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More correct implementation of the FDC FIFO.

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This commit is contained in:
OBattler
2021-09-17 02:18:23 +02:00
parent b57c22df66
commit ef6d3d01db
2 changed files with 48 additions and 23 deletions
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67
src/floppy/fdc.c
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@@ -1892,9 +1892,10 @@ fdc_is_verify(fdc_t *fdc)
int
fdc_data(fdc_t *fdc, uint8_t data)
fdc_data(fdc_t *fdc, uint8_t data, int last)
{
int result = 0;
int i, result = 0;
int n;
if (fdc->deleted & 2) {
/* We're in a VERIFY command, so return with 0. */
@@ -1924,27 +1925,39 @@ fdc_data(fdc_t *fdc, uint8_t data)
}
}
} else {
result = dma_channel_write(fdc->dma_ch, data);
if (fdc->tc)
return -1;
if (result & DMA_OVER) {
fdc->data_ready = 1;
fdc->stat = 0xd0;
fdc->tc = 1;
return -1;
}
if (!fdc->fifo || (fdc->tfifo < 1)) {
dma_channel_write(fdc->dma_ch, data);
fdc->data_ready = 1;
fdc->stat = 0xd0;
if (result & DMA_OVER) {
fdc->tc = 1;
return -1;
}
} else {
fdc_fifo_buf_advance(fdc);
if (fdc->fifobufpos == 0) {
/* FIFO enabled */
fdc_fifo_buf_write(fdc, data);
if (last || (fdc->fifobufpos == 0)) {
/* We have wrapped around, means FIFO is over */
fdc->data_ready = 1;
fdc->stat = 0xd0;
n = (fdc->fifobufpos > 0) ? (fdc->fifobufpos - 1) : fdc->tfifo;
if (fdc->fifobufpos > 0)
fdc->fifobufpos = 0;
for (i = 0; i <= n; i++) {
result = dma_channel_write(fdc->dma_ch, fdc->fifobuf[i]);
if (result & DMA_OVER) {
fdc->tc = 1;
return -1;
}
}
}
}
}
@@ -2057,10 +2070,10 @@ fdc_writeprotect(fdc_t *fdc)
int fdc_getdata(fdc_t *fdc, int last)
{
int data;
int i, data = 0;
if ((fdc->flags & FDC_FLAG_PCJR) || !fdc->dma) {
if ((fdc->flags & FDC_FLAG_PCJR) || !fdc->fifo) {
if ((fdc->flags & FDC_FLAG_PCJR) || !fdc->fifo || (fdc->tfifo < 1)) {
data = fdc->dat;
if (!last)
@@ -2072,20 +2085,32 @@ int fdc_getdata(fdc_t *fdc, int last)
fdc->stat = 0xb0;
}
} else {
data = dma_channel_read(fdc->dma_ch);
if (!fdc->fifo || (fdc->tfifo < 1)) {
data = dma_channel_read(fdc->dma_ch);
if (data & DMA_OVER)
fdc->tc = 1;
if (!fdc->fifo) {
if (!last)
fdc->stat = 0x90;
} else {
fdc_fifo_buf_advance(fdc);
if (fdc->fifobufpos == 0) {
for (i = 0; i <= fdc->tfifo; i++) {
data = dma_channel_read(fdc->dma_ch);
fdc->fifobuf[i] = data;
if (data & DMA_OVER) {
fdc->tc = 1;
break;
}
}
}
data = fdc_fifo_buf_read(fdc);
if (!last && (fdc->fifobufpos == 0))
fdc->stat = 0x90;
}
if (data & DMA_OVER)
fdc->tc = 1;
}
return data & 0xff;