◄SHL op.►  ◄SHR op.►  ◄Summary►  ◄Detail►  ◄Example►  ◄Key to Flags►
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Shift                                            Flags:  O D I T S Z A P C
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Syntax:  SHL dest,1                                      ±       ± ± ? ± ±
         SHL dest,CL
         SHL dest,number (80186/286/386 Only)
 
  Shifts the bits in the destination operand the number of times specified
  by the source operand. SAL and SHL shift the bits left; SAR and SHR
  shift right.
 
  With SHL, SAL, and SHR, the bit shifted off the end of the
  operand is copied into the carry flag and the leftmost or rightmost bit
  opened by the shift is set to 0. With SAR, the bit shifted off the
  end of the operand is copied into the carry flag and the leftmost bit
  opened by the shift retains its previous value (thus preserving the sign
  of the operand). SAL and SHL are synonyms; they have the same
  effect.
 
  On the 8088 and 8086, the source operand can be either CL or 1. On the
  80186-80386 processors, the source operand can be CL or an 8-bit con-
  stant. On the 80186-80386 processors, shift counts larger than 31 are
  masked off, but on the 8088 and 8086, larger shift counts are performed
  despite the inefficiency involved. The overflow flag is only modified by
  single-bit variations of the instruction; for multiple-bit variations it
  is undefined.
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