Basic ABI: SysV i386 Out-of-Process Method Invocation: Caller: eax: pointer to parameter info block (PIB) Call 0x7fff0000 to invoke the method. Upon return: ebx, esi, edi, ebp, esp: preserved eax: pointer to exception, or NULL if none If there is an exception, the user part of the syscall function will search for an exception handling function that covers the calling address. If none is found, it will assume that it is a language without exception handling, and return the exception to the caller in eax. edx: length of exception segment, if any ecx: may be clobbered Callee: eax: object ID edx: segment zero size ecx: total size ebx: method ID esp, ebp, esi, edi: NULL. Jump to 0x7fff0080 to return. Upon return: eax: pointer to exception, or NULL if none edx: length of exception segment, if any ebx, ecx, esi, edi, ebp, esp: may be clobbered Other system calls: eax, edx, ecx: syscall arguments. Call 0x7fff0000 + 0x80 * syscallnum eax: return value edx, ecx: may be clobbered