Question

This is my program:

#include <stdio.h>

#define uart0 0x860
#define uart1 0x880

void send_char( int output )
{
    int nothing;
    //while write on uart1 is not ready, wait
    while(!((*(uart1+8) & 0x0040) && 0x0040)) //+8 eller +2? 2 byte (8 bitar)
    {
        nothing = 0;

    }
    *(uart1+4) = output; // +4 eller +1? en byte (4 bitar)
}

int rec_charx(void)
{
    if(!((*(uart1+8) & 0x0040) && 0x0040)) //+8 eller +2? 2 byte (8 bitar)
    {
        return *(uart1) & 0x000f;
    }
    else
    {
        return -1;
    }
}

The compiler complains:

expected ‘)’ before ‘output’

Why? How can I fix it? I don’t understand the complaint.

Update

We’ve rewritten to program but we still get compilation errors:

#include <stdio.h>

static int* const uart1 = (int*) 0x880;

void send_char( int output )
{
    int nothing;
    //while write on uart1 is not ready, wait
    while(!((uart1[2] & 0x0040) && 0x0040)) //+8 eller +2? 2 byte (8 bitar)
    {
        //do nothing
        nothing = 0;

    }
    uart1[1] = output; // skriv till uart1
}

int rec_charx(void)
{
    if(!((*(uart1+8) & 0x0040) && 0x0040)) //+8 eller +2? 2 byte (8 bitar)
    {
        return *(uart1) & 0x000f;
    }
    else
    {
        return -1;
    }
}

Answer 1

You need to use constants instead of those defines:

#define uart0 0x860
#define uart1 0x880

like so:

const int * uart0 = 0x860;    
const int * uart1 = 0x868;

---

Also noted that incrementing a pointer of type int * by 1, moves it pointing to and address +sizeof(int*). So assuming an int being 4 bytes long, uart1 + 1 would point to address 0x884.