#include <config.h>
#include <proc.h>
#include <riscv.h>
#include <spinlock.h>
#include <string.h>
#include <types.h>
#include <uart.h>

/**
 * Allocate one stack per CPU (hart).
 * Each stack is 4096 bytes, aligned to 16 bytes for safety and performance.
 * The entry assembly code will calculate the proper stack address for the
 * current hart. For more info, read up on stack pointers and see: entry.S
 */
char stack0[4096 * NCPU] __attribute__((aligned(16)));

/* Keep this here and sync on it until we have synchronized printf */
struct spinlock sl = {0};
volatile int    greeted = 0;

/* This is where entry.S drops us of. All cores land here */
void start() {
    u64 id = r_mhartid();

    // Keep each CPU's hartid in its tp (thread pointer) register, for cpuid().
    // This can then be retrieved with r_wp or cpuid(). It is used to index the
    // cpus[] array in mycpu(), which in turn holds state for each individual
    // cpu (struct Cpu).
    w_tp(id);

    acquire(&sl);

    if (!greeted) {
        uart_puts("Hello Neptune!\n");
        greeted = 1;
    }

    uart_puts("Hart number: ");
    uart_putc(id + '0');
    uart_putc('\n');

    release(&sl);

    /* Here we will do a bunch of initialization steps */

    // We should not arrive here, but if we do, hang in a while on wfi.
    while (1) __asm__ volatile("wfi"); // (Wait For Interrupt)
}