Core Registers
A-14
ADSP-2126x SHARC Processor Hardware Reference
8
MU
Multiplier Floating-Point Underflow.
Indicates if the last multiplier oper-
ation’s result underflowed (if set, = 1) or did not underflow
(if cleared, = 0). The multiplier updates MU for all fixed- and float-
ing-point multiplier operations. For floating-point results, the processor
sets MU and the MUS bit in the STKYx/y register if the floating-point
result underflows (unbiased exponent < –126). Denormal operands are
treated as zeros, therefore they never cause underflows. For fixed-point
results, the processor sets MU and the MUS bit in the STKYx/y register if
the result of the multiplier operation is:
• Twos-complement, fractional: with upper 48 bits all zeros or all ones,
lower 32 bits not all zeros
• Unsigned, fractional: with upper 48 bits all zeros, lower 32 bits not all
zeros
If the multiplier operation directs a fixed-point, fractional result to an MR
register, the processor places the underflowed portion of the result in
MR0.
9
MI
Multiplier Floating-Point Invalid Operation.
Indicates if the last multi-
plier operation’s input was invalid (if set, = 1) or valid (if cleared, = 0).
The multiplier updates MI for floating-point multiplier operations. The
processor sets MI and the MIS bit in the STKYx/y register if the ALU
operation:
• Receives a NAN input operand
• Receives an Infinity and zero as input operands
10
AF
ALU Floating-Point Operation.
Indicates if the last ALU operation was
floating-point (if set, = 1) or fixed-point (if cleared, = 0). The ALU
updates AF for all fixed-point and floating-point ALU operations.
11
SV
Shifter Overflow.
Indicates if the last shifter operation’s result overflowed
(if set, = 1) or did not overflow (if cleared, = 0). The shifter updates SV for
all shifter operations. The processor sets SV if the shifter operation:
• Shifts the significant bits to the left of the 32-bit fixed-point field
• Tests, sets, or clears a bit outside of the 32-bit fixed-point field
• Extracts a field that is past or crosses the left edge of the 32-bit
fixed-point field
• Performs a LEFTZ or LEFTO operation that returns a result of 32
Table A-4. ASTATx and ASTATy Register Bit Descriptions (Cont’d)
Bit
Name
Description
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 ...