xref: /aosp_15_r20/external/musl/src/math/roundl.c (revision c9945492fdd68bbe62686c5b452b4dc1be3f8453)
1*c9945492SAndroid Build Coastguard Worker #include "libm.h"
2*c9945492SAndroid Build Coastguard Worker 
3*c9945492SAndroid Build Coastguard Worker #if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
roundl(long double x)4*c9945492SAndroid Build Coastguard Worker long double roundl(long double x)
5*c9945492SAndroid Build Coastguard Worker {
6*c9945492SAndroid Build Coastguard Worker 	return round(x);
7*c9945492SAndroid Build Coastguard Worker }
8*c9945492SAndroid Build Coastguard Worker #elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
9*c9945492SAndroid Build Coastguard Worker 
10*c9945492SAndroid Build Coastguard Worker static const long double toint = 1/LDBL_EPSILON;
11*c9945492SAndroid Build Coastguard Worker 
roundl(long double x)12*c9945492SAndroid Build Coastguard Worker long double roundl(long double x)
13*c9945492SAndroid Build Coastguard Worker {
14*c9945492SAndroid Build Coastguard Worker 	union ldshape u = {x};
15*c9945492SAndroid Build Coastguard Worker 	int e = u.i.se & 0x7fff;
16*c9945492SAndroid Build Coastguard Worker 	long double y;
17*c9945492SAndroid Build Coastguard Worker 
18*c9945492SAndroid Build Coastguard Worker 	if (e >= 0x3fff+LDBL_MANT_DIG-1)
19*c9945492SAndroid Build Coastguard Worker 		return x;
20*c9945492SAndroid Build Coastguard Worker 	if (u.i.se >> 15)
21*c9945492SAndroid Build Coastguard Worker 		x = -x;
22*c9945492SAndroid Build Coastguard Worker 	if (e < 0x3fff-1) {
23*c9945492SAndroid Build Coastguard Worker 		FORCE_EVAL(x + toint);
24*c9945492SAndroid Build Coastguard Worker 		return 0*u.f;
25*c9945492SAndroid Build Coastguard Worker 	}
26*c9945492SAndroid Build Coastguard Worker 	y = x + toint - toint - x;
27*c9945492SAndroid Build Coastguard Worker 	if (y > 0.5)
28*c9945492SAndroid Build Coastguard Worker 		y = y + x - 1;
29*c9945492SAndroid Build Coastguard Worker 	else if (y <= -0.5)
30*c9945492SAndroid Build Coastguard Worker 		y = y + x + 1;
31*c9945492SAndroid Build Coastguard Worker 	else
32*c9945492SAndroid Build Coastguard Worker 		y = y + x;
33*c9945492SAndroid Build Coastguard Worker 	if (u.i.se >> 15)
34*c9945492SAndroid Build Coastguard Worker 		y = -y;
35*c9945492SAndroid Build Coastguard Worker 	return y;
36*c9945492SAndroid Build Coastguard Worker }
37*c9945492SAndroid Build Coastguard Worker #endif
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