Table 4-1: Sprite Data Structure
Memory
Location 16-bit Word Function
N Sprite control word 1 Vertical and horizontal start
position
N+1 Sprite control word 2 Vertical stop position
N+2 Color descriptor low word Color bits for line 1
N+3 Color descriptor high word Color bits for line 1
N+4 Color descriptor low word Color bits for line 2
N+5 Color descriptor high word Color bits for line 2
.
.
.
End-of-data words Two words indicating
the next usage of this sprite
All memory addresses for sprites are word addresses. You will need enough contiguous
memory to provide room for two words for the control information, two words for each
horizontal line in the sprite, and two end-of-data words.
Because this data structure must be accessible by the special-purpose chips, you must
ensure that this data is located within chip memory.
Figure 4-7 shows how the data structure relates to the sprite.
- 102 Sprite Hardware -