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authorGravatarGravatar Vas Crabb <vas@vastheman.com>2017-02-09 01:24:35 +1100
committerGravatarGravatar Vas Crabb <vas@vastheman.com>2017-02-09 01:24:35 +1100
commitfcac51c27406df9af7c113f89defa0b242db20cb (patch) (github)
tree6b37e6c7c366f4a5dd45f1530fbec1714922ac41 /src/mame/drivers/osborne1.cpp
parent9b48fc922cd8b221253102604a99c28164422e7d (diff)
downloadmame-fcac51c27406df9af7c113f89defa0b242db20cb.tar.bz2
mame-fcac51c27406df9af7c113f89defa0b242db20cb.zip
osborne1nv: restore row/col portion masking (fixes horizontal scroll), update comments
Diffstat (limited to 'src/mame/drivers/osborne1.cpp')
-rw-r--r--src/mame/drivers/osborne1.cpp12
1 files changed, 3 insertions, 9 deletions
diff --git a/src/mame/drivers/osborne1.cpp b/src/mame/drivers/osborne1.cpp
index 47621061e41..27128b98927 100644
--- a/src/mame/drivers/osborne1.cpp
+++ b/src/mame/drivers/osborne1.cpp
@@ -83,14 +83,8 @@ TODO:
Centronics parallel over the same physical interface, so this should be
tested, too.
-* Fix emulation of the Nuevo Video board (scrolling, interrupts, CRTC video
- RAM updates). It would be nice to get a schematic for this. The board
- doesn't appear to have adders necessary to combine the MA output of the
- CRTC with the PIA outputs, and without additional connections to the
- mainboard it would be pretty hard to actually get the PIA output at all.
- However, both vertical scrolling and both manual (ctrl-left/right) and
- automatic horizontal scrolling work when booted to stock Osborne CP/M,
- so something must be getting the values to the CRTC.
+* Complete emulation of the Nuevo Video board (interrupts, CRTC video RAM
+ updates). It would be nice to get a schematic for this.
***************************************************************************/
@@ -133,7 +127,7 @@ static ADDRESS_MAP_START( osborne1nv_io, AS_IO, 8, osborne1_state )
AM_RANGE( 0x00, 0x03 ) AM_WRITE(bankswitch_w)
AM_RANGE( 0x04, 0x04 ) AM_DEVREADWRITE("crtc", mc6845_device, status_r, address_w)
AM_RANGE( 0x05, 0x05 ) AM_DEVREADWRITE("crtc", mc6845_device, register_r, register_w)
- // seems to be something at 0x06 as well, but no idea what
+ // seems to be something at 0x06 as well, but no idea what - BIOS writes 0x07 on boot
ADDRESS_MAP_END