A compiler clever enough to know that z is positive with a non-zero
biased exponent could, for example, optimize away the scalbnf(z,n) in
pow() because behavior for left shift of negative values is undefined.
`n` is negative when y*log2(|x|) < -0.5. i.e. |x^y| < sqrt(0.5)
The intended behavior for operator<< in this code is to shift the two's
complement representation of the first operand.
In the pow() functions, the result is added to the IEEE 754 exponent of
z = 2^y'. n may be negative enough to underflow the biased IEEE 754
exponent below zero, which is manifested in the sign bit of j
(which would correspond to the IEEE 754 sign bit).
The conversion from uint32_t to int32_t for out-of-int32_t-range values
is implementation defined. The assumed behavior of interpreting the
uint32_t value as a two's complement representation of a signed value
is already assumed in many parts of the code, such as uses of
GET_FLOAT_WORD() with signed integers.
This code passes all the current tests, and makes some out of tree
fuzzing tests pass again rather than hit UB (detailed in the commentary
of the pull request).
Signed-off-by: Karl Tomlinson <karlt+@karlt.net>
Reviewed by: imp, steve kargl, dim
Pull Request: https://github.com/freebsd/freebsd-src/pull/1137
x = k + y for some integer k and |y| < 1/2
exp2(x) = exp2(k + y) = exp2(k) * exp2(y)
which can be written as 2**k * exp2(y)
The original had x = 2**k + y, which is has an extra 2** in it which
isn't correct.
Confirmed by forumula 2 in Gal and Bachelis referenced in the comments
for the source of this method
https://dl.acm.org/doi/pdf/10.1145/103147.103151
The actual code is correct.
Reviewed by: imp (who added s_exp2.c and wrote the commit message)
Pull Request: https://github.com/freebsd/freebsd-src/pull/1127
These constants are GNU libc extensions that are likely to be adopted
by the next POSIX revision [1]. The definitions can be verified in
a PARI-GP shell session:
* M_El: exp (1)
* M_LOG2El: log (exp (1)) / log (2)
* M_LOG10El: log (exp (1)) / log (10)
* M_LN2l: log (2)
* M_LN10l: log (10)
* M_PIl: Pi
* M_PI_2l: Pi / 2
* M_PI_4l: Pi / 4
* M_1_PIl: 1 / Pi
* M_2_PIl: 2 / Pi
* M_2_SQRTPIl: 2 / sqrt (Pi)
* M_SQRT2l: sqrt (2)
* M_SQRT1_2l: 1 / sqrt (2)
[1] https://austingroupbugs.net/view.php?id=828
Put these behind __BSD_VISIBLE || __XSI_VISIBLE >= 800 to future-proof
these changes. They shouldn't be defined at lower levels of XSI, but don't
have other XSI 800 stuff in place yet.
Signed-off-by: Collin Funk <collin.funk1@gmail.com>
Reviewed by: imp, allanjude
Pull Request: https://github.com/freebsd/freebsd-src/pull/1121
Remove a few more bits of riscv64sf support in libc and libm.
Reduce floating point ABI checks to requiring double hard float.
Reviewed by: imp, jhb
Fixes: 1ca12bd927 Remove the riscv64sf architecture.
Differential Revision: https://reviews.freebsd.org/D44334
Undo the 80-bit "stub" implementation of the 128-bit long double
tgammal(3) function. The latest (as of Feb 2024) version of the
src/contrib/arm-optimised-routines library includes a standalone,
full 128-bit replacement. This needs a small bit of wrapping to
fit it in, but is otherwise a drop-in replacement.
Testing this is hard, as most maths packages blow up as soon as
their 80-bit floating-point capability is exceeded. With 128-bit
tgammal(), this is easy to do, and this is the range that needs to
be checked the most carefully. Using my copy of Maple, I was able
to check that the output was within a few ULP of the correct answer,
right up to the point of 128-bit over- and underflow. Additionally,
the results are no worse, and indeed better than the 80-bit version.
Steve Kargl sent me his libm testing code, which I used to verify
that the excpetions for certain key values were correct. Tested in
this case were +-Inf, +-NaN, +-1 and +-0.
Differential Revision: https://reviews.freebsd.org/D44168
Reviewed by: theraven, andrew, imp
The way the __fp_type_select macro uses the _Generic expression causes
gcc to throw a warning on valid code if the -Wconversion flag is used.
