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dosbox-wii/src/dos/dos_memory.cpp

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/*
* Copyright (C) 2002-2007 The DOSBox Team
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include "dosbox.h"
#include "mem.h"
#include "dos_inc.h"
#include "callback.h"
#define UMB_START_SEG 0x9fff
static Bit16u memAllocStrategy = 0x00;
static void DOS_CompressMemory(void) {
Bit16u mcb_segment=dos.firstMCB;
DOS_MCB mcb(mcb_segment);
DOS_MCB mcb_next(0);
while (mcb.GetType()!=0x5a) {
mcb_next.SetPt((Bit16u)(mcb_segment+mcb.GetSize()+1));
if ((mcb.GetPSPSeg()==0) && (mcb_next.GetPSPSeg()==0)) {
mcb.SetSize(mcb.GetSize()+mcb_next.GetSize()+1);
mcb.SetType(mcb_next.GetType());
} else {
mcb_segment+=mcb.GetSize()+1;
mcb.SetPt(mcb_segment);
}
}
}
void DOS_FreeProcessMemory(Bit16u pspseg) {
Bit16u mcb_segment=dos.firstMCB;
DOS_MCB mcb(mcb_segment);
while (true) {
if (mcb.GetPSPSeg()==pspseg) {
mcb.SetPSPSeg(MCB_FREE);
}
if (mcb.GetType()==0x5a) {
/* check if currently last block reaches up to the PCJr graphics memory */
if ((machine==MCH_PCJR) && (mcb_segment+mcb.GetSize()==0x17fe) &&
(real_readb(0x17ff,0)==0x4d) && (real_readw(0x17ff,1)==8)) {
/* re-enable the memory past segment 0x2000 */
mcb.SetType(0x4d);
} else break;
}
mcb_segment+=mcb.GetSize()+1;
mcb.SetPt(mcb_segment);
}
Bit16u umb_start=dos_infoblock.GetStartOfUMBChain();
if (umb_start==UMB_START_SEG) {
DOS_MCB umb_mcb(umb_start);
while (true) {
if (umb_mcb.GetPSPSeg()==pspseg) {
umb_mcb.SetPSPSeg(MCB_FREE);
}
if (umb_mcb.GetType()!=0x4d) break;
umb_start+=umb_mcb.GetSize()+1;
umb_mcb.SetPt(umb_start);
}
} else if (umb_start!=0xffff) LOG(LOG_DOSMISC,LOG_ERROR)("Corrupt UMB chain: %x",umb_start);
DOS_CompressMemory();
}
Bit16u DOS_GetMemAllocStrategy() {
return memAllocStrategy;
}
bool DOS_SetMemAllocStrategy(Bit16u strat) {
if ((strat&0x3f)<3) {
memAllocStrategy = strat;
return true;
}
/* otherwise an invalid allocation strategy was specified */
return false;
}
bool DOS_AllocateMemory(Bit16u * segment,Bit16u * blocks) {
DOS_CompressMemory();
Bit16u bigsize=0;
Bit16u mem_strat=memAllocStrategy;
Bit16u mcb_segment=dos.firstMCB;
Bit16u umb_start=dos_infoblock.GetStartOfUMBChain();
if (umb_start==UMB_START_SEG) {
/* start with UMBs if requested (bits 7 or 6 set) */
if (mem_strat&0xc0) mcb_segment=umb_start;
} else if (umb_start!=0xffff) LOG(LOG_DOSMISC,LOG_ERROR)("Corrupt UMB chain: %x",umb_start);
DOS_MCB mcb(0);
DOS_MCB mcb_next(0);
DOS_MCB psp_mcb(dos.psp()-1);
char psp_name[9];
psp_mcb.GetFileName(psp_name);
Bit16u found_seg=0,found_seg_size=0;
for (;;) {
mcb.SetPt(mcb_segment);
if (mcb.GetPSPSeg()==0) {
/* Check for enough free memory in current block */
Bit16u block_size=mcb.GetSize();
if (block_size<(*blocks)) {
if (bigsize<block_size) {
/* current block is largest block that was found,
but still not as big as requested */
bigsize=block_size;
}
} else if ((block_size==*blocks) && ((mem_strat & 0x3f)<2)) {
/* MCB fits precisely, use it if search strategy is firstfit or bestfit */
mcb.SetPSPSeg(dos.psp());
*segment=mcb_segment+1;
return true;
} else {
switch (mem_strat & 0x3f) {
case 0: /* firstfit */
mcb_next.SetPt((Bit16u)(mcb_segment+*blocks+1));
mcb_next.SetPSPSeg(MCB_FREE);
mcb_next.SetType(mcb.GetType());
mcb_next.SetSize(block_size-*blocks-1);
mcb.SetSize(*blocks);
mcb.SetType(0x4d);
mcb.SetPSPSeg(dos.psp());
mcb.SetFileName(psp_name);
//TODO Filename
