Microsemi SmartFusion2 - Figure 18 ASR#3

Cortex-M3 Processor (Reference Material)
UG0331 User Guide Revision 15.0 52
You can use the ASR #n operation to divide the value in the register Rm by 2
n
, with the result being
rounded towards negative-infinity.
When the instruction is
ASRS or when ASR #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 shifted out, bit[ n -1], of the
register Rm .
•If
n is 32 or more, then all the bits in the result are set to the value of bit[31] of Rm .
•If
n is 32 or more and the carry flag is updated, it is updated to the value of bit[31] of Rm .
Figure 18 • ASR#3
3.6.3.4.2 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 the following figure.
You can use the
LSR #n operation to divide the value in the register Rm by 2
n
, if the value is regarded as
an unsigned integer.
When the instruction is
LSRS or when LSR #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 shifted out, bit[ n -1], of the
register
Rm .
•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 19 • LSR
Carry
Flag
031 5 4 3 2 1
Carry
Flag
031 5 4 3 2 1
00
0