87 lines
2.2 KiB
C
87 lines
2.2 KiB
C
/***
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*modf.c - modf()
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*
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* Copyright (c) 1991-2001, Microsoft Corporation. All rights reserved.
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*
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*Purpose:
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*
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*Revision History:
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* 8-24-91 GDP written
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* 1-13-92 GDP support IEEE exceptions
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* 6-23-92 GDP modified special return values for NCEG conformance
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* 02-06-95 JWM Mac merge
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* 01-26-01 PML Pentium4 merge
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* 02-28-01 PML Make sure 0.0 fraction return has correct sign
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*
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*******************************************************************************/
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#include <math.h>
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#include <trans.h>
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#include <float.h>
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extern double _frnd(double);
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extern double _copysign (double x, double y);
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/***
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*double modf(double x, double *intptr)
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*
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*Purpose:
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* Split x into fractional and integer part
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* The signed fractional portion is returned
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* The integer portion is stored as a floating point value at intptr
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*
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*Entry:
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*
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*Exit:
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*
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*Exceptions:
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* I
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*******************************************************************************/
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static uintptr_t newcw = (ICW & ~IMCW_RC) | (IRC_CHOP & IMCW_RC);
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#if !defined(_M_IX86)
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double modf(double x, double *intptr)
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#else
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double _modf_default(double x, double *intptr)
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#endif
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{
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uintptr_t savedcw;
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double result,intpart;
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/* save user fp control word */
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savedcw = _ctrlfp(0, 0); /* get old control word */
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_ctrlfp(newcw,IMCW); /* round towards 0 */
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/* check for infinity or NAN */
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if (IS_D_SPECIAL(x)){
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*intptr = QNAN_MODF;
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switch (_sptype(x)) {
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case T_PINF:
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case T_NINF:
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*intptr = x;
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result = _copysign(0, x);
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RETURN(savedcw,result);
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case T_QNAN:
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*intptr = x;
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return _handle_qnan1(OP_MODF, x, savedcw);
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default: //T_SNAN
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result = _s2qnan(x);
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*intptr = result;
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return _except1(FP_I, OP_MODF, x, result, savedcw);
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}
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}
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intpart = _frnd(x); //fix needed: this may set the P exception flag
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//and pollute the fp status word
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*intptr = intpart;
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result = x - intpart;
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if (result == 0.0) {
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/* Make sure fractional part of 0.0 has the correct sign */
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*D_EXP(result) |= (*D_EXP(x) & 0x8000);
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}
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RETURN(savedcw,result);
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}
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