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Hi! I still have problems with the compiler-switches. I have written a program, which should measure how many clock-ticks a multiply&acc. (mla) operation takes on my arm7tdmi-cpu. If I do not use -O2, I get a big measure-overhead and three clock-ticks for a "mla", which is the correct value. If I use optimization, I get a small overhead, but an average of 4.5 clock-ticks: without -O2 Breakpoint 2, main () at multiplikation.mla.mess0bis32.c:75 # mla and Timer-Ticks: 0 15 # mla and Timer-Ticks: 1 17 # mla and Timer-Ticks: 4 27 # mla and Timer-Ticks: 8 38 # mla and Timer-Ticks: 16 66 # mla and Timer-Ticks: 32 110 summe: 6 with -O2 Breakpoint 2, main () at multiplikation.mla.mess0bis32.c:77 # mla and Timer-Ticks: 0 2 # mla and Timer-Ticks: 1 6 # mla and Timer-Ticks: 4 20 # mla and Timer-Ticks: 8 38 # mla and Timer-Ticks: 16 78 # mla and Timer-Ticks: 32 146 summe: 6 I compile with: arm-elf-gcc -mapcs-32 -mapcs-frame -mcpu=arm7tdmi -DAT91M40400 -DDEBUG\ -I/home/hiwi/lache/c/Include -O2 -o multiplikation.mla.mess0bis32.arm\ -Wl,-T/home/hiwi/lache/c/linker/linker.script.sc \ multiplikation.mla.mess0bis32.c arm-elf-gcc -mapcs-32 -mapcs-frame -mcpu=arm7tdmi -DAT91M40400\ -DDEBUG -I/home/hiwi/lache/c/Include -S -O2 multiplikation.mla.mess0bis32.c The funny thing is, that the assembler looks allright... What can that be? Jens-Christian ------ Want more information? See the CrossGCC FAQ, http://www.objsw.com/CrossGCC/ Want to unsubscribe? Send a note to crossgcc-unsubscribe@sourceware.cygnus.com
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