From 90eba82c396b8c545312d852bb9b77f6410663e8 Mon Sep 17 00:00:00 2001
From: Nathan Cannon <neviynhd@gmail.com>
Date: Sat, 21 Oct 2017 16:24:06 +0100
Subject: [PATCH] Hello world now operational. Separate insertion of colour
 codes was required.

---
 kernel.nim | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/kernel.nim b/kernel.nim
index 117c07e..41aa066 100644
--- a/kernel.nim
+++ b/kernel.nim
@@ -17,8 +17,8 @@ type
     lightBrown = 14,
     white = 15
 
-proc vgaEntryColour(fg: VGA_Colour, bg: VGA_Colour): uint8 =
-  result = uint8(ord(fg)) or (uint8(ord(bg)) shl 4)
+proc vgaEntryColour(fg: VGA_Colour, bg: VGA_Colour): int =
+  result = ord(fg) or (ord(bg) shl 4)
 
 proc vgaEntry(c: char, colour: uint8): uint16 =
   result = uint16(c) or (uint16(colour) shl 8)
@@ -30,22 +30,24 @@ const
 
 var
   terminalRow, terminalColumn = 0
-  terminalColour = vgaEntryColour(VGA_Colour.lightGrey, VGA_Colour.black)
+  terminalColour: int
 
-proc terminalWriteAtPoint(writeChar: char, colour: uint8, xPos: int, yPos: int) =
-  let index = terminalBufferBaseAddress + (yPos * vgaWidth + xPos)
-  cast[ptr uint16](index)[] = vgaEntry(writeChar, colour) # Write directly to display memory
+proc terminalWriteAtPoint(writeChar: char, colour: int, xPos: int, yPos: int) =
+  let index = terminalBufferBaseAddress + (yPos * vgaWidth + (xPos * 2))
+  cast[ptr int](index)[] = int(writeChar) # Write directly to display memory
+  cast[ptr int](index+1)[] = terminalColour
 
 proc terminalInitialize() =
+  terminalColour = vgaEntryColour(VGA_Colour.white, VGA_Colour.black)
   for y in 0..<vgaWidth:
     for x in 0..<vgaHeight:
-      terminalWriteAtPoint(' ', 0, x, y)
+      terminalWriteAtPoint(' ', terminalColour, x, y)
 
-proc setTerminalColour(newColour: uint8) =
+proc setTerminalColour(newColour: int) =
   terminalColour = newColour
 
 proc terminalWriteChar(writeChar: char) =
-  if(writeChar == '\r'):
+  if(writeChar == '\L'):
     inc(terminalRow)
     if(terminalRow == vgaHeight): terminalRow = 0
     return
@@ -62,5 +64,5 @@ proc terminalWrite(data: string) =
 
 proc kernelMain() {.exportc: "kernel_main"}=
   terminalInitialize()
-  terminalWrite("Hello World\rThis is Nim!")
+  terminalWrite("Hello World This is Nim!")