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	Number	Readable	Writable	Description
Clip Window Layer 2 Register	$18	true	true	Sets and reads clip-window for Layer 2.
Clip Window Sprites Register	$19	true	true	Sets and reads clip-window for Sprites
Clip Window ULA/LoRes Register	$1A	true	true	Sets and reads clip-window for ULA/LoRes layer.
Clip Window Tilemap Register	$1B	true	true	Sets and reads clip-window for Tilemap.
Clip Window Control Register	$1C	true	true	Controls (resets) the clip-window registers indices.
Active Video Line MSB Register	$1E	true	false	Holds the MSB (only, as bit 0) of the raster line currently being drawn.
Active Video Line LSB Register	$1F	true	false	Holds the eight LSBs of the raster line currently being drawn.
Video Line Interrupt Control Register	$22	true	true	Controls the timing of raster interrupts and the ULA frame interrupt.
Video Line Interrupt Value Register	$23	true	true	Holds the eight LSBs of the line on which a raster interrupt should occur.
ULA X Offset Register	$26	true	true	Pixel X offset (0..255) to use when drawing ULA Layer.
ULA Y Offset Register	$27	true	true	Pixel Y offset (0..191) to use when drawing ULA Layer.
Keymap High Address Register	$28	true	true	PS/2 Keymap address MSB, read (pending) first byte of palette colour
Keymap Low Address Register	$29	false	true	PS/2 Keymap address LSB.
Keymap High Data Register	$2A	false	true	High data to PS/2 Keymap (MSB of data in bit 0)
Keymap Low Data Register	$2B	false	true	Low eight LSBs of PS/2 Keymap data.
DAC B (left) mirror Register	$2C	true	true	DAC B mirror, read current I2S left MSB
DAC A+D (mono) mirror Register	$2D	true	true	SpecDrum port 0xDF / DAC A+D mirror, read current I2S LSB
DAC C (right) mirror Register	$2E	true	true	DAC C mirror, read current I2S right MSB
Tilemap Offset X MSB Register	$2F	true	true	Sets the pixel offset (two high bits) used for drawing Tilemap graphics on the screen.
Tilemap Offset X LSB Register	$30	true	true	Sets the pixel offset (eight low bits) used for drawing Tilemap graphics on the screen.