Alu Status Flags - Analog Devices ADSP-21261 SHARC Hardware Reference Manual

ALU Status Flags

ALU operations update seven status flags in the processing element's arith-
metic status (
ASTATx
all the bits in these registers. The following bits in
the ALU status (a 1 indicates the condition) of the most recent ALU
operation:
• ALU result zero or floating-point underflow. Bit 0 (
• ALU overflow. Bit 1 (
• ALU result negative. Bit 2 (
• ALU fixed-point carry. Bit 3 (
• ALU X input sign for
• ALU floating-point invalid operation. Bit 5 (
• Last ALU operation was a floating-point operation. Bit 10 (
• Compare Accumulation register results of last eight compare opera-
tions. Bits 31-24 (
ALU operations also update four "sticky" status flags in the processing ele-
ment's sticky status (
lists all the bits in these registers. The following bits in
the ALU status (a 1 indicates the condition). Once set, a sticky flag
remains high until explicitly cleared:
• ALU floating-point underflow. Bit 0 (
• ALU floating-point overflow. Bit 1 (
• ALU fixed-point overflow. Bit 2 (
• ALU floating-point invalid operation. Bit 5 (
ADSP-2126x SHARC Processor Hardware Reference
and ) registers.
ASTATy
)
AV
)
AN
AC
,
Abs Mant
)
CACC
and ) registers.
STKYx STKYy
Processing Elements
Table A-4 on page A-12
ASTATx
)
operations. Bit 4 (
)
AI
Table A-5 on page A-18
STKYx
)
AUS
)
AVS
)
AOS
)
AIS
lists
or flag
ASTATy
)
AZ
)
AS
)
AF
or flag
STKYy
2-19