0x1FFF, %r13
@@ -125,10 +125,11 @@ slow_bank_write:
 	ret
 z80_write_bank_reg:
 	and $1, %r13w
-	shl %r15w
+	shr %r15w
+	shl $8, %r13w
+	xor %r12, %r12
 	or %r13w, %r15w
 	and $0x1FF, %r15w
-	xor %r12, %r12
 	cmp $0x80, %r15w
 	jb update_bank_ptr
 	ret
-- 
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