Stack Computers: the new wave © Copyright 1989, Philip Koopman, All Rights Reserved.

Chapter 3
Multiple-stack, 0-operand Machines

This chapter focuses attention on multiple stack, 0-operand machines comprising the MS0 and ML0 categories of the taxonomy described in Chapter 2. In Section 3.1, we shall compare stack machines to conventional complex instruction set computer (CISC) and reduced instruction set computer (RISC) architectures.

In Section 3.2, we shall describe a generic stack machine architecture called the Canonical Stack Machine. We shall cover the hardware at a block diagram level, as well as implementation of the instruction set. This two-stack machine will serve as a point of departure for discussions of real stack machines in subsequent chapters.

In Section 3.3, we shall briefly discuss the Forth programming language. Forth is an unconventional programming language which uses a two-stack model of computation and strongly encourages frequent calls to many small procedures. Many ML0 and MS0 designs have their roots in the Forth language, and are well suited to execution of Forth programs.

• 3.1 WHY THESE MACHINES ARE INTERESTING
• 3.2 A GENERIC STACK MACHINE
  • 3.2.1 Block diagram
    • 3.2.1.1 Data bus
    • 3.2.1.2 Data stack
    • 3.2.1.3 Return stack
    • 3.2.1.4 ALU and top-of-stack register
    • 3.2.1.5 Program counter
    • 3.2.1.6 Program memory
    • 3.2.1.7 I/O
  • 3.2.2 Data operations
    • 3.2.2.1 Reverse Polish Notation
    • 3.2.2.2 Arithmetic and logical operators
    • 3.2.2.3 Stack manipulation operators
    • 3.2.2.4 Memory fetching and storing
    • 3.2.2.5 Literals
  • 3.2.3 Instruction execution
    • 3.2.3.1 Program Counter
    • 3.2.3.2 Conditional branching
    • 3.2.3.3 Subroutine calls
    • 3.2.3.4 Hardwired vs. microcoded instructions
  • 3.2.4 State changing
    • 3.2.4.1 Stack overflow/underflow interrupts
    • 3.2.4.2 I/O service interrupts
    • 3.2.4.3 Task switching
• 3.3 OVERVIEW OF THE FORTH PROGRAMMING LANGUAGE
  • 3.3.1 Forth as a common thread
  • 3.3.2 The Forth virtual machine
    • 3.3.2.1 Stack architecture/RPN
    • 3.3.2.2 Short, frequent procedure calls
  • 3.3.3 Emphasis on interactivity, flexibility

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Phil Koopman -- koopman@cmu.edu