Why mixing Windows and Linux object files causes immediate stack corruption:

1. System V AMD64 ABI (Linux / macOS):
   • First 6 integer/pointer arguments passed in: RDI, RSI, RDX, RCX, R8, R9.
   • Return value in RAX (and RDX for 128-bit).
   • 128-byte Red Zone below RSP that signal handlers won't clobber!
2. Microsoft x64 ABI (Windows):
   • First 4 arguments passed in: RCX, RDX, R8, R9.
   • Mandatory 32-byte Shadow Space (Home Space) allocated by caller on stack above return address!
   • No Red Zone allowed.

Forgetting the 32-byte shadow space in Windows x64 inline assembly is the #1 cause of stack alignment crashes.

System V's 6 register parameters and Red Zone provide slightly faster function call overhead.