PM0056 datasheet(55/156 Pages) STMICROELECTRONICS

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PM0056

The Cortex-M3 instruction set

Note:

If n is 32 or more, then all the bits in the result are cleared to 0.

If n is 33 or more and the carry flag is updated, it is updated to 0.

Figure 15. LSL#3

ROR

Rotate right by n bits moves the left-hand 32-n bits of the register Rm, to the right by n places,

into the right-hand 32-n bits of the result. It also moves the right-hand n bits of the register

into the left-hand n bits of the result (see Figure 16).

When the instruction is RORS or when ROR #n is used in operand2 with the instructions

MOVS, MVNS, ANDS, ORRS, ORNS, EORS, BICS, TEQ or TST, the carry flag is updated

to the last bit rotation, bit[n-1], of the register Rm.

Note:

If n is 32, then the value of the result is same as the value in Rm, and if the carry flag is

updated, it is updated to bit[31] of Rm.

ROR with shift length, n, more than 32 is the same as ROR with shift length n-32.

Figure 16. ROR #3

RRX

Rotate right with extend moves the bits of the register Rm to the right by one bit. And it

copies the carry flag into bit[31] of the result (see Figure 17).

When the instruction is RRXS or when RRX is used in operand2 with the instructions

MOVS, MVNS, ANDS, ORRS, ORNS, EORS, BICS, TEQ or TST, the carry flag is updated

to bit[0] of the register Rm.

Carry

Flag

...

Carry

Flag

...

PM0056 Datasheet(PDF) 55 Page - STMicroelectronics