text: #include "types.h"
  #include "x86.h"
  #include "defs.h"
  #include "date.h"
  #include "param.h"
  #include "memlayout.h"
  #include "mmu.h"
  #include "proc.h"
  
  int sys_fork(void)
  {
    return fork();
  }
  
  int sys_exit(void)
  {
    exit();
    return 0; // not reached
  }
  
  int sys_wait(void)
  {
    return wait();
  }
  
  int sys_waitx(void) // By Order of the Peaky Blinders
  {
    int *wtime, *rtime;
    if (argptr(0, (void *)&wtime, sizeof(int)) < 0)
    {
      return -1;
    }
    if (argptr(1, (void *)&rtime, sizeof(int)) < 0)
    {
      return -1;
    }
    return waitx(wtime, rtime);
  }
  
  int sys_kill(void)
  {
    int pid;
  
    if (argint(0, &pid) < 0)
      return -1;
    return kill(pid);
  }
  
  int sys_getpid(void)
  {
    return myproc()->pid;
  }
  
  int sys_sbrk(void)
  {
    int addr;
    int n;
  
    if (argint(0, &n) < 0)
      return -1;
    addr = myproc()->sz;
    if (growproc(n) < 0)
      return -1;
    return addr;
  }
  
  int sys_procdump(void) // By Order of the Peaky Blinders
  {
    procdump();
    return 0;
  }
  
  int sys_sleep(void)
  {
    int n;
    uint ticks0;
  
    if (argint(0, &n) < 0)
      return -1;
    acquire(&tickslock);
    ticks0 = ticks;
    while (ticks - ticks0 < n)
    {
      if (myproc()->killed)
      {
        release(&tickslock);
        return -1;
      }
      sleep(&ticks, &tickslock);
    }
    release(&tickslock);
    return 0;
  }
  
  // return how many clock tick interrupts have occurred
  // since start.
  int sys_uptime(void)
  {
    uint xticks;
  
    acquire(&tickslock);
    xticks = ticks;
    release(&tickslock);
    return xticks;
  }
  
  int sys_set_priority(void) // By Order of the Peaky Blinders
  {
    int new_priority, pid;
  
    if (argint(0, &new_priority) < 0)
      return -1;
  
    if (argint(1, &pid) < 0)
      return -1;
  
    return set_priority(new_priority, pid);
  }
  