For example, consider the following program:
#include <math.h>
int main()
{
double x = 1.0;
isnan(x);
return 0;
}
which throws a warning:
$ gcc -Wconversion a.c
a.c:5:15: warning: conversion from 'double' to 'float' may change value [-Wfloat-conversion]
5 | isnan(x);
| ^
This happens because the functions are invoked inside of the _Generic.
Looking at the example of _Generic in the C11 specification, one sees
that the parameters are outside of the _Generic expression (see page 79
here: https://www.open-std.org/jtc1/sc22/wg14/www/docs/n1570.pdf).
Reference: https://stackoverflow.com/a/68309379
Signed-off-by: Martin Oliveira <martin.oliveira@eideticom.com>
Reviewed by: imp
Pull Request: https://github.com/freebsd/freebsd-src/pull/841
We have s_fabs.c, but fabs(3) is already provided by libc due to
historical reasons, so it is not compiled into libm. When the linker
does not use --undefined-version, this leads to a complaint about the
symbol being nonexistent, so remove it from Symbol.map.
While here, adjust the comment about some functions being supplied by
libc: while it is true that all these are indeed in libc, libm still
includes its own versions of frexp(3), isnan(3), isnanf(3), and
isnanl(3).
Reported by: Steve Kargl <sgk@troutmask.apl.washington.edu>
MFC after: 3 days
Apply the following automated changes to try to eliminate
no-longer-needed sys/cdefs.h includes as well as now-empty
blank lines in a row.
Remove /^#if.*\n#endif.*\n#include\s+<sys/cdefs.h>.*\n/
Remove /\n+#include\s+<sys/cdefs.h>.*\n+#if.*\n#endif.*\n+/
Remove /\n+#if.*\n#endif.*\n+/
Remove /^#if.*\n#endif.*\n/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/types.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/param.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/capsicum.h>/
Sponsored by: Netflix
Remove ancient SCCS tags from the tree, automated scripting, with two
minor fixup to keep things compiling. All the common forms in the tree
were removed with a perl script.
Sponsored by: Netflix
There's no reason to use the __const construct here. This is a left-over
from supporting K&R and ANSI compilers in the original Sun msun. All
other K&R crutches have been removed. Remove these as well. There's no
semantic difference. And there's already several others in math.h.
Sponsored by: Netflix
LIBCSRCDIR is defined in bsd.libnames.mk, which is read in later in the
Makefile than the line:
.if exists(${LIBCSRCDIR}/${MACHINE_ARCH})
so we test to see if /${MARCHIN_ARCH} exists which it usually doesn't
(but did for me since I mounted 13.2R SD image there). Move to defining
our own LIBC_SRCTOP in terms of SRCTOP to treat these uniformily.
Sponsored by: Netflix
Reviewed by: sjg
Differential Revision: https://reviews.freebsd.org/D41661
This removes the __ieee754_ prefix from a number of the math functions.
msun/src/math_private.h contains the statement that
/*
* ieee style elementary functions
*
* We rename functions here to improve other sources' diffability
* against fdlibm.
*/
#define __ieee754_sqrt sqrt
...
Here, fdlibm refers to https://netlib.org/fdlibm. It is seen from
https://netlib.org/fdlibm/readme that this prefix was used to
differentiate between different standards:
Wrapper functions will twist the result of the ieee754
function to comply to the standard specified by the value
of _LIB_VERSION
if _LIB_VERSION = _IEEE_, return the ieee754 result;
if _LIB_VERSION = _SVID_, return SVID result;
if _LIB_VERSION = _XOPEN_, return XOPEN result;
if _LIB_VERSION = _POSIX_, return POSIX/ANSI result.
(These are macros, see fdlibm.h for their definition.)
AFAICT, FreeBSD has never supported these wrappers. In addition, as C99,
principally the long double, functions were added to libm, this
convention was not maintained. Given that only 148 of 324 files under
lib/msun contain a "Copyright (C) 1993 by Sun Microsystems" statement,
the removal of the __ieee754_ prefix provides consistency across all
source files.
The last time someone compared lib/msun to fdlibm appears to be
commit 3f70824172
Author: David Schultz <das@FreeBSD.org>
Date: Fri Feb 4 18:26:06 2005 +0000
Reduce diffs against vendor source (Sun fdlibm 5.3).
