CSAPP assignments

assignment-1.c

// import modules
#include <stdio.h>
#include <limits.h>
#include <stdlib.h>

// define Stack struct
struct Stack {
        int* arr;
        int top;
        unsigned length;
};

// create stack function
struct Stack* createStack(unsigned len) {
        // create stack
        struct Stack* stack = (struct Stack*) malloc(sizeof(struct Stack));

        // insert values
        stack->length = len;
        stack->top = -1;
        stack->arr = (int*)malloc(stack->length * sizeof(int));

        // return stack
        return stack;
}

// check stack is full
int isFull(struct Stack* stack) {
        // check full
        return stack->top == stack->length - 1;
}

// check stack is empty
int isEmpty(struct Stack* stack) {
        // check empty
        return stack->top == -1;
}

// push item into the stack
int push(struct Stack* stack, int i) {
        // check stack is full
        if (isFull(stack)) {
                return 0;
        }

        // insert item
        stack->arr[++stack->top] = i;

        // return top index
        return stack->top;
}

// pop from stack
int pop(struct Stack* stack) {
        // check stack is empty
        if (isEmpty(stack)) {
                return 0;
        }

        // return top value
        return stack->arr[stack->top--];
}

// main
int main(void) {
        // create a stack
        struct Stack* stack = createStack(100);

        // push items
        push(stack, 10);
        push(stack, 20);
        push(stack, 30);

        // print length
        printf("length: %d\n", stack->length);

        // pop item
        printf("pop: %d\n", pop(stack));

        return 0;
}

assignment-1.s

        .file   "assignment.c"
        .text
        .globl  createStack
        .type   createStack, @function
createStack:
.LFB41:
        .cfi_startproc
        pushq   %rbp
        .cfi_def_cfa_offset 16
        .cfi_offset 6, -16
        pushq   %rbx
        .cfi_def_cfa_offset 24
        .cfi_offset 3, -24
        subq    $8, %rsp
        .cfi_def_cfa_offset 32
        movl    %edi, %ebx
        movl    $16, %edi
        call    malloc@PLT
        movq    %rax, %rbp
        movl    %ebx, 12(%rax)
        movl    $-1, 8(%rax)
        movl    %ebx, %edi
        salq    $2, %rdi
        call    malloc@PLT
        movq    %rax, 0(%rbp)
        movq    %rbp, %rax
        addq    $8, %rsp
        .cfi_def_cfa_offset 24
        popq    %rbx
        .cfi_def_cfa_offset 16
        popq    %rbp
        .cfi_def_cfa_offset 8
        ret
        .cfi_endproc
.LFE41:
        .size   createStack, .-createStack
        .globl  isFull
        .type   isFull, @function
isFull:
.LFB42:
        .cfi_startproc
        movl    12(%rdi), %eax
        subl    $1, %eax
        cmpl    8(%rdi), %eax
        sete    %al
        movzbl  %al, %eax
        ret
        .cfi_endproc
.LFE42:
        .size   isFull, .-isFull
        .globl  isEmpty
        .type   isEmpty, @function
isEmpty:
.LFB43:
        .cfi_startproc
        cmpl    $-1, 8(%rdi)
        sete    %al
        movzbl  %al, %eax
        ret
        .cfi_endproc
.LFE43:
        .size   isEmpty, .-isEmpty
        .globl  push
        .type   push, @function
push:
.LFB44:
        .cfi_startproc
        movl    8(%rdi), %edx
        movl    12(%rdi), %eax
        leal    -1(%rax), %ecx
        movl    $0, %eax
        cmpl    %ecx, %edx
        je      .L5
        movq    (%rdi), %rax
        addl    $1, %edx
        movl    %edx, 8(%rdi)
        movslq  %edx, %rdx
        movl    %esi, (%rax,%rdx,4)
        movl    8(%rdi), %eax
.L5:
        rep ret
        .cfi_endproc
.LFE44:
        .size   push, .-push
        .globl  pop
        .type   pop, @function
pop:
.LFB45:
        .cfi_startproc
        movl    8(%rdi), %edx
        movl    $0, %eax
        cmpl    $-1, %edx
        je      .L8
        movq    (%rdi), %rax
        leal    -1(%rdx), %ecx
        movl    %ecx, 8(%rdi)
        movslq  %edx, %rdx
        movl    (%rax,%rdx,4), %eax
.L8:
        rep ret
        .cfi_endproc
.LFE45:
        .size   pop, .-pop
        .section        .rodata.str1.1,"aMS",@progbits,1
.LC0:
        .string "length: %d\n"
.LC1:
        .string "pop: %d\n"
        .text
        .globl  main
        .type   main, @function
main:
.LFB46:
        .cfi_startproc
        pushq   %rbx
        .cfi_def_cfa_offset 16
        .cfi_offset 3, -16
        movl    $100, %edi
        call    createStack
        movq    %rax, %rbx
        movl    $10, %esi
        movq    %rax, %rdi
        call    push
        movl    $20, %esi
        movq    %rbx, %rdi
        call    push
        movl    $30, %esi
        movq    %rbx, %rdi
        call    push
        movl    12(%rbx), %edx
        leaq    .LC0(%rip), %rsi
        movl    $1, %edi
        movl    $0, %eax
        call    __printf_chk@PLT
        movq    %rbx, %rdi
        call    pop
        movl    %eax, %edx
        leaq    .LC1(%rip), %rsi
        movl    $1, %edi
        movl    $0, %eax
        call    __printf_chk@PLT
        movl    $0, %eax
        popq    %rbx
        .cfi_def_cfa_offset 8
        ret
        .cfi_endproc
.LFE46:
        .size   main, .-main
        .ident  "GCC: (Ubuntu 7.4.0-1ubuntu1~18.04.1) 7.4.0"
        .section        .note.GNU-stack,"",@progbits