*segment=mcb_segment+1;
return true;
case 1: /* bestfit */
if ((found_seg_size==0) || (block_size<found_seg_size)) {
/* first fitting MCB, or smaller than the last that was found */
found_seg=mcb_segment;
found_seg_size=block_size;
}
break;
default: /* everything else is handled as lastfit by dos */
/* MCB is large enough, note it down */
found_seg=mcb_segment;
found_seg_size=block_size;
break;
}
}
}
/* Onward to the next MCB if there is one */
if (mcb.GetType()==0x5a) {
if ((mem_strat&0x80) && (umb_start==UMB_START_SEG)) {
/* bit 7 set: try high memory first, then low */
mcb_segment=dos.firstMCB;
mem_strat&=(~0xc0);
} else {
/* finished searching all requested MCB chains */
if (found_seg) {
/* a matching MCB was found (cannot occur for firstfit) */
if ((mem_strat & 0x3f)==0x01) {
/* bestfit, allocate block at the beginning of the MCB */
mcb.SetPt(found_seg);
mcb_next.SetPt((Bit16u)(found_seg+*blocks+1));
mcb_next.SetPSPSeg(MCB_FREE);
mcb_next.SetType(mcb.GetType());
mcb_next.SetSize(found_seg_size-*blocks-1);
mcb.SetSize(*blocks);
mcb.SetType(0x4d);
mcb.SetPSPSeg(dos.psp());
mcb.SetFileName(psp_name);
//TODO Filename
*segment=found_seg+1;
} else {
/* lastfit, allocate block at the end of the MCB */
mcb.SetPt(found_seg);
if (found_seg_size==*blocks) {
/* use the whole block */
mcb.SetPSPSeg(dos.psp());
//Not consistent with line 124. But how many application will use this information ?
mcb.SetFileName(psp_name);
*segment = found_seg+1;
return true;
}
*segment = found_seg+1+found_seg_size - *blocks;
mcb_next.SetPt((Bit16u)(*segment-1));
mcb_next.SetSize(*blocks);
mcb_next.SetType(mcb.GetType());
mcb_next.SetPSPSeg(dos.psp());
mcb_next.SetFileName(psp_name);
// Old Block
mcb.SetSize(found_seg_size-*blocks-1);
mcb.SetPSPSeg(MCB_FREE);
mcb.SetType(0x4D);
}
return true;
}
/* no fitting MCB found, return size of largest block */
*blocks=bigsize;
DOS_SetError(DOSERR_INSUFFICIENT_MEMORY);
return false;
}
} else mcb_segment+=mcb.GetSize()+1;
}
return false;
}
bool DOS_ResizeMemory(Bit16u segment,Bit16u * blocks) {
if (segment < DOS_MEM_START+1) {
LOG(LOG_DOSMISC,LOG_ERROR)("Program resizes %X, take care",segment);
}
DOS_MCB mcb(segment-1);
if ((mcb.GetType()!=0x4d) && (mcb.GetType()!=0x5a)) {
DOS_SetError(DOSERR_MCB_DESTROYED);
return false;
}
DOS_CompressMemory();
Bit16u total=mcb.GetSize();
DOS_MCB mcb_next(segment+total);
if (*blocks<=total) {
if (GCC_UNLIKELY(*blocks==total)) {
/* Nothing to do */
return true;
}
/* Shrinking MCB */
DOS_MCB mcb_new_next(segment+(*blocks));
mcb.SetSize(*blocks);
mcb_new_next.SetType(mcb.GetType());
if (mcb.GetType()==0x5a) {
/* Further blocks follow */
mcb.SetType(0x4d);
}
mcb_new_next.SetSize(total-*blocks-1);
mcb_new_next.SetPSPSeg(MCB_FREE);
mcb.SetPSPSeg(dos.psp());
return true;
}
/* MCB will grow, try to join with following MCB */
if (mcb.GetType()!=0x5a) {
if (mcb_next.GetPSPSeg()==MCB_FREE) {
total+=mcb_next.GetSize()+1;
}
}
if (*blocks<total) {
if (mcb.GetType()!=0x5a) {
/* save type of following MCB */
mcb.SetType(mcb_next.GetType());
}
mcb.SetSize(*blocks);
mcb_next.SetPt((Bit16u)(segment+*blocks));
mcb_next.SetSize(total-*blocks-1);
mcb_next.SetType(mcb.GetType());
mcb_next.SetPSPSeg(MCB_FREE);
mcb.SetType(0x4d);
mcb.SetPSPSeg(dos.psp());
return true;
}
/* at this point: *blocks==total (fits) or *blocks>total,
in the second case resize block to maximum */
if ((mcb_next.GetPSPSeg()==MCB_FREE) && (mcb.GetType()!=0x5a)) {
/* adjust type of joined MCB */
