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Support for memory allocation strategy: last matching block

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Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@535
This commit is contained in:
Ulf Wohlers 2002-11-25 11:37:04 +00:00
parent 5d874b4efb
commit 87f990907d
3 changed files with 40 additions and 11 deletions
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2
include/dos_inc.h
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@ -140,6 +140,8 @@ bool DOS_ResizeMemory(Bit16u segment,Bit16u * blocks);
bool DOS_FreeMemory(Bit16u segment);
void DOS_FreeProcessMemory(Bit16u pspseg);
Bit16u DOS_GetMemory(Bit16u pages);
void DOS_SetMemAllocStrategy(Bit16u strat);
Bit16u DOS_GetMemAllocStrategy(void);
/* FCB stuff */
bool DOS_FCBOpen(Bit16u seg,Bit16u offset);

3
src/dos/dos.cpp
View file

@ -679,9 +679,10 @@ static Bitu DOS_21Handler(void) {
case 0x58: /* Get/Set Memory allocation strategy */
switch (reg_al) {
case 0: /* Get Strategy */
reg_ax=0; //Low memory first fit
reg_ax=DOS_GetMemAllocStrategy();
break;
case 1: /* Set Strategy */
DOS_SetMemAllocStrategy(reg_bx);
break;
default:
LOG_DEBUG("DOS:58:Not Supported Set//Get memory allocation call %X",reg_al);

46
src/dos/dos_memory.cpp
View file

@ -24,6 +24,7 @@
#define MEM_START 0x60 //First Segment that DOS can use
//#define MEM_START 4000 //First Segment that DOS can use
static Bit16u memAllocStrategy = 0x00;
static void DOS_CompressMemory(void) {
MCB * pmcb;MCB * pmcbnext;
@ -57,6 +58,15 @@ void DOS_FreeProcessMemory(Bit16u pspseg) {
DOS_CompressMemory();
};
Bit16u DOS_GetMemAllocStrategy()
{
return memAllocStrategy;
};
void DOS_SetMemAllocStrategy(Bit16u strat)
{
memAllocStrategy = strat;
};
bool DOS_AllocateMemory(Bit16u * segment,Bit16u * blocks) {
MCB * pmcb;MCB * pmcbnext;
@ -77,17 +87,33 @@ bool DOS_AllocateMemory(Bit16u * segment,Bit16u * blocks) {
*segment=mcb_segment+1;
return true;
} else {
// TODO: Strategy "1": Best matching block
/* If so allocate it */
pmcbnext=(MCB *)HostMake(mcb_segment+*blocks+1,0);
pmcbnext->psp_segment=MCB_FREE;
pmcbnext->type=pmcb->type;
pmcbnext->size=pmcb->size-*blocks-1;
pmcb->size=*blocks;
pmcb->type=0x4D;
pmcb->psp_segment=dos.psp;
//TODO Filename
*segment=mcb_segment+1;
return true;
if ((memAllocStrategy & 0x03)==0) {
pmcbnext=(MCB *)HostMake(mcb_segment+*blocks+1,0);
pmcbnext->psp_segment=MCB_FREE;
pmcbnext->type=pmcb->type;
pmcbnext->size=pmcb->size-*blocks-1;
pmcb->size=*blocks;
pmcb->type=0x4D;
pmcb->psp_segment=dos.psp;
//TODO Filename
*segment=mcb_segment+1;
return true;
} else {
// * Last Block *
// New created block
*segment = mcb_segment+1+pmcb->size-*blocks;
pmcbnext=(MCB *)HostMake(*segment-1,0);
pmcbnext->size = *blocks;
pmcbnext->type = pmcb->type;
pmcbnext->psp_segment = dos.psp;
// Old Block
pmcb->size = pmcb->size-*blocks-1;
pmcb->psp_segment = MCB_FREE;
pmcb->type = 0x4D;
return true;
};
}
}
/* Onward to the next MCB if there is one */