#include "types.h"
#include "riscv.h"
#include "defs.h"
#include "param.h"
#include "memlayout.h"
#include "spinlock.h"
#include "proc.h"

u64
sys_exit(void)
{
  int n;
  argint(0, &n);
  exit(n);
  return 0; // not reached
}

u64
sys_getpid(void)
{
  return myproc()->pid;
}

u64
sys_fork(void)
{
  return fork();
}

u64
sys_wait(void)
{
  u64 p;
  argaddr(0, &p);
  return wait(p);
}

u64
sys_sbrk(void)
{
  u64 addr;
  int n;

  argint(0, &n);
  addr = myproc()->sz;
  if(growproc(n) < 0)
    return -1;
  return addr;
}

u64
sys_sleep(void)
{
  int n;
  u32 ticks0;

  argint(0, &n);
  acquire(&tickslock);
  ticks0 = ticks;
  while(ticks - ticks0 < n) {
    if(killed(myproc())) {
      release(&tickslock);
      return -1;
    }
    sleep(&ticks, &tickslock);
  }
  release(&tickslock);
  return 0;
}

u64
sys_kill(void)
{
  int pid;

  argint(0, &pid);
  return kill(pid);
}

// return how many clock tick interrupts have occurred
// since start.
u64
sys_uptime(void)
{
  u32 xticks;

  acquire(&tickslock);
  xticks = ticks;
  release(&tickslock);
  return xticks;
}

u64
sys_trace(void)
{
  /* TODO: Implement sys_trace */
  return 0;
}