6 files changed, 123 insertions, 103 deletions
diff --git a/kernel/kernel_prelude.hats b/kernel/kernel_prelude.hats
new file mode 100644
index 0000000..048cba1
--- /dev/null
+++ b/kernel/kernel_prelude.hats
@@ -0,0 +1,12 @@
+#ifndef PRELUDE
+#define PRELUDE 1
+
+#include "share/atspre_staload.hats"
+
+staload "kernel/output/writer.sats"
+val () = clear_screen()
+
+staload "kernel/output/print.dats"
+
+#endif
+
diff --git a/kernel/main.dats b/kernel/main.dats
index bbd201a..0a325ff 100644
--- a/kernel/main.dats
+++ b/kernel/main.dats
@@ -1,10 +1,6 @@
-#include "share/atspre_staload.hats"
-
-staload "kernel/writer.sats"
-dynload "kernel/writer.dats"
+#include "kernel/kernel_prelude.hats"
 
 implement main0 () = (
-  clear_screen();
-  put_string("Hello world\n");
-  put_string("GOEIENDSG\n");
-  put_string("GOEIENDSG"))
+  println!("Hello World");
+  println!("Hello World");
+)
diff --git a/kernel/output/print.dats b/kernel/output/print.dats
new file mode 100644
index 0000000..22fe575
--- /dev/null
+++ b/kernel/output/print.dats
@@ -0,0 +1,15 @@
+#include "share/atspre_staload.hats"
+
+#define ATS_DYNLOADFLAG 0
+
+staload "kernel/output/writer.sats"
+
+extern fun print_newline() : void
+implement print_newline() : void = put_string("\n")
+
+extern fun assert_errmsg(b: bool, msg: string) : void
+implement assert_errmsg(b: bool, msg: string) : void = put_string(msg)
+
+overload print with put_string of 1
+
+macdef assertloc(tf) = assert_errmsg (,(tf), $mylocation)
diff --git a/kernel/output/writer.dats b/kernel/output/writer.dats
new file mode 100644
index 0000000..c7731f6
--- /dev/null
+++ b/kernel/output/writer.dats
@@ -0,0 +1,91 @@
+#include "kernel/kernel_prelude.hats"
+
+staload "./writer.sats"
+
+#define ATS_DYNLOADFLAG 0
+
+%{^
+  #define get_buffer() ((void *) 0xB8000)
+%}
+
+extern fun get_buffer():<> buffer = "mac#"
+extern prfun eat_buffer (pf: buffer): void
+extern fun getref (): [l:addr] vtakeoutptr (writer)
+
+fun color_value(c : color): uint8 = 
+  case+ c of 
+    | Black() => i2u8 0
+    | Blue() => i2u8 1
+    | Green() => i2u8 2
+    | Cyan() => i2u8 3
+    | Red() => i2u8 4
+    | Magenta() => i2u8 5
+    | Brown() => i2u8 6
+    | LightGray() => i2u8 7
+    | DarkGray() => i2u8 8
+    | LightBlue() => i2u8 9
+    | LightGreen() => i2u8 10
+    | LightCyan() => i2u8 11
+    | LightRed() => i2u8 12
+    | Pink() => i2u8 13
+    | Yellow() => i2u8 14
+    | White() => i2u8 15
+
+fun code_value(foreground: color, background:color): uint8 = 
+  (color_value(background) << 4) lor color_value(foreground)
+
+local
+var _val: writer 
+
+in
+implement getref () = let
+  extern praxi __assert{l:addr} (ptr: ptr (l)): vtakeout0 (writer@l)
+  prval (pf, fpf) = __assert (addr@(_val))
+in
+  (pf, fpf | addr@(_val))
+end
+end
+
+fun put_char (c : char, writer: &writer) : void = let
+  val buf = get_buffer()
+  val pos = writer.position
+in
+  if (c = '\n') then
+    let 
+      val new_pos = (pos /  BUFFER_WIDTH + 1) * BUFFER_WIDTH
+    in
+      if (new_pos < N) then
+        writer.position := new_pos
+      else
+        clear_screen()
+    end
+  else (
+    buf.1->[writer.position] := @{ ascii_character = c, color_code = writer.color_code};
+
+    if (pos < N - 1) then
+      writer.position := succ(pos)
+    else
+      clear_screen());
+
+  let prval() = eat_buffer buf in () end
+end
+
+
+implement put_string (str : string) : void = let
+  val (pf, fpf | p_val) = getref()
