video.asm contains routines for the background and window.

List of routines:

• bg_fill
• bg_init
• bg_load_tiles
• bg_move
• bg_draw_tiles
• memcpy_vram
• vid_vram_readable

bg_fill

• Creates a filled rectangle background from (x, y) to (x+w, y+h) with a tile

Parameters: A-tile, L-x, H-y, B-width, C-height

Destroys: All

bg_draw_tiles

• Draw tiles in a rectangular pattern onto the screen, based on the tiles pointed by DE.

Parameters: H - screen X, L - screen Y, B - width, C - height, DE - pointer to tile data

Destroys: All

bg_init

• Initializes LCD registers. Enables window, background, and sprites
• Initializes sprite & background palettes

Parameters: None

Destroys: A, HL

bg_load_tiles

• Loads tiles into VRAM

Parameters: A-tile number, B-number of tiles to load, DE-pointer to tile data

Destroys: AF, BC, D, HL

bg_move

• Scrolls the background to (x, y)

Parameters: H-x, L-y

Destroys: A

memcpy_vram

• Block copy of data from/to VRAM.

Parameters: HL-source pointer, DE-destination pointer, BC-size

Destroys: All

vid_vram_readable

• Inefficiently waits for VRAM to be accessible.

Parameters: None

Destroys: AF