Computer instruction set
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The document provides an overview of computer instruction sets, detailing memory reference, register reference, and input/output instructions. It describes how these instructions use specific bits for addressing modes, operation codes, and types of operations. Additionally, the document includes tables summarizing the respective instruction types and their functionalities.
Computer instruction set
- 2. OVERVIEW Memory reference instruction Memory reference instruction table Register reference instruction Register reference instruction table Input output instruction Input output instruction table
- 3. MEMORY REFERENCE INSTRUCTION It uses 12 bits to specify an address Uses 1 bit to specify the addressing mode I o I is 0 for direct address o I is 1 for indirect address (Opcode = 000 through 110) 15 14 12 11 0 (Fig.Memory Reference Instruction) I Opcode Address
- 4. MEMORY REFERENCE INSTRUCTION TABLE
- 5. REGISTER REFERENCE INSTRUCTION Are recognized by the operation code 111 with a 0 at the 15th bit of the instruction An operand from memory is not needed Other 12 bits are used to specify the operation or test to be executed (Opcode = 111,I = 0) 15 12 11 0 (Fig.Register Reference Instruction) 0 1 1 1 Register Operation
- 6. REGISTER REFERENCE INSTRUCTION TABLE
- 7. INPUT OUTPUT INSTRUCTION Reference to memory Recognized by the operation code 111 and 1 at 15th bit position of the instruction Remaining 12 bits used to specify the type of input output operation to be performed (Opcode = 111,I = 1) 15 12 11 0 (Fig.Input Output Instruction) 1 1 1 1 I/O Operation
- 8. I/O INSTRUCTION TABLE Symbol Hexadecimal Code Description INT OUT SKI SKO ION IOF F800 F400 F200 F100 F080 F040 Input Character to AC Output Character from AC Skip on input flag Skip on output flag Interrupt on Interrupt off
- 9. CONCLUSION Instructions are used for various purposes by computer- each instruction having its own individual working . . .
- 10. Thank you . . .
Editor's Notes
- #3: A presentation on: Computer instruction set