xref: /aosp_15_r20/external/musl/src/math/truncl.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
truncl(long double x)4*c9945492SAndroid Build Coastguard Worker long double truncl(long double x)
5*c9945492SAndroid Build Coastguard Worker {
6*c9945492SAndroid Build Coastguard Worker 	return trunc(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 
truncl(long double x)12*c9945492SAndroid Build Coastguard Worker long double truncl(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 	int s = u.i.se >> 15;
17*c9945492SAndroid Build Coastguard Worker 	long double y;
18*c9945492SAndroid Build Coastguard Worker 
19*c9945492SAndroid Build Coastguard Worker 	if (e >= 0x3fff+LDBL_MANT_DIG-1)
20*c9945492SAndroid Build Coastguard Worker 		return x;
21*c9945492SAndroid Build Coastguard Worker 	if (e <= 0x3fff-1) {
22*c9945492SAndroid Build Coastguard Worker 		FORCE_EVAL(x + 0x1p120f);
23*c9945492SAndroid Build Coastguard Worker 		return x*0;
24*c9945492SAndroid Build Coastguard Worker 	}
25*c9945492SAndroid Build Coastguard Worker 	/* y = int(|x|) - |x|, where int(|x|) is an integer neighbor of |x| */
26*c9945492SAndroid Build Coastguard Worker 	if (s)
27*c9945492SAndroid Build Coastguard Worker 		x = -x;
28*c9945492SAndroid Build Coastguard Worker 	y = x + toint - toint - x;
29*c9945492SAndroid Build Coastguard Worker 	if (y > 0)
30*c9945492SAndroid Build Coastguard Worker 		y -= 1;
31*c9945492SAndroid Build Coastguard Worker 	x += y;
32*c9945492SAndroid Build Coastguard Worker 	return s ? -x : x;
33*c9945492SAndroid Build Coastguard Worker }
34*c9945492SAndroid Build Coastguard Worker #endif
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