308 lines
8.9 KiB
C
308 lines
8.9 KiB
C
/*
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* Apple // emulator for *nix
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*
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* This software package is subject to the GNU General Public License
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* version 2 or later (your choice) as published by the Free Software
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* Foundation.
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*
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* THERE ARE NO WARRANTIES WHATSOEVER.
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*
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*/
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/*
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* 65c02 CPU Timing Support. Some source derived from AppleWin.
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*
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* Copyleft 2013 Aaron Culliney
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*
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*/
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#include "common.h"
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#define EXECUTION_PERIOD_NSECS 1000000 // AppleWin: nExecutionPeriodUsec
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double g_fCurrentCLK6502 = CLK_6502;
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bool g_bFullSpeed = false; // HACK TODO FIXME : prolly shouldn't be global anymore -- don't think it's necessary for speaker/soundcore/etc anymore ...
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uint64_t g_nCumulativeCycles = 0; // cumulative cycles since emulator (re)start
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int g_nCpuCyclesFeedback = 0;
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static bool alt_speed_enabled = false;
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double cpu_scale_factor = 1.0;
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double cpu_altscale_factor = 1.0;
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int gc_cycles_timer_0 = 0;
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int gc_cycles_timer_1 = 0;
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uint8_t emul_reinitialize;
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static unsigned int g_nCyclesExecuted; // # of cycles executed up to last IO access
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// -----------------------------------------------------------------------------
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struct timespec timespec_diff(struct timespec start, struct timespec end, bool *negative) {
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struct timespec t;
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if (negative)
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{
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*negative = false;
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}
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// if start > end, swizzle...
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if ( (start.tv_sec > end.tv_sec) || ((start.tv_sec == end.tv_sec) && (start.tv_nsec > end.tv_nsec)) )
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{
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t=start;
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start=end;
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end=t;
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if (negative)
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{
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*negative = true;
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}
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}
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// assuming time_t is signed ...
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if (end.tv_nsec < start.tv_nsec)
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{
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t.tv_sec = end.tv_sec - start.tv_sec - 1;
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t.tv_nsec = 1000000000 + end.tv_nsec - start.tv_nsec;
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}
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else
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{
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t.tv_sec = end.tv_sec - start.tv_sec;
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t.tv_nsec = end.tv_nsec - start.tv_nsec;
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}
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return t;
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}
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static inline struct timespec timespec_add(struct timespec start, unsigned long nsecs) {
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start.tv_nsec += nsecs;
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if (start.tv_nsec > NANOSECONDS)
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{
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start.tv_sec += (start.tv_nsec / NANOSECONDS);
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start.tv_nsec %= NANOSECONDS;
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}
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return start;
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}
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static void _timing_initialize(double scale)
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{
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if (g_bFullSpeed)
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{
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LOG("timing_initialize() emulation at fullspeed ...");
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return;
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}
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g_fCurrentCLK6502 = CLK_6502 * scale;
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// this is extracted out of SetClksPerSpkrSample -- speaker.c
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g_fClksPerSpkrSample = (double) (UINT) (g_fCurrentCLK6502 / (double)SPKR_SAMPLE_RATE);
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SpkrReinitialize();
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LOG("timing_initialize() ... ClockRate:%0.2lf ClockCyclesPerSpeakerSample:%0.2lf", g_fCurrentCLK6502, g_fClksPerSpkrSample);
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}
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static void _switch_to_fullspeed(double scale)
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{
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if (!g_bFullSpeed)
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{
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g_bFullSpeed = true;
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c_disable_sound_hooks();
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}
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}
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static void _switch_to_regular_speed(double scale)
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{
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if (g_bFullSpeed)
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{
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g_bFullSpeed = false;
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c_initialize_sound_hooks();
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}
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_timing_initialize(scale);
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}
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void timing_toggle_cpu_speed()
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{
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alt_speed_enabled = !alt_speed_enabled;
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if (alt_speed_enabled)
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{
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if (cpu_altscale_factor >= CPU_SCALE_FASTEST)
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{
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_switch_to_fullspeed(cpu_altscale_factor);
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}
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else
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{
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_switch_to_regular_speed(cpu_altscale_factor);
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}
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}
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else
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{
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if (cpu_scale_factor >= CPU_SCALE_FASTEST)
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{
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_switch_to_fullspeed(cpu_scale_factor);
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}
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else
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{
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_switch_to_regular_speed(cpu_scale_factor);
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}
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}
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}
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void timing_initialize()
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{
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_timing_initialize(cpu_scale_factor);
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}
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void cpu_thread(void *dummyptr) {
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struct timespec deltat;
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struct timespec t0; // the target timer
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struct timespec ti, tj; // actual time samples
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bool negative = false;
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long drift_adj_nsecs = 0; // generic drift adjustment between target and actual
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#ifndef NDEBUG
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unsigned long dbg_ticks = 0;
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int speaker_neg_feedback = 0;
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int speaker_pos_feedback = 0;
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unsigned int dbg_cycles_executed = 0;
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#endif
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do
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{
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g_nCumulativeCycles = 0;
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static int16_t cycles_adjust = 0;
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LOG("cpu_thread : begin main loop ...");
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clock_gettime(CLOCK_MONOTONIC, &t0);
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emul_reinitialize = 1;
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do {
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// -LOCK----------------------------------------------------------------------------------------- SAMPLE ti
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pthread_mutex_lock(&interface_mutex);
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clock_gettime(CLOCK_MONOTONIC, &ti);
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deltat = timespec_diff(t0, ti, &negative);
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if (deltat.tv_sec)
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{
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// TODO FIXME : this is innocuous when coming out of interface menus, but are there any other edge cases?
