Evolution of Instruction Sets

Instruction Set Architecture (ISA) Abstract interface between the Hardware and lowest-level Software

• 1950: Single Accumulator: EDSAC
• 1953: Accumulator plus Index Registers:  Manchester Mark I, IBM 700 series
• Separation of programming Model from implementation:
  • 1963: High-level language Based:  B5000
  • 1964: Concept of a Family:  IBM 360
• General Purpose Register Machines:
  • 1963-1976:  Load/Store Architecture:  CDC 6600,  Cray 1
  • 1977-1980:  CISC - Complex Instruction Sets computer:  Vax,   Intel 432
  • 1987: RISC: Reduced Instruction Set Computer:  Mips,  Sparc,  HP-PA,  IBM RS6000

  Typical RISC:

  • Simple, no complex addressing
  • Constant length instruction, 32-bit fixed format
  • Large register file
  • Hard wired control unit, no need for micro programming
  • Just about every opposites of CISC