mirror of
https://github.com/brain-hackers/u-boot-brain
synced 2024-06-09 23:36:03 +09:00
83d290c56f
When U-Boot started using SPDX tags we were among the early adopters and there weren't a lot of other examples to borrow from. So we picked the area of the file that usually had a full license text and replaced it with an appropriate SPDX-License-Identifier: entry. Since then, the Linux Kernel has adopted SPDX tags and they place it as the very first line in a file (except where shebangs are used, then it's second line) and with slightly different comment styles than us. In part due to community overlap, in part due to better tag visibility and in part for other minor reasons, switch over to that style. This commit changes all instances where we have a single declared license in the tag as both the before and after are identical in tag contents. There's also a few places where I found we did not have a tag and have introduced one. Signed-off-by: Tom Rini <trini@konsulko.com>
120 lines
3.1 KiB
C
120 lines
3.1 KiB
C
// SPDX-License-Identifier: GPL-2.0+
|
|
/*
|
|
* Borrowed from GCC 4.2.2 (which still was GPL v2+)
|
|
*/
|
|
/* 128-bit long double support routines for Darwin.
|
|
Copyright (C) 1993, 2003, 2004, 2005, 2006, 2007
|
|
Free Software Foundation, Inc.
|
|
|
|
This file is part of GCC.
|
|
*/
|
|
|
|
/*
|
|
* Implementations of floating-point long double basic arithmetic
|
|
* functions called by the IBM C compiler when generating code for
|
|
* PowerPC platforms. In particular, the following functions are
|
|
* implemented: __gcc_qadd, __gcc_qsub, __gcc_qmul, and __gcc_qdiv.
|
|
* Double-double algorithms are based on the paper "Doubled-Precision
|
|
* IEEE Standard 754 Floating-Point Arithmetic" by W. Kahan, February 26,
|
|
* 1987. An alternative published reference is "Software for
|
|
* Doubled-Precision Floating-Point Computations", by Seppo Linnainmaa,
|
|
* ACM TOMS vol 7 no 3, September 1981, pages 272-283.
|
|
*/
|
|
|
|
/*
|
|
* Each long double is made up of two IEEE doubles. The value of the
|
|
* long double is the sum of the values of the two parts. The most
|
|
* significant part is required to be the value of the long double
|
|
* rounded to the nearest double, as specified by IEEE. For Inf
|
|
* values, the least significant part is required to be one of +0.0 or
|
|
* -0.0. No other requirements are made; so, for example, 1.0 may be
|
|
* represented as (1.0, +0.0) or (1.0, -0.0), and the low part of a
|
|
* NaN is don't-care.
|
|
*
|
|
* This code currently assumes big-endian.
|
|
*/
|
|
|
|
#define fabs(x) __builtin_fabs(x)
|
|
#define isless(x, y) __builtin_isless(x, y)
|
|
#define inf() __builtin_inf()
|
|
#define unlikely(x) __builtin_expect((x), 0)
|
|
#define nonfinite(a) unlikely(!isless(fabs(a), inf()))
|
|
|
|
typedef union {
|
|
long double ldval;
|
|
double dval[2];
|
|
} longDblUnion;
|
|
|
|
/* Add two 'long double' values and return the result. */
|
|
long double __gcc_qadd(double a, double aa, double c, double cc)
|
|
{
|
|
longDblUnion x;
|
|
double z, q, zz, xh;
|
|
|
|
z = a + c;
|
|
|
|
if (nonfinite(z)) {
|
|
z = cc + aa + c + a;
|
|
if (nonfinite(z))
|
|
return z;
|
|
x.dval[0] = z; /* Will always be DBL_MAX. */
|
|
zz = aa + cc;
|
|
if (fabs(a) > fabs(c))
|
|
x.dval[1] = a - z + c + zz;
|
|
else
|
|
x.dval[1] = c - z + a + zz;
|
|
} else {
|
|
q = a - z;
|
|
zz = q + c + (a - (q + z)) + aa + cc;
|
|
|
|
/* Keep -0 result. */
|
|
if (zz == 0.0)
|
|
return z;
|
|
|
|
xh = z + zz;
|
|
if (nonfinite(xh))
|
|
return xh;
|
|
|
|
x.dval[0] = xh;
|
|
x.dval[1] = z - xh + zz;
|
|
}
|
|
return x.ldval;
|
|
}
|
|
|
|
long double __gcc_qsub(double a, double b, double c, double d)
|
|
{
|
|
return __gcc_qadd(a, b, -c, -d);
|
|
}
|
|
|
|
long double __gcc_qmul(double a, double b, double c, double d)
|
|
{
|
|
longDblUnion z;
|
|
double t, tau, u, v, w;
|
|
|
|
t = a * c; /* Highest order double term. */
|
|
|
|
if (unlikely(t == 0) /* Preserve -0. */
|
|
|| nonfinite(t))
|
|
return t;
|
|
|
|
/* Sum terms of two highest orders. */
|
|
|
|
/* Use fused multiply-add to get low part of a * c. */
|
|
#ifndef __NO_FPRS__
|
|
asm("fmsub %0,%1,%2,%3" : "=f"(tau) : "f"(a), "f"(c), "f"(t));
|
|
#else
|
|
tau = fmsub(a, c, t);
|
|
#endif
|
|
v = a * d;
|
|
w = b * c;
|
|
tau += v + w; /* Add in other second-order terms. */
|
|
u = t + tau;
|
|
|
|
/* Construct long double result. */
|
|
if (nonfinite(u))
|
|
return u;
|
|
z.dval[0] = u;
|
|
z.dval[1] = (t - u) + tau;
|
|
return z.ldval;
|
|
}
|