【汇编语言实战】二分查找

C语言描述：

#include <stdio.h>

// 二分查找函数
int binarySearch(int arr[], int left, int right, int target) {
    while (left <= right) {
        int mid = left + (right - left) / 2;
        
        // 如果目标值等于中间值，则返回中间值的索引
        if (arr[mid] == target)
            return mid;
        
        // 如果目标值小于中间值，则在左半部分继续查找
        if (arr[mid] > target)
            right = mid - 1;
        // 如果目标值大于中间值，则在右半部分继续查找
        else
            left = mid + 1;
    }
    
    // 如果未找到目标值，则返回-1
    return -1;
}

int main() {
    int arr[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
    int n = sizeof(arr) / sizeof(arr[0]);
    int target;
    scanf("%d",&target);
    
    int result = binarySearch(arr, 0, n - 1, target);
    
    if (result != -1)
        printf("%d\n",result);
    else
        printf("未找到目标值");
    
    return 0;
}

汇编语言：

INCLUDE Irvine32.inc

.data
Numbers DWORD 1,3,7,9,12,13,34,35,88,999,1011,1013
LEN     DWORD ($-Numbers)/4
input   DWORD ?
result  DWORD ?

prompt BYTE "Enter a number to search for: ", 0

.code
main PROC
    mov EDX, OFFSET prompt
    call WriteString

    ; 读取用户输入的数
    call ReadInt
    mov input, EAX

    ; 执行二分查找
    mov EBX, OFFSET Numbers
    mov ECX, LEN
    mov EDX, input
    call BinarySearch

    ; 检查查找结果并输出
    cmp result, -1
    je not_found
    mov EAX, result
    call WriteDec
    jmp end_prog

not_found:
    mov EDX, OFFSET prompt
    call WriteString
    mov EAX, input
    call WriteDec
    mov EDX, OFFSET not_found_msg
    call WriteString

end_prog:
    call Crlf
    call WaitMsg
    exit
main ENDP


BinarySearch PROC

    push ECX
    push ESI
    push EDI

    ;check parameters
    CMP EBX,0
    JZ  FAIL
    CMP ECX,0
    JZ  FAIL


    mov ESI,0
    mov EDI,ECX
    Dec EDI

 L1:
    mov ECX,ESI
    add ECX,EDI
    SAR ECX,1
    mov EAX,[EBX+ECX*4]
    CMP EAX,EDX
    JZ SUCCESS

    CMP ESI,EDI
    JZ FAIL
    CMP EAX,EDX
    JG GREATER

    ;if EAX<EDX
    Mov ESI,ECX
    Inc ESI
    jmp L1

    ;if EAX>EDX
GREATER:
    MOV EDI,ECX
    Dec EDI
    jmp L1

SUCCESS:
    Mov result, ECX
    jmp FINISH

FAIL:
    Mov result,-1
    jmp FINISH

FINISH:
    pop EDI
    pop ESI
    pop ECX

ret
BinarySearch ENDP

not_found_msg BYTE " not found in the array.", 0

END main

运行结果：