mirror of
https://github.com/brain-hackers/u-boot-brain
synced 2024-08-31 06:18:51 +09:00
![Wolfgang Denk](/assets/img/avatar_default.png)
Signed-off-by: Wolfgang Denk <wd@denx.de> [trini: Fixup common/cmd_io.c] Signed-off-by: Tom Rini <trini@ti.com>
121 lines
3.1 KiB
C
121 lines
3.1 KiB
C
/*
|
|
* 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.
|
|
|
|
* SPDX-License-Identifier: GPL-2.0+
|
|
*/
|
|
|
|
/*
|
|
* 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;
|
|
}
|