Core Registers
A-12
ADSP-2126x SHARC Processor Hardware Reference
Table A-4. ASTATx and ASTATy Register Bit Descriptions
Bit
Name
Description
0
AZ
ALU Zero/Floating-Point Underflow.
Indicates if the last ALU operation’s
result was zero (if set, = 1) or non-zero (if cleared, = 0). The ALU updates
AZ for all fixed-point and floating-point ALU operations. AZ can also
indicate a floating-point underflow. During an ALU underflow (indicated
by a set (= 1) AUS bit in the STKYx/y register), the processor sets AZ if the
floating-point result is smaller than can be represented in the output for-
mat.
1
AV
ALU Overflow.
Indicates if the last ALU operation’s result overflowed (if
set, = 1) or did not overflow (if cleared, = 0). The ALU updates AV for all
fixed-point and floating-point ALU operations. For fixed-point results, the
processor sets AV and the AOS bit in the STKYx/y register when the XOR
of the two most significant bits (MSBs) is a 1. For floating-point results,
the processor sets AV and the AVS bit in the STKYx/y register when the
rounded result overflows (unbiased exponent > 127).
2
AN
ALU Negative.
Indicates if the last ALU operation’s result was negative (if
set, = 1) or positive (if cleared, = 0). The ALU updates AN for all
fixed-point and floating-point ALU operations.
3
AC
ALU Fixed-Point Carry.
Indicates if the last ALU operation had a carry
out of the MSB of the result (if set, = 1) or had no carry (if cleared, = 0).
The ALU updates AC for all fixed-point operations. The processor clears
AC during the fixed-point logic operations: PASS, MIN, MAX, COMP,
ABS, and CLIP. The ALU reads the AC flag for the fixed-point accumulate
operations: Addition with Carry and Fixed-point Subtraction with Carry.
4
AS
ALU X-Input Sign (for ABS and MANT).
Indicates if the last ALU ABS
or MANT operation’s input was negative (if set, = 1) or positive (if cleared,
= 0). The ALU updates AS only for fixed- and floating-point ABS and
MANT operations. The ALU clears AS for all operations other than ABS
and MANT.
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 ...