ADSP-2126x SHARC Processor Hardware Reference
4-11
Data Address Generators
By comparison, the following instruction accesses the program memory
location indicated by the value
I15
+
M12
and does not change the value in
I15
:
R6 = PM(M12,I15); /* Pre-modify addressing without update */
Modify (
M
) registers can work with any index (
I
) register in the same DAG
(DAG1 or DAG2). For a list of
I
and
M
registers and their related DAGs,
see
Instructions can also use a number (immediate value), instead of an
M
reg-
ister, as the modifier. The size of an immediate value that can modify an
I
register depends on the instruction type. For all single data access opera-
tions, modify immediate values can be up to 32 bits wide. Instructions
that combine DAG addressing with computations limit the size of the
modify immediate value. In these instructions (multifunction computa-
tions), the modify immediate values can be up to 6 bits wide. The
following example instruction accepts up to 32-bit modifiers:
R1 = DM(0x40000000,I1); /* DM address = I1 + 0x4000 0000 */
Figure 4-3. Pre-Modify and Post-Modify Operations
I
M
+
O UTPUT
I+M
PRE -M OD IFY
NO I REGISTE R UPDATE
SYNTAX:
PM(MX, IX)
DM(MX, IX)
1. OUTPUT
I
M
I+M
+
2. UPDA TE
POST-M ODIFY
I REGISTE R UPDATE
SYNTAX:
PM (IX, MX)
DM(IX, MX)
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 ...