SAM3N0C Atmel Corporation, SAM3N0C Datasheet - Page 143

• Manufacturer Part Number: SAM3N0C
• Manufacturer: Atmel Corporation

10.18.6
10.18.6.1
10.18.6.2
10.18.6.3
10.18.6.4
10.18.6.5
11011A–ATARM–04-Oct-10
MRS
MRS
Syntax
Operation
Restrictions
Condition flags
Examples
R0, PRIMASK ; Read PRIMASK value and write it to R0
Move the contents of a special register to a general-purpose register.
where:
cond
Rd
spec_reg
PRIMASK, BASEPRI, BASEPRI_MAX, FAULTMASK, or CONTROL.
Use MRS in combination with MSR as part of a read-modify-write sequence for updating a PSR,
for example to clear the Q flag.
In process swap code, the programmers model state of the process being swapped out must be
saved, including relevant PSR contents. Similarly, the state of the process being swapped in
must also be restored. These operations use MRS in the state-saving instruction sequence and
MSR in the state-restoring instruction sequence.
BASEPRI_MAX is an alias of BASEPRI when used with the MRS instruction.
See
Rd must not be SP and must not be PC.
This instruction does not change the flags.
MRS{cond} Rd, spec_reg
“MSR” on page
is an optional condition code, see
is the destination register.
can be any of: APSR, IPSR, EPSR, IEPSR, IAPSR, EAPSR, PSR, MSP, PSP,
144.
“Conditional execution” on page
84.
SAM3N
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