1 .\" Copyright (c) 2023 The FreeBSD Foundation
3 .\" This documentation was written by Robert Clausecker <fuz@FreeBSD.org>
4 .\" under sponsorship from the FreeBSD Foundation.
6 .\" Redistribution and use in source and binary forms, with or without
7 .\" modification, are permitted provided that the following conditions
9 .\" 1. Redistributions of source code must retain the above copyright
10 .\" notice, this list of conditions and the following disclaimer.
11 .\" 2. Redistributions in binary form must reproduce the above copyright
12 .\" notice, this list of conditions and the following disclaimer in the
13 .\" documentation and/or other materials provided with the distribution.
15 .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ''AS IS'' AND
16 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 .\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 On some architectures, the
38 provides enhanced implementations of commonly used functions, replacing
39 the architecture-independent implementations used otherwise.
40 Depending on architecture and function, an enhanced
41 implementation of a function may either always be used or the
43 detects at runtime which SIMD instruction set extensions are
44 supported and picks the most suitable implementation automatically.
47 the environment variable
49 can be used to override this mechanism.
51 Enhanced functions are present for the following architectures:
52 .Bl -column FUNCTION_________ aarch64_ arm_ amd64_ i386_ ppc64_ -offset indent
53 .It Em FUNCTION Ta Em AARCH64 Ta Em ARM Ta Em AMD64 Ta Em I386 Ta Em PPC64
54 .It bcmp Ta Ta Ta S1 Ta S
55 .It bcopy Ta Ta S Ta S Ta S Ta SV
56 .It bzero Ta Ta S Ta S Ta S
57 .It div Ta Ta Ta S Ta S
58 .It index Ta S Ta Ta S1
59 .It ldiv Ta Ta Ta S Ta S
61 .It memchr Ta S Ta Ta S1
62 .It memcmp Ta S Ta S Ta S1 Ta S
63 .It memcpy Ta S Ta S Ta S Ta S Ta SV
64 .It memmove Ta S Ta S Ta S Ta S Ta SV
65 .It memset Ta S Ta S Ta S Ta S
66 .It rindex Ta S Ta Ta S1 Ta S
67 .It stpcpy Ta S Ta Ta S1
68 .It stpncpy Ta Ta Ta S1
69 .It strcat Ta Ta Ta S1 Ta S
70 .It strchr Ta S Ta Ta S1 Ta S
71 .It strchrnul Ta S Ta Ta S1
72 .It strcmp Ta S Ta S Ta S1 Ta S
73 .It strcpy Ta S Ta Ta S1 Ta S Ta S2
74 .It strcspn Ta Ta Ta S2
75 .It strlcat Ta Ta Ta S1
76 .It strlcpy Ta Ta Ta S1
77 .It strlen Ta S Ta S Ta S1
78 .It strncmp Ta S Ta S Ta S1 Ta S
79 .It strncpy Ta Ta Ta S1 Ta Ta S2
80 .It strnlen Ta S Ta Ta S1
81 .It strrchr Ta S Ta Ta S1 Ta S
82 .It strpbrk Ta Ta Ta S2
83 .It strsep Ta Ta Ta S2
84 .It strspn Ta Ta Ta S2
85 .It swab Ta Ta Ta Ta S
86 .It timingsafe_bcmp Ta Ta Ta S1
87 .It timingsafe_memcmp Ta Ta Ta S
88 .It wcschr Ta Ta Ta Ta S
89 .It wcscmp Ta Ta Ta Ta S
90 .It wcslen Ta Ta Ta Ta S
91 .It wmemchr Ta Ta Ta Ta S
94 .Sy S Ns :\ scalar (non-SIMD),
95 .Sy 1 Ns :\ amd64 baseline,
98 .Sy 3 Ns :\ x86-64-v3,
99 .Sy 4 Ns :\ x86-64-v4,
100 .Sy V Ns :\ PowerPC\ VSX.
107 controls the level of SIMD enhancements used.
108 If this variable is set to an architecture level from the list below
109 and that architecture level is supported by the processor, SIMD
115 is unset, not recognised, or not supported by the processor, the highest
116 level of SIMD enhancements supported by the processor is used.
118 A suffix beginning with
124 is ignored and may be used for future extensions.
125 The architecture level can be prefixed with a
127 character to force use of the requested architecture level, even if the
128 processor does not advertise that it is supported.
129 This usually causes applications to crash and should only be used for
130 testing purposes or if architecture level detection yields incorrect
133 The architecture levels follow the AMD64 SysV ABI supplement:
134 .Bl -tag -width x86-64-v2
136 scalar enhancements only (no SIMD)
138 cmov, cx8, x87 FPU, fxsr, MMX, osfxsr, SSE, SSE2
140 cx16, lahf/sahf, popcnt, SSE3, SSSE3, SSE4.1, SSE4.2
142 AVX, AVX2, BMI1, BMI2, F16C, FMA, lzcnt, movbe, osxsave
150 .It "Illegal Instruction"
153 if a command is terminated through delivery of a
158 Use of an unsupported architecture level was forced by setting
160 to a string beginning with a
162 character, causing a process to crash due to use of an unsupported
168 prefix or select a supported architecture level.
170 Message may also appear for unrelated reasons.
180 .%A Jan Hubi\[u010D]ka \" \(vc
183 .%B System V Application Binary Interface
185 .%T AMD64 Architecture Processor Supplement
190 Architecture-specific enhanced
192 functions were added starting
210 SIMD-enhanced functions were first added with
221 manual page appeared in
225 .An Robert Clausecker Aq Mt fuz@FreeBSD.org
230 such as cryptographic routines in the kernel or in
231 OpenSSL may also use SIMD enhancements.
232 These enhancements are not subject to the
234 variable and may have their own configuration
238 Use of SIMD enhancements cannot be configured on powerpc64.