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Merge pull request #102 from TomHarte/6532Accuracy

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Improves 6532 counting accuracy
This commit is contained in:
Thomas Harte 2017-03-04 17:04:43 -05:00 committed by GitHub
commit cccdc558e7
4 changed files with 59 additions and 24 deletions
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4
Components/6532/6532.hpp
View File

@ -51,7 +51,7 @@ template <class T> class MOS6532 {
if(address & 0x10)
{
timer_.writtenShift = timer_.activeShift = (decodedAddress - 0x04) * 3 + (decodedAddress / 0x07); // i.e. 0, 3, 6, 10
timer_.value = ((unsigned int)(value) << timer_.activeShift) | ((1 << timer_.activeShift)-1);
timer_.value = ((unsigned int)value << timer_.activeShift) ;
timer_.interrupt_enabled = !!(address&0x08);
interrupt_status_ &= ~InterruptFlag::Timer;
evaluate_interrupts();
@ -119,7 +119,7 @@ template <class T> class MOS6532 {
timer_.value -= number_of_cycles;
} else {
number_of_cycles -= timer_.value;
timer_.value = 0x100 - number_of_cycles;
timer_.value = (0x100 - number_of_cycles) & 0xff;
timer_.activeShift = 0;
interrupt_status_ |= InterruptFlag::Timer;
evaluate_interrupts();

10
Machines/Atari2600/Atari2600.cpp
View File

@ -22,6 +22,7 @@ Machine::Machine() :
tia_input_value_{0xff, 0xff},
cycles_since_speaker_update_(0),
cycles_since_video_update_(0),
cycles_since_6532_update_(0),
frame_record_pointer_(0),
is_ntsc_(true)
{
@ -62,6 +63,7 @@ unsigned int Machine::perform_bus_operation(CPU6502::BusOperation operation, uin
cycles_since_speaker_update_ += cycles_run_for;
cycles_since_video_update_ += cycles_run_for;
cycles_since_6532_update_ += (cycles_run_for / 3);
if(operation != CPU6502::BusOperation::Ready) {
@ -203,6 +205,7 @@ unsigned int Machine::perform_bus_operation(CPU6502::BusOperation operation, uin
// check for a PIA access
if((address&0x1280) == 0x280) {
update_6532();
if(isReadOperation(operation)) {
returnValue &= mos6532_.get_register(address);
} else {
@ -216,7 +219,6 @@ unsigned int Machine::perform_bus_operation(CPU6502::BusOperation operation, uin
}
if(!tia_->get_cycles_until_horizontal_blank(cycles_since_video_update_)) set_ready_line(false);
mos6532_.run_for_cycles(cycles_run_for / 3);
return cycles_run_for / 3;
}
@ -321,6 +323,12 @@ void Machine::update_video()
cycles_since_video_update_ = 0;
}
void Machine::update_6532()
{
mos6532_.run_for_cycles(cycles_since_6532_update_);
cycles_since_6532_update_ = 0;
}
void Machine::synchronise()
{
update_audio();

8
Machines/Atari2600/Atari2600.hpp
View File

@ -77,11 +77,15 @@ class Machine:
// speaker backlog accumlation counter
unsigned int cycles_since_speaker_update_;
void update_audio();
inline void update_audio();
// video backlog accumulation counter
unsigned int cycles_since_video_update_;
void update_video();
inline void update_video();
// RIOT backlog accumulation counter
unsigned int cycles_since_6532_update_;
inline void update_6532();
// output frame rate tracker
struct FrameRecord

61
OSBindings/Mac/Clock SignalTests/6532Tests.swift
View File

@ -21,14 +21,25 @@ class MOS6532Tests: XCTestCase {
with6532 {
// set a count of 128 at single-clock intervals
$0.setValue(128, forRegister:0x14)
XCTAssertEqual($0.value(forRegister: 4), 128)
// run for one clock and the count should now be 127
// run for one more clock and the count should now be 127
$0.run(forCycles: 1)
XCTAssert($0.value(forRegister: 4) == 127, "A single tick should decrease the counter once")
XCTAssertEqual($0.value(forRegister: 4), 127)
// run for a further 200 clock counts; timer should reach -73 = 183
$0.run(forCycles: 200)
XCTAssert($0.value(forRegister: 4) == 183, "Timer should underflow and keep counting")
// run for 127 clocks and the timer should be zero, but the timer flag will not yet be set
$0.run(forCycles: 127)
XCTAssertEqual($0.value(forRegister: 5) & 0x80, 0)
XCTAssertEqual($0.value(forRegister: 4), 0)
// after one more cycle the counter should be 255 and the timer flag will now be set
$0.run(forCycles: 1)
XCTAssertEqual($0.value(forRegister: 5) & 0x80, 0x80)
XCTAssertEqual($0.value(forRegister: 4), 255)
// run for a further 55 clock counts; timer should reach -200
$0.run(forCycles: 55)
XCTAssertEqual($0.value(forRegister: 4), 200)
}
}
@ -37,26 +48,40 @@ class MOS6532Tests: XCTestCase {
with6532 {
// set a count of 28 at eight-clock intervals
$0.setValue(28, forRegister:0x15)
XCTAssertEqual($0.value(forRegister: 4), 28)
// run for seven clock and the count should still be 28
$0.run(forCycles: 7)
XCTAssert($0.value(forRegister: 4) == 28, "The timer should remain unchanged for seven clocks")
// run for a further clock and the count should now be 27
// one further cycle and the timer should hit 27
$0.run(forCycles: 1)
XCTAssert($0.value(forRegister: 4) == 27, "The timer should have decremented once after 8 cycles")
XCTAssertEqual($0.value(forRegister: 4), 27)
// run for a further 7 + 27*8 + 5 = 228 clock counts; timer should reach -5 = 0xfb
$0.run(forCycles: 228)
XCTAssert($0.value(forRegister: 4) == 0xfb, "Timer should underflow and start counting at single-clock pace")
// run for seven clock and the count should still be 27
$0.run(forCycles: 7)
XCTAssertEqual($0.value(forRegister: 4), 27)
// run for a further clock and the count should now be 26
$0.run(forCycles: 1)
XCTAssertEqual($0.value(forRegister: 4), 26)
// run for another 26 * 8 = 208 cycles and the count should hit zero without setting the timer flag, and
// stay there for seven more cycles
$0.run(forCycles: 208)
for _ in 0 ..< 8 {
XCTAssertEqual($0.value(forRegister: 5) & 0x80, 0)
XCTAssertEqual($0.value(forRegister: 4), 0)
$0.run(forCycles: 1)
}
// run six more, and the timer should reach 249, with the interrupt flag set
$0.run(forCycles: 6)
XCTAssertEqual($0.value(forRegister: 5) & 0x80, 0x80)
XCTAssertEqual($0.value(forRegister: 4), 249)
// timer should now resume dividing by eight
$0.run(forCycles: 7)
XCTAssert($0.value(forRegister: 4) == 0xfb, "Timer should remain unchanged for seven cycles")
XCTAssertEqual($0.value(forRegister: 4), 249)
// timer should now resume dividing by eight
$0.run(forCycles: 1)
XCTAssert($0.value(forRegister: 4) == 0xfa, "Timer should decrement after eighth cycle")
XCTAssertEqual($0.value(forRegister: 4), 248)
}
}
@ -64,8 +89,6 @@ class MOS6532Tests: XCTestCase {
with6532 {
// set a count of 1 at single-clock intervals
$0.setValue(1, forRegister:0x1c)
// run for one clock and the count should now be zero
$0.run(forCycles: 1)
// interrupt shouldn't be signalled yet, bit should not be set