ADSP-2126x SHARC Processor Hardware Reference
5-13
Memory
• 32-bit normal word data (2 columns)
• 16-bit short word data (1 column)
Extended-precision normal word data is only accessible if the
IMDWx
bit is set in the
SYSCTL
register. It is left-justified within a three col-
umn location, using bits 47–8 of the location.
Placing 32-Bit Words and 48-Bit Words
When the processor core or I/O processor addresses memory, the word
width of the access determines which columns within the memory are
accessed. For instruction word (48 bits) or extended-precision normal
word data (40 bits), the word width is 48 bits, and the DSP accesses the
memory’s 16-bit columns in groups of three. Because these sets of three
column accesses are packed into a 4 column matrix, there are four rota-
tions of the columns for storing 40- or 48-bit data. The three column
word rotations within the four column matrix appear in
.
For long word (64 bits), normal word (32 bits), and short word (16 bits)
memory accesses, the DSP selects from fixed columns in memory. No
rotations of words within columns occur for these data types.
Figure 5-7. 48-Bit Word Rotations
Column 0
Column 1
Column 2
Column 3
15
0
Rotation 2
Ad
dres
ses
Rotation 3
Rotation 2
Rotation 1
Rotation 1
Rotation 0
15
0
15
0
15
0
Summary of Contents for ADSP-21261 SHARC
Page 30: ...Contents xxx ADSP 2126x SHARC Processor Hardware Reference ...
Page 40: ...Register Diagram Conventions xl ADSP 2126x SHARC Processor Hardware Reference ...
Page 58: ...Differences From Previous SHARCs 1 18 ADSP 2126x SHARC Processor Hardware Reference ...
Page 112: ...Secondary Processing Element PEy 2 54 ADSP 2126x SHARC Processor Hardware Reference ...
Page 178: ...Summary 3 66 ADSP 2126x SHARC Processor Hardware Reference ...
Page 204: ...DAG Instruction Summary 4 26 ADSP 2126x SHARC Processor Hardware Reference ...
Page 322: ...Setting Up DMA 7 32 ADSP 2126x SHARC Processor Hardware Reference ...
Page 436: ...SPORT Programming Examples 9 86 ADSP 2126x SHARC Processor Hardware Reference ...
Page 521: ...ADSP 2126x SHARC Processor Hardware Reference 11 31 Input Data Port rts IDP_ISR end ...
Page 522: ...Input Data Port Programming Example 11 32 ADSP 2126x SHARC Processor Hardware Reference ...
Page 590: ...Timer Programming Examples 14 20 ADSP 2126x SHARC Processor Hardware Reference ...
Page 796: ...I O Processor Registers A 174 ADSP 2126x SHARC Processor Hardware Reference ...
Page 800: ...B 4 ADSP 2126x SHARC Processor Core Manual ...
Page 846: ...Index I 36 ADSP 2126x SHARC Processor Hardware Reference ...