From 30c76c17c9481bf95df91b9d9974bdd4ccb7098f Mon Sep 17 00:00:00 2001
From: Nathan Cannon <neviynhd@gmail.com>
Date: Fri, 20 Oct 2017 18:00:17 +0100
Subject: [PATCH] Added terminal init method.

---
 kernel.nim | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/kernel.nim b/kernel.nim
index 26a6afb..f883f1b 100644
--- a/kernel.nim
+++ b/kernel.nim
@@ -17,12 +17,23 @@ type
     lightBrown = 14,
     white = 15
 
-proc vga_entry_colour(fg: VGA_Colour, bg: VGA_Colour): uint8 =
+proc vgaEntryColour(fg: VGA_Colour, bg: VGA_Colour): uint8 =
   result = uint8(ord(fg) or (ord(bg) shl 4))
 
-proc vga_entry(c: char, colour: uint8): uint16 =
-  result = uint8(c) or (colour shl 8)
+proc vgaEntry(c: char, colour: uint8): uint16 =
+  result = uint16(uint8(c) or (colour shl 8))
 
 const
   vgaWidth = 80
   vgaHeight = 25
+  terminalBufferBaseAddress = 0xB8000
+
+var
+  terminalRow, terminalColumn = 0
+  terminalColour = vgaEntryColour(VGA_Colour.lightGrey, VGA_Colour.black)
+
+proc terminalInitialize() =
+  for y in 0..<vgaWidth:
+    for x in 0..<vgaHeight:
+      let index = terminalBufferBaseAddress + (y * vgaWidth + x)
+      cast[ptr uint16](index)[] = vgaEntry(' ', terminalColour) # Write directly to display memory