mirror of
https://github.com/mauiaaron/apple2.git
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412 lines
13 KiB
C
412 lines
13 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. Source inspired/derived from AppleWin.
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*
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* Simplified timing loop for each execution period:
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*
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* ..{...+....[....|..................|.........]....^....|....^....^....}......
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* ti MBB CHK CHK MBE CHX SPK MBX tj ZZZ
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*
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* - ti : timing sample begin (lock out interface thread)
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* - tj : timing sample end (unlock interface thread)
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* - [ : cpu65_run()
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* - ] : cpu65_run() finished
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* - CHK : incoming timing_checkpoint_cycles() call from IO (bumps cycles_count_total)
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* - CHX : update remainder of timing_checkpoint_cycles() for execution period
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* - MBB : Mockingboard begin
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* - MBE : Mockingboard end/flush (output)
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* - MBX : Mockingboard end video frame (output)
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* - SPK : Speaker output
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* - ZZZ : housekeeping+sleep (or not)
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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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#define DEBUG_TIMING (!defined(NDEBUG) && 0) // enable to print timing stats
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#if DEBUG_TIMING
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# define TIMING_LOG(...) LOG(__VA_ARGS__)
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#else
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# define TIMING_LOG(...)
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#endif
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#define DISK_MOTOR_QUIET_NSECS 2000000
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// VBL constants?
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#define uCyclesPerLine 65 // 25 cycles of HBL & 40 cycles of HBL'
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#define uVisibleLinesPerFrame (64*3) // 192
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#define uLinesPerFrame (262) // 64 in each third of the screen & 70 in VBL
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#define dwClksPerFrame (uCyclesPerLine * uLinesPerFrame) // 17030
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// cycle counting
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double cycles_persec_target = CLK_6502;
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unsigned long long cycles_count_total = 0;
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int cycles_speaker_feedback = 0;
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int32_t cpu65_cycles_to_execute = 0; // cycles-to-execute by cpu65_run()
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int32_t cpu65_cycle_count = 0; // cycles currently excuted by cpu65_run()
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static int32_t cycles_checkpoint_count = 0;
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static unsigned int g_dwCyclesThisFrame = 0;
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// scaling and speed adjustments
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static bool auto_adjust_speed = true;
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double cpu_scale_factor = 1.0;
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double cpu_altscale_factor = 1.0;
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bool is_fullspeed = false;
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static bool alt_speed_enabled = false;
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// misc
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volatile uint8_t emul_reinitialize = 0;
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pthread_t cpu_thread_id = 0;
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pthread_mutex_t interface_mutex = { 0 };
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pthread_cond_t dbg_thread_cond = PTHREAD_COND_INITIALIZER;
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pthread_cond_t cpu_thread_cond = PTHREAD_COND_INITIALIZER;
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// -----------------------------------------------------------------------------
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__attribute__((constructor))
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static void _init_timing(void) {
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pthread_mutexattr_t attr;
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pthread_mutexattr_init(&attr);
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#if !TESTING
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pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
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#endif
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pthread_mutex_init(&interface_mutex, &attr);
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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_PER_SECOND)
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{
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start.tv_sec += (start.tv_nsec / NANOSECONDS_PER_SECOND);
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start.tv_nsec %= NANOSECONDS_PER_SECOND;
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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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is_fullspeed = (scale >= CPU_SCALE_FASTEST);
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if (!is_fullspeed) {
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cycles_persec_target = CLK_6502 * scale;
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}
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#ifdef AUDIO_ENABLED
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speaker_reset();
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//TIMING_LOG("ClockRate:%0.2lf ClockCyclesPerSpeakerSample:%0.2lf", cycles_persec_target, speaker_cycles_per_sample());
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#endif
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}
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static inline void _lock_gui_thread(void) {
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if (pthread_self() != cpu_thread_id) {
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pthread_mutex_lock(&interface_mutex);
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}
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}
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static inline void _unlock_gui_thread(void) {
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if (pthread_self() != cpu_thread_id) {
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pthread_mutex_unlock(&interface_mutex);
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}
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}
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void timing_initialize(void) {
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_lock_gui_thread();
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_timing_initialize(alt_speed_enabled ? cpu_altscale_factor : cpu_scale_factor);
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_unlock_gui_thread();
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}
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void timing_toggle_cpu_speed(void) {
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_lock_gui_thread();
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alt_speed_enabled = !alt_speed_enabled;
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timing_initialize();
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_unlock_gui_thread();
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}
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void timing_set_auto_adjust_speed(bool auto_adjust) {
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_lock_gui_thread();
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auto_adjust_speed = auto_adjust;
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timing_initialize();
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_unlock_gui_thread();
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}
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bool timing_should_auto_adjust_speed(void) {
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double speed = alt_speed_enabled ? cpu_altscale_factor : cpu_scale_factor;
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return auto_adjust_speed && (speed < CPU_SCALE_FASTEST);
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}
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void *cpu_thread(void *dummyptr) {
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assert(pthread_self() == cpu_thread_id);
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#ifdef AUDIO_ENABLED
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DSInit();
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speaker_init();
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MB_Initialize();
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#endif
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reinitialize();
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struct timespec deltat;
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struct timespec disk_motor_time;
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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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int debugging_cycles0 = 0;
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int debugging_cycles = 0;
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#if DEBUG_TIMING
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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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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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if (!is_fullspeed) {
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TIMING_LOG("NOTE : serious divergence from target time ...");
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}
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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 = (cycles_persec_target / 1000); // cycles_persec_target * EXECUTION_PERIOD_NSECS / NANOSECONDS_PER_SECOND
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if (!is_fullspeed) {
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cpu65_cycles_to_execute += cycles_speaker_feedback;
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}
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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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#ifdef AUDIO_ENABLED
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MB_StartOfCpuExecute();
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#endif
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if (is_debugging) {
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debugging_cycles0 = cpu65_cycles_to_execute;
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debugging_cycles = cpu65_cycles_to_execute;
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}
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do {
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if (is_debugging) {
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cpu65_cycles_to_execute = 1;
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}
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cpu65_cycle_count = 0;
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cycles_checkpoint_count = 0;
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cpu65_run(); // run emulation for cpu65_cycles_to_execute cycles ...
