Machine Language Model

There is a one to one mapping of a statement from the Assembly Language Model (GAL) to a Machine Language (ML) instruction. In other words, the assembly language statement is a human readable form of the machine instruction.

ML model

This language model is designed for the convenience and efficient encoding of information (instructions) for the machine. The issues to be considered:

• encoding the parts of an instruction
• using bit fields of different sizes and arrangement for efficient storage and retrieval. You may not need an entire byte to represent a piece of information.
• understanding the instruction execution and instruction cycle

AL model compared

This language modes focuses on the convenience of representing the instruction for the human user.

• Using operation code mnemonics
• Simplified operand expressions and notation
• Reasonable expression of algorithms
• User defined identifiers

More special registers

Other registers relevant to the machine language model in addition to the general purpose registers

• PC (program counter) - contains the address of the next instruction
• SP (stack pointer) - contains the address of the top of the system stack
• IR (instruction register) - holds the current instruction for decoding and execution
• PS (program status register) - holds information about the state of the machine and last instruction
• ALU registers - temporarily hold data entering and leaving the ALU
• Memory access registers: MDR (data register) and MAR (address register) - temporarily hold information to access memory.

Check the Pippin Simulator