Thus our instructions and data are stored in bytes 1 through byte 13 of our symbolic computer. The task of mapping or translating our symbolic program into strings of bits now becomes one of coding the instructions and numeric data into 0's and 1's . The coding of the instructions must conform to the architecture of the computer as defined by the engineering team. All computer architectures have manuals which define the bit patterns for encoding the instructions of the microprocessor. Since the computer architecture of the simple computer is my creation , I have decided on what bit patterns will represent what instrucions.
All instructions are one byte long.
The first 3 bits of an instruction-byte code the operation to perform . The remaining 5 bits code the address of a either a register or a memory location depending on the instruction defined by the first 3 bits. That is ,an instruction which operates on 2 registers would code the addresses of the registers in the remaining 5 bits . A LOAD is coded as 011aammm where aa indicates the register to receive the number and mmm the memory location which contains the value to be loaded . 10100000 would cause the microprocessor to halt operations.