xref: /illumos-gate/usr/src/lib/libm/common/m9x/lrintl.c (revision ddc0e0b5)
125c28e83SPiotr Jasiukajtis /*
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325c28e83SPiotr Jasiukajtis  *
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825c28e83SPiotr Jasiukajtis  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
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2125c28e83SPiotr Jasiukajtis 
2225c28e83SPiotr Jasiukajtis /*
2325c28e83SPiotr Jasiukajtis  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
2425c28e83SPiotr Jasiukajtis  */
2525c28e83SPiotr Jasiukajtis /*
2625c28e83SPiotr Jasiukajtis  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
2725c28e83SPiotr Jasiukajtis  * Use is subject to license terms.
2825c28e83SPiotr Jasiukajtis  */
2925c28e83SPiotr Jasiukajtis 
30*ddc0e0b5SRichard Lowe #pragma weak __lrintl = lrintl
3125c28e83SPiotr Jasiukajtis 
3225c28e83SPiotr Jasiukajtis #include <sys/isa_defs.h>	/* _ILP32 */
3325c28e83SPiotr Jasiukajtis #include "libm.h"
3425c28e83SPiotr Jasiukajtis 
3525c28e83SPiotr Jasiukajtis #if defined(_ILP32)
3625c28e83SPiotr Jasiukajtis #if defined(__sparc)
3725c28e83SPiotr Jasiukajtis 
3825c28e83SPiotr Jasiukajtis #include "fma.h"
3925c28e83SPiotr Jasiukajtis #include "fenv_inlines.h"
4025c28e83SPiotr Jasiukajtis 
4125c28e83SPiotr Jasiukajtis long
lrintl(long double x)4225c28e83SPiotr Jasiukajtis lrintl(long double x) {
4325c28e83SPiotr Jasiukajtis 	union {
4425c28e83SPiotr Jasiukajtis 		unsigned int i[4];
4525c28e83SPiotr Jasiukajtis 		long double q;
4625c28e83SPiotr Jasiukajtis 	} xx;
4725c28e83SPiotr Jasiukajtis 	union {
4825c28e83SPiotr Jasiukajtis 		unsigned int i;
4925c28e83SPiotr Jasiukajtis 		float f;
5025c28e83SPiotr Jasiukajtis 	} tt;
5125c28e83SPiotr Jasiukajtis 	unsigned int hx, sx, frac, l, fsr;
5225c28e83SPiotr Jasiukajtis 	int rm, j;
5325c28e83SPiotr Jasiukajtis 	volatile float dummy;
5425c28e83SPiotr Jasiukajtis 
5525c28e83SPiotr Jasiukajtis 	xx.q = x;
5625c28e83SPiotr Jasiukajtis 	sx = xx.i[0] & 0x80000000;
5725c28e83SPiotr Jasiukajtis 	hx = xx.i[0] & ~0x80000000;
5825c28e83SPiotr Jasiukajtis 
5925c28e83SPiotr Jasiukajtis 	/* handle trivial cases */
6025c28e83SPiotr Jasiukajtis 	if (hx > 0x401e0000) { /* |x| > 2^31 + ... or x is nan */
6125c28e83SPiotr Jasiukajtis 		/* convert an out-of-range float */
6225c28e83SPiotr Jasiukajtis 		tt.i = sx | 0x7f000000;
6325c28e83SPiotr Jasiukajtis 		return ((long) tt.f);
6425c28e83SPiotr Jasiukajtis 	} else if ((hx | xx.i[1] | xx.i[2] | xx.i[3]) == 0) /* x is zero */
6525c28e83SPiotr Jasiukajtis 		return (0L);
6625c28e83SPiotr Jasiukajtis 
6725c28e83SPiotr Jasiukajtis 	/* get the rounding mode */
6825c28e83SPiotr Jasiukajtis 	__fenv_getfsr32(&fsr);
6925c28e83SPiotr Jasiukajtis 	rm = fsr >> 30;
7025c28e83SPiotr Jasiukajtis 
7125c28e83SPiotr Jasiukajtis 	/* flip the sense of directed roundings if x is negative */
7225c28e83SPiotr Jasiukajtis 	if (sx)
7325c28e83SPiotr Jasiukajtis 		rm ^= rm >> 1;
7425c28e83SPiotr Jasiukajtis 
7525c28e83SPiotr Jasiukajtis 	/* handle |x| < 1 */
7625c28e83SPiotr Jasiukajtis 	if (hx < 0x3fff0000) {
7725c28e83SPiotr Jasiukajtis 		dummy = 1.0e30F; /* x is nonzero, so raise inexact */
7825c28e83SPiotr Jasiukajtis 		dummy += 1.0e-30F;
7925c28e83SPiotr Jasiukajtis 		if (rm == FSR_RP || (rm == FSR_RN && (hx >= 0x3ffe0000 &&
8025c28e83SPiotr Jasiukajtis 			((hx & 0xffff) | xx.i[1] | xx.i[2] | xx.i[3]))))
8125c28e83SPiotr Jasiukajtis 			return (sx ? -1L : 1L);
8225c28e83SPiotr Jasiukajtis 		return (0L);
8325c28e83SPiotr Jasiukajtis 	}
8425c28e83SPiotr Jasiukajtis 
8525c28e83SPiotr Jasiukajtis 	/* extract the integer and fractional parts of x */
8625c28e83SPiotr Jasiukajtis 	j = 0x406f - (hx >> 16);		/* 91 <= j <= 112 */
