From 57b753b445e23363c997a8ec1c556e0b0f6e9da3 Mon Sep 17 00:00:00 2001 From: Diego Biurrun Date: Thu, 13 Oct 2016 20:33:15 +0200 Subject: build: Prefer NASM assembler over YASM NASM is more actively maintained and permits generating dependency information as a sideeffect of assembling, thus cutting build times in half. --- doc/optimization.txt | 8 ++++---- doc/platform.texi | 12 ++++++------ 2 files changed, 10 insertions(+), 10 deletions(-) (limited to 'doc') diff --git a/doc/optimization.txt b/doc/optimization.txt index be12d85..3277b9b 100644 --- a/doc/optimization.txt +++ b/doc/optimization.txt @@ -161,8 +161,8 @@ do{ For x86, mark registers that are clobbered in your asm. This means both general x86 registers (e.g. eax) as well as XMM registers. This last one is particularly important on Win64, where xmm6-15 are callee-save, and not -restoring their contents leads to undefined results. In external asm (e.g. -yasm), you do this by using: +restoring their contents leads to undefined results. In external asm, +you do this by using: cglobal function_name, num_args, num_regs, num_xmm_regs In inline asm, you specify clobbered registers at the end of your asm: __asm__(".." ::: "%eax"). @@ -194,12 +194,12 @@ The latter requires a good optimizing compiler which gcc is not. Inline asm vs. external asm --------------------------- Both inline asm (__asm__("..") in a .c file, handled by a compiler such as gcc) -and external asm (.s or .asm files, handled by an assembler such as yasm/nasm) +and external asm (.s or .asm files, handled by an assembler such as nasm/yasm) are accepted in Libav. Which one to use differs per specific case. - if your code is intended to be inlined in a C function, inline asm is always better, because external asm cannot be inlined -- if your code calls external functions, yasm is always better +- if your code calls external functions, external asm is always better - if your code takes huge and complex structs as function arguments (e.g. MpegEncContext; note that this is not ideal and is discouraged if there are alternatives), then inline asm is always better, because predicting diff --git a/doc/platform.texi b/doc/platform.texi index 74b014e..dc20d67 100644 --- a/doc/platform.texi +++ b/doc/platform.texi @@ -69,9 +69,9 @@ OS X on PowerPC or ARM (iPhone) requires a preprocessor from assembly functions. Put the Perl script somewhere in your PATH, Libav's configure will pick it up automatically. -OS X on AMD64 and x86 requires @command{yasm} to build most of the +OS X on AMD64 and x86 requires @command{nasm} to build most of the optimized assembly functions @url{http://mxcl.github.com/homebrew/, Homebrew}, -@url{http://www.gentoo.org/proj/en/gentoo-alt/prefix/bootstrap-macos.xml, Gentoo Prefix} +@url{https://wiki.gentoo.org/wiki/Project:Prefix, Gentoo Prefix} or @url{http://www.macports.org, MacPorts} can easily provide it. @@ -134,7 +134,7 @@ them under @command{MinGW-w64 Win64 Shell} and @command{MinGW-w64 Win32 Shell}. pacman -S make pkgconf diffutils # mingw-w64 packages and toolchains -pacman -S mingw-w64-x86_64-yasm mingw-w64-x86_64-gcc mingw-w64-x86_64-SDL +pacman -S mingw-w64-x86_64-nasm mingw-w64-x86_64-gcc mingw-w64-x86_64-SDL @end example To target 32 bits replace @code{x86_64} with @code{i686} in the command above. @@ -152,14 +152,14 @@ You will need the following prerequisites: @item @uref{http://code.google.com/p/msinttypes/, msinttypes} (if using MSVC 2012 or earlier) @item @uref{http://msys2.github.io/, MSYS2} -@item @uref{http://yasm.tortall.net/, YASM} +@item @uref{http://www.nasm.us/, NASM} (Also available via MSYS2's package manager.) @end itemize To set up a proper environment in MSYS2, you need to run @code{msys_shell.bat} from the Visual Studio or Intel Compiler command prompt. -Place @code{yasm.exe} somewhere in your @code{PATH}. If using MSVC 2012 or +Place @code{nasm.exe} somewhere in your @code{PATH}. If using MSVC 2012 or earlier, place @code{c99wrap.exe} and @code{c99conv.exe} somewhere in your @code{PATH} as well. @@ -307,7 +307,7 @@ These library packages are only available from @uref{http://sourceware.org/cygwinports/, Cygwin Ports}: @example -yasm, libSDL-devel, libfaac-devel, libgsm-devel, libmp3lame-devel, +nasm, libSDL-devel, libfaac-devel, libgsm-devel, libmp3lame-devel, libschroedinger1.0-devel, speex-devel, libtheora-devel, libxvidcore-devel @end example -- cgit v1.1