2004-11-15 01:49 PM
2004-11-01 09:48 PM
Hi:
I have a problem and need your help. I want to Enable or Disable IRQ and FIQ in PSR. But It does not work properly. It is my sample code below. There are 3 steps 1. Enable FIQ, IRQ 2. Disable FIQ, IRQ <--------Fail, CPSR does not change in Realview Register window. 3. Enable FIQ, IRQ <--------Fail Thanks for your help ;************************************************ PRESERVE8 AREA Init, CODE, READONLY Mode_USR EQU 0x10 Mode_FIQ EQU 0x11 Mode_IRQ EQU 0x12 Mode_SVC EQU 0x13 Mode_ABT EQU 0x17 Mode_UNDEF EQU 0x1B Mode_SYS EQU 0x1F ; available on ARM Arch 4 and later I_Bit EQU 0x80 ; when I bit is set, IRQ is disabled F_Bit EQU 0x40 ; when F bit is set, FIQ is disabled ENTRY Reset_Handler MSR CPSR_c, Mode_USR ;Enable FIQ and IRQ MSR CPSR_c, Mode_USR R:F_Bit R:I_Bit ;Disable FIQ, IRQ MSR CPSR_c, Mode_USR END2004-11-15 01:49 PM
If my system runs in USER mode, I want to disable FIQ and IRQ, how to do?