fifo fum

fifo_fun.c

#include <stdio.h>
#include <string.h>
#include <stdarg.h>
#include <stdint.h>
#include <limits.h>
#include "comms_layer.h"

#define MAX_BUFFER_LENGTH   2 //135
#define MAX_TX_FIFO_LENGTH  (MAX_BUFFER_LENGTH * 3)

static char tx_fifo_buffer[MAX_TX_FIFO_LENGTH]; // Triple buffer
static int tx_fifo_head = 0;
static int tx_fifo_tail = 0;

static void tx_putc(char);
static char tx_getc(void);

static void tx_putc(char ch) {
    tx_fifo_buffer[tx_fifo_tail] = ch;
    tx_fifo_tail = (tx_fifo_tail + 1) % MAX_TX_FIFO_LENGTH; // increment and wrap
    // TODO: check if fifo_tail == fifo_head
}

static char tx_getc(void) {
    char ret = tx_fifo_buffer[tx_fifo_head];
    tx_fifo_head = (tx_fifo_head + 1) % MAX_TX_FIFO_LENGTH;
    return ret;
}

int main(int argc, char *argv[]) {
    char packet[] = {5, 10, 1, 2, 3, 4, 0}; // 7 bytes
    printf("hello world, %lu %lu\n", sizeof(packet), strlen(packet)); // 7 6
    
    for (int i=0; i<sizeof(packet); i++) {
        printf("%02x ", packet[i]);
        tx_putc(packet[i]);
    }
    printf("\n");


    return 0;
}