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 Summary ```#include <80c517.h> float log517 ( float val); /* value to take natural logarithm of */ ``` Description The log517 function calculates the natural logarithm for the floating-point number val. The logarithm is the exponent to which the base (e or 2.718282... in the case of natural logs) must be raised to equal val. Or, loge ex = val 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. Return Value The log517 function returns the floating-point natural logarithm of val. If x < 0, log517 returns NaN. If x = 0, log517 returns -INF. See Also Example ```#include <80c517.h> #include /* for printf */ void tst_log517 (void) { float x; float y; x = 2.718282; x *= x; y = log517 (x); /* y = 2 */ printf ("LOG517(%f) = %f\n", x, y); } ```

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