DECCONV(3C-SVR4)    RISC/os Reference Manual     DECCONV(3C-SVR4)



NAME
     decconv: _s2dec, _d2dec, _dec2s, _dec2d - convert between
          binary and decimal values

SYNOPSIS
     #include <ieeefp.h>

     void s2dec (float *x, decimal *d, int p);
     void d2dec (double *x, decimal *d, int p);

     void dec2s (decimal *d, float *x, int p);
     void dec2d (decimal *d, double *x, int p);


DESCRIPTION
     The s2dec function returns a decimal floating-point value,
     given a pointer to a single-precision binary floating-point
     number and a precision specification.

     On input, the value of the ilen field in the decimal should
     be set to tell how many decimal digits should be output in
     the mantissa for rounding purposes.  If the ilen field is
     not in the range 1<ilen<9, a NaN is returned.  If the input
     binary value x is a NaN or infinity, the returned decimal d
     will be a NaN or infinity with the appropriate sign.  The
     exponential component of the returned decimal value is
     always two digits.  The structure decimal is defined in the
     ieeefp.h header file.

     The parameter p (0<p<ilen) specifies how many of the digits
     in the output decimal mantissa string are to be considered
     to be to the right of the implicit decimal point.  If p is
     out of range, a NaN is returned.

     The d2dec function works like the s2dec function except
     that it takes a pointer to a double-precision value for x.
     The ilen field must be in the range of  1<ilen< 17, and the
     exponential component of the returned decimal will contain
     three digits.

     The dec2s function returns a single-precision binary
     floating-point value, given a decimal value and a precision
     specification.

     The parameter p( 0<p<ilen) tells how many of the digits in
     the mantissa string are to be considered to be to the right
     of an implicit decimal point.

     Because the decimal format can represent a larger range of
     numbers than the binary formats, this conversion may over-
     flow or underflow.  Upon overflow or underflow, a signed
     infinity (signed zero) is returned, and the appropriate



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DECCONV(3C-SVR4)    RISC/os Reference Manual     DECCONV(3C-SVR4)



     sticky bit is set.

     The mantissa and exponent strings may contain leading zero
     characters.  But, once all leading 0 characters are removed,
     the mantissa string should have a length  > 0  and  < 9 .
     The exponent string should have a length  > 0  and  < 2 .
     The special case of d==0  (decimal) is detected, in which
     case the trailing 0 characters in the string are not
     removed.

     The dec2d function is analogous to the dec2s function
     except that it returns a double-precision value.  After
     leading 0 characters are removed, the mantissa string should
     contain no more than 17 digits and the exponent string
     should contain no more than three digits.

     Rounding is performed according to the current rounding
     mode.  The default is round-to-nearest.

     Calling these functions may result in the following excep-
     tions:  overflow, underflow, inexact result, invalid opera-
     tion.

SEE ALSO
     fpgetround(3C).






























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