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Diffstat (limited to 'Build/source/libs/libpng/libpng-src/INSTALL')
| -rw-r--r-- | Build/source/libs/libpng/libpng-src/INSTALL | 67 |
1 files changed, 59 insertions, 8 deletions
diff --git a/Build/source/libs/libpng/libpng-src/INSTALL b/Build/source/libs/libpng/libpng-src/INSTALL index 48b1250492b..e8edb7240f4 100644 --- a/Build/source/libs/libpng/libpng-src/INSTALL +++ b/Build/source/libs/libpng/libpng-src/INSTALL @@ -16,10 +16,11 @@ Contents XI. Prepending a prefix to exported symbols XII. Configuring for compiler xxx: XIII. Removing unwanted object code - XIV. Changes to the build and configuration of libpng in libpng-1.5.x - XV. Setjmp/longjmp issues - XVI. Common linking failures - XVII. Other sources of information about libpng + XIV. Enabling or disabling hardware optimizations + XV. Changes to the build and configuration of libpng in libpng-1.5.x + XVI. Setjmp/longjmp issues + XVII. Common linking failures + XVIII. Other sources of information about libpng I. Simple installation @@ -281,7 +282,57 @@ library to fail if they call functions not available in your library. The size of the library itself should not be an issue, because only those sections that are actually used will be loaded into memory. -XIV. Changes to the build and configuration of libpng in libpng-1.5.x +XIV. Enabling or disabling hardware optimizations + +Certain hardware capabilites, such as the Intel SSE instructions, +are normally detected at run time. Enable them with configure options +such as one of + + --enable-arm-neon=yes + --enable-mips-msa=yes + --enable-intel-sse=yes + --enable-powerpc-vsx=yes + +or enable them all at once with + + --enable-hardware-optimizations=yes + +or, if you are not using "configure", you can use one +or more of + + CPPFLAGS += "-DPNG_ARM_NEON" + CPPFLAGS += "-DPNG_MIPS_MSA" + CPPFLAGS += "-DPNG_INTEL_SSE" + CPPFLAGS += "-DPNG_POWERPC_VSX" + +See for example scripts/makefile.linux-opt + +If you wish to avoid using them, +you can disable them via the configure option + + --disable-hardware-optimizations + +to disable them all, or + + --enable-intel-sse=no + +to disable a particular one, +or via compiler-command options such as + + CPPFLAGS += "-DPNG_ARM_NEON_OPT=0, -DPNG_MIPS_MSA_OPT=0, + -DPNG_INTEL_SSE_OPT=0, -DPNG_POWERPC_VSX_OPT=0" + +If you are using cmake, hardware optimizations are "on" +by default. To disable them, use + + cmake . -DPNG_ARM_NEON=no -DPNG_INTEL_SSE=no \ + -DPNG_MIPS_MSA=no -DPNG_POWERPC_VSX=no + +or disable them all at once with + + cmake . -DPNG_HARDWARE_OPTIMIZATIONS=no + +XV. Changes to the build and configuration of libpng in libpng-1.5.x Details of internal changes to the library code can be found in the CHANGES file and in the GIT repository logs. These will be of no concern to the vast @@ -372,7 +423,7 @@ $PREFIX/include directory). Do not edit pnglibconf.h after you have built libpng, because than the settings would not accurately reflect the settings that were used to build libpng. -XV. Setjmp/longjmp issues +XVI. Setjmp/longjmp issues Libpng uses setjmp()/longjmp() for error handling. Unfortunately setjmp() is known to be not thread-safe on some platforms and we don't know of @@ -390,7 +441,7 @@ This requires setjmp/longjmp, so you must either build the library with PNG_SETJMP_SUPPORTED defined, or with PNG_SIMPLIFIED_READ_SUPPORTED and PNG_SIMPLIFIED_WRITE_SUPPORTED undefined. -XVI. Common linking failures +XVII. Common linking failures If your application fails to find libpng or zlib entries while linking: @@ -402,7 +453,7 @@ If your application fails to find libpng or zlib entries while linking: If you are using the vstudio project, observe the WARNING in project/vstudio/README.txt. -XVII. Other sources of information about libpng: +XVIII. Other sources of information about libpng: Further information can be found in the README and libpng-manual.txt files, in the individual makefiles, in png.h, and the manual pages |