86 lines
2.3 KiB
Nim
86 lines
2.3 KiB
Nim
import vga
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type
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VGAMemory = ptr array[0..2000, VGADoubleByte]
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const
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vgaWidth = 80
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vgaHeight = 25
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terminalBufferBaseAddress = 0xB8000
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vgaMem = cast[VGAMemory](terminalBufferBaseAddress)
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var
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terminalRow, terminalColumn = 0
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terminalColour: int
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proc terminalWriteAtPoint(writeChar: char, colour: int, xPos: int, yPos: int) =
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let index = yPos * vgaWidth + xPos
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vgaMem[index] = vga.vgaEntry(writeChar, terminalColour)
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proc terminalClear*() =
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for x in 0..<vgaWidth:
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for y in 0..<vgaHeight:
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terminalWriteAtPoint(' ', terminalColour, x, y)
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terminalRow = 0
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terminalColumn = 0
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proc terminalInitialize*() =
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terminalColour = vgaEntryColour(VGA_Colour.lightGreen, VGA_Colour.red)
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terminalClear()
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proc terminalScroll() =
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for y in 0..< (vgaHeight - 1):
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for x in 0..<vgaWidth:
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let xval = x * 2
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let index1 = y * vgaWidth + x
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let index2 = (y + 1) * vgaWidth + x
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vgaMem[index1] = vgaMem[index2]
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for x in 0..<vgaWidth: # Blank the "new" bottom line
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terminalWriteAtPoint(' ', terminalColour, x, vgaHeight - 1)
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proc setTerminalColour(newColour: int) =
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terminalColour = newColour
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proc terminalWriteChar(writeChar: char) =
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if(writeChar == '\L'):
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if(terminalRow < vgaHeight - 1): inc(terminalRow)
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else: # If we are at the bottom of the screen then scroll the screen.
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terminalScroll()
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terminalColumn = 0
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return
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terminalWriteAtPoint(writeChar, terminalColour, terminalColumn, terminalRow)
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inc(terminalColumn)
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if(terminalColumn == vgaWidth):
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terminalColumn = 0
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if(terminalRow < vgaHeight - 1): inc(terminalRow)
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else: # If we are at the bottom of the screen then scroll the screen.
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terminalScroll()
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proc terminalWrite*(data: string) =
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for character in data:
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terminalWriteChar(character)
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proc terminalWrite*(data: char) =
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terminalWriteChar(data)
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var parsedData = ['0','0','0','0','0','0','0','0','0','0']
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proc terminalWrite*(data: int) =
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if(data == 0):
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terminalWrite('0')
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return
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var input = data
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var i = 0
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if(input < 0):
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terminalWrite('-')
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input = input * -1
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while(input != 0):
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let parsedChar: char = char(48 + (input mod 10))
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parsedData[i] = parsedChar
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i = i + 1
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input = input div 10
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while i > 0:
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i = i - 1
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terminalWrite(parsedData[i])
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