Datasheet

SAM4E [DATASHEET]
Atmel-11157D-ATARM-SAM4E16-SAM4E8-Datasheet_12-Jun-14
50
12.4.1.8 Program Status Register
Name: PSR
Access: Read/Write
Reset: 0x000000000
The Program Status Register (PSR) combines:
• Application Program Status Register (APSR)
• Interrupt Program Status Register (IPSR)
• Execution Program Status Register (EPSR).
These registers are mutually exclusive bitfields in the 32-bit PSR.
The PSR accesses these registers individually or as a combination of any two or all three registers, using the register
name as an argument to the MSR or MRS instructions. For example:
•Read of all the registers using PSR with the MRS instruction
• Write to the APSR N, Z, C, V and Q bits using APSR_nzcvq with the MSR instruction.
The PSR combinations and attributes are:
Notes: 1. The processor ignores writes to the IPSR bits.
2. Reads of the EPSR bits return zero, and the processor ignores writes to these bits.
See the instruction descriptions “MRS” and “MSR” for more information about how to access the program status registers.
31 30 29 28 27 26 25 24
NZCVQ ICI/IT T
23 22 21 20 19 18 17 16
–
15 14 13 12 11 10 9 8
ICI/IT – ISR_NUMBER
76543210
ISR_NUMBER
Name Access Combination
PSR Read/Write
(1)(2)
APSR, EPSR, and IPSR
IEPSR Read-only EPSR and IPSR
IAPSR Read/Write
(1)
APSR and IPSR
EAPSR Read/Write
(2)
APSR and EPSR