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Use special physical memory access for dma transfers

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Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@2086
This commit is contained in:
Sjoerd van der Berg 2004-12-22 19:49:24 +00:00
parent d1d89dc803
commit fba8482ce1
3 changed files with 36 additions and 12 deletions
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32
src/hardware/dma.cpp
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@ -22,10 +22,31 @@
#include "inout.h"
#include "dma.h"
#include "pic.h"
#include "paging.h"
DmaChannel *DmaChannels[8];
DmaController *DmaControllers[2];
static void DMA_BlockRead(PhysPt pt,void * data,Bitu size) {
Bit8u * write=(Bit8u *) data;
for ( ; size ; size--, pt++) {
Bitu page = pt >> 12;
if (page < LINK_START)
page = paging.firstmb[page];
*write++=phys_readb(page*4096 + (pt & 4095));
}
}
static void DMA_BlockWrite(PhysPt pt,void * data,Bitu size) {
Bit8u * read=(Bit8u *) data;
for ( ; size ; size--, pt++) {
Bitu page = pt >> 12;
if (page < LINK_START)
page = paging.firstmb[page];
phys_writeb(page*4096 + (pt & 4095), *read++);
}
}
static void DMA_WriteControllerReg(DmaController * cont,Bitu reg,Bitu val,Bitu len) {
DmaChannel * chan;Bitu i;
Bitu base=cont->chanbase;
@ -121,7 +142,8 @@ static Bitu DMA_ReadControllerReg(DmaController * cont,Bitu reg,Bitu len) {
}
return ret;
default:
LOG_MSG("Trying to read undefined DMA Red %x",reg);
LOG_MSG("Trying to read undefined DMA port %x",reg);
break;
}
return 0xffffffff;
}
@ -180,12 +202,12 @@ Bitu DmaChannel::Read(Bitu want, Bit8u * buffer) {
again:
Bitu left=(currcnt+1);
if (want<left) {
MEM_BlockRead(pagebase+(curraddr << DMA16),buffer,want << DMA16);
DMA_BlockRead(pagebase+(curraddr << DMA16),buffer,want << DMA16);
done+=want;
curraddr+=want;
currcnt-=want;
} else {
MEM_BlockRead(pagebase+(curraddr << DMA16),buffer,left << DMA16);
DMA_BlockRead(pagebase+(curraddr << DMA16),buffer,left << DMA16);
buffer+=left << DMA16;
want-=left;
done+=left;
@ -208,12 +230,12 @@ Bitu DmaChannel::Write(Bitu want, Bit8u * buffer) {
again:
Bitu left=(currcnt+1);
if (want<left) {
MEM_BlockWrite(pagebase+(curraddr << DMA16),buffer,want << DMA16);
DMA_BlockWrite(pagebase+(curraddr << DMA16),buffer,want << DMA16);
done+=want;
curraddr+=want;
currcnt-=want;
} else {
MEM_BlockWrite(pagebase+(curraddr << DMA16),buffer,left << DMA16);
DMA_BlockWrite(pagebase+(curraddr << DMA16),buffer,left << DMA16);
buffer+=left << DMA16;
want-=left;
done+=left;