6502/CLK
1
0
Fork 0
mirror of https://github.com/TomHarte/CLK.git synced 2025-01-27 06:35:04 +00:00
Code Issues Projects Releases Wiki Activity

Rationalises reload logic and cuts storage.

Browse Source 
Failure point is now chaining, I think.
This commit is contained in:
Thomas Harte 2021-08-02 20:14:01 -04:00
parent 77c627e822
commit 38848ca2db
3 changed files with 35 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
Components/6526/Implementation/6526Implementation.hpp
View File

@ -248,9 +248,9 @@ void MOS6526<BusHandlerT, personality>::run_for(const HalfCycles half_cycles) {
pending_ &= PendingClearMask;
// TODO: use CNT potentially to clock timer A, elimiante conditional above.
counter_[0].advance(false);
counter_[1].advance(counter_[0].hit_zero);
posit_interrupt((counter_[0].hit_zero ? 0x01 : 0x00) | (counter_[1].hit_zero ? 0x02 : 0x00));
const bool timer1_did_reload = counter_[0].advance(false);
const bool timer2_did_reload = counter_[1].advance(timer1_did_reload);
posit_interrupt((timer1_did_reload ? 0x01 : 0x00) | (timer2_did_reload ? 0x02 : 0x00));
}
}

42
Components/6526/Implementation/6526Storage.hpp
View File

@ -30,7 +30,6 @@ struct MOS6526Storage {
uint16_t reload = 0;
uint16_t value = 0;
uint8_t control = 0;
bool hit_zero = false;
template <int shift> void set_reload(uint8_t v) {
reload = (reload & (0xff00 >> shift)) | uint16_t(v << shift);
@ -46,16 +45,19 @@ struct MOS6526Storage {
control = v;
}
void advance(bool chained_input) {
bool advance(bool chained_input) {
// TODO: remove most of the conditionals here.
pending <<= 1;
//
// Apply feeder states inputs: anything that
// will take effect in the future.
//
if(control & 0x10) {
pending |= ReloadInOne;
control &= ~0x10;
}
if((control & 0x01) || chained_input) {
pending |= ApplyClockInTwo;
}
@ -63,24 +65,40 @@ struct MOS6526Storage {
pending |= OneShotInOne;
}
if((pending & ReloadNow) || (hit_zero && (pending & ApplyClockInTwo))) {
value = reload;
pending &= ~ApplyClockNow; // Skip one decrement.
}
//
// Perform a timer tick and decide whether a reload is prompted.
//
if(pending & ApplyClockNow) {
--value;
hit_zero = !value;
} else {
hit_zero = false;
}
const bool should_reload = !value && (pending & ApplyClockInOne);
// Schedule a reload if so ordered.
if(should_reload) {
pending |= ReloadNow; // Combine this decision with a deferred
// input from the force-reoad test above.
// If this was one-shot, stop.
if(pending&(OneShotInOne | OneShotNow)) {
control &= ~1;
pending &= ~(ApplyClockInOne|ApplyClockInTwo);
}
}
if(hit_zero && pending&(OneShotInOne | OneShotNow)) {
control &= ~1;
// Reload if scheduled.
if(pending & ReloadNow) {
value = reload;
pending &= ~ApplyClockInOne; // Skip one decrement.
}
//
// Clear any bits that would flow into the wrong field.
//
pending &= PendingClearMask;
return should_reload;
}
private:

4
OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj
View File

@ -6225,7 +6225,7 @@
CODE_SIGN_IDENTITY = "-";
CODE_SIGN_STYLE = Automatic;
DEVELOPMENT_TEAM = DV3346VVUN;
ENABLE_HARDENED_RUNTIME = YES;
ENABLE_HARDENED_RUNTIME = NO;
FRAMEWORK_SEARCH_PATHS = (
"$(inherited)",
"$(USER_LIBRARY_DIR)/Frameworks",
@ -6275,7 +6275,7 @@
CODE_SIGN_IDENTITY = "-";
CODE_SIGN_STYLE = Automatic;
DEVELOPMENT_TEAM = DV3346VVUN;
ENABLE_HARDENED_RUNTIME = YES;
ENABLE_HARDENED_RUNTIME = NO;
FRAMEWORK_SEARCH_PATHS = (
"$(inherited)",
"$(USER_LIBRARY_DIR)/Frameworks",