Memory Map

Actual locations are up for much discussion.

Memory Mapped Registers (all values are little-endian)

Graphics Registers

0xA0000: 16bit screen width
0xA0002: 16bit screen height
0xA0004: 8bit screen bits per pixel. Bits are divided evenly across the color space with preference given for the odd bit to green, then to blue. Special cases for 1 bpp and 2 bpp.
- 1 bpp: black or white
- 2 bpp: 2 levels of grey (0%, 33%, 66%, 100%)
- 3 bpp: 1 bit red, 1 bit green, 1 bit blue. Possible colors: black, white, red, green, blue, yellow, cyan, magenta).
- 4 bpp: 1 bit red, 2 bits green, 1 bit blue.
- 5 bpp: 1 bit red, 2 bits green, 2 bits blue.
- 6 bpp: 2 bits red, 2 bits green, 2 bits blue.
- 7 bpp: 2 bits red, 3 bits green, 2 bits blue.
- 8 bpp: 2 bits red, 3 bits green, 3 bits blue.
- etc
- 24 bpp: max value with meaning
0xA0005: 8bit screen refresh rate
0xA0006: 8bit Horizontal aspect
0xA0007: 8bit Vertical aspect
0xA0008: 32bit pointer to current framebuffer. Expected to read width * height * bpp bits from this memory location to draw current frame

IO Registers

Joy 0

Joy 1

Joy 2

Joy 3

Keyboard

0xA0200: Currently pressed key(s) of some sort. Possibly based on SFML keycodes.

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