3 ms·
I owned a TI99/4a as a kid and at the time I was interested in the TMS9900 archictecture. I always thought the workspace-pointer-to-register-set could make for
by ams6110 9y ago
I owned a TI99/4a as a kid and at the time I was interested in the TMS9900 archictecture.
I always thought the workspace-pointer-to-register-set could make for some easy multitasking context switches. You just change the workspace pointer and immediately you're working in another context.
In practice it was slow though compared to processors with real registers.
- abecedarius 9y agoI had one too. The really shocking bottleneck though was this: just 256 bytes of RAM were CPU-addressable; the 16k bytes it was advertised to come with were video RAM. If you bought the "mini memory" 4k expansion and coded in assembler, the speed seemed competitive with other home computers around then. Apparently it was coding in BASIC through the video memory bottleneck (and iirc an extra level of interpretation? I think I read somewhere that their BASIC interpreter was written in an interpreted VM code) that made your programs so slow on the TI-99. (Added: https://en.wikipedia.org/wiki/Texas_Instruments_TI-99/4A#VDP_RAM_and_GPL https://en.wikipedia.org/wiki/Texas_Instruments_TI-99/4A#VDP...)