1001 ----- print number from stack (stdio.pvvs)
1010 ----- stackrotate (stack.pvvs)
1011 ----- stackrotatereverse (stack.pvvs)
+ 1100 ----- deepdup (stack.pvvs)
010xxx - math functions
10000 ----- random (math.pvvs)
10001 ----- absolute value (math.pvvs)
111000 ----- dump heap (debug.pvvs)
111001 ----- dump stack (debug.pvvs)
1xxxxxx - reserved for less common entry points
- 1000000 ----- slurp registers (heap.pvvs)
- 1000001 ----- spew registers (heap.pvvs)
+ 1000000 ----- lowbitand (logic.pvvs)
+ 1000001 ----- isnegative (math.pvvs)
1000010 ----- print sign of number (stdio.pvvs)
1000011 ----- print magnitude of number (stdio.pvvs)
1000100 ----- print string from stack (stdio.pvvs)