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A few serial port fixes, now passes Norton Diagnostics tests as well.

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This commit is contained in:
OBattler 2024-12-13 04:22:02 +01:00
parent 20feee1e00
commit 3434d7d868
1 changed files with 21 additions and 8 deletions
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29
src/device/serial.c
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@ -197,6 +197,8 @@ serial_receive_timer(void *priv)
/* Raise Data Ready interrupt. */
dev->lsr |= 0x01;
dev->int_status |= SERIAL_INT_RECEIVE;
if (dev->lsr & 0x02)
dev->int_status |= SERIAL_INT_LSR;
serial_update_ints(dev);
}
@ -266,10 +268,6 @@ serial_move_to_txsr(serial_t *dev)
/* Update interrupts to signal THRE and that TXSR is no longer empty. */
serial_update_ints(dev);
}
if (dev->transmit_enabled & 2)
dev->baud_cycles++;
else
dev->baud_cycles = 0; /* If not moving while transmitting, reset BAUDOUT cycle count. */
if (!dev->fifo_enabled || (fifo_get_count(dev->xmit_fifo) == 0x0))
dev->transmit_enabled &= ~1; /* Stop moving. */
dev->transmit_enabled |= 2; /* Start transmitting. */
@ -303,16 +301,26 @@ static void
serial_transmit_timer(void *priv)
{
serial_t *dev = (serial_t *) priv;
int delay = 8; /* STOP to THRE delay is 8 BAUDOUT cycles. */
/*
Norton Diagnostics waits for up to 2 bit periods, this is
confirmed by the NS16550A timings graph, which shows operation
as follows after write: 1 bit of delay, then start bit, and at
the end of the start bit, move from THR to TXSR.
*/
int delay = 1;
if (dev->transmit_enabled & 3) {
/*
If already transmitting, move from THR to TXSR at the end of
the last data bit.
*/
if ((dev->transmit_enabled & 1) && (dev->transmit_enabled & 2))
delay = dev->data_bits; /* Delay by less if already transmitting. */
delay = dev->data_bits + 1;
dev->baud_cycles++;
/* We have processed (total bits) BAUDOUT cycles, transmit the byte. */
if ((dev->baud_cycles == dev->bits) && (dev->transmit_enabled & 2))
/* We have processed (delay + total bits) BAUDOUT cycles, transmit the byte. */
if ((dev->baud_cycles == (dev->bits + 1)) && (dev->transmit_enabled & 2))
serial_process_txsr(dev);
/* We have processed (data bits) BAUDOUT cycles. */
@ -614,6 +622,11 @@ serial_write(uint16_t addr, uint8_t val, void *priv)
dev->msr = new_msr;
if (dev->msr & 0x0f) {
dev->int_status |= SERIAL_INT_MSR;
serial_update_ints(dev);
}
/* TODO: Why reset the FIFO's here?! */
fifo_reset(dev->xmit_fifo);
fifo_reset(dev->rcvr_fifo);