在移植到ARM的过程中，无法使用指针访问数组

Question

I am new to the ARM platform.

Below code has been used in an function for finding out the conjugate multiplication of some complex numbers of samples and sliding it to a some samples.

This code was working properly in native compiler in linux 12.04 version. When running the same code in ARM, it doesn't execute that function. It just exits from the code running.

#include<stdio.h>

int main()
{
    float aa[12]={1,1,1,1,1,1,1,1,1,1,1,1};
    float *x=aa,*y=x+6,real=0,imag=0;

    fn_ComplexMultiply_addthem(x,y,6,&real,&imag);

    printf("real value = %f\n",real);
    printf("real value = %f\n",imag);
}

void fn_ComplexMultiply_addthem(float *x, float *y, float len, float *re, float *im)
{
    int j;

    for( j=0; j<len; j+=2)
    {
        *re += (x[j]*(y[j]));
        *re -= (x[j+1]*(-y[j+1]));
        *im += (x[j]*(-y[j+1]));
        *im += (x[j+1]*(y[j]));
    }
}

I couldn't understand the reason for it. Each pointer is pointing to some value then it should give me the result whatever the may be right. Instead its just exits from the simulation.

Will it problem with some other things like memory such as stack or others? Please help me to debug this one.

Answer 1

The program is invalid because fn_ComplexMultiply_addthem is used before it is declared, and an implicit declaration would not match the actual definition.

In addition, float len makes no sense. We don't use floating point numbers for counting.

Change len to int and add the function declaration before main :

void fn_ComplexMultiply_addthem(float *x, float *y, int len, float *re, float *im);

ALWAYS enable compiler warning and treat them as errors ( -Wall -Werror for gcc and clang).