xref: /aosp_15_r20/external/musl/src/math/scalbnf.c (revision c9945492fdd68bbe62686c5b452b4dc1be3f8453) 
1*c9945492SAndroid Build Coastguard Worker #include <math.h>
2*c9945492SAndroid Build Coastguard Worker #include <stdint.h>
3*c9945492SAndroid Build Coastguard Worker 
scalbnf(float x,int n)4*c9945492SAndroid Build Coastguard Worker float scalbnf(float x, int n)
5*c9945492SAndroid Build Coastguard Worker {
6*c9945492SAndroid Build Coastguard Worker 	union {float f; uint32_t i;} u;
7*c9945492SAndroid Build Coastguard Worker 	float_t y = x;
8*c9945492SAndroid Build Coastguard Worker 
9*c9945492SAndroid Build Coastguard Worker 	if (n > 127) {
10*c9945492SAndroid Build Coastguard Worker 		y *= 0x1p127f;
11*c9945492SAndroid Build Coastguard Worker 		n -= 127;
12*c9945492SAndroid Build Coastguard Worker 		if (n > 127) {
13*c9945492SAndroid Build Coastguard Worker 			y *= 0x1p127f;
14*c9945492SAndroid Build Coastguard Worker 			n -= 127;
15*c9945492SAndroid Build Coastguard Worker 			if (n > 127)
16*c9945492SAndroid Build Coastguard Worker 				n = 127;
17*c9945492SAndroid Build Coastguard Worker 		}
18*c9945492SAndroid Build Coastguard Worker 	} else if (n < -126) {
19*c9945492SAndroid Build Coastguard Worker 		y *= 0x1p-126f * 0x1p24f;
20*c9945492SAndroid Build Coastguard Worker 		n += 126 - 24;
21*c9945492SAndroid Build Coastguard Worker 		if (n < -126) {
22*c9945492SAndroid Build Coastguard Worker 			y *= 0x1p-126f * 0x1p24f;
23*c9945492SAndroid Build Coastguard Worker 			n += 126 - 24;
24*c9945492SAndroid Build Coastguard Worker 			if (n < -126)
25*c9945492SAndroid Build Coastguard Worker 				n = -126;
26*c9945492SAndroid Build Coastguard Worker 		}
27*c9945492SAndroid Build Coastguard Worker 	}
28*c9945492SAndroid Build Coastguard Worker 	u.i = (uint32_t)(0x7f+n)<<23;
29*c9945492SAndroid Build Coastguard Worker 	x = y * u.f;
30*c9945492SAndroid Build Coastguard Worker 	return x;
31*c9945492SAndroid Build Coastguard Worker }
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