Access Word Size; Long Word (64-Bit) Accesses - Analog Devices ADSP-21261 SHARC Hardware Reference Manual

"Internal Memory Data Width" on page 5-18.
48-bit words and 16-, 32-, or 64-bit words at the same address are not
allowed, mixed read/writes of 16-, 32-, and 64-bit words to the same
address are allowed.
32-Bit Words and 48-Bit Words" on page 5-16.
The DSP's DM and PM buses support 24 combinations of regis-
ter-to-memory data access options. The following factors influence the
data access type:
• Size of words—short word, normal word, extended-precision nor-
mal word, or long word
• Number of words—single or dual-data move
• Mode of DSP—SISD, SIMD, or broadcast load

Access Word Size

The DSP's internal memory accommodates the following word sizes:
• 64-bit word data
• 48-bit instruction words
• 40-bit extended-precision normal word data
• 32-bit normal word data
• 16-bit short word data

Long Word (64-Bit) Accesses

A program makes a long word (64-bit) access to internal memory using an
access to a long word address. Programs can also make a 64-bit access
through normal word addressing with the
register move with the
memory accesses appear in the processor model data sheet.
ADSP-2126x SHARC Processor Hardware Reference
For more information, see "Restrictions on Mixing
mnemonic. The address ranges for internal
LW
While mixed accesses of
mnemonic or through a
LW
Memory
PX
5-23