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Hi, this may be a bug in the m68k machine description for gcc. In order to confirm it, can you please re-run your compile and link commands, but add the option '-v' to the each of the command lines, to generate a verbose listing of the compiler's activity; and then please post the output to the list. Until we get this sorted out, the safest option is to not use -mshort or -mrtd. This is very surprising. These two options have existed in gcc for a long time. Thanks for your great detective work! Scott scott@objsw.com Arjan Koers wrote: > > Hi All, > > I am using GNU GCC (from objsw.com) to build a library > that can be loaded into an embedded 68340 system. The software on > this system is using Pascal calling conventions. > > The closest I could get to Pascal calling conventions with GCC is by > using the -mrtd option when compiling: > gcc -b 68k -mcpu32 -mshort -mrtd -c -o file.o file.c > The order of the arguments on the stack is still wrong, but I can > live with that. > > GCC does not use the -mrtd calling convention for all functions that > get called. > My own functions get called with the -mrtd calling convention, and > library functions like strcpy and sin too (called function pops > arguments from stack). > Functions like __floatsidf are not called with this calling > convention (calling function pops arguments from stack). > > With and without the -mrtd option, the asm output of the function > call looks something like this (argument is popped after call): > x = (double)i; > 3001e: 306e 0008 moveaw %fp@(8),%a0 > 30022: 2f08 movel %a0,%sp@- > 30024: 4eb9 0003 0050 jsr 30050 <__floatsidf> > 3002a: 588f addql #4,%sp > 3002c: 2d40 fff8 movel %d0,%fp@(-8) > 30030: 2d41 fffc movel %d1,%fp@(-4) > > The linked __floatsidf function is as expected: > > gcc -b 68k -mcpu32 -mshort -mrtd -Tlinkfile.ld -o file.cof file.o > 00030050 <__floatsidf>: > 30050: 4e56 0000 linkw %fp,#0 > .... > 300ca: 4e5e unlk %fp > 300aa: 4e74 0004 rtd #4 > > gcc -b 68k -mcpu32 -mshort -Tlinkfile.ld -o file.cof file.o > 00030050 <__floatsidf>: > 30050: 4e56 0000 linkw %fp,#0 > .... > 300ca: 4e5e unlk %fp > 300cc: 4e75 rts > > When linking with -mrtd, the stack gets corrupted: The function > arguments are popped twice for __floatsidf. > When linking without -mrtd, the stack gets corrupted too: The > function arguments aren't popped for strcpy. > > Is there a solution to this problem that does not involve > editing asm intermediate files? > > A call to strcpy is changed to a call to bcopy if optimisation is > turned on and the string is long enough. The stack gets corrupted > again: > > strcpy(pch, "Testing my 'Hello World!' string"); > 30044: 3f3c 0021 movew #33,%sp@- > 30048: 2f02 movel %d2,%sp@- > 3004a: 487a ffc4 pea %pc@(30010 <.text>) > 3004e: 4eb9 0003 0064 jsr 30064 <bcopy> > > 00030064 <bcopy>: > 30064: 4e56 0000 linkw %fp,#0 > 30068: 2f2e 0010 movel %fp@(16),%sp@- > 3006c: 2f2e 0008 movel %fp@(8),%sp@- > 30070: 2f2e 000c movel %fp@(12),%sp@- > 30074: 4eb9 0003 0080 jsr 30080 <memmove> > 3007a: 4e5e unlk %fp > 3007c: 4e74 000c rtd #12 > > I can solve this by replacing 'movew #33,%sp@-' by 'movel #33,%sp@-', > but I would like to fix this without having to edit the intermediate > asm files. Another solution is not using the -mshort option, but > the int size preferably is 16-bit. > > Thanks, > > Arjan Koers. > _______________________________________________ > New CrossGCC FAQ: http://www.objsw.com/CrossGCC > _______________________________________________ > To remove yourself from the crossgcc list, send > mail to crossgcc-request@cygnus.com with the > text 'unsubscribe' (without the quotes) in the > body of the message. _______________________________________________ New CrossGCC FAQ: http://www.objsw.com/CrossGCC _______________________________________________ To remove yourself from the crossgcc list, send mail to crossgcc-request@cygnus.com with the text 'unsubscribe' (without the quotes) in the body of the message.