Appendix D: TOY Programming Cheatsheet
This appendix summarizes the 16 TOY instructions.
TOY REFERENCE CARD INSTRUCTION FORMATS | . . . . | . . . . | . . . . | . . . .| Format RR: | opcode | d | s | t | (0-6, A-B) Format A: | opcode | d | addr | (7-9, C-F) ARITHMETIC and LOGICAL operations 1: add R[d] <- R[s] + R[t] 2: subtract R[d] <- R[s] - R[t] 3: and R[d] <- R[s] & R[t] 4: xor R[d] <- R[s] ^ R[t] 5: shift left R[d] <- R[s] << R[t] 6: shift right R[d] <- R[s] >> R[t] TRANSFER between registers and memory 7: load address R[d] <- addr 8: load R[d] <- M[addr] 9: store M[addr] <- R[d] A: load indirect R[d] <- M[R[t]] B: store indirect M[R[t]] <- R[d] CONTROL 0: halt halt C: branch zero if (R[d] == 0) PC <- addr D: branch positive if (R[d] > 0) PC <- addr E: jump register PC <- R[d] F: jump and link R[d] <- PC; PC <- addr Register 0 always reads 0. Loads from M[FF] come from stdin. Stores to M[FF] go to stdout. 16-bit registers (two's complement) 16-bit memory locations 8-bit program counter