diff options
| author | Christophe Gisquet <christophe.gisquet@gmail.com> | 2015-02-08 12:18:27 +0100 |
|---|---|---|
| committer | Michael Niedermayer <michaelni@gmx.at> | 2015-02-17 13:08:04 +0100 |
| commit | bc8e044d8c3277958c920091412b77d4e7411d96 (patch) | |
| tree | 61173f1e201e5e458cd1d1a8c4353cdf1b0f8eea /doc/optimization.txt | |
| parent | d9293c776ed9129acaf3d41fb727380c293dc943 (diff) | |
x86/doc/Makefile: DBG=1 to preprocess external asm
The macro hell sometimes make it difficult to trace the source of
an error, so it is easier to analyze the preprocessed output.
This patch makes this automatical by specifying DBG=1 on the
command line: a file ffmpeg/dir/file.asm gets preprocessed to
builddir/dir/file.dbg.asm, which is then compiled.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Diffstat (limited to 'doc/optimization.txt')
| -rw-r--r-- | doc/optimization.txt | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/doc/optimization.txt b/doc/optimization.txt index 94a4277326..1a0b98cd0e 100644 --- a/doc/optimization.txt +++ b/doc/optimization.txt @@ -191,6 +191,11 @@ __asm__() block. Use external asm (nasm/yasm) or inline asm (__asm__()), do not use intrinsics. The latter requires a good optimizing compiler which gcc is not. +When debugging a x86 external asm compilation issue, if lost in the macro +expansions, add DBG=1 to your make command-line: the input file will be +preprocessed, stripped of the debug/empty lines, then compiled, showing the +actual lines causing issues. + Inline asm vs. external asm --------------------------- Both inline asm (__asm__("..") in a .c file, handled by a compiler such as gcc) |