64 lines
1.9 KiB
C
64 lines
1.9 KiB
C
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/***
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*testfdiv.c - routine to test for correct operation of x86 FDIV instruction.
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*
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* Copyright (c) 1994-2001, Microsoft Corporation. All rights reserved.
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*
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*Purpose:
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* Detects early steppings of Pentium with incorrect FDIV tables using
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* 'official' Intel test values. Returns 1 if flawed Pentium is detected,
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* 0 otherwise.
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*
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*Revision History:
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* 12-19-94 JWM file added
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* 12-22-94 JWM Now safe for TNT, et al
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* 01-13-95 JWM underscores added for ANSI compatibility
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* 12-12-95 SKS Skip redundant Pentium test on uni-processor systems
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* 12-13-95 SKS Call LoadLibrary() rather than GetModuleHandle()
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* since "kernel32.dll" is always going to be present.
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* 01-18-96 JWM Now handles possible failure of SetThreadAffinityMask(),
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* incorporating various suggestions of MarkL.
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* 05-29-96 JWM No longer loops through affinity mask; instead, uses MarkL's
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* new IsProcessorFeaturePresent() API if possible, only tests
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* 1st processor if not.
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*
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*******************************************************************************/
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#include <windows.h>
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int _ms_p5_test_fdiv(void)
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{
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double dTestDivisor = 3145727.0;
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double dTestDividend = 4195835.0;
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double dRslt;
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_asm {
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fld qword ptr [dTestDividend]
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fdiv qword ptr [dTestDivisor]
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fmul qword ptr [dTestDivisor]
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fsubr qword ptr [dTestDividend]
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fstp qword ptr [dRslt]
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}
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return (dRslt > 1.0);
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}
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/*
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* Multiprocessor Pentium test: returns 1 if any processor is a flawed
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* Pentium, 0 otherwise.
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*/
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int _ms_p5_mp_test_fdiv(void)
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{
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#define PF_FLOATING_POINT_PRECISION_ERRATA 0
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HINSTANCE LibInst;
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FARPROC pIsProcessorFeaturePresent;
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if ((LibInst = GetModuleHandle("KERNEL32")) &&
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(pIsProcessorFeaturePresent = GetProcAddress(LibInst, "IsProcessorFeaturePresent")))
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return (*pIsProcessorFeaturePresent)(PF_FLOATING_POINT_PRECISION_ERRATA);
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else
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return _ms_p5_test_fdiv();
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}
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