mirror of
https://gitea.wildfiregames.com/0ad/0ad
synced 2026-06-19 14:53:56 -07:00
a3696c0b91
lib/sysdep: clean up by moving OS and cpu-arch folders into "os" and "arch" folders This was SVN commit r6162.
92 lines
2.5 KiB
C++
92 lines
2.5 KiB
C++
/**
|
|
* =========================================================================
|
|
* File : pmt.cpp
|
|
* Project : 0 A.D.
|
|
* Description : Timer implementation using ACPI PM timer
|
|
* =========================================================================
|
|
*/
|
|
|
|
// license: GPL; see lib/license.txt
|
|
|
|
#include "precompiled.h"
|
|
#include "pmt.h"
|
|
|
|
#include "lib/sysdep/os/win/win.h"
|
|
#include "lib/sysdep/acpi.h"
|
|
#include "lib/sysdep/os/win/mahaf.h"
|
|
#include "lib/bits.h"
|
|
|
|
#pragma pack(push,1)
|
|
struct FADT
|
|
{
|
|
AcpiTable header;
|
|
u8 unused[40];
|
|
u32 pmTimerPortAddress;
|
|
u8 unused2[32];
|
|
u32 flags;
|
|
};
|
|
#pragma pack(pop)
|
|
|
|
static const u32 TMR_VAL_EXT = BIT(8);
|
|
|
|
//-----------------------------------------------------------------------------
|
|
|
|
LibError CounterPMT::Activate()
|
|
{
|
|
// mahaf is needed for port I/O.
|
|
if(!mahaf_Init())
|
|
return ERR::FAIL; // NOWARN (no Administrator privileges)
|
|
if(!acpi_Init())
|
|
return ERR::FAIL; // NOWARN (happens on Win2k; see mahaf_IsPhysicalMappingDangerous)
|
|
// (note: it's called FADT, but the signature is "FACP")
|
|
const FADT* fadt = (const FADT*)acpi_GetTable("FACP");
|
|
if(!fadt)
|
|
WARN_RETURN(ERR::NO_SYS);
|
|
m_portAddress = u16_from_larger(fadt->pmTimerPortAddress);
|
|
|
|
return INFO::OK;
|
|
}
|
|
|
|
void CounterPMT::Shutdown()
|
|
{
|
|
acpi_Shutdown();
|
|
mahaf_Shutdown();
|
|
}
|
|
|
|
bool CounterPMT::IsSafe() const
|
|
{
|
|
// the PMT has one issue: "Performance counter value may unexpectedly
|
|
// leap forward" (Q274323). This happens on some buggy Pentium-era
|
|
// systems under heavy PCI bus load. We are clever and observe that
|
|
// the TSC implementation would be used on such systems (because it
|
|
// has higher precedence and is safe on P5 CPUs), so the PMT is fine
|
|
// in general.
|
|
return true;
|
|
}
|
|
|
|
u64 CounterPMT::Counter() const
|
|
{
|
|
return mahaf_ReadPort32(m_portAddress);
|
|
}
|
|
|
|
/**
|
|
* WHRT uses this to ensure the counter (running at nominal frequency)
|
|
* doesn't overflow more than once during CALIBRATION_INTERVAL_MS.
|
|
**/
|
|
size_t CounterPMT::CounterBits() const
|
|
{
|
|
// (see previous acpi_GetTable call)
|
|
const FADT* fadt = (const FADT*)acpi_GetTable("FACP");
|
|
debug_assert(fadt); // Activate made sure FADT is available
|
|
const size_t counterBits = (fadt->flags & TMR_VAL_EXT)? 32 : 24;
|
|
return counterBits;
|
|
}
|
|
|
|
/**
|
|
* initial measurement of the tick rate. not necessarily correct
|
|
* (e.g. when using TSC: os_cpu_ClockFrequency isn't exact).
|
|
**/
|
|
double CounterPMT::NominalFrequency() const
|
|
{
|
|
return (double)PMT_FREQ;
|
|
}
|