From 394902f4099c6a01a423904f3b815972592651ca Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Sat, 18 Jun 2016 13:57:10 -0400
Subject: [PATCH] Switched to clocking the 6522 by the half-cycle. Very trivial
test now passes.
---
Components/6522/6522.hpp | 55 ++++++++++++-------
Machines/Vic-20/Vic20.cpp | 4 +-
.../Mac/Clock SignalTests/6522Tests.swift | 17 ++++++
.../Mac/Clock SignalTests/MOS6522Bridge.mm | 2 +-
4 files changed, 54 insertions(+), 24 deletions(-)
diff --git a/Components/6522/6522.hpp b/Components/6522/6522.hpp
index 816f7ce8d..b0edbd770 100644
--- a/Components/6522/6522.hpp
+++ b/Components/6522/6522.hpp
@@ -144,30 +144,38 @@ template <class T> class MOS6522 {
{
}
- void run_for_cycles(unsigned int number_of_cycles)
+ void run_for_half_cycles(unsigned int number_of_cycles)
{
- _registers.timer[0] -= number_of_cycles;
- _registers.timer[1] -= number_of_cycles;
-
- if(!_registers.timer[1] && _timer_is_running[1])
+ while(number_of_cycles--)
{
- _timer_is_running[1] = false;
- _registers.interrupt_flags |= InterruptFlag::Timer2;
- reevaluate_interrupts();
- }
+ if(_is_phase2)
+ {
+ _registers.timer[0] --;
+ _registers.timer[1] --;
- if(!_registers.timer[0] && _timer_is_running[0])
- {
- _registers.interrupt_flags |= InterruptFlag::Timer1;
- reevaluate_interrupts();
+ if(!_registers.timer[1] && _timer_is_running[1])
+ {
+ _timer_is_running[1] = false;
+ _registers.interrupt_flags |= InterruptFlag::Timer2;
+ reevaluate_interrupts();
+ }
- // TODO: reload shouldn't occur for a further 1.5 cycles
- if(_registers.auxiliary_control&0x40)
- _registers.timer[0] = _registers.timer_latch[0];
- else
- _timer_is_running[0] = false;
+ if(!_registers.timer[0] && _timer_is_running[0])
+ {
+ _registers.interrupt_flags |= InterruptFlag::Timer1;
+ reevaluate_interrupts();
+
+ // TODO: reload shouldn't occur for a further 1.5 cycles
+ if(_registers.auxiliary_control&0x40)
+ _registers.timer[0] = _registers.timer_latch[0];
+ else
+ _timer_is_running[0] = false;
+ }
+ // TODO: lots of other status effects
+ }
+
+ _is_phase2 ^= true;
}
- // TODO: lots of other status effects
}
bool get_interrupt_line()
@@ -178,13 +186,18 @@ template <class T> class MOS6522 {
MOS6522() :
_timer_is_running{false, false},
- _last_posted_interrupt_status(false)
+ _last_posted_interrupt_status(false),
+ _is_phase2(false)
{}
private:
- // Intended to be overwritten
+ // Intended to be overridden
uint8_t get_port_input(int port) { return 0xff; }
void set_port_output(int port, uint8_t value) {}
+// void set_interrupt_status(bool status) {}
+
+ // Phase toggle
+ bool _is_phase2;
// Delegate and communications
bool _last_posted_interrupt_status;
diff --git a/Machines/Vic-20/Vic20.cpp b/Machines/Vic-20/Vic20.cpp
index 5a60dcc1d..71888551f 100644
--- a/Machines/Vic-20/Vic20.cpp
+++ b/Machines/Vic-20/Vic20.cpp
@@ -79,8 +79,8 @@ unsigned int Machine::perform_bus_operation(CPU6502::BusOperation operation, uin
}
}
- _userPortVIA.run_for_cycles(1);
- _keyboardVIA.run_for_cycles(1);
+ _userPortVIA.run_for_half_cycles(2);
+ _keyboardVIA.run_for_half_cycles(2);
return 1;
}
diff --git a/OSBindings/Mac/Clock SignalTests/6522Tests.swift b/OSBindings/Mac/Clock SignalTests/6522Tests.swift
index 833d17621..567337c4a 100644
--- a/OSBindings/Mac/Clock SignalTests/6522Tests.swift
+++ b/OSBindings/Mac/Clock SignalTests/6522Tests.swift
@@ -10,4 +10,21 @@ import XCTest
import Foundation
class MOS6522Tests: XCTestCase {
+
+ private func with6522(action: (MOS6522Bridge) -> ()) {
+ let bridge = MOS6522Bridge()
+ action(bridge)
+ }
+
+ func testTimerCount() {
+ with6522 {
+ $0.setValue(10, forRegister: 4)
+ $0.setValue(0, forRegister: 5)
+
+ $0.runForHalfCycles(10)
+
+ XCTAssert($0.valueForRegister(4) == 5, "Low order byte of timer should be 5; was \($0.valueForRegister(4))")
+ XCTAssert($0.valueForRegister(5) == 0, "High order byte of timer should be 5; was \($0.valueForRegister(5))")
+ }
+ }
}
diff --git a/OSBindings/Mac/Clock SignalTests/MOS6522Bridge.mm b/OSBindings/Mac/Clock SignalTests/MOS6522Bridge.mm
index 0f1a725ed..329dbb06a 100644
--- a/OSBindings/Mac/Clock SignalTests/MOS6522Bridge.mm
+++ b/OSBindings/Mac/Clock SignalTests/MOS6522Bridge.mm
@@ -49,7 +49,7 @@ class VanillaVIA: public MOS::MOS6522<VanillaVIA> {
- (void)runForHalfCycles:(NSUInteger)numberOfHalfCycles
{
- _via.run_for_cycles(numberOfHalfCycles);
+ _via.run_for_half_cycles(numberOfHalfCycles);
}
@end