' Explicit ASM EFFECTS metadata is opt-in. Ordinary #ASM remains opaque.
FUNCTION PBMAIN() AS LONG
  #ASM EFFECTS
  READ RAX
  WRITE RAX
  CLOBBER R10
  FLAGS_WRITE ZF, CF
  MEMORY READWRITE
  STACK PRESERVE
  CONTROL FALLTHROUGH
  FEATURES SSE2
  CODE
    mov rax, rax
  #ENDASM
  FUNCTION = 0
END FUNCTION