For each of the following four assembly programs, explain what they compute and why.
Suggest changes to make them more sensible.

This homework is due next Friday. Each problem is 5 points. Submission instructions will
be emailed later---look out for an email from Rishav.

The idea of these exercises is to understand exactly what the instructions do. You
can build and run these programs, use GDB or another debugger, or any other approach you like.
No matter what you do, you have to explain the result.

A note on AIs: We fed these to perplexity.ai in a single shot per program, and it had them
all wrong.  Extra points for some generic (not problem-specific) prompt that would make
perplexity get them right.

===[ 1. Hello hello!

       .file   "p1.c"
       .text
       .section        .rodata
.LC0:
       .string "Hello"
       .text
       .globl  main
       .type   main, @function
main:
       pushq   %rbp
       movq    %rsp, %rbp
       subq    $16, %rsp
       movl    $10, -4(%rbp)
.L2:
       subl    $1, -4(%rbp)
       leaq    .LC0(%rip), %rax
       movq    %rax, %rdi
       call    puts@PLT
       jns     .L2

===[ 2. Interacting with integers.

       .file   "p2.c"
       .text
       .section        .rodata
.LC0:
       .string "%x\n"
       .text
       .globl  main
       .type   main, @function
main:
       pushq   %rbp
       movq    %rsp, %rbp
       subq    $16, %rsp
       movl    $65535, -6(%rbp)
       movl    $43690, -4(%rbp)
       movl    -6(%rbp), %eax
       leaq    .LC0(%rip), %rdx
       movl    %eax, %esi
       movq    %rdx, %rdi
       movl    $0, %eax
       call    printf@PLT
       movl    $0, %eax
       leave
       ret

===[ 3. I can has alignment?

        .file   "p3.c"
        .text
        .section        .rodata
.LC1:
        .word   65
        .text
        .globl  main
        .type   main,   @function
main:
        pushq   %rbp
        movq    %rsp,   %rbp
        subq    $16,    %rsp
        movq    $0,     %rcx
.L1:
        jmp .L3
.L2:
        pushq   %rcx
        movq    %rbp,   %rax
        subq    $16,    %rax
        movq    %rax,   %rdi
        call    puts@PLT
        leave
        ret
.L3:
        pushq   %rax
        movq    $1,     %rax
        addq    %rax,   %rcx
        popq    %rax
        cmpq    .LC1(%rip),     %rcx
        je      .L2
        jmp     .L1

===[ 4.  I can has strings? 

        .file   "p4.c"
        .text
        .section        .rodata
.LC0:
        .string "Uh oh!\n"
        .string ":)\n"
        .text
        .globl  main
        .type   main,   @function
L1:
        push    %rax
        leaq    .LC0(%rip), %rcx
        addq    $7,     %rcx
        ret
main:
        pushq   %rbp
        movq    %rsp,   %rbp
        subq    $16,    %rsp
        leaq    .LCO(%rip), %rax
        call    L1
        movq    %rcx,   %rax
        movq    %rax,   %rdi
        call    puts@PLT
        leave
        ret
.LCO:
        leaq    .LC0(%rip), %rax
        movq    %rax,   %rdi
        call    puts@PLT
        leave
        ret