Datasheet

11011B–ATARM–21-Feb-12

SAM3N

The PSR bit assignments are:

Access 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 all of the registers using PSR with the MRS instruction

• write to the APSR using APSR with the MSR instruction.

The PSR combinations and attributes are:

See the instruction descriptions “MRS” on page 143 and “MSR” on page 144 for more informa-

tion about how to access the program status registers.

10.4.3.6 Application Program Status Register

The APSR contains the current state of the condition flags from previous instruction executions.

See the register summary in Table 10-2 on page 44 for its attributes. The bit assignments are:

•N

Negative or less than flag:

0 = operation result was positive, zero, greater than, or equal

1 = operation result was negative or less than.

•Z

Zero flag:

0 = operation result was not zero

1 = operation result was zero.

31 30 29 28 27 26 25 24

N Z C V Q ICI/IT T

23 22 21 20 19 18 17 16

Reserved

15 14 13 12 11 10 9 8

ICI/IT Reserved

ISR_NUMBER

76543210

ISR_NUMBER

Table 10-3. PSR register combinations

PSR RW

(1), (2)

1. The processor ignores writes to the IPSR bits.

2. Reads of the EPSR bits return zero, and the proces-

sor ignores writes to the these bits.

APSR, EPSR, and IPSR

IEPSR RO EPSR and IPSR

IAPSR RW

(1)

APSR and IPSR

EAPSR RW

(2)

APSR and EPSR