diff options
author | Thiago Macieira <thiago.macieira@intel.com> | 2011-12-29 18:09:46 -0200 |
---|---|---|
committer | Qt by Nokia <qt-info@nokia.com> | 2012-03-28 14:54:12 +0200 |
commit | d43fe0b672a665fc366f7d4a91a522959801165d (patch) | |
tree | 07ef87adf783aea20725597f8732c2bc0b037f65 /src/corelib/global/qfeatures.h | |
parent | d2b1c2ef1f1fea3200d8dee5c58fe79649fd13bb (diff) |
Remove the old code using MMX registers.
There are only 8 MMX registers, each 64-bit wide, and they alias the
x87 registers. The access to the MMX register cannot use the new
VEX-prefix instructions either.
All of the functions being replaced are either present in the
qdrawhelper_sse2.cpp and qdrawhelper_ssse3.cpp files, or the plain C++
function in qdrawhelper.cpp is vectorised when compiled with
-ftree-vectorize (enabled in -O3), if SSE2 support is enabled.
All x86-64 processors have SSE2, so this is a net improvement for
64-bit builds. For 32-bit builds, without further support this will
cause the code to use non-vector or x87 instructions, which aren't the
best. The solution will come in another commit.
Change-Id: I4a22d8a2516b79172867510202d0fd627db54807
Reviewed-by: Samuel Rødal <samuel.rodal@nokia.com>
Diffstat (limited to 'src/corelib/global/qfeatures.h')
0 files changed, 0 insertions, 0 deletions