diff options
Diffstat (limited to 'distrib/sdl-1.2.12/src/timer/macos/FastTimes.c')
| -rw-r--r-- | distrib/sdl-1.2.12/src/timer/macos/FastTimes.c | 352 |
1 files changed, 0 insertions, 352 deletions
diff --git a/distrib/sdl-1.2.12/src/timer/macos/FastTimes.c b/distrib/sdl-1.2.12/src/timer/macos/FastTimes.c deleted file mode 100644 index 8eb4260..0000000 --- a/distrib/sdl-1.2.12/src/timer/macos/FastTimes.c +++ /dev/null @@ -1,352 +0,0 @@ -/* File "FastTimes.c" - Original code by Matt Slot <fprefect@ambrosiasw.com> */ -/* Created 4/24/99 - This file is hereby placed in the public domain */ -/* Updated 5/21/99 - Calibrate to VIA, add TBR support, renamed functions */ -/* Updated 10/4/99 - Use AbsoluteToNanoseconds() in case Absolute = double */ -/* Updated 2/15/00 - Check for native Time Manager, no need to calibrate */ -/* Updated 2/19/00 - Fixed default value for gScale under native Time Mgr */ -/* Updated 3/21/00 - Fixed ns conversion, create 2 different scale factors */ -/* Updated 5/03/00 - Added copyright and placed into PD. No code changes */ -/* Updated 8/01/00 - Made "Carbon-compatible" by replacing LMGetTicks() */ - -/* This file is Copyright (C) Matt Slot, 1999-2000. It is hereby placed into - the public domain. The author makes no warranty as to fitness or stability */ - -#include <Gestalt.h> -#include <LowMem.h> -#include <CodeFragments.h> -#include <DriverServices.h> -#include <Timer.h> - -#include "FastTimes.h" - -#ifdef TARGET_CPU_PPC -#undef GENERATINGPOWERPC /* stop whining */ -#define GENERATINGPOWERPC TARGET_CPU_PPC -#endif - -/* **** **** **** **** **** **** **** **** **** **** **** **** **** **** **** */ -/* **** **** **** **** **** **** **** **** **** **** **** **** **** **** **** */ -/* - On 680x0 machines, we just use Microseconds(). - - On PowerPC machines, we try several methods: - * DriverServicesLib is available on all PCI PowerMacs, and perhaps - some NuBus PowerMacs. If it is, we use UpTime() : Overhead = 2.1 µsec. - * The PowerPC 601 has a built-in "real time clock" RTC, and we fall - back to that, accessing it directly from asm. Overhead = 1.3 µsec. - * Later PowerPCs have an accurate "time base register" TBR, and we - fall back to that, access it from PowerPC asm. Overhead = 1.3 µsec. - * We can also try Microseconds() which is emulated : Overhead = 36 µsec. - - On PowerPC machines, we avoid the following: - * OpenTransport is available on all PCI and some NuBus PowerMacs, but it - uses UpTime() if available and falls back to Microseconds() otherwise. - * InputSprocket is available on many PowerMacs, but again it uses - UpTime() if available and falls back to Microseconds() otherwise. - - Another PowerPC note: certain configurations, especially 3rd party upgrade - cards, may return inaccurate timings for the CPU or memory bus -- causing - skew in various system routines (up to 20% drift!). The VIA chip is very - accurate, and it's the basis for the Time Manager and Microseconds(). - Unfortunately, it's also very slow because the MacOS has to (a) switch to - 68K and (b) poll for a VIA event. - - We compensate for the drift by calibrating a floating point scale factor - between our fast method and the accurate timer at startup, then convert - each sample quickly on the fly. I'd rather not have the initialization - overhead -- but it's simply necessary for accurate timing. You can drop - it down to 30 ticks if you prefer, but that's as low as I'd recommend. - - Under MacOS 9, "new world" Macs (iMacs, B+W G3s and G+W G4s) have a native - Time Manager implementation: UpTime(), Microseconds(), and TickCount() are - all based on the same underlying counter. This makes it silly to calibrate - UpTime() against TickCount(). We now check for this feature using Gestalt(), - and skip the whole calibration step if possible. - -*/ -/* **** **** **** **** **** **** **** **** **** **** **** **** **** **** **** */ -/* **** **** **** **** **** **** **** **** **** **** **** **** **** **** **** */ - -#define RTCToNano(w) ((double) (w).hi * 1000000000.0 + (double) (w).lo) -#define WideTo64bit(w) (*(UInt64 *) &(w)) - -/* LMGetTicks() is not in Carbon and TickCount() has a fair bit of overhead, - so for speed we always read lowmem directly. This is a Mac OS X no-no, but - it always work on