Oh man. The 9900 architecture was awesome. Designed at a time when bipolar memory was faster than TTL logic, it put the register file in main memory. Only the P

Oh man. The 9900 architecture was awesome. Designed at a time when bipolar memory was faster than TTL logic, it put the register file in main memory. Only the PC, STATUS register and "WORKSPACE POINTER" were on the CPU. The general purpose registers were in memory, pointed to by the WP. It was trivial to implement threads on that machine, just execute a BLWP (branch and load workspace pointer) when jumping between threads.