Rotate instructions
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The document summarizes different rotate instructions in microprocessors - ROL, ROR, RCL, and RCR. ROL rotates bits left without affecting the carry flag, while ROR rotates bits right without affecting carry. RCL rotates bits left and propagates the carry flag, and RCR rotates bits right while propagating the carry flag. Examples are provided for each instruction to demonstrate how they modify register values and flags.
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Rotate instructions
- 1. Microprocessor & its Applications Module 3 Continued…… Dr. Girisha G S Dept. of CSE SoE, DSU, Bengaluru 1
- 2. Agenda • Rotate Instructions - ROL, ROR, RCL, RCR 2
- 3. Rotate Instructions – ROL, ROR, RCL, RCR ROL – Rotate Left without carry Syntax: ROL Dest, Count Examples: Flags Affected: CF, OF AL = D5H CF CF ; AL=ABH MOV CL, 04 ROL BL,CL ROL AL,1 ;
- 4. ROR -Rotate Right without carry Examples: ROR AL,1 ; AL=D5H ; AL = EAH MOV CL, 04 ROR BL,CL Syntax: ROR Dest, Count Flags Affected: CF, OF CF C F
- 5. RCL – Rotate Through Carry Left RCR – Rotate Through Carry Right Syntax: RCL Dest, Count Syntax: RCR Dest, Count ; AL=D5H ; AL=6AH CF CF Examples: RCR AL,1 ; AL=D5H ; AL=AAH Examples: RCL AL,1
Editor's Notes
- #6: RCR instruction rotates the bits in the operand specified by op1 towards right by the count specified in op2.