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Fixed start address in emulated CGA mode.

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This commit is contained in:
Volker Ruppert 2024-01-06 15:05:33 +01:00
parent 6d433ec44b
commit c9c0237af3
1 changed files with 4 additions and 0 deletions
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4
bochs/iodev/display/vgacore.cc
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@ -1385,6 +1385,7 @@ void bx_vgacore_c::update(void)
/* CGA 320x200x4 start */
start_addr <<= 1;
for (yc=0, yti=0; yc<iHeight; yc+=Y_TILESIZE, yti++) {
for (xc=0, xti=0; xc<iWidth; xc+=X_TILESIZE, xti++) {
if (GET_TILE_UPDATED (xti, yti)) {
@ -2069,6 +2070,9 @@ void bx_vgacore_c::mem_write(bx_phy_address addr, Bit8u value)
if ((BX_VGA_THIS s.CRTC.reg[0x17] & 1) == 0) { // MAP13 (CGA 320x200x4 / 640x200x2)
unsigned xc, yc;
if ((BX_VGA_THIS s.CRTC.reg[0x17] & 0x40) == 0) {
start_addr <<= 1;
}
offset -= start_addr;
if (offset >= 0x2000) {
yc = (((offset - 0x2000) / (320 / 4)) << 1) + 1;