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fix graphics rom checksum position

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Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@3194
This commit is contained in:
Sebastian Strohhäcker 2008-08-09 15:37:15 +00:00
parent b374d8c93f
commit 34cc1838d0
1 changed files with 5 additions and 9 deletions
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14
src/ints/int10_memory.cpp
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@ -16,7 +16,7 @@
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
/* $Id: int10_memory.cpp,v 1.26 2008-03-14 18:16:34 c2woody Exp $ */
/* $Id: int10_memory.cpp,v 1.27 2008-08-09 15:37:15 c2woody Exp $ */
#include "dosbox.h"
#include "mem.h"
@ -75,7 +75,6 @@ void INT10_LoadFont(PhysPt font,bool reload,Bitu count,Bitu offset,Bitu map,Bitu
}
static Bitu checksumlocation = 0; //Same type as int10.rom.used
void INT10_SetupRomMemory(void) {
/* This should fill up certain structures inside the Video Bios Rom Area */
PhysPt rom_base=PhysMake(0xc000,0);
@ -185,10 +184,6 @@ void INT10_SetupRomMemory(void) {
if (IS_TANDY_ARCH) {
RealSetVec(0x44,int10.rom.font_8_first);
}
if (IS_EGAVGA_ARCH) { //EGA/VGA. Just to be safe
//Reserve checksum location
checksumlocation = int10.rom.used++;
}
}
void INT10_ReloadRomFonts(void) {
@ -218,10 +213,11 @@ void INT10_SetupRomMemoryChecksum(void) {
/* Sum of all bytes in rom module 256 should be 0 */
Bit8u sum = 0;
PhysPt rom_base = PhysMake(0xc000,0);
for (Bitu i = 0;i < 32 * 1024;i++) //32 KB romsize
sum += phys_readb(rom_base + i); //OVERFLOW IS OKAY
Bitu last_rombyte = 32*1024 - 1; //32 KB romsize
for (Bitu i = 0;i < last_rombyte;i++)
sum += phys_readb(rom_base + i); //OVERFLOW IS OKAY
sum = 256 - sum;
phys_writeb(rom_base + checksumlocation,sum);
phys_writeb(rom_base + last_rombyte,sum);
}
}