Hypothesized Official Name: ClearRect
BCALL Address: 4D44h
Fill a rectangle with solid white.
- HL = X coordinate of left edge
- DE = X coordinate of right edge (must be at most 319)
- B = Y coordinate of top edge (from top of screen)
- C = Y coordinate of bottom edge (must be greater than or equal to B and at most 239)
- (fillRectColor) = 0FFFFh
The rectangle is drawn only to the LCD, never to the graph buffer.
The dimensions of the filled area are (HL-DE+1) × (C-B+1). The routine checks for HL > DE (in which case nothing is drawn), but doesn't check for B > C, and doesn't check that the provided coordinates are valid.
The interrupt state (IFF) is preserved.