#include <80c517.h>

float acos517 (
  float x);      /* number to calculate arc cosine of */

The acos517 function calculates the arc cosine of the floating-point number x.

Note

• This routine uses the arithmetic unit of the Infineon C517x/C509 to provide accelerated execution speed. Do not use this routine with a CPU that does not support this feature.

The acos517 function returns the arc cosine of x.

For x ∈ [-1, 1], acos517(x) → [0, π].
For x ∈ (-∞, -1) ∪ (1, ∞), acos517(x) → NaN.

acos, asin, asin517, atan, atan2, atan517

#include <80c517.h>
#include <stdio.h> /* for printf */

void tst_acos (void) {
  float x;
  float y;

  for (x = -1.0; x <= 1.0; x += 0.1) {
    y = acos517 (x);
    printf ("ACOS517(%f) = %f\n", x, y);
  }
}