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correct ega machine graphics clock values (hal);

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better handling of aspect correction for ega machine with certain modes


Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@3142
This commit is contained in:
Sebastian Strohhäcker 2008-04-13 19:50:47 +00:00
parent e421cd96d2
commit 533b4bf359
1 changed files with 8 additions and 7 deletions
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15
src/hardware/vga_draw.cpp
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@ -16,7 +16,7 @@
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
/* $Id: vga_draw.cpp,v 1.98 2008-04-12 20:32:19 c2woody Exp $ */
/* $Id: vga_draw.cpp,v 1.99 2008-04-13 19:50:47 c2woody Exp $ */
#include <string.h>
#include <math.h>
@ -989,10 +989,10 @@ void VGA_SetupDrawing(Bitu val) {
} else {
switch ((vga.misc_output >> 2) & 3) {
case 0:
clock = 25175000;
clock = (machine==MCH_EGA) ? 14318180 : 25175000;
break;
case 1:
clock = 28322000;
clock = (machine==MCH_EGA) ? 16257000 : 28322000;
break;
}
}
@ -1097,25 +1097,26 @@ void VGA_SetupDrawing(Bitu val) {
//Base pixel width around 100 clocks horizontal
//For 9 pixel text modes this should be changed, but we don't support that anyway :)
//Seems regular vga only listens to the 9 char pixel mode with character mode enabled
double pwidth = 100.0 / htotal;
double pwidth = (machine==MCH_EGA) ? (114.0 / htotal) : (100.0 / htotal);
//Base pixel height around vertical totals of modes that have 100 clocks horizontal
//Different sync values gives different scaling of the whole vertical range
//VGA monitor just seems to thighten or widen the whole vertical range
double pheight;
double target_total = (machine==MCH_EGA) ? 262.0 : 449.0;
Bitu sync = vga.misc_output >> 6;
switch ( sync ) {
case 0: // This is not defined in vga specs,
// Kiet, seems to be slightly less than 350 on my monitor
//340 line mode, filled with 449 total
pheight = (480.0 / 340.0) * ( 449.0 / vtotal );
pheight = (480.0 / 340.0) * ( target_total / vtotal );
break;
case 1: //400 line mode, filled with 449 total
pheight = (480.0 / 400.0) * ( 449.0 / vtotal );
pheight = (480.0 / 400.0) * ( target_total / vtotal );
break;
case 2: //350 line mode, filled with 449 total
//This mode seems to get regular 640x400 timing and goes for a loong retrace
//Depends on the monitor to stretch the screen
pheight = (480.0 / 350.0) * ( 449.0 / vtotal );
pheight = (480.0 / 350.0) * ( target_total / vtotal );
break;
case 3: //480 line mode, filled with 525 total
pheight = (480.0 / 480.0) * ( 525.0 / vtotal );