Setting Computational Modes
2-12
ADSP-2126x SHARC Processor Hardware Reference
Setting Computational Modes
The
MODE1
register controls the operating mode of the processing ele-
lists all the bits in
MODE1
. The following bits
in
MODE1
control computational modes:
• Floating-point data format. Bit 16 (
RND32
) directs the computa-
tional units to round floating-point data to 32 bits (if 1) or round
to 40 bits (if 0).
• Rounding mode. Bit 15 (
TRUNC
) directs the computational units to
round results with round-to-zero (if 1) or round-to-nearest (if 0).
• ALU saturation. Bit 13 (
ALUSAT
) directs the computational units to
saturate results on positive or negative fixed-point overflows (if 1)
or return unsaturated results (if 0).
• Short word sign extension. Bit 14 (
SSE
) directs the computational
units to sign extended short word 16-bit data (if 1) or zero-fill the
upper 16 bits (if 0).
• Secondary processor element (PEy). Bit 21 (
PEYEN
) enables compu-
tations in PEy (SIMD mode) (if 1) or disables PEy Single
Instruction Single Data (SISD mode) (if 0).
32-Bit Floating-Point Format (Normal Word)
In the default mode of the DSP (
RND32
bit=1), the multiplier and ALU
support a single-precision floating-point format, which is specified in the
IEEE 754/854 standard. For more information on this standard, see
. This format is IEEE 754/854 compati-
ble for single-precision floating-point operations in all respects except:
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 ...