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https://gitea.wildfiregames.com/0ad/0ad
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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.
92 lines
2.5 KiB
C++
92 lines
2.5 KiB
C++
/**
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* =========================================================================
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* File : pmt.cpp
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* Project : 0 A.D.
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* Description : Timer implementation using ACPI PM timer
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* =========================================================================
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*/
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// license: GPL; see lib/license.txt
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#include "precompiled.h"
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#include "pmt.h"
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#include "lib/sysdep/win/win.h"
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#include "lib/sysdep/acpi.h"
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#include "lib/sysdep/win/mahaf.h"
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#include "lib/bits.h"
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#pragma pack(push,1)
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struct FADT
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{
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AcpiTable header;
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u8 unused[40];
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u32 pmTimerPortAddress;
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u8 unused2[32];
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u32 flags;
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};
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#pragma pack(pop)
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static const u32 TMR_VAL_EXT = BIT(8);
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//-----------------------------------------------------------------------------
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LibError CounterPMT::Activate()
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{
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// mahaf is needed for port I/O.
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if(!mahaf_Init())
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return ERR::FAIL; // NOWARN (no Administrator privileges)
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if(!acpi_Init())
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return ERR::FAIL; // NOWARN (happens on Win2k; see mahaf_IsPhysicalMappingDangerous)
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// (note: it's called FADT, but the signature is "FACP")
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const FADT* fadt = (const FADT*)acpi_GetTable("FACP");
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if(!fadt)
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WARN_RETURN(ERR::NO_SYS);
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m_portAddress = u16_from_larger(fadt->pmTimerPortAddress);
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return INFO::OK;
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}
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void CounterPMT::Shutdown()
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{
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acpi_Shutdown();
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mahaf_Shutdown();
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}
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bool CounterPMT::IsSafe() const
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{
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// the PMT has one issue: "Performance counter value may unexpectedly
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// leap forward" (Q274323). This happens on some buggy Pentium-era
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// systems under heavy PCI bus load. We are clever and observe that
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// the TSC implementation would be used on such systems (because it
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// has higher precedence and is safe on P5 CPUs), so the PMT is fine
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// in general.
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return true;
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}
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u64 CounterPMT::Counter() const
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{
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return mahaf_ReadPort32(m_portAddress);
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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 CounterPMT::CounterBits() const
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{
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// (see previous acpi_GetTable call)
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const FADT* fadt = (const FADT*)acpi_GetTable("FACP");
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debug_assert(fadt); // Activate made sure FADT is available
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const uint counterBits = (fadt->flags & TMR_VAL_EXT)? 32 : 24;
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return counterBits;
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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 CounterPMT::NominalFrequency() const
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{
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return (double)PMT_FREQ;
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}
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