Datasheet

172
SAM4S [DATASHEET]
11100E–ATARM–24-Jul-13
In unprivileged software writes to unallocated or execution state bits in the PSR are ignored.
Note: When the user writes to BASEPRI_MAX, the instruction writes to BASEPRI only if either:
Rn is non-zero and the current BASEPRI value is 0
Rn is non-zero and less than the current BASEPRI value.
See “MRS” .
Restrictions
Rn must not be SP and must not be PC.
Condition Flags
This instruction updates the flags explicitly based on the value in Rn.
Examples
MSR CONTROL, R1 ; Read R1 value and write it to the CONTROL register
12.6.11.8NOP
No Operation.
Syntax
NOP{cond}
where:
cond is an optional condition code, see
“Conditional Execution” .
Operation
NOP does nothing. NOP is not necessarily a time-consuming NOP. The processor might remove it from the pipeline
before it reaches the execution stage.
Use NOP for padding, for example to place the following instruction on a 64-bit boundary.
Condition Flags
This instruction does not change the flags.
Examples
NOP ; No operation
12.6.11.9SEV
Send Event.
Syntax
SEV{cond}
where:
cond is an optional condition code, see “Conditional Execution” .
Operation
SEV is a hint instruction that causes an event to be signaled to all processors within a multiprocessor system. It also sets
the local event register to 1, see “Power Management” .
Condition Flags
This instruction does not change the flags.
Examples
SEV ; Send Event