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On 13-Sep-98 Guido Pohl wrote: > What is the best way to handle the interrupt service routines? I really > do not mean assembler for the interrupt routines itself ;-)! > > One possible solution. that I can think of, is to use somekind of a > wrapper function written in assembler, which one and only function is to > call the actual c-function. This is the method I have used. You also need to push all the 68k registers onto the stack before calling the C function. The code I have also pushes the current stack pointer to make the saved registers and the 68k exception data available as an argument to the C function. This is useful for BusError etc. but it is an additional overhead which you may not want. I can send you the code if it helps. > Another way would be to write a header and trailer for the c-function > that clean up the stack. The header would fake the stack, i.e. it would > put the status register on the stack. The trailer would then have an rte > after it cleaned up the stack frame of the c-function. I don't know of a way of doing this with gcc, but if anyone does it would save one level of call/return. -- Mark Powell, Senior Software Engineer, Primagraphics Limited New Cambridge House, Litlington, nr.Royston, Herts, SG8 0SS, UK Tel. +44 1763 852222, Fax. 853324, medp@primag.co.uk, http://www.primag.co.uk