The most recent fdlibm RCS string that appears in a Sun Microsystem
copyrighted file is date "95/01/18". With Oracle Corporation's
acquisition of Sun Microsystems in 2009, it is unlikely that fdlibm will
ever be updated. A search for fdlibm at https://opensource.oracle.com/
yields no hits.
Finally, OpenBSD removed the use of this prefix over 21 years ago. pSee
revision 1.6 of OpenBSD's math_private.h.
Note: this does not drop the __ieee754_ prefix from the trigonometric
argument reduction functions, e.g., __ieee754_rem_pio2. These functions
are internal to the libm and exported through Symbol.map; and thus,
reserved for the implementation.
PR: 272783
MFC after: 1 week
patch to fix half-cycle trigonometric functions
Paul Zimmermann, a MPFR developer, contacted me about large errors in
the half-cycle trigonometric functions. I've have investigated these
issues and developed the attached patch. The float, double, and ld80
(long double) changes have been tested.
Caveat emptor: The ld128 changes have not been compiled. The ld128
changes have not been tested. I do not have access to a system that
uses ld128 floating point.
Here is an itemized list of changes:
* lib/msun/src/math_private.h:
. Add fast floor macros to compute the integer part of |x| for
0 <= |x| 01xp(N-1), where N is the precision of the type of x.
These macros are used in the half-cycle trigonometric functions
(e.g., sinpi(x)).
. The FFLOOR80 macros is used with the Intel 80-bit extended double
functions. This macors corrects an off-by-one error, which led to
enormous error for |x| > 0x1p32.
* lib/msun/src/s_cospif.c:
* lib/msun/src/s_cospi.c:
* lib/msun/ld80/s_cospil.c:
. Update Copyright years.
. Use FFLOOR*() macro to get integer part of |x|.
. Correct handle the range 0x1p(N-1) <= |x| < 0x1pN. Here, one needs
to determine if the integral value of |x| is even or odd to choose
+1 or -1. If |x| >= 0x1pN, always return +1.
* lib/msun/src/s_sinpif.c:
* lib/msun/src/s_sinpi.c:
* lib/msun/ld80/s_sinpil.c:
. Update Copyright years.
. Use FFLOOR*() macro to get integer part of |x|.
* lib/msun/src/s_tanpif.c:
* lib/msun/src/s_tanpi.c:
* lib/msun/ld80/s_tanpil.c:
. Update Copyright years.
. For +-0.5, return +-inf. Previously, tanpi[fl]() returned an NaN.
. Use FFLOOR*() to get integer part of |x|. Need to determine if the
integer part is even or odd. This is used to set +-0 for |x|
integral
and +-inf for (n+1/2).
. For 0x1p(N-1) <= |x| < 0x1pN need to determine if x is an even or
odd
integer to select +0 or -0. For |x| >= 0x1pN, it is always an even
integer, select 0.
. Note, tanpi[fl](x) is an odd function, so one needs to consider
tanpi[fl](-|x|) = - tanpi[fl](|x|).
* lib/msun/ld128/s_cospil.c:
* lib/msun/ld128/s_sinpil.c:
* lib/msun/ld128/s_tanpil.c:
. Update Copyright years.
. These routines use an FFLOOR128 macros, which likely should be
replaced by a bit twiddling algorithm.
. The same considerations above are applied to 0x1p112 <= |x| <
0x1p113,
and |x| >= 0x1p113 cases.
. Note, even and odd determination used fmodl(x,2.), which is likely
slow.
PR: 272742
MFC after: 1 week
David Das (das@) committed Bruce Evan's (bde's) WIP code for
expl() and logl() in git revision 25a4d6bfda. That code
included instrumentation that allowed bde to generate pari
scripts used in testing/debugging. This patch removes that
instrumentation as it is unlikely that others will ever use it.
* math/libm/msun/src/math_private.h:
. Remove bde's macros for the generation of pari scripts.
* math/libm/msun/ld128/s_expl.c:
* math/libm/msun/ld128/s_logl.c:
* math/libm/msun/ld80/s_expl.c:
* math/libm/msun/ld80/s_logl.c:
. Remove bde's DOPRINT_START macro.
. Change RETURNP to RETURNF.
. Change RETURN2P to RETURNF. Adjust arguments as needed.
. Change RETURNPI to RETURNI.
. Change RETURN2PI to RETURNI. Adjust arguments as needed.
