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Very minor: avoid division and modulus when unnecessary.

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This commit is contained in:
Thomas Harte 2022-06-03 15:39:29 -04:00
parent 3d059cb751
commit a61f7e38b6
1 changed files with 4 additions and 2 deletions
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6
Machines/Apple/Macintosh/Macintosh.cpp
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@ -50,6 +50,7 @@
namespace {
constexpr int CLOCK_RATE = 7833600;
constexpr auto KEYBOARD_CLOCK_RATE = HalfCycles(CLOCK_RATE / 100000);
// Former default PRAM:
@ -557,6 +558,7 @@ template <Analyser::Static::Macintosh::Target::Model model> class ConcreteMachin
// The VIA runs at one-tenth of the 68000's clock speed, in sync with the E clock.
// See: Guide to the Macintosh Hardware Family p149 (PDF p188). Some extra division
// may occur here in order to provide VSYNC at a proper moment.
// Possibly route vsync.
if(time_since_video_update_ < time_until_video_event_) {
via_clock_ += duration;
@ -586,8 +588,8 @@ template <Analyser::Static::Macintosh::Target::Model model> class ConcreteMachin
// The keyboard also has a clock, albeit a very slow one — 100,000 cycles/second.
// Its clock and data lines are connected to the VIA.
keyboard_clock_ += duration;
const auto keyboard_ticks = keyboard_clock_.divide(HalfCycles(CLOCK_RATE / 100000));
if(keyboard_ticks > HalfCycles(0)) {
if(keyboard_clock_ >= KEYBOARD_CLOCK_RATE) {
const auto keyboard_ticks = keyboard_clock_.divide(KEYBOARD_CLOCK_RATE);
keyboard_.run_for(keyboard_ticks);
via_.set_control_line_input(MOS::MOS6522::Port::B, MOS::MOS6522::Line::Two, keyboard_.get_data());
via_.set_control_line_input(MOS::MOS6522::Port::B, MOS::MOS6522::Line::One, keyboard_.get_clock());