From e82fd502c153a2a693b5129fe002765c66ee5982 Mon Sep 17 00:00:00 2001
From: TomW <TomW@localhost>
Date: Fri, 18 Dec 2015 21:06:01 +0000
Subject: [PATCH] Implemented another SN76496/NCR8496 difference - latter can
 not update noise register on write with top bit clear.

---
 src/sound_sn76489.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/sound_sn76489.c b/src/sound_sn76489.c
index ee7542e..c854667 100644
--- a/src/sound_sn76489.c
+++ b/src/sound_sn76489.c
@@ -144,7 +144,7 @@ void sn76489_write(uint16_t addr, uint8_t data, void *p)
         }
         else
         {
-                if ((sn76489->firstdat & 0x70) == 0x60)
+                if ((sn76489->firstdat & 0x70) == 0x60 && (sn76489->type == SN76496))
                 {
                         if ((data & 4) != (sn76489->noise & 4) || sn76489->type == SN76496)
                                 sn76489->shift = 0x4000;
@@ -154,7 +154,7 @@ void sn76489_write(uint16_t addr, uint8_t data, void *p)
                         if (!sn76489->latch[0])
                                 sn76489->latch[0] = 1024 << 6;
                 }
-                else
+                else if ((sn76489->firstdat & 0x70) != 0x60)
                 {
                         sn76489->freqhi[sn76489->lasttone] = data & 0x7F;
                         freq = sn76489->freqlo[sn76489->lasttone] | (sn76489->freqhi[sn76489->lasttone] << 4);