I used advice from https://stackoverflow.com/questions/106387/is-it-possible-to-detect-32-bit-v... and reworked my patch like this: --- /dev/null 2020-07-19 09:07:01.788494015 +0300 +++ multilib.sh 2020-08-02 02:34:58.444933214 +0300 @@ -0,0 +1,54 @@ +#!/bin/sh + +mkdir -p 8bit 10bit 12bit + + +cd 12bit +if [ $(uname -m) == 'x86_64' ]; then + # 64-bit stuff here +cmake ../source -DHIGH_BIT_DEPTH=ON -DENABLE_ASSEMBLY=ON -DEXPORT_C_API=OFF -DENABLE_SHARED=OFF -DENABLE_CLI=OFF -DMAIN12=ON +else + # 32-bit stuff here +cmake ../source -DHIGH_BIT_DEPTH=ON -DENABLE_ASSEMBLY=OFF -DEXPORT_C_API=OFF -DENABLE_SHARED=OFF -DENABLE_CLI=OFF -DMAIN12=ON +fi +make -j 1 + +cd ../10bit +if [ $(uname -m) == 'x86_64' ]; then + # 64-bit stuff here +cmake ../source -DHIGH_BIT_DEPTH=ON -DENABLE_ASSEMBLY=ON -DEXPORT_C_API=OFF -DENABLE_SHARED=OFF -DENABLE_CLI=OFF +else + # 32-bit stuff here +cmake ../source -DHIGH_BIT_DEPTH=ON -DENABLE_ASSEMBLY=OFF -DEXPORT_C_API=OFF -DENABLE_SHARED=OFF -DENABLE_CLI=OFF +fi +make -j 1 + +cd ../8bit +ln -sf ../10bit/libx265.a libx265_main10.a +ln -sf ../12bit/libx265.a libx265_main12.a +cmake ../source -DEXTRA_LIB="x265_main10.a;x265_main12.a" -DENABLE_SHARED=OFF -DEXTRA_LINK_FLAGS=-L. -DLINKED_10BIT=ON -DLINKED_12BIT=ON +make -j 1 + +# rename the 8bit library, then combine all three into libx265.a +mv libx265.a libx265_main.a + +uname=`uname` +if [ "$uname" = "Linux" ] +then + +# On Linux, we use GNU ar to combine the static libraries together +ar -M <<EOF +CREATE libx265.a +ADDLIB libx265_main.a +ADDLIB libx265_main10.a +ADDLIB libx265_main12.a +SAVE +END +EOF + +else + +# Mac/BSD libtool +libtool -static -o libx265.a libx265_main.a libx265_main10.a libx265_main12.a 2>/dev/null + +fi hopefully it should enable assembly for 10/12 bit depth on x86_64, and disable it on my i686 - but UNTESTED for now due to lack of sleep.