Merge branch 'mtrace' of git+ssh://amsterdam.csail.mit.edu/home/am0/6.828/xv6 into mtrace

4147120f · Silas Boyd-Wickizer · 7b828881 · d76c5f01 · 4147120f · 4147120f
--- a/Makefile
+++ b/Makefile
@@ -170,6 +170,7 @@ UPROGS=\
 	_usertests\
 	_wc\
 	_zombie\
+	_halt\

 fs.img: mkfs README $(UPROGS)
 	./mkfs fs.img README $(UPROGS)

--- a/halt.c
+++ b/halt.c
+#include "types.h"
+#include "user.h"
+
+int
+main(int argc, char *argv[])
+{
+  halt();
+  exit();
+}
--- a/syscall.c
+++ b/syscall.c
@@ -98,6 +98,7 @@ extern int sys_unlink(void);
 extern int sys_wait(void);
 extern int sys_write(void);
 extern int sys_uptime(void);
+extern int sys_halt(void);

 static int (*syscalls[])(void) = {
 [SYS_chdir]   sys_chdir,
@@ -121,6 +122,7 @@ static int (*syscalls[])(void) = {
 [SYS_wait]    sys_wait,
 [SYS_write]   sys_write,
 [SYS_uptime]  sys_uptime,
+[SYS_halt]    sys_halt,
 };

 void

--- a/syscall.h
+++ b/syscall.h
@@ -20,3 +20,4 @@
 #define SYS_sbrk   19
 #define SYS_sleep  20
 #define SYS_uptime 21
+#define SYS_halt   22 
--- a/sysproc.c
+++ b/sysproc.c
@@ -87,3 +87,14 @@ sys_uptime(void)
  release(&tickslock);
  return xticks;
 }
+
+int
+sys_halt(void)
+{
+  int i;
+  const char s[] = "Shutdown";
+
+  for(i = 0; i < 8; i++)
+    outb(0x8900, s[i]);
+  return 0;
+}
--- a/user.h
+++ b/user.h
@@ -22,6 +22,7 @@ int getpid(void);
 char* sbrk(int);
 int sleep(int);
 int uptime(void);
+void halt(void);

 // ulib.c
 int stat(char*, struct stat*);

--- a/usys.S
+++ b/usys.S
@@ -29,3 +29,4 @@ SYSCALL(getpid)
 SYSCALL(sbrk)
 SYSCALL(sleep)
 SYSCALL(uptime)
+SYSCALL(halt)