mcb.SetType(mcb_next.GetType());
}
mcb.SetSize(total);
mcb.SetPSPSeg(dos.psp());
if (*blocks==total) return true; /* block fit exactly */
*blocks=total; /* return maximum */
DOS_SetError(DOSERR_INSUFFICIENT_MEMORY);
return false;
}
bool DOS_FreeMemory(Bit16u segment) {
//TODO Check if allowed to free this segment
if (segment < DOS_MEM_START+1) {
LOG(LOG_DOSMISC,LOG_ERROR)("Program tried to free %X ---ERROR",segment);
DOS_SetError(DOSERR_MB_ADDRESS_INVALID);
return false;
}
DOS_MCB mcb(segment-1);
if ((mcb.GetType()!=0x4d) && (mcb.GetType()!=0x5a)) {
DOS_SetError(DOSERR_MB_ADDRESS_INVALID);
return false;
}
mcb.SetPSPSeg(MCB_FREE);
// DOS_CompressMemory();
return true;
}
void DOS_BuildUMBChain(bool umb_active,bool ems_active) {
if (umb_active && (machine!=MCH_TANDY)) {
Bit16u first_umb_seg = 0xd000;
Bit16u first_umb_size = 0x2000;
if(ems_active || (machine == MCH_PCJR)) first_umb_size = 0x1000;
dos_infoblock.SetStartOfUMBChain(UMB_START_SEG);
dos_infoblock.SetUMBChainState(0); // UMBs not linked yet
DOS_MCB umb_mcb(first_umb_seg);
umb_mcb.SetPSPSeg(0); // currently free
umb_mcb.SetSize(first_umb_size-1);
umb_mcb.SetType(0x5a);
/* Scan MCB-chain for last block */
Bit16u mcb_segment=dos.firstMCB;
DOS_MCB mcb(mcb_segment);
while (mcb.GetType()!=0x5a) {
mcb_segment+=mcb.GetSize()+1;
mcb.SetPt(mcb_segment);
}
/* A system MCB has to cover the space between the
regular MCB-chain and the UMBs */
Bit16u cover_mcb=(Bit16u)(mcb_segment+mcb.GetSize()+1);
mcb.SetPt(cover_mcb);
mcb.SetType(0x4d);
mcb.SetPSPSeg(0x0008);
mcb.SetSize(first_umb_seg-cover_mcb-1);
mcb.SetFileName("SC ");
} else {
dos_infoblock.SetStartOfUMBChain(0xffff);
dos_infoblock.SetUMBChainState(0);
}
}
bool DOS_LinkUMBsToMemChain(Bit16u linkstate) {
/* Get start of UMB-chain */
Bit16u umb_start=dos_infoblock.GetStartOfUMBChain();
if (umb_start!=UMB_START_SEG) {
if (umb_start!=0xffff) LOG(LOG_DOSMISC,LOG_ERROR)("Corrupt UMB chain: %x",umb_start);
return true;
}
if ((linkstate&1)==(dos_infoblock.GetUMBChainState()&1)) return true;
/* Scan MCB-chain for last block before UMB-chain */
Bit16u mcb_segment=dos.firstMCB;
Bit16u prev_mcb_segment=dos.firstMCB;
DOS_MCB mcb(mcb_segment);
while ((mcb_segment!=umb_start) && (mcb.GetType()!=0x5a)) {
prev_mcb_segment=mcb_segment;
mcb_segment+=mcb.GetSize()+1;
mcb.SetPt(mcb_segment);
}
DOS_MCB prev_mcb(prev_mcb_segment);
switch (linkstate) {
case 0x0000: // unlink
if ((prev_mcb.GetType()==0x4d) && (mcb_segment==umb_start)) {
prev_mcb.SetType(0x5a);
}
dos_infoblock.SetUMBChainState(0);
break;
case 0x0001: // link
if (mcb.GetType()==0x5a) {
mcb.SetType(0x4d);
dos_infoblock.SetUMBChainState(1);
}
break;
default:
LOG_MSG("Invalid link state %x when reconfiguring MCB chain",linkstate);
return false;
}
return true;
}
static Bitu DOS_default_handler(void) {
LOG(LOG_CPU,LOG_ERROR)("DOS rerouted Interrupt Called %X",lastint);
return CBRET_NONE;
}
static CALLBACK_HandlerObject callbackhandler;
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");
Bitu ihseg = 0x70;
Bitu ihofs = 0x08;
real_writeb(ihseg,ihofs+0x00,(Bit8u)0xFE); //GRP 4
real_writeb(ihseg,ihofs+0x01,(Bit8u)0x38); //Extra Callback instruction
real_writew(ihseg,ihofs+0x02,callbackhandler.Get_callback()); //The immediate word
real_writeb(ihseg,ihofs+0x04,(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(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);
}
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