139 lines
3.6 KiB
C++
139 lines
3.6 KiB
C++
/////////////////////////////////////////////////////////////////////////
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// $Id: slowdown_timer.cc,v 1.6 2001-10-03 13:10:38 bdenney Exp $
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/////////////////////////////////////////////////////////////////////////
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//
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#include "bochs.h"
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#include <errno.h>
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#if BX_USE_SLOWDOWN_TIMER
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#define BX_HAVE_USLEEP 1
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//These need to stay printfs because they are useless in the log file.
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#define BX_SLOWDOWN_PRINTF_FEEDBACK 0
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#define SECINUSEC 1000000
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#define usectosec(a) ((a)/SECINUSEC)
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#define sectousec(a) ((a)*SECINUSEC)
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#define nsectousec(a) ((a)/1000)
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#if BX_HAVE_USLEEP
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# define Qval 10000
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#else
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# define Qval SECINUSEC
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#endif
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#define MAXMULT 1.5
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#define REALTIME_Q SECINUSEC
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bx_slowdown_timer_c bx_slowdown_timer;
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bx_slowdown_timer_c::bx_slowdown_timer_c() {
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s.start_time=0;
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s.start_emulated_time=0;
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s.timer_handle=BX_NULL_TIMER_HANDLE;
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}
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int
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bx_slowdown_timer_c::init() {
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s.MAXmultiplier=MAXMULT;
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s.Q=Qval;
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if(s.MAXmultiplier<1)
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s.MAXmultiplier=1;
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s.start_time=sectousec(time(NULL));
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s.start_emulated_time = bx_pc_system.time_usec();
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s.lasttime=0;
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s.timer_handle=bx_pc_system.register_timer(this, timer_handler, 100 , 1, 1);
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bx_pc_system.deactivate_timer(s.timer_handle);
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bx_pc_system.activate_timer(s.timer_handle,(Bit32u)s.Q,0);
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return 0;
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}
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void
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bx_slowdown_timer_c::timer_handler(void * this_ptr) {
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bx_slowdown_timer_c * class_ptr = (bx_slowdown_timer_c *) this_ptr;
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class_ptr->handle_timer();
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}
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void
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bx_slowdown_timer_c::handle_timer() {
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Bit64u total_emu_time = (bx_pc_system.time_usec()) - s.start_emulated_time;
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Bit64u wanttime = s.lasttime+s.Q;
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Bit64u totaltime = sectousec(time(NULL)) - s.start_time;
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Bit64u thistime=(wanttime>totaltime)?wanttime:totaltime;
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#if BX_SLOWDOWN_PRINTF_FEEDBACK
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printf("Entering slowdown timer handler.\n");
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#endif
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/* Decide if we're behind.
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* Set interrupt interval accordingly. */
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if(totaltime > total_emu_time) {
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bx_pc_system.deactivate_timer(s.timer_handle);
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bx_pc_system.activate_timer(s.timer_handle,
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(Bit32u)((Bit64u)
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(s.MAXmultiplier * (float)s.Q)),
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0);
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#if BX_SLOWDOWN_PRINTF_FEEDBACK
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printf("running at MAX speed\n");
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#endif
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} else {
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bx_pc_system.deactivate_timer(s.timer_handle);
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bx_pc_system.activate_timer(s.timer_handle,s.Q,0);
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#if BX_SLOWDOWN_PRINTF_FEEDBACK
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printf("running at NORMAL speed\n");
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#endif
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}
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/* Make sure we took at least one time quantum. */
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/* This is a little strange. I'll try to explain.
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* We're running bochs one second ahead of real time.
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* this gives us a very precise division on whether
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* we're ahead or behind the second line.
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* Basically, here's how it works:
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* *****|******************|***********...
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* Time Time+1sec
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* <^Bochs doesn't delay.
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* ^>Bochs delays.
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* <^Bochs runs at MAX speed.
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* ^>Bochs runs at normal
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*/
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if(wanttime > (totaltime+REALTIME_Q)) {
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#if BX_HAVE_USLEEP
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usleep(s.Q);
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#else
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sleep(usectosec(s.Q));
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#endif
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//delay(wanttime-totaltime);
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/*alternatively: delay(Q);
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* This works okay because we share the delay between
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* two time quantums.
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*/
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#if BX_SLOWDOWN_PRINTF_FEEDBACK
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printf("DELAYING for a quantum\n");
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#endif
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}
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s.lasttime=thistime;
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//Diagnostic info:
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if(wanttime > (totaltime+REALTIME_Q)) {
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if(totaltime > total_emu_time) {
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if(0) printf("Solving OpenBSD problem.\n");
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} else {
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if(0) printf("too fast.\n");
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}
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} else {
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if(totaltime > total_emu_time) {
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if(0) printf("too slow.\n");
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} else {
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if(0) printf("sometimes invalid state, normally okay.\n");
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}
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}
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}
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#endif
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