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heathkit/tlb.cpp: Fix graphics mode display (#11534)

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Mark Garlanger 2023-09-08 15:57:07 -05:00 committed by GitHub
parent cf839391db
commit 07ca153ba9
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1 changed files with 5 additions and 10 deletions
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15
src/mame/heathkit/tlb.cpp
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@ -17,12 +17,6 @@
TODO:
- INS8250 needs to implement "Set Break" (LCR, bit 6) before Break key
will function as expected.
- 49/50 row mode does not work when DOT clocks are programmed as documented
in the manual. It does work when DOT clock is fixed at the 20.282 MHz
rate.
- In 49/50 row mode, character descenders are cut off.
- fix GP-19 graphics mode only showing the top half of the image (on the
visible screen).
****************************************************************************/
/***************************************************************************
@ -1272,7 +1266,7 @@ void heath_gp19_tlb_device::mem_map(address_map &map)
// ROMs 1, 2, 3
map(0x0000, 0x02fff).rom();
// Optional external board - Program ROM 4, external I/O
// Optional external board - Program ROM 4(not aware if any ever existed), external I/O
// map(0x3000, 0x03fff).rom();
map(0x4000, 0x40ff).mirror(0x3f00).ram();
@ -1291,7 +1285,7 @@ void heath_gp19_tlb_device::io_map(address_map &map)
// Switch on GP-19 board
map(0x70, 0x70).mirror(0x07).portr("SW1");
// Optional Auxiliary I/O connector
// Optional Auxiliary I/O connector(not aware if any ever existed)
// map(0x78, 0x78).mirror(0x07);
}
@ -1341,7 +1335,7 @@ MC6845_UPDATE_ROW(heath_gp19_tlb_device::crtc_update_row)
{
for (int x = 0; x < x_count; x++)
{
uint8_t const gfx = m_p_videoram[(ma + x) & 0x3fff] ^ screen_inv;
uint8_t const gfx = m_p_videoram[((ma << 1) + ( ra * x_count ) + x) & 0x3fff] ^ screen_inv;
for (int b = 0; 8 > b; ++b)
{
@ -1351,6 +1345,8 @@ MC6845_UPDATE_ROW(heath_gp19_tlb_device::crtc_update_row)
}
else
{
uint16_t base = m_char_gen_a11 ? 0x800 : 0x0;
for (int x = 0; x < x_count; x++)
{
uint8_t inv = (x == cursor_x) ? 0xff : 0;
@ -1365,7 +1361,6 @@ MC6845_UPDATE_ROW(heath_gp19_tlb_device::crtc_update_row)
inv ^= screen_inv;
// select proper character set
uint16_t base = m_char_gen_a11 ? 0x800 : 0x0;
uint8_t const gfx = m_p_chargen[base | (chr << 4) | ra] ^ inv;
// Display a scanline of a character (8 pixels)