* Explicitly no MMU, just a flat, shared memory space. Think threads, not
processes.
-Version: 1
+Version: 2
Instruction Word Formats
------------------------
| 000100 | SHIFT | Pop TOS & NOS. Shift NOS by TOS bits to the left/right. |
| 000101 | CMPSWP | Compare-and-swap with ptr, old_val & new_val on stack. |
| 000110 | TEST | Pop TOS and set PSW according to value. |
-| 000111 | BRZ | Pop TOS. If PSW_Z==1, then set PC to popped value. |
+| 000111 | BRZ | Pop TOS & NOS. If NOS==0, then set PC to TOS value. |
| 000010 | LOAD | Pop address from TOS, dereference and store to TOS. |
| 000011 | STORE | Pop address from TOS, pop data from NOS, deref and store. |
| 000001 | NOP | Do nothing. |