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Takes further aim at the conters.

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I think test cases are needed, probably.
This commit is contained in:
Thomas Harte 2021-07-24 16:06:49 -04:00
parent ceca32ceb3
commit fcd6b7b0ea
2 changed files with 25 additions and 27 deletions
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33
Components/6526/Implementation/6526Implementation.hpp
View File

@ -68,16 +68,10 @@ void MOS6526<BusHandlerT, personality>::write(int address, uint8_t value) {
break;
// Counters; writes set the reload values.
case 4: counter_[0].reload = (counter_[0].reload & 0xff00) | uint16_t(value << 0); break;
case 5:
counter_[0].reload = (counter_[0].reload & 0x00ff) | uint16_t(value << 8);
counter_[0].is_counting = true;
break;
case 6: counter_[1].reload = (counter_[1].reload & 0xff00) | uint16_t(value << 0); break;
case 7:
counter_[1].reload = (counter_[1].reload & 0x00ff) | uint16_t(value << 8);
counter_[1].is_counting = true;
break;
case 4: counter_[0].template set_reload<0>(value); break;
case 5: counter_[0].template set_reload<8>(value); break;
case 6: counter_[1].template set_reload<0>(value); break;
case 7: counter_[1].template set_reload<8>(value); break;
// Time-of-day clock.
//
@ -141,23 +135,8 @@ void MOS6526<BusHandlerT, personality>::write(int address, uint8_t value) {
} break;
// Control.
case 14:
if(value & 0x10) {
counter_[0].value = counter_[0].reload;
counter_[0].is_counting = true;
}
counter_[0].control = value & 0xef;
printf("Ignoring control A write: %02x\n", value);
break;
case 15:
if(value & 0x10) {
counter_[1].value = counter_[1].reload;
counter_[1].is_counting = true;
}
counter_[1].control = value;
printf("Ignoring control B write: %02x\n", value);
break;
case 14: counter_[0].template set_control<false>(value); break;
case 15: counter_[1].template set_control<true>(value); break;
default:
printf("Unhandled 6526 write: %02x to %d\n", value, address);

19
Components/6526/Implementation/6526Storage.hpp
View File

@ -32,6 +32,25 @@ struct MOS6526Storage {
uint8_t control = 0;
bool is_counting = false;
template <int shift> void set_reload(uint8_t v) {
reload = (reload & (0xff00 >> shift)) | uint16_t(v << shift);
if constexpr (shift == 8) {
if(!is_counting) {
is_counting = true;
value = reload;
}
}
}
template <bool is_counter_2> void set_control(uint8_t v) {
control = v & 0xef;
if(v & 0x10) {
value = reload;
}
is_counting |= (v & 0x18) == 0x10;
}
int subtract(int count) {
if(control & 8) {
// One-shot.