Atmel ARM-Based Evaluation Kit for SAM4S16C, 32-Bit ARM® Cortex® Microcontroller ATSAM4S-WPIR-RD ATSAM4S-WPIR-RD Data Sheet
Product codes
ATSAM4S-WPIR-RD
SAM4S Series [DATASHEET]
Atmel-11100G-ATARM-SAM4S-Datasheet_27-May-14
160
12.6.7 Saturating Instructions
The table below shows the saturating instructions.
For signed n-bit saturation, this means that:
If the value to be saturated is less than -2
n
-1
, the result returned is -2
n-1
If the value to be saturated is greater than 2
n
-1
-1, the result returned is 2
n-1
-1
Otherwise, the result returned is the same as the value to be saturated.
For unsigned n-bit saturation, this means that:
If the value to be saturated is less than 0, the result returned is 0
If the value to be saturated is greater than 2
n
-1, the result returned is 2
n
-1
Otherwise, the result returned is the same as the value to be saturated.
If the returned result is different from the value to be saturated, it is called saturation. If saturation occurs, the
instruction sets the Q flag to 1 in the APSR. Otherwise, it leaves the Q flag unchanged. To clear the Q flag to 0, the
MSR
instruction must be used; see
To read the state of the Q flag, the
MRS
instruction must be used; see
.
Table 12-22.
Saturating Instructions
Mnemonic
Description
SSAT
Signed Saturate
SSAT16
Signed Saturate Halfword
USAT
Unsigned Saturate
USAT16
Unsigned Saturate Halfword
QADD
Saturating Add
QSUB
Saturating Subtract
QSUB16
Saturating Subtract 16
QASX
Saturating Add and Subtract with Exchange
QSAX
Saturating Subtract and Add with Exchange
QDADD
Saturating Double and Add
QDSUB
Saturating Double and Subtract
UQADD16
Unsigned Saturating Add 16
UQADD8
Unsigned Saturating Add 8
UQASX
Unsigned Saturating Add and Subtract with Exchange
UQSAX
Unsigned Saturating Subtract and Add with Exchange
UQSUB16
Unsigned Saturating Subtract 16
UQSUB8
Unsigned Saturating Subtract 8