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Disable blanking if its start value is beyond the total display height. Fixes Ms. Pac-PC and Pac-PC II.

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Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@3611
This commit is contained in:
Ralf Grillenberger 2010-05-16 19:02:30 +00:00
parent 1188f7882d
commit 23c7394b75
1 changed files with 27 additions and 25 deletions
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52
src/hardware/vga_draw.cpp
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@ -1148,33 +1148,35 @@ void VGA_SetupDrawing(Bitu /*val*/) {
// Vertical blanking tricks
vblank_skip = 0;
if (IS_VGA_ARCH) { // others need more investigation
if (vbend > vtotal) {
// blanking wraps to the start of the screen
vblank_skip = vbend&0x7f;
// on blanking wrap to 0, the first line is not blanked
// this is used by the S3 BIOS and other S3 drivers in some SVGA modes
if((vbend&0x7f)==1) vblank_skip = 0;
// it might also cut some lines off the bottom
if(vbstart < vdend) {
vdend = vbstart;
}
LOG(LOG_VGA,LOG_WARN)("Blanking wrap to line %d", vblank_skip);
} else if (vbstart==1) {
// blanking is used to cut lines at the start of the screen
vblank_skip = vbend;
LOG(LOG_VGA,LOG_WARN)("Upper %d lines of the screen blanked", vblank_skip);
} else if (vbstart < vdend) {
if(vbend < vdend) {
// the game wants a black bar somewhere on the screen
LOG(LOG_VGA,LOG_WARN)("Unsupported blanking: line %d-%d",vbstart,vbend);
} else {
// blanking is used to cut off some lines from the bottom
vdend = vbstart;
if (vbstart < vtotal) { // There will be no blanking at all otherwise
if (vbend > vtotal) {
// blanking wraps to the start of the screen
vblank_skip = vbend&0x7f;
// on blanking wrap to 0, the first line is not blanked
// this is used by the S3 BIOS and other S3 drivers in some SVGA modes
if((vbend&0x7f)==1) vblank_skip = 0;
// it might also cut some lines off the bottom
if(vbstart < vdend) {
vdend = vbstart;
}
LOG(LOG_VGA,LOG_WARN)("Blanking wrap to line %d", vblank_skip);
} else if (vbstart==1) {
// blanking is used to cut lines at the start of the screen
vblank_skip = vbend;
LOG(LOG_VGA,LOG_WARN)("Upper %d lines of the screen blanked", vblank_skip);
} else if (vbstart < vdend) {
if(vbend < vdend) {
// the game wants a black bar somewhere on the screen
LOG(LOG_VGA,LOG_WARN)("Unsupported blanking: line %d-%d",vbstart,vbend);
} else {
// blanking is used to cut off some lines from the bottom
vdend = vbstart;
}
}
vdend -= vblank_skip;
}
vdend -= vblank_skip;
}
// Display end
vga.draw.delay.vdend = vdend * vga.draw.delay.htotal;