APSR Application Program Status Register when FEAT_AA32 is implemented Hold program status and control information. Some of the fields in this register are permitted to return the value of the PSTATE field on a read. This is an exception to the general rule that an UNKNOWN field must not return information that cannot be obtained, at the current Privilege level, by an architected mechanism. For more information see 'The Application Program Status Register, APSR'. PSTATE APSR is a 32-bit register. N 31 31 31 Negative condition flag. Set to bit[31] of the result of the last flag-setting instruction. If the result is regarded as a two's complement signed integer, then N is set to 1 if the result was negative, and N is set to 0 if the result was positive or zero. Z 30 30 30 Zero condition flag. Set to 1 if the result of the last flag-setting instruction was zero, and to 0 otherwise. A result of zero often indicates an equal result from a comparison. C 29 29 29 Carry condition flag. Set to 1 if the last flag-setting instruction resulted in a carry condition, for example an unsigned overflow on an addition. V 28 28 28 Overflow condition flag. Set to 1 if the last flag-setting instruction resulted in an overflow condition, for example a signed overflow on an addition. Q 27 27 27 Cumulative saturation bit. Set to 1 to indicate that overflow or saturation occurred in some instructions. 26 23 26:23 Reserved, RES0. PAN 22 22 0 Privileged Access Never. This field is UNKNOWN, but is permitted to return the value of PSTATE.PAN field. On writes, this field is treated as Do-Not-Modify. AU When FEAT_PAN is implemented 22 22 22 Reserved, RES0. Otherwise 21 20 21:20 Reserved, RES0. GE 19 16 19:16 Greater than or Equal flags, for parallel addition and subtraction. 15 10 15:10 Reserved, RES0. E 9 9 9 Endianness. This field is UNKNOWN, but is permitted to return the value of PSTATE.E field. On writes, this field is treated as Do-Not-Modify. AU A 8 8 8 SError exception mask. This field is UNKNOWN, but is permitted to return the value of PSTATE.A field. On writes, this field is treated as Do-Not-Modify. AU I 7 7 7 IRQ interrupt mask. This field is UNKNOWN, but is permitted to return the value of PSTATE.I field. On writes, this field is treated as Do-Not-Modify. AU F 6 6 6 FIQ interrupt mask. This field is UNKNOWN, but is permitted to return the value of PSTATE.F field. On writes, this field is treated as Do-Not-Modify. AU 5 5 5 Reserved, RES0. M[4:0] 4 0 4:0 Mode. This field is UNKNOWN, but is permitted to return the value of PSTATE.M[4:0] field. On writes, this field is treated as Do-Not-Modify. AU APSR can be read using the MRS instruction and written using the MSR (register) or MSR (immediate) instructions. The MSR (register) and MRS instructions used to access APSR are data-independent-time instructions as described in About PSTATE.DIT. 2026-03-26 20:27:25 2026-03_rel