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Makes a first attempt at some sort of interrupt functionality.

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This commit is contained in:
Thomas Harte 2021-07-26 16:40:42 -04:00
parent e671cc6056
commit 87dcd82f69
3 changed files with 72 additions and 4 deletions
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8
Machines/Amiga/Amiga.cpp
View File

@ -82,6 +82,7 @@ class ConcreteMachine:
const auto changes = chipset_.run_for(cycle.length);
cia_a_.advance_tod(changes.vsyncs);
cia_b_.advance_tod(changes.hsyncs);
mc68000_.set_interrupt_level(changes.interrupt_level);
// Check for assertion of reset.
if(cycle.operation & Microcycle::Reset) {
@ -89,6 +90,13 @@ class ConcreteMachine:
LOG("Reset; PC is around " << PADHEX(8) << mc68000_.get_state().program_counter);
}
// Autovector interrupts.
if(cycle.operation & Microcycle::InterruptAcknowledge) {
mc68000_.set_is_peripheral_address(true);
} else {
mc68000_.set_is_peripheral_address(false);
}
// Do nothing if no address is exposed.
if(!(cycle.operation & (Microcycle::NewAddress | Microcycle::SameAddress))) return HalfCycles(0);

56
Machines/Amiga/Chipset.cpp
View File

@ -16,6 +16,27 @@
using namespace Amiga;
namespace {
enum InterruptFlag: uint16_t {
SerialPortTransmit = 1 << 0,
DiskBlock = 1 << 1,
Software = 1 << 2,
IOPortsAndTimers = 1 << 3,
Copper = 1 << 4,
VerticalBlank = 1 << 5,
Blitter = 1 << 6,
AudioChannel0 = 1 << 7,
AudioChannel1 = 1 << 8,
AudioChannel2 = 1 << 9,
AudioChannel3 = 1 << 10,
SerialPortReceive = 1 << 11,
DiskSyncMatch = 1 << 12,
External = 1 << 13,
};
}
Chipset::Chipset(uint16_t *ram, size_t size) :
blitter_(ram, size) {
}
@ -33,9 +54,37 @@ Chipset::Changes Chipset::run_for(HalfCycles length) {
changes.vsyncs = y_ / 312;
y_ %= 312;
// y = 0 => start of vertical blank.
if(changes.vsyncs) {
interrupt_requests_ |= InterruptFlag::VerticalBlank;
update_interrupts();
}
changes.interrupt_level = interrupt_level_;
return changes;
}
void Chipset::update_interrupts() {
interrupt_level_ = 0;
const uint16_t enabled_requests = interrupt_enable_ & interrupt_requests_ & 0x3fff;
if(enabled_requests && (interrupt_enable_ & 0x4000)) {
if(enabled_requests & (InterruptFlag::External)) {
interrupt_level_ = 6;
} else if(enabled_requests & (InterruptFlag::SerialPortReceive | InterruptFlag::DiskSyncMatch)) {
interrupt_level_ = 5;
} else if(enabled_requests & (InterruptFlag::AudioChannel0 | InterruptFlag::AudioChannel1 | InterruptFlag::AudioChannel2 | InterruptFlag::AudioChannel3)) {
interrupt_level_ = 4;
} else if(enabled_requests & (InterruptFlag::Copper | InterruptFlag::VerticalBlank | InterruptFlag::Blitter)) {
interrupt_level_ = 3;
} else if(enabled_requests & (InterruptFlag::External)) {
interrupt_level_ = 2;
} else if(enabled_requests & (InterruptFlag::SerialPortTransmit | InterruptFlag::DiskBlock | InterruptFlag::Software)) {
interrupt_level_ = 1;
}
}
}
void Chipset::perform(const CPU::MC68000::Microcycle &cycle) {
using Microcycle = CPU::MC68000::Microcycle;
@ -119,11 +168,18 @@ void Chipset::perform(const CPU::MC68000::Microcycle &cycle) {
update_interrupts();
LOG("Interrupt enable mask modified by " << PADHEX(4) << cycle.value16() << "; is now " << std::bitset<16>{interrupt_enable_});
break;
case Read(0x01c):
cycle.set_value16(interrupt_enable_);
break;
case Write(0x09c):
ApplySetClear(interrupt_requests_);
update_interrupts();
LOG("Interrupt request modified by " << PADHEX(4) << cycle.value16() << "; is now " << std::bitset<16>{interrupt_requests_});
break;
case Read(0x01e):
cycle.set_value16(interrupt_requests_);
break;
// Display management.
case Write(0x08e): {

12
Machines/Amiga/Chipset.hpp
View File

@ -29,7 +29,7 @@ class Chipset {
struct Changes {
int hsyncs = 0;
int vsyncs = 0;
// TODO: interrupt change?
int interrupt_level = 0;
};
/// Advances the stated amount of time.
@ -38,15 +38,19 @@ class Chipset {
/// Performs the provided microcycle, which the caller guarantees to be a memory access.
void perform(const CPU::MC68000::Microcycle &);
/// Provides the chipset's current interrupt level.
int get_interrupt_level() {
return interrupt_level_;
}
private:
// MARK: - Interrupts.
uint16_t interrupt_enable_ = 0;
uint16_t interrupt_requests_ = 0;
int interrupt_level_ = 0;
void update_interrupts() {
// TODO.
}
void update_interrupts();
// MARK: - DMA Control and Blitter.