From 8d4ef822b68483e3b525664aecf333db216976dd Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Thu, 14 Nov 2019 07:08:11 +0300
Subject: [PATCH] 1

---
 vlib/compiler/main.v |  6 +++---
 vlib/os/bare/bare.S  | 28 ++++++++++++++++++++++++++++
 vlib/os/bare/bare.v  | 16 ++++++++++++++++
 3 files changed, 47 insertions(+), 3 deletions(-)
 create mode 100644 vlib/os/bare/bare.S
 create mode 100644 vlib/os/bare/bare.v

diff --git a/vlib/compiler/main.v b/vlib/compiler/main.v
index c415918da7..999c34bcd4 100644
--- a/vlib/compiler/main.v
+++ b/vlib/compiler/main.v
@@ -957,9 +957,9 @@ pub fn new_v(args[]string) &V {
 		out_name_c = out_name.all_after(os.path_separator) + '_shared_lib.c'
 	}
 	$if !linux {
-	if pref.is_bare {
-		verror('-bare only works on Linux for now')
-	}	
+		if pref.is_bare && !out_name.ends_with('.c') {
+			verror('-bare only works on Linux for now')
+		}	
 	}
 	return &V{
 		os: _os
diff --git a/vlib/os/bare/bare.S b/vlib/os/bare/bare.S
new file mode 100644
index 0000000000..eb7c83401e
--- /dev/null
+++ b/vlib/os/bare/bare.S
@@ -0,0 +1,28 @@
+.intel_syntax noprefix
+.text
+    .globl _start, syscall5
+
+    _start:
+        xor rbp,rbp
+        pop rdi
+        mov rsi,rsp
+        and rsp,-16
+        call main
+
+        mov rdi,rax /* syscall param 1 = rax (ret value of main) */
+        mov rax,60 /* SYS_exit */
+        syscall
+
+        ret /* should never be reached, but if the OS somehow fails
+               to kill us, it will cause a segmentation fault */
+
+    syscall5:
+        mov rax,rdi
+        mov rdi,rsi
+        mov rsi,rdx
+        mov rdx,rcx
+        mov r10,r8
+        mov r8,r9
+        syscall
+        ret
+
diff --git a/vlib/os/bare/bare.v b/vlib/os/bare/bare.v
new file mode 100644
index 0000000000..d7b57ee4aa
--- /dev/null
+++ b/vlib/os/bare/bare.v
@@ -0,0 +1,16 @@
+fn syscall5(number, arg1, arg2, arg3, arg4, arg5 voidptr) voidptr
+
+fn write(fd int, data voidptr, nbytes u64) int {
+	return 	 syscall5(
+          1, // SYS_write
+           fd,
+            data,
+            nbytes,
+            0, // ignored
+            0  // ignored
+        )
+}
+
+fn main() {
+C.write(1, "hallo\n", 6)
+}