Function emit_memcmp 

pub fn emit_memcmp() -> Function

Emit memcmp(ptr_a: i32, ptr_b: i32, len: i32) -> i32 — byte-by-byte comparison.

Returns 1 if all len bytes at ptr_a and ptr_b are identical, 0 otherwise. Used by val_eq for string content comparison and val_record_get for key lookup.