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author Vas Crabb <vas@vastheman.com>2015-10-30 22:41:25 +1100
committer Vas Crabb <vas@vastheman.com>2015-10-30 22:41:39 +1100
commit841fd6adf62dca3486fb807157c90df9b99ffd37 (patch)
tree68f89b47cec23f156d9ec7dd5efa92165ef26a40
parent48bb0957aa08c6a0abaee6831a094a99f499b5a5 (diff)
osborne1: buffer vertical scroll at start of visible area
-rw-r--r--src/mame/machine/osborne1.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/src/mame/machine/osborne1.c b/src/mame/machine/osborne1.c
index 1ee97af8687..c9341d61dba 100644
--- a/src/mame/machine/osborne1.c
+++ b/src/mame/machine/osborne1.c
@@ -209,8 +209,6 @@ WRITE8_MEMBER( osborne1_state::video_pia_port_a_w )
WRITE8_MEMBER( osborne1_state::video_pia_port_b_w )
{
- m_scroll_y = data & 0x1F;
-
m_beep_state = BIT(data, 5);
if (BIT(data, 6))
@@ -345,9 +343,14 @@ TIMER_CALLBACK_MEMBER(osborne1_state::video_callback)
// Check for start/end of visible area and clear/set CA1 on video PIA
if (y == 0)
+ {
+ m_scroll_y = m_pia1->b_output() & 0x1F;
m_pia1->ca1_w(0);
+ }
else if (y == 240)
+ {
m_pia1->ca1_w(1);
+ }
if (y < 240)
{