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56 lines
1.2 KiB
56 lines
1.2 KiB
/***
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*frexp.c - get mantissa and exponent of a floating point number
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*
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* Copyright (c) 1991-1991, 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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*
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*******************************************************************************/
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#include <math.h>
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#include <trans.h>
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/***
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*double frexp(double x, double *expptr)
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*
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*Purpose:
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* The nomalized fraction f is returned: .5<=f<1
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* The exponent is stored in the object pointed by expptr
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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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* NAN: domain error
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*
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*******************************************************************************/
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double frexp(double x, int *expptr)
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{
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unsigned int savedcw;
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double man;
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/* save user fp control word */
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savedcw = _maskfp();
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/* check for infinity or NAN */
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if (IS_D_SPECIAL(x)){
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*expptr = INT_NAN;
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switch (_sptype(x)) {
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case T_PINF:
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return _except1(FP_I, OP_FREXP, x, D_INF, savedcw);
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case T_NINF:
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return _except1(FP_I, OP_FREXP, x, -D_INF, savedcw);
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case T_QNAN:
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return _handle_qnan1(OP_FREXP, x, savedcw);
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default: //T_SNAN
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return _except1(FP_I, OP_FREXP, x, _s2qnan(x), savedcw);
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}
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}
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man = _decomp(x, expptr);
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RETURN(savedcw,man);
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}
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