+  implement string_foreach$fwork<writer> (c,env) = put_char(c,env)
+  val _ =  string_foreach_env<writer> (g1ofg0(str),!p_val)
+  prval() = fpf(pf)
+in  
+end
+
+implement clear_screen() : void = let
+  val (pf, fpf | p_val) = getref()
+  fun loop {n : nat | n < N - 1} .<N-n>. (i : int n, wr : &writer) : void = 
+    (put_char('\0', wr); if (i < N - 2) then loop(i+1,wr))
+  val () = !p_val := @{position = 0, color_code = code_value(White,Black)}
+in
+  loop(0,!p_val);
+  !p_val.position := 0;
+  let prval() = fpf(pf) in () end
+end
diff --git a/kernel/writer.sats b/kernel/output/writer.sats
index 65a2ea9..fd33424 100644
--- a/kernel/writer.sats
+++ b/kernel/output/writer.sats
@@ -30,3 +30,4 @@ castfn i2u8 {n: nat} (i: int n): uint8 n
 
 fun put_string (str : string) : void
 fun clear_screen() : void
+
diff --git a/kernel/writer.dats b/kernel/writer.dats
deleted file mode 100644
index 3e75a90..0000000
--- a/kernel/writer.dats
+++ /dev/null
@@ -1,95 +0,0 @@
-#include "share/atspre_staload.hats"
-
-staload "kernel/writer.sats"
-
-%{^
-  #define get_buffer() ((void *) 0xB8000)
-%}
-
-extern fun get_buffer():<> buffer = "mac#"
-extern prfun eat_buffer (pf: buffer): void
-
-staload WRITER = {
-  staload "kernel/writer.sats"
-  extern fun getref (): [l:addr] vtakeoutptr (writer)
-
-  fun color_value(c : color): uint8 = 
-    case+ c of 
-      | Black() => i2u8 0
-      | Blue() => i2u8 1
-      | Green() => i2u8 2
-      | Cyan() => i2u8 3
-      | Red() => i2u8 4
-      | Magenta() => i2u8 5
-      | Brown() => i2u8 6
-      | LightGray() => i2u8 7
-      | DarkGray() => i2u8 8
-      | LightBlue() => i2u8 9
-      | LightGreen() => i2u8 10
-      | LightCyan() => i2u8 11
-      | LightRed() => i2u8 12
-      | Pink() => i2u8 13
-      | Yellow() => i2u8 14
-      | White() => i2u8 15
-
-  fun code_value(foreground: color, background:color): uint8 = 
-    (color_value(background) << 4) lor color_value(foreground)
-
-  local
-
-  var _val: writer = @{position = 0, color_code = code_value(White,Black)} : writer
-  val p_val = addr@(_val)
-
-  in
-
-  implement getref () = let
-    extern praxi __assert{l:addr} (ptr: ptr (l)): vtakeout0 (writer@l)
-    prval (pf, fpf) = __assert (p_val)
-  in
-    (pf, fpf | p_val)
-  end
-  end
-}
-
-fun put_char (c : char, writer: &writer) : void = let
-  val buf = get_buffer()
-  val pos = writer.position
-in
-  if (c = '\n') then
-    let 
-      val new_pos = (pos /  BUFFER_WIDTH + 1) * BUFFER_WIDTH
-    in
-      if (new_pos < N) then
-        writer.position := new_pos
-      else
-        clear_screen()
-    end
-  else (
-    buf.1->[writer.position] := @{ ascii_character = c, color_code = writer.color_code};
-
-    if (pos < N - 1) then
-      writer.position := succ(pos)
-    else
-      clear_screen());
-
-  let prval() = eat_buffer buf in () end
-end
-
-
-implement put_string (str : string) : void = let
-  val (pf, fpf | p_val) = $WRITER.getref()
-  implement string_foreach$fwork<writer> (c,env) = put_char(c,env)
-  val _ =  string_foreach_env<writer> (g1ofg0(str),!p_val)
-  prval() = fpf(pf)
-in  end
-
-implement clear_screen() : void = let
-  val (pf, fpf | p_val) = $WRITER.getref()
-  fun loop {n : nat | n < N - 1} .<N-n>. (i : int n, wr : &writer) : void = 
-    (put_char('\0', wr); if (i < N - 2) then loop(i+1,wr))
-in
-  !p_val.position := 0;
-  loop(0,!p_val);
-  !p_val.position := 0;
-  let prval() = fpf(pf) in () end
-end