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Shift output even if nobody is listening.

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This commit is contained in:
Thomas Harte 2020-11-11 20:04:48 -05:00
parent a15af1df5e
commit 80358cf5bd
1 changed files with 23 additions and 26 deletions
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49
Components/DiskII/IWM.cpp
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@ -263,41 +263,38 @@ void IWM::run_for(const Cycles cycles) {
} break;
case ShiftMode::Writing:
if(drives_[active_drive_] && drives_[active_drive_]->is_writing()) {
while(cycles_since_shift_ + integer_cycles >= bit_length_) {
const auto cycles_until_write = bit_length_ - cycles_since_shift_;
while(cycles_since_shift_ + integer_cycles >= bit_length_) {
const auto cycles_until_write = bit_length_ - cycles_since_shift_;
if(drives_[active_drive_]) {
drives_[active_drive_]->run_for(cycles_until_write);
// Output a flux transition if the top bit is set.
drives_[active_drive_]->write_bit(shift_register_ & 0x80);
shift_register_ <<= 1;
}
shift_register_ <<= 1;
integer_cycles -= cycles_until_write.as_integral();
cycles_since_shift_ = Cycles(0);
integer_cycles -= cycles_until_write.as_integral();
cycles_since_shift_ = Cycles(0);
--output_bits_remaining_;
if(!output_bits_remaining_) {
if(!(write_handshake_ & 0x80)) {
write_handshake_ |= 0x80;
shift_register_ = next_output_;
output_bits_remaining_ = 8;
// LOG("Next byte: " << PADHEX(2) << int(shift_register_));
} else {
write_handshake_ &= ~0x40;
drives_[active_drive_]->end_writing();
// printf("\n");
LOG("Overrun; done.");
select_shift_mode();
}
--output_bits_remaining_;
if(!output_bits_remaining_) {
if(!(write_handshake_ & 0x80)) {
write_handshake_ |= 0x80;
shift_register_ = next_output_;
output_bits_remaining_ = 8;
// LOG("Next byte: " << PADHEX(2) << int(shift_register_));
} else {
write_handshake_ &= ~0x40;
if(drives_[active_drive_]) drives_[active_drive_]->end_writing();
LOG("Overrun; done.");
select_shift_mode();
}
}
}
cycles_since_shift_ = integer_cycles;
if(drives_[active_drive_] && integer_cycles) {
drives_[active_drive_]->run_for(cycles_since_shift_);
}
} else {
if(drives_[active_drive_]) drives_[active_drive_]->run_for(cycles);
cycles_since_shift_ = integer_cycles;
if(drives_[active_drive_] && integer_cycles) {
drives_[active_drive_]->run_for(cycles_since_shift_);
}
break;