8725c28e83SPiotr Jasiukajtis 	xx.i[0] = 0x10000 | (xx.i[0] & 0xffff);
8825c28e83SPiotr Jasiukajtis 	if (j >= 96) {				/* 96 <= j <= 112 */
8925c28e83SPiotr Jasiukajtis 		l = xx.i[0] >> (j - 96);
9025c28e83SPiotr Jasiukajtis 		frac = ((xx.i[0] << 1) << (127 - j)) | (xx.i[1] >> (j - 96));
9125c28e83SPiotr Jasiukajtis 		if (((xx.i[1] << 1) << (127 - j)) | xx.i[2] | xx.i[3])
9225c28e83SPiotr Jasiukajtis 			frac |= 1;
9325c28e83SPiotr Jasiukajtis 	} else {				/* 91 <= j <= 95 */
9425c28e83SPiotr Jasiukajtis 		l = (xx.i[0] << (96 - j)) | (xx.i[1] >> (j - 64));
9525c28e83SPiotr Jasiukajtis 		frac = (xx.i[1] << (96 - j)) | (xx.i[2] >> (j - 64));
9625c28e83SPiotr Jasiukajtis 		if ((xx.i[2] << (96 - j)) | xx.i[3])
9725c28e83SPiotr Jasiukajtis 			frac |= 1;
9825c28e83SPiotr Jasiukajtis 	}
9925c28e83SPiotr Jasiukajtis 
10025c28e83SPiotr Jasiukajtis 	/* round */
10125c28e83SPiotr Jasiukajtis 	if (frac && (rm == FSR_RP || (rm == FSR_RN && (frac > 0x80000000U ||
10225c28e83SPiotr Jasiukajtis 		(frac == 0x80000000 && (l & 1))))))
10325c28e83SPiotr Jasiukajtis 		l++;
10425c28e83SPiotr Jasiukajtis 
10525c28e83SPiotr Jasiukajtis 	/* check for result out of range (note that z is |x| at this point) */
10625c28e83SPiotr Jasiukajtis 	if (l > 0x80000000U || (l == 0x80000000U && !sx)) {
10725c28e83SPiotr Jasiukajtis 		tt.i = sx | 0x7f000000;
10825c28e83SPiotr Jasiukajtis 		return ((long) tt.f);
10925c28e83SPiotr Jasiukajtis 	}
11025c28e83SPiotr Jasiukajtis 
11125c28e83SPiotr Jasiukajtis 	/* raise inexact if need be */
11225c28e83SPiotr Jasiukajtis 	if (frac) {
11325c28e83SPiotr Jasiukajtis 		dummy = 1.0e30F;
11425c28e83SPiotr Jasiukajtis 		dummy += 1.0e-30F;
11525c28e83SPiotr Jasiukajtis 	}
11625c28e83SPiotr Jasiukajtis 
11725c28e83SPiotr Jasiukajtis 	/* negate result if need be */
11825c28e83SPiotr Jasiukajtis 	if (sx)
11925c28e83SPiotr Jasiukajtis 		l = -l;
12025c28e83SPiotr Jasiukajtis 	return ((long) l);
12125c28e83SPiotr Jasiukajtis }
12225c28e83SPiotr Jasiukajtis #elif defined(__x86)
12325c28e83SPiotr Jasiukajtis long
lrintl(long double x)12425c28e83SPiotr Jasiukajtis lrintl(long double x) {
12525c28e83SPiotr Jasiukajtis 	/*
12625c28e83SPiotr Jasiukajtis 	 * Note: The following code works on x86 (in the default rounding
12725c28e83SPiotr Jasiukajtis 	 * precision mode), but one ought to just use the fistpl instruction
12825c28e83SPiotr Jasiukajtis 	 * instead.
12925c28e83SPiotr Jasiukajtis 	 */
13025c28e83SPiotr Jasiukajtis 	union {
13125c28e83SPiotr Jasiukajtis 		unsigned i[3];
13225c28e83SPiotr Jasiukajtis 		long double e;
13325c28e83SPiotr Jasiukajtis 	} xx, yy;
13425c28e83SPiotr Jasiukajtis 	int ex;
13525c28e83SPiotr Jasiukajtis 
13625c28e83SPiotr Jasiukajtis 	xx.e = x;
13725c28e83SPiotr Jasiukajtis 	ex = xx.i[2] & 0x7fff;
13825c28e83SPiotr Jasiukajtis 	if (ex < 0x403e) {	/* |x| < 2^63 */
13925c28e83SPiotr Jasiukajtis 		/* add and subtract a power of two to round x to an integer */
14025c28e83SPiotr Jasiukajtis 		yy.i[2] = (xx.i[2] & 0x8000) | 0x403e;
14125c28e83SPiotr Jasiukajtis 		yy.i[1] = 0x80000000;
14225c28e83SPiotr Jasiukajtis 		yy.i[0] = 0;
14325c28e83SPiotr Jasiukajtis 		x = (x + yy.e) - yy.e;
14425c28e83SPiotr Jasiukajtis 	}
14525c28e83SPiotr Jasiukajtis 
14625c28e83SPiotr Jasiukajtis 	/* now x is nan, inf, or integral */
14725c28e83SPiotr Jasiukajtis 	return ((long) x);
14825c28e83SPiotr Jasiukajtis }
14925c28e83SPiotr Jasiukajtis #else
15025c28e83SPiotr Jasiukajtis #error Unknown architecture
15125c28e83SPiotr Jasiukajtis #endif	/* defined(__sparc) || defined(__x86) */
15225c28e83SPiotr Jasiukajtis #else
15325c28e83SPiotr Jasiukajtis #error Unsupported architecture
15425c28e83SPiotr Jasiukajtis #endif	/* defined(_ILP32) */
155