IBM System/7 Functional Characteristics - All about the IBM 1130 ...

Shift Left Logical (PSLL)0 5 8 11 15Op code Mod Count0 0 0 1 0 X X X 0 0 1 XXXXX1 1 1 1 11111 0-7 2 or 3 XAll 16 bits in the index register (R), or the accumulator if R=000, are shifted leftby the number specified in the count field.All bits shifted out of the high-order position (bit 0) are lost. The last bit shiftedout of position 0 (shift count=0) sets the carry indicator according to the value of thebit shifted out. Vacated low-order bit positions are set to 0's.The shift count field can specify any decimal value from 0 to 16. Shift counts greaterthan 16 are invalid and cause a program check interruption. A shift count of 0 is validand serves a useful purpose. Although no shifting takes place, this is a simple methodof setting the result indicators to reflect the current contents of the R register. Ashift count of 16 puts O's in all bits of the R register.The overflow indicator is not changed. The carry indicator is set on or off to reflectthe last bit shifted out of bit 0. The result indicators are changed to reflect the finalcontents of the R register. For a shift count greater than 0, the result-even indicatoris always set on, because vacated bits are automatically set to 0's.Example:Assume a left shift of two bits in the accumulator0 5 8 15PSLL instruction Op code R Mod Count0 0 0 1 0 0 0 0 0 0 1 010 0 1 0i i i I I I I I II i 11 0 2 2Carry indicator Accumulator0 15Original valueX0 shifted in15/After first shift0 shifted inAfter second shiftProcessor Instructions 4-25InINN x " "II' "