From e871378f8ff6da3bc222508f962067df68a109dc Mon Sep 17 00:00:00 2001
From: Nathan Cannon <neviynhd@gmail.com>
Date: Sun, 22 Oct 2017 00:22:32 +0100
Subject: [PATCH] Added printing of ints to the screen.

---
 kernel/arch/i386/tty.nim | 53 ++++++++++++++++++++++++++++++++++------
 kernel/kernel.nim        |  4 ++-
 2 files changed, 49 insertions(+), 8 deletions(-)

diff --git a/kernel/arch/i386/tty.nim b/kernel/arch/i386/tty.nim
index c70dc8c..98086e9 100644
--- a/kernel/arch/i386/tty.nim
+++ b/kernel/arch/i386/tty.nim
@@ -12,30 +12,69 @@ var
 
 proc terminalWriteAtPoint(writeChar: char, colour: int, xPos: int, yPos: int) =
   let index = terminalBufferBaseAddress + (yPos * bufferWidthSkip + (xPos * 2))
-  cast[ptr int16](index)[] = vga.vgaEntry(writeChar, terminalColour) # Write directly to display memory
+  cast[ptr int16](index)[] = vga.vgaEntry(writeChar, terminalColour)
 
-proc terminalInitialize*() =
-  terminalColour = vgaEntryColour(VGA_Colour.lightGreen, VGA_Colour.red)
+proc terminalClear*() =
   for x in 0..<vgaWidth:
     for y in 0..<vgaHeight:
       terminalWriteAtPoint(' ', terminalColour, x, y)
+  terminalRow = 0
+  terminalColumn = 0
+
+proc terminalInitialize*() =
+  terminalColour = vgaEntryColour(VGA_Colour.lightGreen, VGA_Colour.red)
+  terminalClear()
+
+proc terminalScroll() =
+  for y in 0..< (vgaHeight - 1):
+    for x in 0..<vgaWidth:
+      let xval = x * 2
+      let index1 = terminalBufferBaseAddress + (y * bufferWidthSkip + xval)
+      let index2 = terminalBufferBaseAddress +
+        ((y + 1) * bufferWidthSkip + xval)
+      cast[ptr int16](index1)[] = cast[ptr int16](index2)[]
 
 proc setTerminalColour(newColour: int) =
   terminalColour = newColour
 
 proc terminalWriteChar(writeChar: char) =
   if(writeChar == '\L'):
-    inc(terminalRow)
+    if(terminalRow < vgaHeight): inc(terminalRow)
+    #else: # If we are at the bottom of the screen then scroll the screen.
+      #terminalScroll()
     terminalColumn = 0
-    if(terminalRow == vgaHeight): terminalRow = 0
     return
   terminalWriteAtPoint(writeChar, terminalColour, terminalColumn, terminalRow)
   inc(terminalColumn)
   if(terminalColumn == vgaWidth):
     terminalColumn = 0
-    inc(terminalRow)
-    if(terminalRow == vgaHeight): terminalRow = 0
+    if(terminalRow < vgaHeight): inc(terminalRow)
+    #else: # If we are at the bottom of the screen then scroll the screen.
+      #terminalScroll()
 
 proc terminalWrite*(data: string) =
   for character in data:
     terminalWriteChar(character)
+
+proc terminalWrite*(data: char) =
+  terminalWriteChar(data)
+
+var parsedData = ['0','0','0','0','0','0','0','0','0','0']
+
+proc terminalWrite*(data: int) =
+  var input = data
+  var i = 0
+  if(input < 0):
+    terminalWrite('-')
+  if(input == 0):
+    terminalWrite('0')
+  else:
+    while(input > 0):
+      let parsedChar: char = char(48 + (input mod 10))
+      parsedData[i] = parsedChar
+      i = i + 1
+      input = input div 10
+  while i > 0:
+    i = i - 1
+    terminalWrite(parsedData[i])
+
diff --git a/kernel/kernel.nim b/kernel/kernel.nim
index f444e0c..eb37f8d 100644
--- a/kernel/kernel.nim
+++ b/kernel/kernel.nim
@@ -2,4 +2,6 @@ import tty
 
 proc kernelMain() {.exportc: "kernel_main"}=
   terminalInitialize()
-  terminalWrite("Hello World!\LNim here!")
+  terminalWrite("Hello World!\LNim here!\L")
+  for i in 0..10:
+    terminalWrite(i)