UNIT-II DEPARTMENT OF INFORMATION TECHNOLOGY::SVECW Page 1
UNIT-2 MACHINE INSTRUCTION SET
ADDRESSING MODES Figure 2.1
Addressing Modes UNIT-II DEPARTMENT OF INFORMATION TECHNOLOGY::SVECW Page 2 The address field or fields in atypical instruction format are relatively small. We should be able to reference a large range of locations in main memory. For this, a variety of addressing techniques has been employed. The most common
addressing techniques are • Immediate
• Direct
•
Indirect • Register
•
Register indirect • Displacement
• Stack Table Basic Addressing Modes Table 2.1 indicates the address calculation performed for each addressing mode. Different opcodes will use different addressing modes. Also, one or more bits in the instruction
format can be used as a mode field. The value of the mode field determines which addressing mode is to be used.
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