https://github.com/akkartik/mu/blob/main/linux/ex14.subx

     1 # Multiply 2 numbers.
     2 #
     3 # To run:
     4 #   $ bootstrap/bootstrap translate ex14.subx -o ex14
     5 #   $ bootstrap/bootstrap run ex14
     6 # Expected result:
     7 #   $ echo $?
     8 #   6
     9
    10 == code
    11 #   instruction                     effective address                                                   register    displacement    immediate
    12 # . op          subop               mod             rm32          base        index         scale       r32
    13 # . 1-3 bytes   3 bits              2 bits          3 bits        3 bits      3 bits        2 bits      2 bits      0/1/2/4 bytes   0/1/2/4 bytes
    14
    15 Entry:
    16     b8/copy-to-eax  1/imm32
    17     b9/copy-to-ecx  2/imm32
    18     bb/copy-to-ebx  3/imm32
    19
    20     69/multiply                     3/mod/direct    1/rm32/ecx    .           .             .           3/r32/ebx                   3/imm32           # ebx = ecx * 3
    21
    22 $exit:
    23     # exit(ebx)
    24     e8/call  syscall_exit/disp32
    25
    26 # . . vim:nowrap:textwidth=0