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This commit is contained in:
Thomas Harte 2023-11-22 15:21:45 -05:00
parent e0f72f2048
commit df9e9c2c4d
1 changed files with 19 additions and 0 deletions
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19
Machines/PCCompatible/PCCompatible.cpp
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@ -259,6 +259,13 @@ class i8255PortHandler : public Intel::i8255::PortHandler {
void set_value(int port, uint8_t value) {
switch(port) {
case 1:
// b7: 0 => enable keyboard read; 1 => don't;
// b6: 0 => hold keyboard clock low; 1 => don't;
// b5: 1 => disable IO check; 0 => don't;
// b4: 1 => disable memory parity check; 0 => don't;
// b3: [5150] cassette motor control; [5160] high or low switches select;
// b2: [5150] high or low switches select; [5160] 1 => disable turbo mode;
// b1, b0: speaker control.
high_switches_ = value & 0x08;
speaker_.set_control(value & 0x01, value & 0x02);
break;
@ -266,8 +273,20 @@ class i8255PortHandler : public Intel::i8255::PortHandler {
printf("PPI: %02x to %d\n", value, port);
}
// KB Status Port 61h high bits:
//; 01 - normal operation. wait for keypress, when one comes in,
//; force data line low (forcing keyboard to buffer additional
//; keypresses) and raise IRQ1 high
//; 11 - stop forcing data line low. lower IRQ1 and don't raise it again.
//; drop all incoming keypresses on the floor.
//; 10 - lower IRQ1 and force clock line low, resetting keyboard
//; 00 - force clock line low, resetting keyboard, but on a 01->00 transition,
//; IRQ1 would remain high
uint8_t get_value(int port) {
switch(port) {
case 2:
// Common:
//