> No. The C/C++ ABI is quite uniform across architectures. The first 1..N (N is ISA dependant) parameters that can fit into a CPU register are passed via regist

> No. The C/C++ ABI is quite uniform across architectures. The first 1..N (N is ISA dependant) parameters that can fit into a CPU register are passed via registers. Here is the "System V i386 ABI" mentioned above: https://refspecs.linuxfoundation.org/elf/abi386-4.pdf https://refspecs.linuxfoundation.org/elf/abi386-4.pdf (from https://refspecs.linuxfoundation.org/ https://refspecs.linuxfoundation.org/). It clearly passes all arguments on the stack, and none on registers ("Function Calling Sequence" starting on page 35). That is the ABI used on 32-bit x86 Linux if you don't specify -mregparm (which the kernel uses); since the author was calling the compiler directly (which was necessary because the kernel makefiles only have rules for building C files, not C++ files), there was a mismatch between the -mregparm used by the kernel and the default ABI used by the C++ compiler, which was fixed by also passing -mregparm to the C++ compiler.