From c3ca04dd5ad55797db342760c46929843e4c1b27 Mon Sep 17 00:00:00 2001
From: Nathan Cannon <neviynhd@gmail.com>
Date: Sat, 21 Oct 2017 18:35:13 +0100
Subject: [PATCH] Added x2 multiplication for row placement. Means newlines
 actually work properly.

---
 kernel.nim | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/kernel.nim b/kernel.nim
index bb1f548..83684c3 100644
--- a/kernel.nim
+++ b/kernel.nim
@@ -27,19 +27,20 @@ const
   vgaWidth = 80
   vgaHeight = 25
   terminalBufferBaseAddress = 0xB8000
+  bufferWidthSkip = vgaWidth * 2
 
 var
   terminalRow, terminalColumn = 0
   terminalColour: int
 
 proc terminalWriteAtPoint(writeChar: char, colour: int, xPos: int, yPos: int) =
-  let index = terminalBufferBaseAddress + (yPos * vgaWidth + (xPos * 2))
+  let index = terminalBufferBaseAddress + (yPos * bufferWidthSkip + (xPos * 2))
   cast[ptr int16](index)[] = vgaEntry(writeChar, terminalColour) # Write directly to display memory
 
 proc terminalInitialize() =
   terminalColour = vgaEntryColour(VGA_Colour.lightGreen, VGA_Colour.red)
-  for y in 0..<vgaWidth:
-    for x in 0..<vgaHeight:
+  for x in 0..<vgaWidth:
+    for y in 0..<vgaHeight:
       terminalWriteAtPoint(' ', terminalColour, x, y)
 
 proc setTerminalColour(newColour: int) =
@@ -48,6 +49,7 @@ proc setTerminalColour(newColour: int) =
 proc terminalWriteChar(writeChar: char) =
   if(writeChar == '\L'):
     inc(terminalRow)
+    terminalColumn = 0
     if(terminalRow == vgaHeight): terminalRow = 0
     return
   terminalWriteAtPoint(writeChar, terminalColour, terminalColumn, terminalRow)
@@ -63,5 +65,5 @@ proc terminalWrite(data: string) =
 
 proc kernelMain() {.exportc: "kernel_main"}=
   terminalInitialize()
-  terminalWrite("Hello World\LThis is Nim!")
+  terminalWrite("Hello World!\LNim here!")