Question

我将非常感谢以下代码提供的一些帮助。该代码应该为表格，对象的数量和对有多少负值和奇数值的数量进行引用。然后它应该将负值的数量发送到存储器中的一个表，并将奇数值的数量发送到存储器中的另一个表。我尝试比较为零，我尝试找到最后一位，我尝试了注册表的xor，没有任何作用。重要的是所有值都是很长的类型。

.type max_1_ind, @function
.global max_1_ind

max_1_ind:
    movq    %rdi, %r8         # object table address from rdi to r8
    xor     %r11, %r11
    xor     %r12, %r12
    movq    %rcx, %r14        # rcx is needed for the loop
    movq    %rsi, %rcx        # number of objects for the loop counter
    xor     %r15, %r15
loop:
    movq    (%r8), %r15
    and     $1, %r15        
    jc      increase
continue:
    movq     (%r8), %r15
    test     %r15, %r15
    jne      increase2            
continue2:
    inc      %r8                 
    dec      %rcx
    cmpq     $0, %rcx
    jne      loop

    movq     %r11, (%rdx)
    movq     %r14, %rcx
    movq     %r12, (%rcx)

finish:
    xor      %rax, %rax
    ret

increase:
    inc      %r11                
    jmp      continue
increase2:
    inc      %r12                
    jmp      continue2

＆＃34; c＆＃34;调用此函数的程序

#include <stdio.h>
#include <stdlib.h>

extern long long max_1_ind(long long *tab, long long n, long long *even_cnt, long long *neg_cnt);

int main(void) {
  long long tab[4] = {6, 2, -20, 3};
  long long count = 4;
  long long even_cnt[1] = {0};
  long long neg_cnt[1] = {0};
  max_1_ind(tab, count, even_cnt, neg_cnt);
  printf("Result: %lld, %lld\n", *even_cnt, *neg_cnt);
  return 0; 
}

Answer 1

感谢您的深刻回答。是的，我犯了inc。现在代码正常工作。

#include <stdio.h>
#include <stdlib.h>

extern long long max_1_ind(long long *tab, long long n, long long *even_cnt, long long *neg_cnt);

int m(long long * tab, long long n, long long *even_cnt, long long *neg_cnt){
        int counter = n;
    while(counter>-1){
            //printf("%lld \n",tab[counter]);
        if(tab[counter]<0){
            neg_cnt[0]++;
        }
                if ((tab[counter] & 1) ==0){
            even_cnt[0]++;
        }
        counter--;
    }
        return 0;
}

int main(void) {
  long long tab[4] = {6, 40, -20, -3};
  long long count = 4;
  long long even_cnt[1] = {0};
  long long neg_cnt[1] = {0};
  max_1_ind(tab, count, even_cnt, neg_cnt);
  printf("Wynik Asembler: %lld, %lld\n", *even_cnt, *neg_cnt);
  return 0;
}

汇编代码：

.type max_1_ind, @function
#long long max_1_ind(long long *tab, long long n, long long *even_cnt, long long *neg_cnt);
.global max_1_ind

                # %rdi, %rsi, %rdx, %rcx, %r8 and %r9


max_1_ind:
    movq    %rdi, %r8         
        xor     %r11, %r11
        xor     %r12, %r12
        movq    %rsi, %rcx        
        xor     %r15, %r15

loop:
        movq    (%r8), %r15
        andq    $1, %r15        
        jz      increase

continue:
        movq     (%r8), %r15
        testq    %r15, %r15
        js       increase2  

continue2:
        addq     $8, %r8                 
        dec      %rcx
        cmpq     $0, %rcx
        jne      loop

        movq     %r11, (%rdx)
        movq     %r14, %rcx
        movq     %r12, (%rcx)

finish:
        xor      %rax, %rax
        ret

increase:
        inc      %r11                
        jmp      continue

increase2:
        inc      %r12                
        jmp      continue2

装配64位GAS，计算奇数和负数

1 个答案: