https://github.com/akkartik/mu/blob/main/linux/307size.subx

     1 # Size of an array in bytes.
     2
     3 == code
     4
     5 size:  # in: (addr array _) -> result/eax: int
     6     # . prologue
     7     55/push-ebp
     8     89/<- %ebp 4/r32/esp
     9     # eax = in
    10     8b/-> *(ebp+8) 0/r32/eax
    11     #
    12     8b/-> *eax 0/r32/eax
    13 $size:end:
    14     # . epilogue
    15     89/<- %esp 5/r32/ebp
    16     5d/pop-to-ebp
    17     c3/return