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11100B–ATARM–31-Jul-12
SAM4S Series [Preliminary]
11.6.11.7
MSR
Move the contents of a general-purpose register into the specified special register.
Syntax
MSR{cond} spec_reg, Rn
where:
cond
is an optional condition code, see
Rn
is the source register.
spec_reg
can be any of: APSR, IPSR, EPSR, IEPSR, IAPSR, EAPSR, PSR, MSP, PSP,
PRIMASK, BASEPRI, BASEPRI_MAX, FAULTMASK, or CONTROL.
Operation
The register access operation in MSR depends on the privilege level. Unprivileged software can
only access the APSR. See
“Application Program Status Register”
. Privileged software can
access all special registers.
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.
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
Summary of Contents for SAM4S Series
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