what is the meaning of _AX = 1000 in the following C program?

Question

I am a beginner in C programming language, recently I have started learning functions, I have studied that functions use keyword return to return a value in the caller function. For example the following program.

int getVal(){
 return 1000;
}

int main(){
int x = getVal();
printf("x = %d",x);
return 0;
}

will print x = 1000

but I am confused that (under turbo C compiler 32 bit) why the following program is producing output as x = 1000 too. Please explain.

int get_val(){
 _AX = 1000;
}

int main(){
int x = get_val();
printf("x = %d",x);
return 0;
}