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
Thank you for coming back to share your solution :)