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Simplified writing to VGA so as to not use 2 separate 8bit inserts. Now using a single 16bit insert.

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This commit is contained in:
neviyn 2017-10-21 17:14:13 +01:00
parent 7faa974542
commit 4d19433c17
1 changed files with 3 additions and 4 deletions
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7
kernel.nim
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@ -20,8 +20,8 @@ type
proc vgaEntryColour(fg: VGA_Colour, bg: VGA_Colour): int = proc vgaEntryColour(fg: VGA_Colour, bg: VGA_Colour): int =
result = ord(fg) or (ord(bg) shl 4) result = ord(fg) or (ord(bg) shl 4)
proc vgaEntry(c: char, colour: uint8): uint16 = proc vgaEntry(c: char, colour: int): int16 =
result = uint16(c) or (uint16(colour) shl 8) result = int16(int(c) or (colour shl 8))
const const
vgaWidth = 80 vgaWidth = 80
@ -34,8 +34,7 @@ var
proc terminalWriteAtPoint(writeChar: char, colour: int, xPos: int, yPos: int) = proc terminalWriteAtPoint(writeChar: char, colour: int, xPos: int, yPos: int) =
let index = terminalBufferBaseAddress + (yPos * vgaWidth + (xPos * 2)) let index = terminalBufferBaseAddress + (yPos * vgaWidth + (xPos * 2))
cast[ptr int8](index)[] = int8(writeChar) # Write directly to display memory cast[ptr int16](index)[] = vgaEntry(writeChar, terminalColour) # Write directly to display memory
cast[ptr int8](index+1)[] = int8(terminalColour)
proc terminalInitialize() = proc terminalInitialize() =
terminalColour = vgaEntryColour(VGA_Colour.lightGreen, VGA_Colour.red) terminalColour = vgaEntryColour(VGA_Colour.lightGreen, VGA_Colour.red)