std: expose exit syscall

1 files changed, 19 insertions, 0 deletions

diff --git a/std/std.zig b/std/std.zig
index 8b19628441..ea3b0d20f6 100644
--- a/std/std.zig
+++ b/std/std.zig
@@ -1,6 +1,20 @@
 const SYS_write : isize = 1;
+const SYS_exit : isize = 60;
 const stdout_fileno : isize = 1;
 
+fn syscall1(number: isize, arg1: isize) -> isize {
+    var result : isize;
+    asm volatile ("
+        mov %[number], %%rax
+        mov %[arg1], %%rdi
+        syscall
+        mov %%rax, %[ret]"
+        : [ret] "=m" (result)
+        : [number] "r" (number), [arg1] "r" (arg1)
+        : "rcx", "r11", "rax", "rdi");
+    return result;
+}
+
 fn syscall3(number: isize, arg1: isize, arg2: isize, arg3: isize) -> isize {
     var result : isize;
     asm volatile ("
@@ -20,6 +34,11 @@ pub fn write(fd: isize, buf: &const u8, count: usize) -> isize {
     return syscall3(SYS_write, fd, buf as isize, count as isize);
 }
 
+pub fn exit(status: i32) -> unreachable {
+    syscall1(SYS_exit, status as isize);
+    unreachable;
+}
+
 // TODO error handling
 // TODO handle buffering and flushing
 pub fn print_str(str : string) -> isize {