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Attempted to simplify the logic behind the most common 6522 usage.
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@ -242,46 +242,61 @@ template <class T> class MOS6522 {
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*/
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inline void run_for_half_cycles(unsigned int number_of_cycles)
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{
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while(number_of_cycles--)
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#define phase2() \
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_registers.last_timer[0] = _registers.timer[0];\
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_registers.last_timer[1] = _registers.timer[1];\
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\
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if(_registers.timer_needs_reload)\
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{\
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_registers.timer_needs_reload = false;\
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_registers.timer[0] = _registers.timer_latch[0];\
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}\
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else\
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_registers.timer[0] --;\
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\
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_registers.timer[1] --;
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// IRQ is raised on the half cycle after overflow
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#define phase1() \
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if((_registers.timer[1] == 0xffff) && !_registers.last_timer[1] && _timer_is_running[1])\
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{\
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_timer_is_running[1] = false;\
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_registers.interrupt_flags |= InterruptFlag::Timer2;\
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reevaluate_interrupts();\
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}\
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\
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if((_registers.timer[0] == 0xffff) && !_registers.last_timer[0] && _timer_is_running[0])\
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{\
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_registers.interrupt_flags |= InterruptFlag::Timer1;\
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reevaluate_interrupts();\
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\
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if(_registers.auxiliary_control&0x40)\
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_registers.timer_needs_reload = true;\
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else\
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_timer_is_running[0] = false;\
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}
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if(_is_phase2)
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{
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if(_is_phase2)
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{
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_registers.last_timer[0] = _registers.timer[0];
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_registers.last_timer[1] = _registers.timer[1];
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phase2();
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number_of_cycles--;
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}
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if(_registers.timer_needs_reload)
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{
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_registers.timer_needs_reload = false;
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_registers.timer[0] = _registers.timer_latch[0];
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}
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else
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_registers.timer[0] --;
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while(number_of_cycles > 2)
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{
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phase1();
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phase2();
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number_of_cycles -= 2;
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}
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_registers.timer[1] --;
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}
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else
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{
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// IRQ is raised on the half cycle after overflow
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if((_registers.timer[1] == 0xffff) && !_registers.last_timer[1] && _timer_is_running[1])
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{
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_timer_is_running[1] = false;
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_registers.interrupt_flags |= InterruptFlag::Timer2;
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reevaluate_interrupts();
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}
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if((_registers.timer[0] == 0xffff) && !_registers.last_timer[0] && _timer_is_running[0])
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{
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_registers.interrupt_flags |= InterruptFlag::Timer1;
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reevaluate_interrupts();
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if(_registers.auxiliary_control&0x40)
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_registers.timer_needs_reload = true;
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else
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_timer_is_running[0] = false;
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}
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}
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_is_phase2 ^= true;
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if(number_of_cycles)
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{
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phase1();
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_is_phase2 = true;
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}
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else
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{
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_is_phase2 = false;
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}
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}
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@ -51,7 +51,7 @@ std::shared_ptr<Outputs::CRT::CRT> VideoOutput::get_crt()
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void VideoOutput::run_for_cycles(int number_of_cycles)
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{
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// Vertical: 0–39: pixels; otherwise blank; 48–53 sync
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// Vertical: 0–39: pixels; otherwise blank; 48–53 sync, 54–56 colour burst
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// Horizontal: 0–223: pixels; otherwise blank; 256–259 sync
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while(number_of_cycles--)
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@ -78,6 +78,7 @@ void VideoOutput::run_for_cycles(int number_of_cycles)
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}
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}
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State new_state = Blank;
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if(
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(h_counter >= 48 && h_counter <= 53) ||
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