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220622dde5
This patch adds a new macro, libm_alias_finite, to define all _finite symbol. It sets all _finite symbol as compat symbol based on its first version (obtained from the definition at built generated first-versions.h). The <fn>f128_finite symbols were introduced in GLIBC 2.26 and so need special treatment in code that is shared between long double and float128. It is done by adding a list, similar to internal symbol redifinition, on sysdeps/ieee754/float128/float128_private.h. Alpha also needs some tricky changes to ensure we still emit 2 compat symbols for sqrt(f). Passes buildmanyglibc. Co-authored-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
145 lines
3.9 KiB
C
145 lines
3.9 KiB
C
/* e_hypotl.c -- long double version of e_hypot.c.
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* Conversion to long double by Ulrich Drepper,
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* Cygnus Support, drepper@cygnus.com.
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*/
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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 SunPro, 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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/* __ieee754_hypotl(x,y)
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*
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* Method :
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* If (assume round-to-nearest) z=x*x+y*y
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* has error less than sqrt(2)/2 ulp, than
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* sqrt(z) has error less than 1 ulp (exercise).
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*
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* So, compute sqrt(x*x+y*y) with some care as
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* follows to get the error below 1 ulp:
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*
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* Assume x>y>0;
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* (if possible, set rounding to round-to-nearest)
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* 1. if x > 2y use
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* x1*x1+(y*y+(x2*(x+x1))) for x*x+y*y
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* where x1 = x with lower 32 bits cleared, x2 = x-x1; else
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* 2. if x <= 2y use
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* t1*y1+((x-y)*(x-y)+(t1*y2+t2*y))
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* where t1 = 2x with lower 32 bits cleared, t2 = 2x-t1,
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* y1= y with lower 32 bits chopped, y2 = y-y1.
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*
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* NOTE: scaling may be necessary if some argument is too
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* large or too tiny
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*
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* Special cases:
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* hypot(x,y) is INF if x or y is +INF or -INF; else
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* hypot(x,y) is NAN if x or y is NAN.
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*
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* Accuracy:
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* hypot(x,y) returns sqrt(x^2+y^2) with error less
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* than 1 ulps (units in the last place)
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*/
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#include <math.h>
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#include <math_private.h>
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#include <math-underflow.h>
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#include <libm-alias-finite.h>
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long double __ieee754_hypotl(long double x, long double y)
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{
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long double a,b,t1,t2,y1,y2,w;
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uint32_t j,k,ea,eb;
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GET_LDOUBLE_EXP(ea,x);
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ea &= 0x7fff;
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GET_LDOUBLE_EXP(eb,y);
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eb &= 0x7fff;
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if(eb > ea) {a=y;b=x;j=ea; ea=eb;eb=j;} else {a=x;b=y;}
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SET_LDOUBLE_EXP(a,ea); /* a <- |a| */
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SET_LDOUBLE_EXP(b,eb); /* b <- |b| */
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if((ea-eb)>0x46) {return a+b;} /* x/y > 2**70 */
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k=0;
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if(__builtin_expect(ea > 0x5f3f,0)) { /* a>2**8000 */
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if(ea == 0x7fff) { /* Inf or NaN */
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uint32_t exp __attribute__ ((unused));
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uint32_t high,low;
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w = a+b; /* for sNaN */
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if (issignaling (a) || issignaling (b))
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return w;
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GET_LDOUBLE_WORDS(exp,high,low,a);
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if(((high&0x7fffffff)|low)==0) w = a;
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GET_LDOUBLE_WORDS(exp,high,low,b);
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if(((eb^0x7fff)|(high&0x7fffffff)|low)==0) w = b;
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return w;
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}
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/* scale a and b by 2**-9600 */
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ea -= 0x2580; eb -= 0x2580; k += 9600;
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SET_LDOUBLE_EXP(a,ea);
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SET_LDOUBLE_EXP(b,eb);
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}
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if(__builtin_expect(eb < 0x20bf, 0)) { /* b < 2**-8000 */
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if(eb == 0) { /* subnormal b or 0 */
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uint32_t exp __attribute__ ((unused));
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uint32_t high,low;
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GET_LDOUBLE_WORDS(exp,high,low,b);
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if((high|low)==0) return a;
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SET_LDOUBLE_WORDS(t1, 0x7ffd, 0x80000000, 0); /* t1=2^16382 */
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b *= t1;
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a *= t1;
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k -= 16382;
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GET_LDOUBLE_EXP (ea, a);
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GET_LDOUBLE_EXP (eb, b);
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if (eb > ea)
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{
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t1 = a;
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a = b;
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b = t1;
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j = ea;
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ea = eb;
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eb = j;
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}
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} else { /* scale a and b by 2^9600 */
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ea += 0x2580; /* a *= 2^9600 */
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eb += 0x2580; /* b *= 2^9600 */
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k -= 9600;
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SET_LDOUBLE_EXP(a,ea);
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SET_LDOUBLE_EXP(b,eb);
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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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uint32_t high;
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GET_LDOUBLE_MSW(high,a);
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SET_LDOUBLE_WORDS(t1,ea,high,0);
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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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uint32_t high;
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GET_LDOUBLE_MSW(high,b);
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a = a+a;
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SET_LDOUBLE_WORDS(y1,eb,high,0);
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y2 = b - y1;
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GET_LDOUBLE_MSW(high,a);
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SET_LDOUBLE_WORDS(t1,ea+1,high,0);
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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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uint32_t exp;
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t1 = 1.0;
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GET_LDOUBLE_EXP(exp,t1);
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SET_LDOUBLE_EXP(t1,exp+k);
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w *= t1;
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math_check_force_underflow_nonneg (w);
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return w;
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} else return w;
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}
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libm_alias_finite (__ieee754_hypotl, __hypotl)
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