fastsincos: fast double precision Sine and Cosine

• Weak alias: sincos
• C Prototype:
  • void fastsincos (double x, double s, double c);
  • Inputs:
    • double x - the double precision input value.
  • Outputs:
    • double s - Sine of x.
    • double c - Cosine of x.
• Fortran Subroutine Interface:
  • SUBROUTINE FASTSINCOS(X,S,C)
  • Inputs:
    • DOUBLE PRECISION X - the double precision input value.
  • Outputs:
    • DOUBLE PRECISION S - Sine of X.
    • DOUBLE PRECISION C - Cosine of X.
• Notes:
  • fastsincos computes the Sine and Cosine functions of its argument x.
    
    This function can provide a significant performance advantage for applications that require both the sine and cosine of an angle, such as axis and matrix rotation. This is a relaxed version of sincos, suitable for use with fastmath compiler flags or applications not requiring full error handling. Denormal inputs may produce unpredictable results. Error inputs produce C99 return values. The routine is accurate to better than 2 ulp over the valid input range.
• Special case return values:

  • Input	Output
    QNaN	same QNaN
    SNaN	same NaN converted to QNaN
    +infinity	QNaN
    -infinity	QNaN

• Performance:
  • 99 cycles for most valid inputs < 5e5.