Week 5 - 8086 Assembly language programming PDF

Preview

Summary

8086 Assembly language programming...

Description

Wednesday October 2nd, 2019

Kristen Gallagher Computer Architecture Week 5 80x86 Assembly Language Programming 8086 Instruction Set - Divided intro 6 types o Data Transfer (register/memory)  MOV  LEA o Arithmetic  ADD  SUB  MUL/IMUL (signed multiply)  DIV/IDIV (signed division)  DEC  INC  NEG o Logical and bit Manipulation  AND  OR  XOR  NOT o String o

o

Program Execution Control  CMP  JMP  JL  JLE  JG  JGE  LOOP Processor Control

Memory Operations - Transfer data between processor and memory (RAM) - In the 80x86 architecture, most arithmetic/logic operations can address memory o CISC (Complex Instruction Set Computer) - In processors like ARM only 2 operations (LOAD and STORE) can access memory o RISC (Reduced Instruction Set Computer - 80x86 assembly instructions use square brackets [ ] to indicate that the memory address enclosed is being accessed o ex. MOV [BX], 0x0A -- Important: On the 8086 the address in square brackets is just the 16-bit offset

Kristen Gallagher

Wednesday October 2nd, 2019

Setting the Base Address (Segment) - before accessing memory with the MOV instruction, we should make sure the data segment is set correctly - note that “immediate” moves to segment registers are not allowed, so we need to do it in 2 steps...