crosscflags

open source bios with linux platform, very good and can be reused.

#!/bin/sh

host=$1
target=$2

if test "$host" = "powerpc" -o "$host" = "mips" -o "$host" = "s390" \
	   -o "$host" = "sparc32" -o "$host" = "sparc64" \
	   -o "$host" = "m68k" -o "$host" = "armv4b"; then
    hostbigendian="yes"
else
    hostbigendian="no"
fi

# host long bits test
if test "$host" = "sparc64" -o "$host" = "ia64" \
	   -o "$host" = "amd64" -o "$host" = "alpha"; then
    hostlongbits="64"
else
    hostlongbits="32"
fi

if test "$target" = "powerpc" -o "$target" = "mips" -o "$target" = "s390" \
	   -o "$target" = "sparc32" -o "$target" = "sparc64" \
	   -o "$target" = "m68k" -o "$target" = "armv4b"; then
    targetbigendian="yes"
else
    targetbigendian="no"
fi

# target long bits test
if test "$target" = "sparc64" -o "$target" = "ia64" \
	   -o "$target" = "amd64" -o "$target" = "alpha"; then
    targetlongbits="64"
else
    targetlongbits="32"
fi

if test "$targetbigendian" = "$hostbigendian"; then
    cflags="-USWAP_ENDIANNESS"
else
    cflags="-DSWAP_ENDIANNESS"
fi

if test "$targetlongbits" = "$hostlongbits"; then
    cflags="$cflags -DNATIVE_BITWIDTH_EQUALS_HOST_BITWIDTH"
elif test "$targetlongbits" -lt "$hostlongbits"; then
    cflags="$cflags -DNATIVE_BITWIDTH_SMALLER_THAN_HOST_BITWIDTH"
else
    cflags="$cflags -DNATIVE_BITWIDTH_LARGER_THAN_HOST_BITWIDTH"
fi

if test "$host" = "x86" -a "$targetlongbits" = "64"; then
    cflags="$cflags -DNEED_FAKE_INT128_T"
fi

echo "$cflags"