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path: root/src/math/exp10f.c
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#define _GNU_SOURCE
#include <math.h>
#include <stdint.h>

float exp10f(float x)
{
	static const float p10[] = {
		1e-7f, 1e-6f, 1e-5f, 1e-4f, 1e-3f, 1e-2f, 1e-1f,
		1, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7
	};
	float n, y = modff(x, &n);
	union {float f; uint32_t i;} u = {n};
	/* fabsf(n) < 8 without raising invalid on nan */
	if ((u.i>>23 & 0xff) < 0x7f+3) {
		if (!y) return p10[(int)n+7];
		y = exp2f(3.32192809488736234787031942948939f * y);
		return y * p10[(int)n+7];
	}
	return exp2(3.32192809488736234787031942948939 * x);
}

weak_alias(exp10f, pow10f);