PR: 272765
MFC after: 1 week
In order to compile lib32 libraries and other 32-bit code on arm64,
<machine/foo.h> needs to be redirected to an arm header rather
than arm64 when building with -m32. Ifdef the arm64 headers that
are installed in /usr/include/machine and used by user-level software
(including references from /usr/include/*.h) so that if __arm__ is
defined when including the arm64 version, <arm/foo.h> is included
rather than using the rest of the file's contents. Some arm headers
had no arm64 equivalent; headers were added just to do the redirection.
These files use #error if __arm__ is not defined to guard against
confusion. Also add an include/arm Makefile, and modify Makefiles
as needed to install everything, including the arm files in
/usr/include/arm. fenv.h comes from lib/msun/arm/fenv.h.
The new arm64 headers are:
acle-compat.h
cpuinfo.h
sysreg.h
Reviewed by: jrtc27, imp
Differential Revision: https://reviews.freebsd.org/D40944
The current versions of lib/msun/src/s_cospi.c, s_sinpi.c and s_tanpi.c
all exhibit the same defect. After checking for various numeric ranges,
they check to see whether the input argument is a NaN or an Infinity.
However, the code uses a value of 0x7f80000 instead of the correct value
of 0x7ff00000.
If you review s_cospif.c, s_sinpif.c, and s_tanpif.c, you will see that
the equivalent statements in these functions are accurate and have
appropriate source comments.
The impact of these defects is to flag some valid input values as
invalid and raise a pole error (divide by zero).
Reported by: Paul Green <Paul.Green@stratus.com>
PR: 272539
MFC after: 1 week
The sincos() man page notes the function was added to msun in FreeBSD
9.0 which must have been an oversight in the review as it was commited
to 12.0 and then backported to the 11 branch.
So I have provided a diff to correct this to the first FreeBSD version
it did ship with which was 11.2.
Reviewed by: dim, imp
MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D40308
The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.
Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix
Simplify the tests for 32-bit arm soft float support. For the files
included only on arm, drop the test entirely. For others, test
MACHINE_CPUARCH against arm.
No functional change intended. File lists appear the same before / after
the change.
Sponsored by: Netflix
Reviewed by: emaste
Differential Revision: https://reviews.freebsd.org/D38582
Summary:
This knob can be used to make buildsystem prefer generic C implentations of
various functions, instead of machine-specific assembler ones.
Test Plan: `make buildworld` on amd64
Reviewed by: imp, emaste
Differential Revision: https://reviews.freebsd.org/D36076
MFC after: 3 days
- s/modfied/modified/
- s/minimun/minimum/
While here, fix some mandoc warnings:
- whitespace at end of input line
- unusual Xr punctuation
- missing comma before name
Obtained from: NetBSD
MFC after: 5 days
Damian McGuckin <damianm at esi dot com dot au> noted that the accuracy
claims in the code for cbrt(3) and cbrtl(3) were incorrect. Fix the
comments to more accurately describe the accuracies.
PR: 265603
MFC after: 3 days
Since https://github.com/llvm/llvm-project/commit/ca75ac5f04f2, clang 15
has a new warning about _Generic selection expressions, such as used in
math.h:
lib/libc/gdtoa/_ldtoa.c:82:10: error: due to lvalue conversion of the controlling expression, association of type 'volatile float' will never be selected because it is qualified [-Werror,-Wunreachable-code-generic-assoc]
switch (fpclassify(u.e)) {
^
lib/msun/src/math.h:109:2: note: expanded from macro 'fpclassify'
__fp_type_select(x, __fpclassifyf, __fpclassifyd, __fpclassifyl)
^
lib/msun/src/math.h:85:14: note: expanded from macro '__fp_type_select'
volatile float: f(x), \
^
This is because the controlling expression always undergoes lvalue
conversion first, dropping any cv-qualifiers. The 'const', 'volatile',
and 'volatile const' associations will therefore never be used.
MFC after: 1 week
Reviewed by: theraven
Differential Revision: https://reviews.freebsd.org/D35815
Summary:
These functions are missing from the library itself, and exist solely in
the header. This breaks a few ports that expect libm to have the
symbols in the library itself.
Questions on MFC-ability: Can this be MFC'd to 13.2, and how?
Reviewers: imp, emaste, kib
Reviewed By: kib
Differential Revision: https://reviews.freebsd.org/D35204
There are some sections which could be improved
and work to do so is on going. The work will be
covered via 'X-MFC-WITH' commits.
