void DOS_SetupMemory(void) {
/* Let dos claim a few bios interrupts. Makes DOSBox more compatible with
* buggy games, which compare against the interrupt table. (probably a
* broken linked list implementation) */
Bit16u ihseg = 0x70;
Bit16u ihofs = 0x08;
real_writeb(ihseg,ihofs,(Bit8u)0xCF); //An IRET Instruction
RealSetVec(0x01,RealMake(ihseg,ihofs)); //BioMenace (offset!=4)
RealSetVec(0x02,RealMake(ihseg,ihofs)); //BioMenace (segment<0x8000)
RealSetVec(0x03,RealMake(ihseg,ihofs)); //Alien Incident (offset!=0)
RealSetVec(0x04,RealMake(ihseg,ihofs)); //Shadow President (lower byte of segment!=0)
RealSetVec(0x0f,RealMake(ihseg,ihofs)); //Always a tricky one (soundblaster irq)
// Create a dummy device MCB with PSPSeg=0x0008
DOS_MCB mcb_devicedummy((Bit16u)DOS_MEM_START);
mcb_devicedummy.SetPSPSeg(MCB_DOS); // Devices
mcb_devicedummy.SetSize(1);
mcb_devicedummy.SetType(0x4d); // More blocks will follow
// mcb_devicedummy.SetFileName("SD ");
Bit16u mcb_sizes=2;
// Create a small empty MCB (result from a growing environment block)
DOS_MCB tempmcb((Bit16u)DOS_MEM_START+mcb_sizes);
tempmcb.SetPSPSeg(MCB_FREE);
tempmcb.SetSize(4);
mcb_sizes+=5;
tempmcb.SetType(0x4d);
// Lock the previous empty MCB
DOS_MCB tempmcb2((Bit16u)DOS_MEM_START+mcb_sizes);
tempmcb2.SetPSPSeg(0x40); // can be removed by loadfix
tempmcb2.SetSize(16);
mcb_sizes+=17;
tempmcb2.SetType(0x4d);
DOS_MCB mcb((Bit16u)DOS_MEM_START+mcb_sizes);
mcb.SetPSPSeg(MCB_FREE); //Free
mcb.SetType(0x5a); //Last Block
if (machine==MCH_TANDY) {
/* memory up to 608k available, the rest (to 640k) is used by
the tandy graphics system's variable mapping of 0xb800 */
mcb.SetSize(0x9BFF - DOS_MEM_START - mcb_sizes);
} else if (machine==MCH_PCJR) {
/* memory from 128k to 640k is available */
mcb_devicedummy.SetPt((Bit16u)0x2000);
mcb_devicedummy.SetPSPSeg(MCB_FREE);
mcb_devicedummy.SetSize(0x9FFF - 0x2000);
mcb_devicedummy.SetType(0x5a);
/* exclude PCJr graphics region */
mcb_devicedummy.SetPt((Bit16u)0x17ff);
mcb_devicedummy.SetPSPSeg(MCB_DOS);
mcb_devicedummy.SetSize(0x800);
mcb_devicedummy.SetType(0x4d);
/* memory below 96k */
mcb.SetSize(0x1800 - DOS_MEM_START - (2+mcb_sizes));
mcb.SetType(0x4d);
} else {
/* complete memory up to 640k available */
/* last paragraph used to add UMB chain to low-memory MCB chain */
mcb.SetSize(0x9FFE - DOS_MEM_START - mcb_sizes);
}
dos.firstMCB=DOS_MEM_START;
dos_infoblock.SetFirstMCB(DOS_MEM_START);
}
void DOS_SetupMemory(void) {
/* Let dos claim a few bios interrupts. Makes DOSBox more compatible with
* buggy games, which compare against the interrupt table. (probably a
* broken linked list implementation) */
callbackhandler.Allocate(&DOS_default_handler,"DOS default int");
real_writeb(0x70,4,(Bit8u)0xFE); //GRP 4
real_writeb(0x70,5,(Bit8u)0x38); //Extra Callback instruction
real_writew(0x70,6,callbackhandler.Get_callback()); //The immediate word
real_writeb(0x70,8,(Bit8u)0xCF); //An IRET Instruction
real_writed(0,0x01*4,0x700004);
real_writed(0,0x02*4,0x700004); //BioMenace (segment<0x8000)
real_writed(0,0x03*4,0x700004); //Alien Incident (offset!=0)
real_writed(0,0x04*4,0x700004); //Shadow President (lower byte of segment!=0)
// real_writed(0,0x0f*4,0x700004); //Always a tricky one (soundblaster irq)
// Create a dummy device MCB with PSPSeg=0x0008
DOS_MCB mcb_devicedummy((Bit16u)DOS_MEM_START);
mcb_devicedummy.SetPSPSeg(MCB_DOS); // Devices
mcb_devicedummy.SetSize(1);
mcb_devicedummy.SetType(0x4d); // More blocks will follow
// mcb_devicedummy.SetFileName("SD ");
Bit16u mcb_sizes=2;
// Create a small empty MCB (result from a growing environment block)
DOS_MCB tempmcb((Bit16u)DOS_MEM_START+mcb_sizes);
tempmcb.SetPSPSeg(MCB_FREE);
tempmcb.SetSize(4);
mcb_sizes+=5;
tempmcb.SetType(0x4d);
// Lock the previous empty MCB
DOS_MCB tempmcb2((Bit16u)DOS_MEM_START+mcb_sizes);
tempmcb2.SetPSPSeg(0x40); // can be removed by loadfix
tempmcb2.SetSize(16);
mcb_sizes+=17;
tempmcb2.SetType(0x4d);
DOS_MCB mcb((Bit16u)DOS_MEM_START+mcb_sizes);
mcb.SetPSPSeg(MCB_FREE); //Free
mcb.SetType(0x5a); //Last Block
if (machine==MCH_TANDY) {
/* memory up to 608k available, the rest (to 640k) is used by
the tandy graphics system's variable mapping of 0xb800 */
mcb.SetSize(0x97FE - DOS_MEM_START - mcb_sizes);
} else if (machine==MCH_PCJR) {
/* memory from 128k to 640k is available */
mcb_devicedummy.SetPt((Bit16u)0x2000);
mcb_devicedummy.SetPSPSeg(MCB_FREE);
mcb_devicedummy.SetSize(0x9FFE - 0x2000);
mcb_devicedummy.SetType(0x5a);
/* exclude PCJr graphics region */
mcb_devicedummy.SetPt((Bit16u)0x17ff);
mcb_devicedummy.SetPSPSeg(MCB_DOS);
mcb_devicedummy.SetSize(0x800);
mcb_devicedummy.SetType(0x4d);
/* memory below 96k */
mcb.SetSize(0x1800 - DOS_MEM_START - (2+mcb_sizes));
mcb.SetType(0x4d);
} else {
/* complete memory up to 640k available */
mcb.SetSize(0x9FFE - DOS_MEM_START - mcb_sizes);
}
dos.firstMCB=DOS_MEM_START;
dos_infoblock.SetFirstMCB(DOS_MEM_START);
}