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Attempts a complete wiring of 68901 interrupts.

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This commit is contained in:
Thomas Harte
2019-10-25 22:36:01 -04:00
parent 51b4b5551d
commit 872897029e
3 changed files with 66 additions and 9 deletions
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Components/68901/MFP68901.cpp
+23 -7
View File
@@ -50,7 +50,9 @@ uint8_t MFP68901::read(int address) {
case 0x0a:
LOG("Read: interrupt mask B");
return uint8_t(interrupt_mask_);
case 0x0b: LOG("Read: vector"); break;
case 0x0b:
LOG("Read: vector");
return interrupt_vector_;
case 0x0c: LOG("Read: timer A control"); break;
case 0x0d: LOG("Read: timer B control"); break;
case 0x0e: LOG("Read: timers C/D control"); break;
@@ -106,7 +108,10 @@ void MFP68901::write(int address, uint8_t value) {
interrupt_mask_ = (interrupt_mask_ & 0xff00) | value;
update_interrupts();
break;
case 0x0b: LOG("Write: vector " << PADHEX(2) << int(value)); break;
case 0x0b:
LOG("Write: vector " << PADHEX(2) << int(value));
interrupt_vector_ = value;
break;
case 0x0c:
case 0x0d: {
const auto timer = address - 0xc;
@@ -261,11 +266,12 @@ void MFP68901::end_interrupts(int interrupt) {
}
void MFP68901::update_interrupts() {
const bool old_interrupt_line = interrupt_line_;
interrupt_pending_ = interrupt_in_service_ & interrupt_enable_;
interrupt_line_ = interrupt_pending_ & interrupt_mask_;
if(interrupt_line_) {
LOG("Should produce interrupt...");
if(interrupt_delegate_ && interrupt_line_ != old_interrupt_line) {
interrupt_delegate_->mfp68901_did_change_interrupt_status(this);
}
}
@@ -273,7 +279,17 @@ bool MFP68901::get_interrupt_line() {
return interrupt_line_;
}
uint16_t MFP68901::acknowledge_interrupt() {
// TODO.
return 0;
uint8_t MFP68901::acknowledge_interrupt() {
uint8_t selected_interrupt = 15;
uint16_t interrupt_mask = 0x8000;
while(!(interrupt_pending_ & interrupt_mask) && interrupt_mask) {
interrupt_mask >>= 1;
--selected_interrupt;
}
end_interrupts(interrupt_mask);
return (interrupt_vector_ & 0xf0) | selected_interrupt;
}
void MFP68901::set_interrupt_delegate(InterruptDelegate *delegate) {
interrupt_delegate_ = delegate;
}
Components/68901/MFP68901.hpp
+9 -1
View File
@@ -35,7 +35,12 @@ class MFP68901 {
uint8_t get_port_output();
bool get_interrupt_line();
uint16_t acknowledge_interrupt();
uint8_t acknowledge_interrupt();
struct InterruptDelegate {
virtual void mfp68901_did_change_interrupt_status(MFP68901 *) = 0;
};
void set_interrupt_delegate(InterruptDelegate *delegate);
private:
// MARK: - Timers
@@ -69,6 +74,8 @@ class MFP68901 {
// MARK: - Interrupts
InterruptDelegate *interrupt_delegate_ = nullptr;
// Ad hoc documentation: there seems to be a four-stage process here.
// This is my current understanding:
//
@@ -88,6 +95,7 @@ class MFP68901 {
int interrupt_pending_ = 0;
int interrupt_mask_ = 0;
bool interrupt_line_ = false;
uint8_t interrupt_vector_ = 0;
enum Interrupt {
GPIP0 = (1 << 0),