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if (is_debugging) {
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debugging_cycles -= cpu65_cycle_count;
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if (c_debugger_should_break() || (debugging_cycles <= 0)) {
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int err = 0;
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if ((err = pthread_cond_signal(&dbg_thread_cond))) {
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ERRLOG("pthread_cond_signal : %d", err);
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}
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if ((err = pthread_cond_wait(&cpu_thread_cond, &interface_mutex))) {
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ERRLOG("pthread_cond_wait : %d", err);
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}
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if (debugging_cycles <= 0) {
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cpu65_cycle_count = debugging_cycles0 - debugging_cycles/*<=0*/;
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break;
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}
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}
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}
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if (emul_reinitialize) {
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reinitialize();
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}
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} while (is_debugging);
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#if DEBUG_TIMING
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dbg_cycles_executed += cpu65_cycle_count;
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#endif
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g_dwCyclesThisFrame += cpu65_cycle_count;
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#ifdef AUDIO_ENABLED
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MB_UpdateCycles(); // update 6522s (NOTE: do this before updating cycles_count_total)
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#endif
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timing_checkpoint_cycles();
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#if CPU_TRACING
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cpu65_trace_checkpoint();
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#endif
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#ifdef AUDIO_ENABLED
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speaker_flush(); // play audio
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#endif
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if (g_dwCyclesThisFrame >= dwClksPerFrame) {
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g_dwCyclesThisFrame -= dwClksPerFrame;
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#ifdef AUDIO_ENABLED
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MB_EndOfVideoFrame();
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#endif
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}
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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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if (timing_should_auto_adjust_speed()) {
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disk_motor_time = timespec_diff(disk6.motor_time, tj, &negative);
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assert(!negative);
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if (!is_fullspeed &&
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#ifdef AUDIO_ENABLED
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!speaker_is_active() &&
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#endif
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!video_dirty() && (!disk6.motor_off && (disk_motor_time.tv_sec || disk_motor_time.tv_nsec > DISK_MOTOR_QUIET_NSECS)) )
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{
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TIMING_LOG("auto switching to full speed");
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_timing_initialize(CPU_SCALE_FASTEST);
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}
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}
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if (!is_fullspeed) {
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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)
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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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TIMING_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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#if DEBUG_TIMING
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// collect timing statistics
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if (speaker_neg_feedback > cycles_speaker_feedback)
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{
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speaker_neg_feedback = cycles_speaker_feedback;
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}
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if (speaker_pos_feedback < cycles_speaker_feedback)
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{
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speaker_pos_feedback = cycles_speaker_feedback;
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}
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dbg_ticks += EXECUTION_PERIOD_NSECS;
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if ((dbg_ticks % NANOSECONDS_PER_SECOND) == 0)
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{
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TIMING_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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}
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if (timing_should_auto_adjust_speed()) {
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if (is_fullspeed && (
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#ifdef AUDIO_ENABLED
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speaker_is_active() ||
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#endif
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video_dirty() || (disk6.motor_off && (disk_motor_time.tv_sec || disk_motor_time.tv_nsec > DISK_MOTOR_QUIET_NSECS))) )
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{
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double speed = alt_speed_enabled ? cpu_altscale_factor : cpu_scale_factor;
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if (speed < CPU_SCALE_FASTEST) {
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TIMING_LOG("auto switching to configured speed");
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_timing_initialize(speed);
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}
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}
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}
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} while (!emul_reinitialize);
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reinitialize();
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} while (1);
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return NULL;
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}
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unsigned int CpuGetCyclesThisVideoFrame(void) {
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timing_checkpoint_cycles();
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return g_dwCyclesThisFrame + cycles_checkpoint_count;
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}
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// Called when an IO-reg is accessed & accurate global cycle count info is needed
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void timing_checkpoint_cycles(void) {
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assert(pthread_self() == cpu_thread_id);
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const int32_t d = cpu65_cycle_count - cycles_checkpoint_count;
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assert(d >= 0);
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cycles_count_total += d;
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cycles_checkpoint_count = cpu65_cycle_count;
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}
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