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LOG("NOTE : serious divergence from target time ...");
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t0 = ti;
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deltat = timespec_diff(t0, ti, &negative);
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}
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t0 = timespec_add(t0, EXECUTION_PERIOD_NSECS); // expected interval
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drift_adj_nsecs = negative ? ~deltat.tv_nsec : deltat.tv_nsec;
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// set up increment & decrement counters
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cpu65_cycles_to_execute = (g_fCurrentCLK6502 / 1000); // g_fCurrentCLK6502 * EXECUTION_PERIOD_NSECS / NANOSECONDS
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cpu65_cycles_to_execute += g_nCpuCyclesFeedback;
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cpu65_cycles_to_execute -= cycles_adjust;
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if (cpu65_cycles_to_execute < 0)
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{
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cpu65_cycles_to_execute = 0;
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}
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cpu65_cycle_count = 0;
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g_nCyclesExecuted = 0;
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#ifdef AUDIO_ENABLED
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MB_StartOfCpuExecute();
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#endif
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cpu65_run(); // run emulation for cpu65_cycles_to_execute cycles ...
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cycles_adjust = cpu65_cycles_to_execute; // counter is decremented in cpu65_run()
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if (cycles_adjust < 0)
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{
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cycles_adjust = ~cycles_adjust +1; // cycles_adjust *= -1
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}
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#ifndef NDEBUG
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dbg_cycles_executed += cpu65_cycle_count;
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#endif
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unsigned int uExecutedCycles = cpu65_cycle_count;
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#ifdef AUDIO_ENABLED
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MB_UpdateCycles(uExecutedCycles); // Update 6522s (NB. Do this before updating g_nCumulativeCycles below)
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// N.B.: IO calls that depend on accurate timing will update g_nCyclesExecuted
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const unsigned int nRemainingCycles = uExecutedCycles - g_nCyclesExecuted;
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g_nCumulativeCycles += nRemainingCycles;
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if (!g_bFullSpeed)
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{
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SpkrUpdate(uExecutedCycles); // play audio
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}
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// N.B.: technically this is not the end of the video frame...
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MB_EndOfVideoFrame();
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#endif
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clock_gettime(CLOCK_MONOTONIC, &tj);
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pthread_mutex_unlock(&interface_mutex);
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// -UNLOCK--------------------------------------------------------------------------------------- SAMPLE tj
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deltat = timespec_diff(ti, tj, &negative);
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assert(!negative);
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long sleepfor = 0;
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if (!deltat.tv_sec && !g_bFullSpeed)
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{
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sleepfor = EXECUTION_PERIOD_NSECS - drift_adj_nsecs - deltat.tv_nsec;
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}
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if (sleepfor <= 0)
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{
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// lagging ...
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static time_t throttle_warning = 0;
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if (t0.tv_sec - throttle_warning > 0)
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{
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LOG("lagging... %ld . %ld", deltat.tv_sec, deltat.tv_nsec);
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throttle_warning = t0.tv_sec;
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}
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}
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else
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{
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deltat.tv_sec = 0;
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deltat.tv_nsec = sleepfor;
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nanosleep(&deltat, NULL);
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}
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#ifndef NDEBUG
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// collect timing statistics
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if (speaker_neg_feedback > g_nCpuCyclesFeedback)
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{
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speaker_neg_feedback = g_nCpuCyclesFeedback;
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}
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if (speaker_pos_feedback < g_nCpuCyclesFeedback)
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{
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speaker_pos_feedback = g_nCpuCyclesFeedback;
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}
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dbg_ticks += EXECUTION_PERIOD_NSECS;
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if ((dbg_ticks % NANOSECONDS) == 0)
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{
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LOG("tick:(%ld.%ld) real:(%ld.%ld) cycles exe: %d ... speaker feedback: %d/%d", t0.tv_sec, t0.tv_nsec, ti.tv_sec, ti.tv_nsec, dbg_cycles_executed, speaker_neg_feedback, speaker_pos_feedback);
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dbg_cycles_executed = 0;
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dbg_ticks = 0;
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speaker_neg_feedback = 0;
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speaker_pos_feedback = 0;
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}
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#endif
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} while (!emul_reinitialize);
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reinitialize();
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} while (1);
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}
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// From AppleWin...
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// Called when an IO-reg is accessed & accurate cycle info is needed
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void CpuCalcCycles(const unsigned long nExecutedCycles)
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{
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// Calc # of cycles executed since this func was last called
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const long nCycles = nExecutedCycles - g_nCyclesExecuted;
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assert(nCycles >= 0);
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g_nCumulativeCycles += nCycles;
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g_nCyclesExecuted = nExecutedCycles;
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}
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