Analyzing the Assembly from Modern Warfare II (2022) campaign

This was originally posted to the Modern Warfare II subreddit, but it was deleted by the moderators for being off-topic :(

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Some of you probably noticed that the missile control computers – where you got asked to read the first letter of the second row and first column, etc – had Assembly code shown.

I wanted to actually check if the Assembly made sense and was valid or if it was just garbage (ala /r/ItsAUnixSystem).

Here’s my annotated version* of the Assembly shown in the last mission

    ;Put the base/frame pointer onto the top of the stack
    PUSHL %EBP

    ;Make the base pointer point to the address of the stack pointer
    MOVL %ESP, %EBP

    ;Lower the stack pointer by exactly 4 bytes. On x86 the stack "grows" down,
    ;so it has to be decremented to make room for additional variables.
    SUBL $0x4, %ESP

    ;"Zero out" the memory at address 0x00A9'FF1C
    MOVL $0X0, 0x00A9FF1C

    ;Sets up a comparison between: 
    ;* the contents of memory address 0x00A9'FF1C
    ;* 0x636 (1590 in decimal).
    CMPL $0x636, 0x00A9FF1C

    ; In the previous instruction, we compared the two values
    ; (the result of that comparison is stored in separate registers)
    ; This instruction is saying, if 0x636 is less than the value stored at address 0x00A9'FF1C, 
    ; then "jump to" (i.e. set the program counter) address 0x001C'011AC
    JLE 0x001C011AC

    ; Finally, jump to memory address 0x001C011B8
    JMP 0x001C011B8

This looks like a valid snippet so far.

And the first example, which is from the “Dark Water” mission:

    PUSHL %EBP
    MOVL %ESP, %EBP
    ; It's kind of odd that this is here, since it's basically a useless instruction.
    ; Unless it was done intentionally to show that there's no local variables going to be used.
    SUBL $0x0, %ESP
    MOVL $0x8, 0x00A9FF1C
    CMPL $0x65, 0x00A9FF1C
    JLE 0x001C011AC
    JMP 0x001C011B8

This is very similar to the other snippet – using the same instructions, just some different values. Seems to mostly check out. Good job Infinity Ward.