But for some reason, you could only work with 28 sprites instead of the maximum of 32. So, what was the reason behind this?
One reason may have been space.
Of the 16 KiB RAM, build-in TI-BASIC uses 2 KiB for screen handling (including 80 bytes line buffer) (*1), leaving a bit less than 12 KiB for programm and data.
For Extended BASIC it is essential to be able to support programs of similar size as with TI-BASIC - this includes the ability to load (old) TI-BASIC programs. Thus memory requirement should at best not exceed what has been set by TI-BASIC. At the same time it needs memory to hold additional data like:
- Sprite attributes table
- Sprite motion table |
- Some system data area
- An extended crunch buffer
- And a new edit buffer for the improved editor
All of this would have end up at ~500 Bytes less memory available. By reducing the the character table (*2) as well as the sprite tables this was reduced to ~300 bytes. In addition some data areas (like line symbol table) wouldd be moved into RAM expansion if present.
So while it seams little, it's safe to assume that they tried hard to reduce the memory footprint.
Was this another ploy by Texas Instruments to cripple what home users could do in an attempt at selling more "TI Branded" software?
Another ploy? Like a secret conspiration? Serious, why on earth should TI do so?
*1 - Plus another ~2KiB for file buffers when a disk unit is installed (more with number of files set above 3)
*2 - Extended BASIC reduced the available glyphs by 16 to 30..143.