Analog Devices ADSP-BF53x Blackfin Reference page 377

Also See
Store High Data Register
Special Applications
To write consecutive, aligned 16-bit values for high-performance DSP
operations, use the Store Data Register instructions instead of these
Half-Word instructions. The Half-Word Store instructions use only half
the available 32-bit data bus bandwidth, possibly imposing a bottleneck
constriction in the data flow rate.
ADSP-BF53x/BF56x Blackfin Processor Programming Reference
Half, Store Data Register
Load / Store
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