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viacuda: One exit path for read.

This commit is contained in:
joevt 2024-04-20 00:05:29 -07:00 committed by dingusdev
parent b454ab45fe
commit 4479ecb1bb
1 changed files with 20 additions and 8 deletions
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28
devices/common/viacuda.cpp
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@ -139,37 +139,49 @@ void ViaCuda::cuda_init() {
} }
uint8_t ViaCuda::read(int reg) { uint8_t ViaCuda::read(int reg) {
uint8_t value;
/* reading from some VIA registers triggers special actions */ /* reading from some VIA registers triggers special actions */
switch (reg & 0xF) { switch (reg & 0xF) {
case VIA_B: case VIA_B:
return (this->via_regs[VIA_B]); value = (this->via_regs[VIA_B]);
break;
case VIA_A: case VIA_A:
case VIA_ANH: case VIA_ANH:
value = this->via_regs[reg & 0xF];
LOG_F(WARNING, "Attempted read from VIA Port A!"); LOG_F(WARNING, "Attempted read from VIA Port A!");
break; break;
case VIA_IER: case VIA_IER:
return (this->_via_ier | 0x80); // bit 7 always reads as "1" value = (this->_via_ier | 0x80); // bit 7 always reads as "1"
break;
case VIA_IFR: case VIA_IFR:
return this->_via_ifr; value = this->_via_ifr;
break;
case VIA_T1CL: case VIA_T1CL:
this->_via_ifr &= ~VIA_IF_T1; this->_via_ifr &= ~VIA_IF_T1;
update_irq(); update_irq();
return this->calc_counter_val(this->t1_counter, this->t1_start_time) & 0xFFU; value = this->calc_counter_val(this->t1_counter, this->t1_start_time) & 0xFFU;
break;
case VIA_T1CH: case VIA_T1CH:
return this->calc_counter_val(this->t1_counter, this->t1_start_time) >> 8; value = this->calc_counter_val(this->t1_counter, this->t1_start_time) >> 8;
break;
case VIA_T2CL: case VIA_T2CL:
this->_via_ifr &= ~VIA_IF_T2; this->_via_ifr &= ~VIA_IF_T2;
update_irq(); update_irq();
return this->calc_counter_val(this->t2_counter, this->t2_start_time) & 0xFFU; value = this->calc_counter_val(this->t2_counter, this->t2_start_time) & 0xFFU;
break;
case VIA_T2CH: case VIA_T2CH:
return this->calc_counter_val(this->t2_counter, this->t2_start_time) >> 8; value = this->calc_counter_val(this->t2_counter, this->t2_start_time) >> 8;
break;
case VIA_SR: case VIA_SR:
value = this->via_regs[reg & 0xF];
this->_via_ifr &= ~VIA_IF_SR; this->_via_ifr &= ~VIA_IF_SR;
update_irq(); update_irq();
break; break;
default:
value = this->via_regs[reg & 0xF];
} }
return (this->via_regs[reg & 0xF]); return value;
} }
void ViaCuda::write(int reg, uint8_t value) { void ViaCuda::write(int reg, uint8_t value) {