《基于TI DSP的通用算法实现》程序代码
源代码在线查看: example 2-17.c
/* Example 2 - 17. Double-Precision Floating-Point Square Root C Listing for sqrt */
/***************************************************************/
/* SQRDPC.c Syd Poland 6-24-98 _sqrt function in C for 'C67xx */
/***************************************************************/
double sqrt(double A)
{
double ZERO=0.0, HALF=0.5, K15=1.5, AH, X0, X1, X2, X3, Y ;
if (A < ZERO) A = -A ; /* square root of absolute A */
AH = A * HALF ;
X0 = _rsqrdp(A) ;
X1 = X0 * (K15 - (AH*X0)*X0 ) ;
X2 = X1 * (K15 - (AH*X1)*X1 );
X3 = X2 * (K15 - (AH*X2)*X2 );
Y = A * X3 ;
return (Y) ;
}