Obtained from: OpenBSD
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D34759
All supported compilers (modern versions of GCC and clang) support
this.
Many places didn't have an #else so would just silently do the wrong
thing. Ancient versions of icc (the original motivation for this) are
no longer a compiler FreeBSD supports.
PR: 263102 (exp-run)
Reviewed by: brooks, imp
Differential Revision: https://reviews.freebsd.org/D34797
. Disconnect imprecise.c from the build. This file can be deleted.
. Add b_tgammal.c to the build for ld80 and ld128 targets. The ld128
is a 'git mv' of imprecise.c to ld128/b_tgammal.c.
* lib/msun/ld80/b_expl.c:
. New file. Implement __exp__D for ld80 targets. This is based on
bsdsrc/b_exp.c.
* lib/msun/ld80/b_logl.c:
. New file. Implement __log__D for ld80 targets. This is based on
bsdsrc/b_log.c.
* lib/msun/ld80/b_tgammal.c b/lib/msun/ld80/b_tgammal.c
. New file. Implement tgammal(x) for ld80 targets.
Submitted by: Steve Kargl
Differential Revision: https://reviews.freebsd.org/D33444
Reviewed by: pfg
. Disconnect b_exp.c and b_log.c from the build.
* lib/msun/bsdsrc/b_exp.c:
. Replace scalb() usage with C99's ldexp().
. Replace finite(x) usage with C99's isfinite().
. Whitespace changes towards style(9).
. Remove include of "mathimpl.h". It is no longer needed.
. Remove #if 0 ... #endif code, which has been present since svn r93211
(2002-03-26).
. New minimax polynomial coefficients.
. Add comments to explain origins of some constants.
. Use ansi-C prototype. Remove K&R prototype. Add static to prototype.
* lib/msun/bsdsrc/b_log.c:
. Remove include of "mathimpl.h". It is no longer needed.
. Fix comments to actually describe the code.
. Reduce minimax polynomial from degree 4 to degree 3.
This uses newly computed coefficients.
. Use ansi-C prototype. Remove K&R prototype. Add static to prototype.
. Remove volatile in declaration of u1.
. Alphabetize decalaration list.
. Whitespace changes towards style(9).
. In argument reduction of x to g and m, replace use of logb() and
ldexp() with a single call to frexp(). Add code to get 1 <= g < 2.
. Remove #if 0 ... #endif code, which has been present since svn r93211
(2002-03-26).
. The special case m == -1022, replace logb() with ilogb().
* lib/msun/bsdsrc/b_tgamma.c:
. Update comments. Fix comments where needed.
. Add float.h to get LDBL_MANT_DIG for weak reference of tgammal to tgamma.
. Remove include of "mathimpl.h". It is no longer needed.
. Use "math.h" instead of <math.h>.
. Add '#include math_private.h"
. Add struct Double from mathimpl.h and include b_log.c and b_exp.c.
. Remove forward declarations of neg_gam(), small_gam(), smaller_gam,
large_gam() and ratfun_gam() by re-arranging the code to move these
function above their first reference.
. New minimax coefficients for polynomial in large_gam().
. New splitting of a0 into a0hi nd a0lo, which include additional
bits of precision.
. Use ansi-C prototype. Remove K&R prototype.
. Replace the TRUNC() macro with a simple cast of a double entities
to float before assignment (functional changes).
. Replace sin(M_PI*z) with sinpi(z) and cos(M_PI*(0.5-z)) with cospi(0.5-z).
Submitted by: Steve Kargl
Differential Revision: https://reviews.freebsd.org/D33444
Reviewed by: pfg
This look like a copy and paste leftover.
Reported by: enh@google.com (via freebsd-numerics@)
Reviewed by: Steve Kargl <sgk@troutmask.apl.washington.edu>
MFC after: 3 days
Some of the functions in msun can be implemented using a compiler
builtin function to generate a small number of instructions. Implement
this support in fma, fmax, fmin, and sqrt on arm64.
Care must be taken as the builtin can be implemented as a function
call on some architectures that lack direct support. In these cases
we need to use the original code path.
As we don't set errno on failure build with -fno-math-errno so the
toolchain doesn't convert a builtin into a function call when it
detects a failure, e.g. gcc will add a call to sqrt when the input
is negative leading to an infinite loop.
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D32801
