ACCT 002 Lecture Notes - Lecture 17: Instruction Set, Complex Instruction Set Computing, Ia-32

• School: College of The Sequoias
• Department: Accounting (ACCT)
• Course: ACCT 002
• Professor: Chaojibai

Document Summary

8 instruction set architectures, part 2: symbolic notation, copy instruction. Fetches per operation: problem: operand override, we destroy content at b, solution is to store b in a new variable c, one-address instructions, have implicit source (called an accumulator, example: Load a: add b, store c, means: Immediate addressing: opcode specifier | operand, add | # - 1. Jnz 10 (simple counting loop: advantages, fast, no additional calculations needed to obtain operand, disadvantages, operand value must be known, operand value cannot be changed. Limited number of bits available: notation: move #200, r0, meaning: [r0] 200, direct addressing / absolute addressing, opcode specifier | memory or register address, add | 13. Jnz | 10: # - 1, advantages, operand separate from instruction, can be changed, full word length available, disadvantages, more memory accesses, more store occupation, notation: add r1,r2, meaning: [r2] [r2] + [r1]