Posted on November 02, 2004 at 06:48 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
END
