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mos6551: Clear IRQ state upon hardware reset

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(nw) Not doing this at device_start time avoids a race condition in digel804 that was causing the Z80 interrupt to be raised in advance of machine_start..
This commit is contained in:
AJR 2020-04-10 17:50:47 -04:00
parent 17e0358bb8
commit e619ff316e
1 changed files with 11 additions and 11 deletions
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22
src/devices/machine/mos6551.cpp
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@ -129,7 +129,6 @@ void mos6551_device::device_start()
m_internal_clock->set_unscaled_clock(m_xtal); m_internal_clock->set_unscaled_clock(m_xtal);
output_irq(1);
output_txd(1); output_txd(1);
output_rxc(1); output_rxc(1);
output_rts(1); output_rts(1);
@ -155,6 +154,9 @@ void mos6551_device::device_reset()
write_command(0); write_command(0);
write_control(0); write_control(0);
m_irq_state = 0;
update_irq();
} }
void mos6551_device::output_irq(int irq) void mos6551_device::output_irq(int irq)
@ -280,18 +282,15 @@ uint8_t mos6551_device::read_status()
{ {
uint8_t status = m_status; uint8_t status = m_status;
if (!machine().side_effects_disabled()) if (m_cts)
{ {
if (m_cts) status &= ~SR_TDRE;
{ }
status &= ~SR_TDRE;
}
if (m_irq_state != 0) if (!machine().side_effects_disabled() && m_irq_state != 0)
{ {
m_irq_state = 0; m_irq_state = 0;
update_irq(); update_irq();
}
} }
return status; return status;
@ -317,6 +316,7 @@ void mos6551_device::write_reset(uint8_t data)
{ {
m_status &= ~SR_OVERRUN; m_status &= ~SR_OVERRUN;
m_irq_state &= ~(IRQ_DCD | IRQ_DSR); m_irq_state &= ~(IRQ_DCD | IRQ_DSR);
update_irq();
write_command(m_command & ~0x1f); write_command(m_command & ~0x1f);
} }