Analog Devices ADSP-BF53x Blackfin, Reference

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ADSP-BF53x/BF56x Blackfin Processor Programming Reference 19-11
Vector Operations
Notice that the history bit code depends on the
A0
shift direction. The bit
for
src_reg_1
is always shifted onto
A0
first, followed by the bit for
src_reg_0
.
The single operand versions behave similarly.
Single 16-Bit Operand Behavior
If the dual source register contains the data shown in Table 19-10 the des-
tination register receives the data shown in Table 19-11 .
The ASL version shifts
A0
left one bit position and appends an LSB to
indicate the source of the maximum.
Conversely, the ASR version shifts
A0
right one bit position and appends
an MSB to indicate the source of the maximum.
Table 19-10. Source Registers Contain
31................24 23................16 15..................8 7....................0
src_reg y1 y0
Table 19-11. Destination Register Contains
31................24 23................16 15..................8 7....................0
dest_reg_lo Maximum, y1 or y0
Table 19-12. ASL Version Shifts
A0.X A0.W
A0 00000000 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXB