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Attempted to simplify the logic behind the most common 6522 usage.

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This commit is contained in:
Thomas Harte 2016-10-27 21:06:31 -04:00
parent e5fe37f089
commit 2eda0b3c86
2 changed files with 54 additions and 38 deletions
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89
Components/6522/6522.hpp
View File

@ -242,46 +242,61 @@ template <class T> class MOS6522 {
*/
inline void run_for_half_cycles(unsigned int number_of_cycles)
{
while(number_of_cycles--)
#define phase2() \
_registers.last_timer[0] = _registers.timer[0];\
_registers.last_timer[1] = _registers.timer[1];\
\
if(_registers.timer_needs_reload)\
{\
_registers.timer_needs_reload = false;\
_registers.timer[0] = _registers.timer_latch[0];\
}\
else\
_registers.timer[0] --;\
\
_registers.timer[1] --;
// IRQ is raised on the half cycle after overflow
#define phase1() \
if((_registers.timer[1] == 0xffff) && !_registers.last_timer[1] && _timer_is_running[1])\
{\
_timer_is_running[1] = false;\
_registers.interrupt_flags |= InterruptFlag::Timer2;\
reevaluate_interrupts();\
}\
\
if((_registers.timer[0] == 0xffff) && !_registers.last_timer[0] && _timer_is_running[0])\
{\
_registers.interrupt_flags |= InterruptFlag::Timer1;\
reevaluate_interrupts();\
\
if(_registers.auxiliary_control&0x40)\
_registers.timer_needs_reload = true;\
else\
_timer_is_running[0] = false;\
}
if(_is_phase2)
{
if(_is_phase2)
{
_registers.last_timer[0] = _registers.timer[0];
_registers.last_timer[1] = _registers.timer[1];
phase2();
number_of_cycles--;
}
if(_registers.timer_needs_reload)
{
_registers.timer_needs_reload = false;
_registers.timer[0] = _registers.timer_latch[0];
}
else
_registers.timer[0] --;
while(number_of_cycles > 2)
{
phase1();
phase2();
number_of_cycles -= 2;
}
_registers.timer[1] --;
}
else
{
// IRQ is raised on the half cycle after overflow
if((_registers.timer[1] == 0xffff) && !_registers.last_timer[1] && _timer_is_running[1])
{
_timer_is_running[1] = false;
_registers.interrupt_flags |= InterruptFlag::Timer2;
reevaluate_interrupts();
}
if((_registers.timer[0] == 0xffff) && !_registers.last_timer[0] && _timer_is_running[0])
{
_registers.interrupt_flags |= InterruptFlag::Timer1;
reevaluate_interrupts();
if(_registers.auxiliary_control&0x40)
_registers.timer_needs_reload = true;
else
_timer_is_running[0] = false;
}
}
_is_phase2 ^= true;
if(number_of_cycles)
{
phase1();
_is_phase2 = true;
}
else
{
_is_phase2 = false;
}
}

3
Machines/Oric/Video.cpp
View File

@ -51,7 +51,7 @@ std::shared_ptr<Outputs::CRT::CRT> VideoOutput::get_crt()
void VideoOutput::run_for_cycles(int number_of_cycles)
{
// Vertical: 0–39: pixels; otherwise blank; 48–53 sync
// Vertical: 0–39: pixels; otherwise blank; 48–53 sync, 54–56 colour burst
// Horizontal: 0–223: pixels; otherwise blank; 256–259 sync
while(number_of_cycles--)
@ -78,6 +78,7 @@ void VideoOutput::run_for_cycles(int number_of_cycles)
}
}
State new_state = Blank;
if(
(h_counter >= 48 && h_counter <= 53) ||