those systems that don't have a native Time Manager (ie, - anything before MacOS 9) -- regardless whether we are in Carbon or not! */ -#define MyLMGetTicks() (*(volatile UInt32 *) 0x16A) - -#if GENERATINGPOWERPC - -static asm UnsignedWide PollRTC(void); -static asm UnsignedWide PollTBR(void); -static Ptr FindFunctionInSharedLib(StringPtr libName, StringPtr funcName); - -static Boolean gInited = false; -static Boolean gNative = false; -static Boolean gUseRTC = false; -static Boolean gUseTBR = false; -static double gScaleUSec = 1.0 / 1000.0; /* 1 / ( nsec / usec) */ -static double gScaleMSec = 1.0 / 1000000.0; /* 1 / ( nsec / msec) */ - -/* Functions loaded from DriverServicesLib */ -typedef AbsoluteTime (*UpTimeProcPtr)(void); -typedef Nanoseconds (*A2NSProcPtr)(AbsoluteTime); -static UpTimeProcPtr gUpTime = NULL; -static A2NSProcPtr gA2NS = NULL; - -#endif /* GENERATINGPOWERPC */ - -/* **** **** **** **** **** **** **** **** **** **** **** **** **** **** **** */ -/* **** **** **** **** **** **** **** **** **** **** **** **** **** **** **** */ - -void FastInitialize() { - SInt32 result; - - if (!gInited) { - -#if GENERATINGPOWERPC - - /* Initialize the feature flags */ - gNative = gUseRTC = gUseTBR = false; - - /* We use CFM to find and load needed symbols from shared libraries, so - the application doesn't have to weak-link them, for convenience. */ - gUpTime = (UpTimeProcPtr) FindFunctionInSharedLib( - "\pDriverServicesLib", "\pUpTime"); - if (gUpTime) gA2NS = (A2NSProcPtr) FindFunctionInSharedLib( - "\pDriverServicesLib", "\pAbsoluteToNanoseconds"); - if (!gA2NS) gUpTime = nil; /* Pedantic but necessary */ - - if (gUpTime) { - /* If we loaded UpTime(), then we need to know if the system has - a native implementation of the Time Manager. If so, then it's - pointless to calculate a scale factor against the missing VIA */ - - /* gestaltNativeTimeMgr = 4 in some future version of the headers */ - if (!Gestalt(gestaltTimeMgrVersion, &result) && - (result > gestaltExtendedTimeMgr)) - gNative = true; - } - else { - /* If no DriverServicesLib, use Gestalt() to get the processor type. - Only NuBus PowerMacs with old System Software won't have DSL, so - we know it should either be a 601 or 603. */ - - /* Use the processor gestalt to determine which register to use */ - if (!Gestalt(gestaltNativeCPUtype, &result)) { - if (result == gestaltCPU601) gUseRTC = true; - else if (result > gestaltCPU601) gUseTBR = true; - } - } - - /* Now calculate a scale factor to keep us accurate. */ - if ((gUpTime && !gNative) || gUseRTC || gUseTBR) { - UInt64 tick, usec1, usec2; - UnsignedWide wide; - - /* Wait for the beginning of the very next tick */ - for(tick = MyLMGetTicks() + 1; tick > MyLMGetTicks(); ); - - /* Poll the selected timer and prepare it (since we have time) */ - wide = (gUpTime) ? (*gA2NS)((*gUpTime)()) : - ((gUseRTC) ? PollRTC() : PollTBR()); - usec1 = (gUseRTC) ? RTCToNano(wide) : WideTo64bit(wide); - - /* Wait for the exact 60th tick to roll over */ - while(tick + 60 > MyLMGetTicks()); - - /* Poll the selected timer again and prepare it */ - wide = (gUpTime) ? (*gA2NS)((*gUpTime)()) : - ((gUseRTC) ? PollRTC() : PollTBR()); - usec2 = (gUseRTC) ? RTCToNano(wide) : WideTo64bit(wide); - - /* Calculate a scale value that will give microseconds per second. - Remember, there are actually 60.15 ticks in a second, not 60. */ - gScaleUSec = (60.0 * 1000000.0) / ((usec2 - usec1) * 60.15); - gScaleMSec = gScaleUSec / 1000.0; - } - -#endif /* GENERATINGPOWERPC */ - - /* We've initialized our globals */ - gInited = true; - } - } - -/* **** **** **** **** **** **** **** **** **** **** **** **** **** **** **** */ -/* **** **** **** **** **** **** **** **** **** **** **** **** **** **** **** */ - -UInt64 FastMicroseconds() { - UnsignedWide wide; - UInt64 usec; - -#if GENERATINGPOWERPC - /* Initialize globals the first time we are called */ - if (!gInited) FastInitialize(); - - if (gNative) { - /* Use DriverServices if it's available -- it's fast and compatible */ - wide = (*gA2NS)((*gUpTime)()); - usec = (double) WideTo64bit(wide) * gScaleUSec + 0.5; - } - else if (gUpTime) { - /* Use DriverServices if it's available -- it's fast and compatible */ - wide = (*gA2NS)((*gUpTime)()); - usec = (double) WideTo64bit(wide) * gScaleUSec + 0.5; - } - else if (gUseTBR) { - /* On a recent PowerPC, we poll the TBR directly */ - wide = PollTBR(); - usec = (double) WideTo64bit(wide) * gScaleUSec + 0.5; - } - else if (gUseRTC) { - /* On a 601, we can poll the RTC instead */ - wide = PollRTC(); - usec = (double) RTCToNano(wide) * gScaleUSec + 0.5; - } - else -#endif /* GENERATINGPOWERPC */ - { - /* If all else fails, suffer the mixed mode overhead */ - Microseconds(&wide); - usec = WideTo64bit(wide); - } - - return(usec); - } - -/* **** **** **** **** **** **** **** **** **** **** **** **** **** **** **** */ -/* **** **** **** **** **** **** **** **** **** **** **** **** **** **** **** */ - -UInt64 FastMilliseconds() { - UnsignedWide wide; - UInt64 msec; - -#if GENERATINGPOWERPC - /* Initialize globals the first time we are called */ - if (!gInited) FastInitialize(); - - if (gNative) { - /* Use DriverServices if it's available -- it's fast and compatible */ - wide = (*gA2NS)((*gUpTime)()); - msec = (double) WideTo64bit(wide) * gScaleMSec + 0.5; - } - else if (gUpTime) { - /* Use DriverServices if it's available -- it's fast and compatible */ - wide = (*gA2NS)((*gUpTime)()); - msec = (double) WideTo64bit(wide) * gScaleMSec + 0.5; - } - else if (gUseTBR) { - /* On a recent PowerPC, we poll the TBR directly */ - wide = PollTBR(); - msec = (double) WideTo64bit(wide) * gScaleMSec + 0.5; - } - else if (gUseRTC) { - /* On a 601, we can poll the RTC instead */ - wide = PollRTC(); - msec = (double) RTCToNano(wide) * gScaleMSec + 0.5; - } - else -#endif /* GENERATINGPOWERPC */ - { - /* If all else fails, suffer the mixed mode overhead */ - Microseconds(&wide); - msec = ((double) WideTo64bit(wide) + 500.0) / 1000.0; - } - - return(msec); - } - -/* **** **** **** **** **** **** **** **** **** **** **** **** **** **** **** */ -/* **** **** **** **** **** **** **** **** **** **** **** **** **** **** **** */ - -StringPtr FastMethod() { - StringPtr method = "\p<Unknown>"; - -#if GENERATINGPOWERPC - /* Initialize globals the first time we are called */ - if (!gInited) FastInitialize(); - - if (gNative) { - /* The Time Manager and UpTime() are entirely native on this machine */ - method = "\pNative UpTime()"; - } - else if (gUpTime) { - /* Use DriverServices if it's available -- it's fast and compatible */ - method = "\pUpTime()"; - } - else if (gUseTBR) { - /* On a recent PowerPC, we poll the TBR directly */ - method = "\pPowerPC TBR"; - } - else if (gUseRTC) { - /* On a 601, we can poll the RTC instead */ - method = "\pPowerPC RTC"; - } - else -#endif /* GENERATINGPOWERPC */ - { - /* If all else fails, suffer the mixed mode overhead */ - method = "\pMicroseconds()"; - } - - return(method); - } - -/* **** **** **** **** **** **** **** **** **** **** **** **** **** **** **** */ -/* **** **** **** **** **** **** **** **** **** **** **** **** **** **** **** */ -#pragma mark - - -#if GENERATINGPOWERPC -asm static UnsignedWide PollRTC_() { -entry PollRTC /* Avoid CodeWarrior glue */ - machine 601 -@AGAIN: - mfrtcu r4 /* RTCU = SPR 4 */ - mfrtcl r5 /* RTCL = SPR 5 */ - mfrtcu r6 - cmpw r4,r6 - bne @AGAIN - stw r4,0(r3) - stw r5,4(r3) - blr - } - -/* **** **** **** **** **** **** **** **** **** **** **** **** **** **** **** */ -/* **** **** **** **** **** **** **** **** **** **** **** **** **** **** **** */ - -asm static UnsignedWide PollTBR_() { -entry PollTBR /* Avoid CodeWarrior glue */ - machine 604 -@AGAIN: - mftbu r4 /* TBRU = SPR 268 */ - mftb r5 /* TBRL = SPR 269 */ - mftbu r6 - cmpw r4,r6 - bne @AGAIN - stw r4,0(r3) - stw r5,4(r3) - blr - } - -/* **** **** **** **** **** **** **** **** **** **** **** **** **** **** **** */ -/* **** **** **** **** **** **** **** **** **** **** **** **** **** **** **** */ - -static Ptr FindFunctionInSharedLib(StringPtr libName, StringPtr funcName) { - OSErr error = noErr; - Str255 errorStr; - Ptr func = NULL; - Ptr entry = NULL; - CFragSymbolClass symClass; - CFragConnectionID connID; - - /* Find CFM containers for the current archecture -- CFM-PPC or CFM-68K */ - if (/* error = */ GetSharedLibrary(libName, kCompiledCFragArch, - kLoadCFrag, &connID, &entry, errorStr)) return(NULL); - if (/* error = */ FindSymbol(connID, funcName, &func, &symClass)) - return(NULL); - - return(func); - } -#endif /* GENERATINGPOWERPC */ |