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Logical Group Instructions (Part-V) - CMA, CMC, STC

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CMA:
  • This instruction complements the contents of the accumulator.
  • The result is stored in the accumulator.
  • Only CY flag is modified.
  • It is a one byte instruction.
  • Implied addressing mode is used.
Example:
If A= 1000 1000 = 88H
CMA ; This instruction will complement each bit A= 0111 0111 = 77H.

CMC:
  • This instruction complements the carry flag.
  • If CY = 1 then this instruction will make CY = 0.
  • Only CY flag is modified.
  • It is a one byte instruction.
  • Implied addressing mode is used.
Example:
If CY=1
CMC ; This instruction complements the CY flag CY=0.

STC:
  • This instruction sets the carry flag.
  • This will make CY=1.
  • Only CY flag is modified.
  • It is a one byte instruction.
  • Implied addressing mode is used.
Example:
STC ; This instruction will set CY flag CY=1.
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