Notes for Particular Systems

AIX 4.3

Targets `*-*-aix4.[3-9]*' have shared libraries disabled since they seem to fail on AIX 4.3.

OpenBSD 2.6

m4 in this release of OpenBSD has a bug in eval that makes it unsuitable for `.asm' file processing. `./configure' will detect the problem and either abort or choose another m4 in the @env{PATH}. The bug is fixed in OpenBSD 2.7, so either upgrade or use GNU m4.

Sparc V8

Using CPU target `sparcv8' or `supersparc' on relevant systems will give a significant performance increase over the V7 code.

SunOS 4

/usr/bin/m4 lacks various features needed to process `.asm' files, and instead `./configure' will automatically use /usr/5bin/m4, which we believe is always available (if not then use GNU m4).

x86 Pentium and PentiumPro

The Intel Pentium P5 code is good for its intended P5, but quite slow when run on Intel P6 class chips (PPro, P-II, P-III). `i386' is a better choice if you're making binaries that must run on both.

x86 MMX and old GAS

Old versions of GAS don't support MMX instructions, in particular version 1.92.3 that comes with FreeBSD 2.2.8 doesn't (and unfortunately there's no newer assembler for that system). If the target CPU has MMX code but the assembler doesn't support it, a warning is given and non-MMX code is used instead. This will be an inferior build, since the MMX code that's present is there because it's faster than the corresponding plain integer code.

x86 GCC 2.95.2 `-march=pentiumpro'

GCC 2.95.2 miscompiles `mpz/powm.c' when `-march=pentiumpro' is used, so that option is omitted from the @env{CFLAGS} chosen for relevant CPUs. The problem is believed to be fixed in GCC 2.96.

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