Chapter 3 SignalGP instruction set
Below, we document the instruction set used in our GP system for our experiments.
Abbreviations:
- EOP: End of program
- Reg: local register
- Reg[0] indicates the value at the register specified by an instruction’s first argument, Reg[1] indicates the value at the register specified by an instruction’s second argument, and Reg[2] indicates the value at the register specified by the instruction’s third argument.
- Reg[0], Reg[1], etc: Register 0, Register 1, etc.
- Input: input buffer
- Follows same scheme as Reg
- Output: output buffer
- Follows same scheme as Reg
- Global: global memory buffer
- Follows same scheme as Reg
- Arg: Instruction argument
- Arg[i] indicates the i’th instruction argument (an integer encoded in the genome)
- E.g., Arg[0] is an instruction’s first argument
Instructions that would produce undefined behavior (e.g., division by zero) are treated as no operations.
3.1 Default Instructions
I.e., instructions used across all diagnostic tasks.
| Instruction | Arguments Used | Description |
|---|---|---|
Nop |
0 | No operation |
Not |
1 | Reg[0] = !Reg[0] |
Inc |
1 | Reg[0] = Reg[0] + 1 |
Dec |
1 | Reg[0] = Reg[0] - 1 |
Add |
3 | Reg[0] = Reg[1] + Reg[2] |
Sub |
3 | Reg[0] = Reg[1] - Reg[2] |
Mult |
3 | Reg[0] = Reg[1] * Reg[2] |
Div |
3 | Reg[0] = Reg[1] / Reg[2] |
Mod |
3 | Reg[0] = Reg[1] % Reg[2] |
Nand |
2 | Reg[0] = !(R1g[0] & Reg[2]) |
TestEqu |
3 | Reg[0] = Reg[1] == Reg[2] |
TestNEqu |
3 | Reg[0] = Reg[1] != Reg[2] |
TestLess |
3 | Reg[0] = Reg[1] < Reg[2] |
TestLessEqu |
3 | Reg[0] = Reg[1] <= Reg[2] |
TestGreater |
3 | Reg[0] = Reg[1] > Reg[2] |
TestGreaterEqu |
3 | Reg[0] = Reg[1] >= Reg[2] |
SetMem |
2 | Reg[0] = Arg[1] |
Terminal |
1 | Reg[0] = double value encoded by instruction tag |
CopyMem |
2 | Reg[0] = Reg[1] |
SwapMem |
2 | Swap(Reg[0], Reg[1]) |
InputToWorking |
2 | Reg[0] = Input[1] |
WorkingToOutput |
2 | Output[1] = Reg[0] |
If |
1 | If Reg[0] != 0, proceed. Otherwise skip to the next Close or EOP. |
While |
1 | While Reg[0] != 0, loop. Otherwise skip to next Close or EOP. |
Close |
0 | Indicate the end of a control block of code (e.g., loop, if). |
Break |
0 | Break out of current control flow (e.g., loop). |
Call |
0 | Call a function, using this instruction’s tag to determine which function is called. |
Routine |
0 | Same as call, but local memory is shared. Sort of like a jump that will jump back when the routine ends. |
Return |
0 | Return from the current function call. |
WorkingToGlobal |
2 | Global[1] = Reg[0] |
GlobalToWorking |
2 | Reg[1] = Global[0] |
FullGlobalToWorking |
0 | Copy entire global memory buffer into working memory buffer |
FullWorkingToGlobal |
0 | Copy entire working memory buffer into global memory buffer |
Note that Nand performs a bitwise operation.