1*c9945492SAndroid Build Coastguard Worker #define _GNU_SOURCE
2*c9945492SAndroid Build Coastguard Worker #include <math.h>
3*c9945492SAndroid Build Coastguard Worker #include <stdint.h>
4*c9945492SAndroid Build Coastguard Worker
exp10(double x)5*c9945492SAndroid Build Coastguard Worker double exp10(double x)
6*c9945492SAndroid Build Coastguard Worker {
7*c9945492SAndroid Build Coastguard Worker static const double p10[] = {
8*c9945492SAndroid Build Coastguard Worker 1e-15, 1e-14, 1e-13, 1e-12, 1e-11, 1e-10,
9*c9945492SAndroid Build Coastguard Worker 1e-9, 1e-8, 1e-7, 1e-6, 1e-5, 1e-4, 1e-3, 1e-2, 1e-1,
10*c9945492SAndroid Build Coastguard Worker 1, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7, 1e8, 1e9,
11*c9945492SAndroid Build Coastguard Worker 1e10, 1e11, 1e12, 1e13, 1e14, 1e15
12*c9945492SAndroid Build Coastguard Worker };
13*c9945492SAndroid Build Coastguard Worker double n, y = modf(x, &n);
14*c9945492SAndroid Build Coastguard Worker union {double f; uint64_t i;} u = {n};
15*c9945492SAndroid Build Coastguard Worker /* fabs(n) < 16 without raising invalid on nan */
16*c9945492SAndroid Build Coastguard Worker if ((u.i>>52 & 0x7ff) < 0x3ff+4) {
17*c9945492SAndroid Build Coastguard Worker if (!y) return p10[(int)n+15];
18*c9945492SAndroid Build Coastguard Worker y = exp2(3.32192809488736234787031942948939 * y);
19*c9945492SAndroid Build Coastguard Worker return y * p10[(int)n+15];
20*c9945492SAndroid Build Coastguard Worker }
21*c9945492SAndroid Build Coastguard Worker return pow(10.0, x);
22*c9945492SAndroid Build Coastguard Worker }
23*c9945492SAndroid Build Coastguard Worker
24*c9945492SAndroid Build Coastguard Worker weak_alias(exp10, pow10);
25