forgot to git add

e1f627d7 · Nickolai Zeldovich · 989c0584 · e1f627d7 · e1f627d7 · e1f627d7
--- a/thrtest.c
+++ b/thrtest.c
+#include "types.h"
+#include "stat.h"
+#include "user.h"
+#include "xv6-mtrace.h"
+#include "x86.h"
+#include "uspinlock.h"
+
+static struct uspinlock l;
+static volatile uint tcount;
+enum { nthread = 1 };
+
+void
+thr(uint arg)
+{
+  acquire(&l);
+  printf(1, "thrtest[%d]: arg 0x%x esp %x\n", getpid(), arg, resp());
+  tcount++;
+  release(&l);
+  exit();
+}
+
+int
+main(void)
+{
+  acquire(&l);
+  printf(1, "thrtest[%d]: start\n", getpid());
+
+  for(uint i = 0; i < nthread; i++) {
+    sbrk(4096);
+    uint *tstack = (uint*) sbrk(0);
+    tstack[-1] = 0xc0ffee00 | i;
+
+    int tid = forkt(&tstack[-2], thr);
+    printf(1, "thrtest[%d]: child %d esp %x\n", getpid(), tid, resp());
+  }
+
+  release(&l);
+  exit();
+
+  do{
+    printf(1, "thrtest[%d]: %d\n", getpid(), tcount);
+    for(uint i = 0; i < 100000; i++)
+      ;
+    //sleep(1);
+  }while(tcount < nthread);
+}
--- a/uspinlock.h
+++ b/uspinlock.h
+#pragma once
+#include "x86.h"
+
+struct uspinlock {
+  uint locked;       // Is the lock held?
+};
+
+static void inline __attribute__((always_inline))
+acquire(struct uspinlock *lk)
+{
+  while(xchg(&lk->locked, 1) != 0)
+    ;
+}
+
+static void inline __attribute__((always_inline))
+release(struct uspinlock *lk)
+{
+  xchg(&lk->locked, 0);
+}
+
--- a/uthread.S
+++ b/uthread.S
+#include "syscall.h"
+#include "traps.h"
+
+.globl forkt
+forkt:
+  movl 4(%esp), %ecx	## new stack ptr
+  movl 8(%esp), %edx	## function ptr
+
+  pushl $1		## flag for sys_fork
+  pushl $0		## return address (dummy)
+  movl $SYS_fork, %eax
+  int $T_SYSCALL
+  addl $8, %esp
+
+  cmpl $0, %eax
+  jne 1f
+
+  movl %eax, %esp
+  jmp *%ecx
+
+1:
+  ret
+