Loko is a pretty new Scheme compiler: https://scheme.fail/

It implements everything down to assembler on bare metal.

You can easily analyze what is going on by disassembling the code:

    > (disassemble car)
    Disassembly for #<procedure car loko/runtime/pairs.sls:81:0>
   
      entry:
       2073E8 83F8F8       (cmp eax #xFFFFFFF8)
       2073EB 0F8506000000 (jnz L0)
     ; (set! rax (car rdi))
       2073F1 488B47FE     (mov rax (mem64+ rdi #x-2))
       2073F5 F8           (clc)
       2073F6 C3           (ret)
      L0:
       2073F7 E9749CFFFF   (jmp (+ rip #x-638C))
    >