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Date: Mon, 01 Nov 1999 19:04:43 +0100 From: Kai Schaeffer <kschaeffer@schaeffer-apparatebau.de> I have a little Problem, with the optimization of the gcc (m68k, version 2.8.1). I want to wait until a value of a variable changes. So I write something like that: char c; test() { c=1; while(c); } The changing of 'c' happens in an interrupt routine. If I turn the optimization with -O2 on, the compiler produces code like this: move.b c,%d0 .L6: tst.b %d0 jbne .L6 Of course the programm doesn't notice the changing of the value of 'c'. Are there any arguments for a variable that the compiler doesn't use a register? The canonical solution is to change char c; to volatile char c; ------ 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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