Print the values of the register sp

print_sp.c

#include <stdio.h>

void print_sp(int startOffset, endOffset)
{
    int i;
    unsigned *pp = (unsigned*)&p;
    register unsigned sp asm ("sp");
    pp = (unsigned*)sp;

    for (i = startOffset; i <= endOffset; i+=4) {
        if (i < 0) {
            printf("*(sp%d): %x\n", i, *(pp+i));
        } else if (i == 0) {
            printf("*(sp): %x\n", *(pp+i));
        } else { // i > 0
            printf("*(sp+%d): %x\n", i, *(pp+i));
        }
    }
}

int main()
{
    int startOffset = -20, endOffset = 20;
    print_sp(a, b);  
}