apple2ix/src/timing.h

128 lines
3.2 KiB
C

/*
* Apple // emulator for *ix
*
* This software package is subject to the GNU General Public License
* version 3 or later (your choice) as published by the Free Software
* Foundation.
*
* Copyright 2013-2015 Aaron Culliney
*
*/
/*
* 65c02 CPU Timing Support.
*
*/
#ifndef _TIMING_H_
#define _TIMING_H_
#include "common.h"
#if !defined(NANOSECONDS_PER_SECOND)
#define NANOSECONDS_PER_SECOND 1000000000UL
#endif
// At a rate of ~1000x/sec, the emulator will (1) determine the number X of 65c02 instructions to execute and then
// executes them, (2) perform post-instruction-churn bookkeeping, and (3) sleep for a calculated interval.
//
// * The actual wall clock time to perform the emulated churn and bookkeeping is used to determine the sleep interval
//
// * The speaker provides feedback to the calculation of X (the number of instructions to churn)
#define EXECUTION_CHURN_RATE 1000UL
#define EXECUTION_PERIOD_NSECS 1000000UL // NANOSECONDS_PER_SECOND / EXECUTION_CHURN_RATE
// timing values cribbed from AppleWin ... reference: Sather's _Understanding the Apple IIe_
// TODO: revisit this if/when attempting to actually sync up VBL/VSYNC to actual device vsync
// 14318181.81...
#define _M14 (157500000.0 / 11.0)
#define _M14_INT (157500000 / 11)
// 65 cycles per 912 14M clocks = 1020484.45 ...
#define CLK_6502 ((_M14 * 65.0) / 912.0)
#define CLK_6502_INT ((_M14_INT * 65) / 912)
#define CPU_SCALE_SLOWEST 0.25
#define CPU_SCALE_FASTEST0 4.0
#define CPU_SCALE_FASTEST 4.05
#ifdef INTERFACE_CLASSIC
# define CPU_SCALE_STEP_DIV 0.01
# define CPU_SCALE_STEP 0.05
#endif
extern unsigned long long cycles_count_total;// cumulative cycles count from machine reset
extern double cycles_persec_target; // CLK_6502 * current CPU scale
extern int cycles_speaker_feedback; // current -/+ speaker requested feedback
extern double cpu_scale_factor; // scale factor #1
extern double cpu_altscale_factor; // scale factor #2
extern bool is_fullspeed; // emulation in full native speed?
extern bool alt_speed_enabled;
extern READONLY pthread_t cpu_thread_id;
/*
* calculate the difference between two timespec structures
*/
struct timespec timespec_diff(struct timespec start, struct timespec end, bool *negative);
/*
* start CPU thread
*/
void timing_startCPU(void);
/*
* stop CPU thread
*/
void timing_stopCPU(void);
/*
* toggles CPU speed between configured values
*/
void timing_toggleCPUSpeed(void);
#if !MOBILE_DEVICE
/*
* check whether automatic adjusting of CPU speed is configured.
*/
bool timing_shouldAutoAdjustSpeed(void);
#endif
/*
* initialize timing
*/
void timing_initialize(void);
#ifdef AUDIO_ENABLED
/*
* force audio reinitialization
*/
void timing_reinitializeAudio(void);
#endif
/*
* Pause timing/CPU thread.
*
* This may block for a short amount of time to grab the appropriate mutex. CPU thread is blocked upon function return,
* until call to cpu_resume() is made.
*/
void cpu_pause(void);
/*
* Resume timing/CPU thread
*/
void cpu_resume(void);
/*
* Is the CPU paused?
*/
bool cpu_isPaused(void);
/*
* checkpoints current cycle count and updates total (for timing-dependent I/O)
*/
void timing_checkpoint_cycles(void);
#endif // whole file