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author | couriersud <couriersud@arcor.de> | 2015-04-24 01:10:37 +0200 |
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committer | couriersud <couriersud@arcor.de> | 2015-04-24 01:10:37 +0200 |
commit | e08ddc8cad0d30ca3490fca8689f8fe4a87674b1 (patch) | |
tree | 18dcd47cdd62990f1891b7e9ddf965bf9ad06c0e | |
parent | 5a4269232b9cada4a30579001393417b89154996 (diff) |
Properly document address deconding for GFX roms in cardline.
[Couriersud]
-rw-r--r-- | src/mame/drivers/cardline.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/src/mame/drivers/cardline.c b/src/mame/drivers/cardline.c index 5ecfc3c57c5..1ee1cfc6b71 100644 --- a/src/mame/drivers/cardline.c +++ b/src/mame/drivers/cardline.c @@ -97,7 +97,15 @@ MC6845_UPDATE_ROW( cardline_state::crtc_update_row ) gfx_ofs = 0; - if(m_video&2) + // bits 0 and 1 seem to be chip select lines. None of those selected + // most likely would put the output lines into a floating (threestate) + // state. The next statement doesn't add functioality but documents + // how this works. + + if(m_video & 1) + gfx_ofs = 0; + + if(m_video & 2) gfx_ofs = 0x1000; gfx = memregion("gfx1")->base(); |