Figure 10. Asr#3; Figure 11. Lsr#3 - ST STM32F0 Series Programming Manual

PM0215
ASR
Arithmetic shift 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. And it copies the original bit[31] of the
register into the left-hand n bits of the result (see
You can use the ASR operation to divide the signed value in the register Rm by 2
result being rounded towards negative-infinity.
When the instruction is ASRS, the carry flag is updated to the last bit shifted out, bit[n-1], of
the register Rm.
Note: 1 If n is 32 or more, all the bits in the result are set to the value of bit[31] of Rm.
2 If n is 32 or more and the carry flag is updated, it is updated to the value of bit[31] of Rm.

Figure 10. ASR#3


LSR
Logical shift 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. And it sets the left-hand n bits of the result
to 0 (see
You can use the LSR #n operation to divide the value in the register Rm by 2
regarded as an unsigned integer.
When the instruction is LSRS, the carry flag is updated to the last bit shifted out, bit[n-1], of
the register Rm.
Note: 1 If n is 32 or more, then all the bits in the result are cleared to 0.
2 If n is 33 or more and the carry flag is updated, it is updated to 0.

Figure 11. LSR#3


Figure 11).
  
Doc ID 022979 Rev 1
The STM32 Cortex-M0 instruction set
Figure 10: ASR#3).


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