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Fixes to disable a channel once count has reached 0 in single cycle mode.

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Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@935
This commit is contained in:
Sjoerd van der Berg 2003-04-16 08:10:18 +00:00
parent 948d4a65af
commit df814b12ce
1 changed files with 35 additions and 14 deletions
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49
src/hardware/dma.cpp
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@ -53,11 +53,12 @@ struct DMA_CHANNEL {
Bit16u base_address;
Bit16u base_count;
Bit16u current_address;
Bit32u current_count;
Bitu current_count;
Bit8u page;
bool masked;
PhysPt address;
bool addr_changed;
bool enabled;
DMA_EnableCallBack enable_callback;
};
@ -70,6 +71,8 @@ struct DMA_CONTROLLER {
};
static DMA_CONTROLLER dma[2];
void DMA_TestChannel(DMA_CHANNEL * chan);
static Bit8u read_dma(Bit32u port) {
/* only use first dma for now */
DMA_CONTROLLER * cont=&dma[0];
@ -120,6 +123,7 @@ static void write_dma(Bit32u port,Bit8u val) {
} else {
chan->base_address=(chan->base_address & 0x00ff) | (val<<8);
}
// LOG_MSG("DMA:Address %X",chan->base_address);
cont->flipflop=!cont->flipflop;
chan->addr_changed=true;
break;
@ -130,8 +134,10 @@ static void write_dma(Bit32u port,Bit8u val) {
} else {
chan->base_count=(chan->base_count & 0x00ff) | (val<<8);
}
// LOG_MSG("DMA:count %X",chan->base_count);
cont->flipflop=!cont->flipflop;
chan->addr_changed=true;
DMA_TestChannel(chan);
break;
case 0x08: /* Command Register */
if (val != 4) LOG(LOG_ERROR,"DMA1:Illegal command %2X",val);
@ -150,7 +156,7 @@ static void write_dma(Bit32u port,Bit8u val) {
case 0x0a: /* single mask bit register */
chan=&cont->chan[val & 0x3];
chan->masked=(val & 4)>0;
if (chan->enable_callback) chan->enable_callback(!chan->masked);
DMA_TestChannel(chan);
break;
case 0x0b: /* mode register */
chan=&cont->chan[val & 0x3];
@ -161,7 +167,7 @@ static void write_dma(Bit32u port,Bit8u val) {
if (chan->mode.address_decrement) {
LOG(LOG_ERROR,"DMA:Address Decrease not supported yet");
}
DMA_TestChannel(chan);
break;
case 0x0c: /* Clear Flip/Flip */
cont->flipflop=true;
@ -194,6 +200,7 @@ INLINE void ResetDMA8(DMA_CHANNEL * chan) {
chan->address=(chan->page << 16)+chan->base_address;
chan->current_count=chan->base_count+1;
chan->current_address=chan->base_address;
// LOG_MSG("DMA8:Setup at address %X:%X count %X",chan->page<<12,chan->base_address,chan->current_count);
}
@ -217,6 +224,8 @@ Bitu DMA_8_Read(Bitu dmachan,Bit8u * buffer,Bitu count) {
count=chan->current_count;
chan->current_address+=count;;
chan->current_count=0;
if (chan->enable_callback) chan->enable_callback(false);
chan->enabled=false;
return count;
} else {
buffer+=chan->current_count;
@ -269,8 +278,6 @@ Bitu DMA_8_Write(Bitu dmachan,Bit8u * buffer,Bitu count) {
}
Bitu DMA_16_Read(Bitu dmachan,Bit8u * buffer,Bitu count) {
return 0;
@ -282,23 +289,37 @@ Bitu DMA_16_Write(Bitu dmachan,Bit8u * buffer,Bitu count) {
return 0;
}
void DMA_TestChannel(DMA_CHANNEL * chan) {
if (!chan->enable_callback) return;
bool enabled;
if (chan->masked) enabled=false;
else {
if (chan->mode.autoinit_enable) enabled=true;
else if (chan->current_count || chan->addr_changed) enabled=true;
else enabled=false;
}
if (enabled == chan->enabled) return;
chan->enabled=enabled;
chan->enable_callback(enabled);
}
void DMA_SetEnableCallBack(Bitu channel,DMA_EnableCallBack callback) {
DMA_CHANNEL * chan;
if (channel<4) {
dma[0].chan[channel].enable_callback=callback;
if (callback) callback(!dma[0].chan[channel].masked);
return;
}
if (channel<8) {
dma[1].chan[channel-4].enable_callback=callback;
if (callback) callback(!dma[1].chan[channel-4].masked);
}
chan=&dma[0].chan[channel];
} else if (channel<8) {
chan=&dma[1].chan[channel-4];
} else return;
chan->enabled=false;
chan->enable_callback=callback;
DMA_TestChannel(chan);
}
void DMA_Init(Section* sec) {
for (Bit32u i=0;i<0x10;i++) {
Bitu i;
for (i=0;i<0x10;i++) {
IO_RegisterWriteHandler(i,write_dma,"DMA1");
IO_RegisterReadHandler(i,read_dma,"DMA1");
}