CASM/string.asm at master · s0chu/CASM · GitHub

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                    section .text

                    global format_decimal
                    global format_node
                    global format_string
                    global format_pointer
                    global format_key
                    global format_string_scanf
                    global format_empty_command
                    global format_max_size_allowed
                    global format_key_nonexistent
                    global format_long
                    global format_invalid_update_syntax

                    global unknown_command
                    global inside_func

                    global strcpy
                    global strlen
                    global strcmp
                    global strstr
                    global strchr

strlen:
    push rbp
    mov rbp , rsp

    sub rsp , 8

    %define i -8
    mov dword [rbp + i] , 0

    .for:
        mov eax , [rbp + i]
        cmp byte [rdi + rax] , 0
        jz .done
        inc dword [rbp + i]
        jmp .for
    .done:

    %undef i
    mov rsp , rbp
    pop rbp
    ret

strcpy:
    push rbp
    mov rbp , rsp

    sub rsp , 8
    %define i -8

    mov dword [rbp + i] , 0

    .for:
        mov eax , dword [rbp + i]
        mov bl , [rsi + rax]
        mov byte [rdi + rax] , bl
        cmp byte [rsi + rax] , 0
        jz .done
        inc dword [rbp + i]
        jmp .for
    .done:

    mov rsp , rbp
    pop rbp

    ; %undef i
    ret


strcmp:
    push rbp
    mov rbp , rsp

    .for:
        cmp byte [rdi] , 0
        jnz .else

        cmp byte [rsi] , 0
        jnz .else

            jmp .ret0

        .else:

            mov al , byte [rdi]
            cmp al , byte [rsi]

            jb .ret2
            ja .ret1

        inc rdi
        inc rsi
        jmp .for
    .done:

    .ret0:
        mov rax , 0
        jmp strcmp.finish
    .ret1:
        mov rax , 1
        jmp strcmp.finish
    .ret2:
        mov rax , -1
        jmp strcmp.finish
    .finish:

    mov rsp , rbp
    pop rbp
    ret

strstr:
    push rbp
    mov rbp , rsp

    .for1:
            mov rbx , 0
            mov rax , rdi

            .for2:
                cmp byte [rsi + rbx] , 0
                je .return

                cmp byte [rdi + rbx] , 0
                je .done1

                mov cl , [rsi + rbx]
                cmp [rdi + rbx] , cl

                jne .skip

                inc rbx
                jmp .for2
            .done2:

        .skip:
        inc rdi
        jmp .for1
    .done1:

    mov rax , 0
    .return:

    mov rsp , rbp
    pop rbp
    ret

strchr:
    push rbp
    mov rbp , rsp

    .for:
        cmp byte [rdi] , 0
        je .done

        mov rax , rdi
        cmp byte [rdi] , sil

        je .return

        inc rdi
        jmp .for
    .done:

    mov rax , 0

    .return:

    mov rsp , rbp
    pop rbp
    ret
                section .data

            format_string_scanf: db "%s" , 0
            format_decimal: db "%d" , 10 , 0
            format_long: db "%lld" , 10 , 0
            format_string:  db "%s" , 10 , 0
            format_node:    db "left:%10p right:%10p height:%5d key: %6s value: %5d addr: %10p" , 10 , 0
            format_key:     db "%s" , 10 , 0
            format_pointer: db "%p" , 10 , 0
            format_empty_command: db "Empty commands are not allowed" , 10 , 0
            format_max_size_allowed: db "Variable name must have maximum 19 characters" , 10 , 0
            format_key_nonexistent: db "Key doesn't exist" , 10 , 0
            format_invalid_update_syntax: db "Invalid syntax" , 10 , 0
            unknown_command: db "Unknown command!" , 0
            inside_func: db "inside" , 0