[TUHS] recreating C source from binary

Hi, I'm trying to re-create the source files for the Z8000 UNIX I have on my Z8000 system (it is a S8000+ZEUS clone). Easy programs like sync.c where easy. But when argc/argv is involved, I'm not able to generate 1:1 matching binary code. I'm working on /etc/unlink for now. I tried the following C file: char whatstr[] = "(a)[$]unlink.c 2.1 07/23/82 21:19:30 - 87wega3.2"; main(argc, argv) int argc; char **argv; { if(argc!=2) { write(2, "Usage: /etc/unlink name\n", 24); exit(1); } unlink(argv[1]); exit(0); } The original ASM code for the beginning of main() until the argc check is: 0042 abf3 dec r15,#4 0044 5df60000 ldl %0000(r15),rr6 0048 0b070002 cp r7,#%0002 The ASM code my C file generates is: 0042 abf3 dec r15,#4 0044 1df6 ldl @r15,rr6 0046 0b070002 cp r7,#%0002 keep in mine, that r15 is considered as the "stack pointer". I wonder how to get the ldl from the original binary. I also tried to declare argv with "char *argv[]" which resulted in the same code. Forcing the compiler to store argv into a register by using the "register" keyword results in completly different code: (sp = stack pointer = r15) #17 adb unlink ADB: P8000 1.6 ? 0x0042/i %0042: dec sp,#6 ? %0044: ld %0004(sp),r14 ? %0048: ld %0002(sp),r7 ? %004c: ld r14,r6 ? %004e: cp r7,#%0002 ? $q #18 Maybe the C compiler used to compile /etc/unlink differs from the C compiler shipped with the system (maybe an older version) but I don't want this to be true for now ;) Anyone with deeper ASM and C knowledge than me sees what could be done here? Before someone asks - yes I'm sure the source file was in C and not ASM based on the whatstr. Symboltable of the original /etc/unlink is empty as well (striped binary). Regards, Oliver