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7a5655edde
cpu.cpp: avoided the need for wrapper functions by calling the OS-specific function directly (declared in central header, implemented in the platform's cpp file) avoid the need for init in cpu and ia32 via if(!init) Init() pattern. optimized memcpy now requires SSE support remove error-prone CAS macro; replace with cpu_CAS config: no longer require inline asm for float->int conversions lib_error: remove special-case in CHECK_ERR for windows (no longer needed) This was SVN commit r5365.
85 lines
2 KiB
C++
85 lines
2 KiB
C++
/**
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* =========================================================================
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* File : tgt.cpp
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* Project : 0 A.D.
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* Description : Timer implementation using timeGetTime
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* =========================================================================
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*/
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// license: GPL; see lib/license.txt
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// note: WinMM is delay-loaded to avoid dragging it in when this timer
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// implementation isn't used. (this is relevant because its startup is
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// fairly slow)
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#include "precompiled.h"
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#include "tgt.h"
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#include "lib/sysdep/win/win.h"
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#include <mmsystem.h>
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#if MSC_VERSION
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#pragma comment(lib, "winmm.lib")
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#endif
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// "Guidelines For Providing Multimedia Timer Support" claims that
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// speeding the timer up to 2 ms has little impact, while 1 ms
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// causes significant slowdown.
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static const UINT PERIOD_MS = 2;
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LibError CounterTGT::Activate()
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{
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// note: timeGetTime is always available and cannot fail.
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MMRESULT ret = timeBeginPeriod(PERIOD_MS);
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debug_assert(ret == TIMERR_NOERROR);
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return INFO::OK;
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}
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void CounterTGT::Shutdown()
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{
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timeEndPeriod(PERIOD_MS);
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}
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bool CounterTGT::IsSafe() const
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{
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// the only point of criticism is the possibility of falling behind
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// due to lost interrupts. this can happen to any interrupt-based timer
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// and some systems may lack a counter-based timer, so consider TGT
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// 'safe'. note that it is still only chosen when all other timers fail.
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return true;
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}
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u64 CounterTGT::Counter() const
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{
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return timeGetTime();
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}
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/**
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* WHRT uses this to ensure the counter (running at nominal frequency)
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* doesn't overflow more than once during CALIBRATION_INTERVAL_MS.
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**/
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uint CounterTGT::CounterBits() const
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{
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return 32;
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}
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/**
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* initial measurement of the tick rate. not necessarily correct
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* (e.g. when using TSC: cpu_ClockFrequency isn't exact).
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**/
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double CounterTGT::NominalFrequency() const
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{
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return 1000.0;
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}
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/**
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* actual resolution [s]
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**/
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double CounterTGT::Resolution() const
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{
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return PERIOD_MS*1e-3;
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}
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