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New ems code to use a handler instead of mapping for the pageframe

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Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@283
This commit is contained in:
Sjoerd van der Berg 2002-09-16 14:16:28 +00:00
parent bfa82478cb
commit 032402542d
1 changed files with 37 additions and 3 deletions
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40
src/ints/ems.cpp
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@ -28,6 +28,7 @@
#include "inout.h"
#include "dos_inc.h"
#define EMM_USEHANDLER 1
#define EMM_PAGEFRAME 0xE000
#define EMM_MAX_HANDLES 50 /* 255 Max */
@ -97,8 +98,23 @@ struct EMM_Handle {
static EMM_Handle emm_handles[EMM_MAX_HANDLES];
static EMM_Page emm_pages[EMM_MAX_PAGES];
static EMM_Mapping emm_mappings[EMM_MAX_PHYS];
static HostPt emm_pagebase[EMM_MAX_PHYS];
Bitu call_int67;
#if EMM_USEHANDLER
Bit8u EMM_ReadHandler(PhysPt start) {
start-=EMM_PAGEFRAME * 16;
Bitu page=start>>14;
return readb(emm_pagebase[page]+(start&0x3fff));
}
void EMM_WriteHandler(PhysPt start,Bit8u val) {
start-=EMM_PAGEFRAME * 16;
Bitu page=start>>14;
writeb(emm_pagebase[page]+(start&0x3fff),val);
}
#endif
static Bit16u EMM_GetFreePages(void) {
Bit16u count=0;
for (Bitu index=0;index<EMM_MAX_PAGES;index++) {
@ -206,13 +222,21 @@ static Bit8u EMM_MapPage(Bitu phys_page,Bit16u handle,Bit16u log_page) {
log_page--;
}
/* Do the actual mapping */
#if EMM_USEHANDLER
emm_pagebase[phys_page]=(HostPt) emm_pages[index].memory;
#else
MEM_SetupMapping(PAGE_COUNT(PhysMake(EMM_PAGEFRAME,phys_page*EMM_PAGE_SIZE)),PAGE_COUNT(PAGE_SIZE),emm_pages[index].memory);
#endif
return EMM_NO_ERROR;
} else if (log_page==NULL_PAGE) {
/* Unmapping it is */
emm_mappings[phys_page].handle=NULL_HANDLE;
emm_mappings[phys_page].page=NULL_PAGE;
#if EMM_USEHANDLER
emm_pagebase[phys_page]=memory+EMM_PAGEFRAME*16+phys_page*16*1024;
#else
MEM_ClearMapping(PAGE_COUNT(PhysMake(EMM_PAGEFRAME,phys_page*EMM_PAGE_SIZE)),PAGE_COUNT(PAGE_SIZE));
#endif
return EMM_NO_ERROR;
} else {
/* Illegal logical page it is */
@ -364,7 +388,11 @@ static Bitu INT67_Handler(void) {
break;
}
break;
case 0x50: // Map/Unmap multiple handle pages
case 0x4f: /* Save Partial Page Map */
LOG_ERROR("EMS:Call %2X Subfunction %2X not supported",reg_ah,reg_al);
reg_ah=EMM_FUNC_NOSUP;
break;
case 0x50: /* Map/Unmap multiple handle pages */
reg_ah = EMM_NO_ERROR;
switch (reg_al) {
case 0x00: // use physical page numbers
@ -433,7 +461,6 @@ void EMS_Init(void) {
DOS_Device * newdev = new device_EMM();
DOS_AddDevice(newdev);
/* Add a little hack so it appears that there is an actual ems device installed */
char * emsname="EMMXXXX0";
Bit16u seg=DOS_GetMemory(2); //We have 32 bytes
@ -458,6 +485,13 @@ void EMS_Init(void) {
emm_mappings[i].page=NULL_PAGE;
emm_mappings[i].handle=NULL_HANDLE;
}
#if EMM_USEHANDLER
/* Setup page handler */
MEM_SetupPageHandlers(PAGE_COUNT(EMM_PAGEFRAME*16),PAGE_COUNT(64*1024),EMM_ReadHandler,EMM_WriteHandler);
emm_pagebase[0]=memory+EMM_PAGEFRAME*16;
emm_pagebase[1]=memory+EMM_PAGEFRAME*16+16*1024;
emm_pagebase[2]=memory+EMM_PAGEFRAME*16+32*1024;
emm_pagebase[3]=memory+EMM_PAGEFRAME*16+48*1024;
#endif
}