90 lines
2.8 KiB
C
90 lines
2.8 KiB
C
/* Copyright (C) 1989-2017 Free Software Foundation, Inc.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 3, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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3.1, as published by the Free Software Foundation.
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You should have received a copy of the GNU General Public License and
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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<http://www.gnu.org/licenses/>. */
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/* This is a temporary specialization of code from libgcc/libgcc2.c. */
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typedef float KFtype __attribute__ ((mode (KF)));
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typedef __complex float KCtype __attribute__ ((mode (KC)));
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#define COPYSIGN(x,y) __builtin_copysignq (x, y)
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#define INFINITY __builtin_infq ()
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#define FABS __builtin_fabsq
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#define isnan __builtin_isnan
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#define isinf __builtin_isinf
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#define isfinite __builtin_isfinite
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KCtype
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__divkc3 (KFtype a, KFtype b, KFtype c, KFtype d)
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{
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KFtype denom, ratio, x, y;
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KCtype res;
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/* ??? We can get better behavior from logarithmic scaling instead of
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the division. But that would mean starting to link libgcc against
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libm. We could implement something akin to ldexp/frexp as gcc builtins
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fairly easily... */
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if (FABS (c) < FABS (d))
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{
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ratio = c / d;
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denom = (c * ratio) + d;
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x = ((a * ratio) + b) / denom;
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y = ((b * ratio) - a) / denom;
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}
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else
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{
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ratio = d / c;
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denom = (d * ratio) + c;
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x = ((b * ratio) + a) / denom;
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y = (b - (a * ratio)) / denom;
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}
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/* Recover infinities and zeros that computed as NaN+iNaN; the only cases
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are nonzero/zero, infinite/finite, and finite/infinite. */
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if (isnan (x) && isnan (y))
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{
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if (c == 0.0 && d == 0.0 && (!isnan (a) || !isnan (b)))
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{
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x = COPYSIGN (INFINITY, c) * a;
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y = COPYSIGN (INFINITY, c) * b;
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}
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else if ((isinf (a) || isinf (b)) && isfinite (c) && isfinite (d))
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{
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a = COPYSIGN (isinf (a) ? 1 : 0, a);
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b = COPYSIGN (isinf (b) ? 1 : 0, b);
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x = INFINITY * (a * c + b * d);
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y = INFINITY * (b * c - a * d);
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}
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else if ((isinf (c) || isinf (d)) && isfinite (a) && isfinite (b))
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{
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c = COPYSIGN (isinf (c) ? 1 : 0, c);
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d = COPYSIGN (isinf (d) ? 1 : 0, d);
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x = 0.0 * (a * c + b * d);
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y = 0.0 * (b * c - a * d);
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}
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}
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__real__ res = x;
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__imag__ res = y;
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return res;
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}
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