ax_ext

Find supported SIMD extensions by requesting cpuid. When an SIMD extension is found, the -m"simdextensionname" is added to SIMD_FLAGS (only if compilator support it) (ie : if "sse2" is available "-msse2" is added to SIMD_FLAGS)

This macro calls:

  AC_SUBST(SIMD_FLAGS)

And defines:

  HAVE_MMX / HAVE_SSE / HAVE_SSE2 / HAVE_SSE3 / HAVE_SSSE3

AC_DEFUN([AX_EXT],
[
  AC_REQUIRE([AX_GCC_X86_CPUID])

  AX_GCC_X86_CPUID(0x00000001)
  ecx=`echo $ax_cv_gcc_x86_cpuid_0x00000001 | cut -d ":" -f 3`
  edx=`echo $ax_cv_gcc_x86_cpuid_0x00000001 | cut -d ":" -f 4`

 AC_CACHE_CHECK([whether mmx is supported], [ax_have_mmx_ext],
  [
    ax_have_mmx_ext=no
    if test "$((0x$edx>>23&0x01))" = 1; then
      ax_have_mmx_ext=yes
    fi
  ])

 AC_CACHE_CHECK([whether sse is supported], [ax_have_sse_ext],
  [
    ax_have_sse_ext=no
    if test "$((0x$edx>>25&0x01))" = 1; then
      ax_have_sse_ext=yes
    fi
  ])

 AC_CACHE_CHECK([whether sse2 is supported], [ax_have_sse2_ext],
  [
    ax_have_sse2_ext=no
    if test "$((0x$edx>>26&0x01))" = 1; then
      ax_have_sse2_ext=yes
    fi
  ])

 AC_CACHE_CHECK([whether sse3 is supported], [ax_have_sse3_ext],
  [
    ax_have_sse3_ext=no
    if test "$((0x$ecx&0x01))" = 1; then
      ax_have_sse3_ext=yes
    fi
  ])

 AC_CACHE_CHECK([whether ssse3 is supported], [ax_have_ssse3_ext],
  [
    ax_have_ssse3_ext=no
    if test "$((0x$ecx>>9&0x01))" = 1; then
      ax_have_ssse3_ext=yes
    fi
  ])

  if test "$ax_have_mmx_ext" = yes; then
    AC_DEFINE(HAVE_MMX,,[Support mmx instructions])
    AX_CHECK_COMPILER_FLAGS(-mmmx, SIMD_FLAGS="$SIMD_FLAGS -mmmx", [])
  fi

  if test "$ax_have_sse_ext" = yes; then
    AC_DEFINE(HAVE_SSE,,[Support SSE (Streaming SIMD Extensions) instructions])
    AX_CHECK_COMPILER_FLAGS(-msse, SIMD_FLAGS="$SIMD_FLAGS -msse", [])
  fi

  if test "$ax_have_sse2_ext" = yes; then
    AC_DEFINE(HAVE_SSE2,,[Support SSE2 (Streaming SIMD Extensions 2) instructions])
    AX_CHECK_COMPILER_FLAGS(-msse2, SIMD_FLAGS="$SIMD_FLAGS -msse2", [])
  fi

  if test "$ax_have_sse3_ext" = yes; then
    AC_DEFINE(HAVE_SSE3,,[Support SSE3 (Streaming SIMD Extensions 3) instructions])
    AX_CHECK_COMPILER_FLAGS(-msse3, SIMD_FLAGS="$SIMD_FLAGS -msse3", [])
  fi

  if test "$ax_have_ssse3_ext" = yes; then
    AC_DEFINE(HAVE_SSSE3,,[Support SSSE3 (Supplemental Streaming SIMD Extensions 3) instructions])
  fi

  AC_SUBST(SIMD_FLAGS)
])

Copyright © 2008 Christophe Tournayre <turn3r@users.sourceforge.net>

Copying and distribution of this file, with or without modification, are permitted in any medium without royalty provided the copyright notice and this notice are preserved.