cant write to APSR register cortex-M23

Hello all,

i m doing test software for processor registers arm cortex m-23 , every thing is good except the xPSR registers , now i cant write to APSR register ? i changed the control register to be Privileged and to be unprivileged but without any useful. please if there any settings i have to set to access writing to APSR register . thank you.

.syntax unified
.cpu cortex-m23
.thumb

pattern5            =     0xA0000000

.....

.....

ldr r0, =pattern5
msr APSR_nzcvq, r0       /////  Here the APSR register value does not changed.

mrs r1, APSR
cmp r1, r0
bne .T_APSR_Exit