a0ee07829a
This brings us up to date with FreeBSD HEAD, fixes various bugs, unifies the set of functions we support on ARM, MIPS, and x86, fixes "long double", adds ISO C99 support, and adds basic unit tests. It turns out that our "long double" functions have always been broken for non-normal numbers. This patch fixes that by not using the upstream implementations and just forwarding to the regular "double" implementation instead (since "long double" on Android is just "double" anyway, which is what BSD doesn't support). All the tests pass on ARM, MIPS, and x86, plus glibc on x86-64. Bug: 3169850 Bug: 8012787 Bug: https://code.google.com/p/android/issues/detail?id=6697 Change-Id: If0c343030959c24bfc50d4d21c9530052c581837
125 lines
3.2 KiB
C
125 lines
3.2 KiB
C
/* From: @(#)e_hypot.c 1.3 95/01/18 */
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/*
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* ====================================================
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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*
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* Developed at SunSoft, a Sun Microsystems, Inc. business.
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* Permission to use, copy, modify, and distribute this
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* software is freely granted, provided that this notice
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* is preserved.
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* ====================================================
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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/* long double version of hypot(). See e_hypot.c for most comments. */
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#include <float.h>
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#include "fpmath.h"
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#include "math.h"
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#include "math_private.h"
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#define GET_LDBL_MAN(h, l, v) do { \
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union IEEEl2bits uv; \
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\
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uv.e = v; \
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h = uv.bits.manh; \
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l = uv.bits.manl; \
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} while (0)
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#undef GET_HIGH_WORD
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#define GET_HIGH_WORD(i, v) GET_LDBL_EXPSIGN(i, v)
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#undef SET_HIGH_WORD
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#define SET_HIGH_WORD(v, i) SET_LDBL_EXPSIGN(v, i)
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#define DESW(exp) (exp) /* delta expsign word */
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#define ESW(exp) (MAX_EXP - 1 + (exp)) /* expsign word */
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#define MANT_DIG LDBL_MANT_DIG
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#define MAX_EXP LDBL_MAX_EXP
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#if LDBL_MANL_SIZE > 32
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typedef uint64_t man_t;
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#else
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typedef uint32_t man_t;
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#endif
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long double
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hypotl(long double x, long double y)
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{
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long double a=x,b=y,t1,t2,y1,y2,w;
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int32_t j,k,ha,hb;
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GET_HIGH_WORD(ha,x);
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ha &= 0x7fff;
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GET_HIGH_WORD(hb,y);
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hb &= 0x7fff;
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if(hb > ha) {a=y;b=x;j=ha; ha=hb;hb=j;} else {a=x;b=y;}
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a = fabsl(a);
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b = fabsl(b);
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if((ha-hb)>DESW(MANT_DIG+7)) {return a+b;} /* x/y > 2**(MANT_DIG+7) */
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k=0;
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if(ha > ESW(MAX_EXP/2-12)) { /* a>2**(MAX_EXP/2-12) */
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if(ha >= ESW(MAX_EXP)) { /* Inf or NaN */
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man_t manh, manl;
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/* Use original arg order iff result is NaN; quieten sNaNs. */
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w = fabsl(x+0.0)-fabsl(y+0.0);
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GET_LDBL_MAN(manh,manl,a);
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if (manh == LDBL_NBIT && manl == 0) w = a;
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GET_LDBL_MAN(manh,manl,b);
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if (hb >= ESW(MAX_EXP) && manh == LDBL_NBIT && manl == 0) w = b;
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return w;
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}
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/* scale a and b by 2**-(MAX_EXP/2+88) */
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ha -= DESW(MAX_EXP/2+88); hb -= DESW(MAX_EXP/2+88);
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k += MAX_EXP/2+88;
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SET_HIGH_WORD(a,ha);
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SET_HIGH_WORD(b,hb);
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}
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if(hb < ESW(-(MAX_EXP/2-12))) { /* b < 2**-(MAX_EXP/2-12) */
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if(hb <= 0) { /* subnormal b or 0 */
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man_t manh, manl;
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GET_LDBL_MAN(manh,manl,b);
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if((manh|manl)==0) return a;
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t1=0;
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SET_HIGH_WORD(t1,ESW(MAX_EXP-2)); /* t1=2^(MAX_EXP-2) */
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b *= t1;
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a *= t1;
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k -= MAX_EXP-2;
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} else { /* scale a and b by 2^(MAX_EXP/2+88) */
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ha += DESW(MAX_EXP/2+88);
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hb += DESW(MAX_EXP/2+88);
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k -= MAX_EXP/2+88;
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SET_HIGH_WORD(a,ha);
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SET_HIGH_WORD(b,hb);
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}
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}
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/* medium size a and b */
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w = a-b;
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if (w>b) {
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t1 = a;
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union IEEEl2bits uv;
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uv.e = t1; uv.bits.manl = 0; t1 = uv.e;
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t2 = a-t1;
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w = sqrtl(t1*t1-(b*(-b)-t2*(a+t1)));
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} else {
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a = a+a;
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y1 = b;
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union IEEEl2bits uv;
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uv.e = y1; uv.bits.manl = 0; y1 = uv.e;
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y2 = b - y1;
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t1 = a;
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uv.e = t1; uv.bits.manl = 0; t1 = uv.e;
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t2 = a - t1;
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w = sqrtl(t1*y1-(w*(-w)-(t1*y2+t2*b)));
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}
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if(k!=0) {
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u_int32_t high;
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t1 = 1.0;
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GET_HIGH_WORD(high,t1);
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SET_HIGH_WORD(t1,high+DESW(k));
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return t1*w;
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} else return w;
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}
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