Statement List (STL) - DCE FEL ČVUT v Praze

Shift and Rotate Instructions
11.2 Rotate Instructions
11.2.1 Overview of Rotate Instructions
Description
You can use the Rotate instructions to rotate the entire contents of accumulator 1 bit
by bit to the left or to the right (see also CPU Registers). The Rotate instructions
trigger functions that are similar to the shift functions described in Section 14.1.
However, the vacated bit places are filled with the signal states of the bits that are
shifted out of the accumulator.
The number that follows the rotate instruction or a value in the low byte of the low
word of accumulator 2 indicates the number of bits by which to rotate. Depending on
the instruction, rotation takes place via the CC 1 bit of the status word. The CC 0 bit
of the status word is reset to 0.
The following Rotate instructions are available:
• RLD Rotate Left Double Word (32-Bit)
• RRD Rotate Right Double Word (32-Bit)
• RLDA Rotate ACCU 1 Left via CC 1 (32-Bit)
• RRDA Rotate ACCU 1 Right via CC 1 (32-Bit)
Statement List (STL) for S7-300 and S7-400 Programming
11-14 A5E00706960-01