Hello, I have take a piece of source at http://www.arm.com and tried to compile it using the CARM compiler. The code is shown below:
/* NewState=1 will enable IRQ, NewState=0 will disable IRQ */ /* ARM core must be in a privileged mode, e.g. supervisor */ void ChangeIRQ(unsigned int NewState) { int my_cpsr; __asm { MRS my_cpsr, CPSR /* get current program status */ ORR my_cpsr, my_cpsr,#0x80 /* set IRQ disable bit flag */ BIC my_cpsr, my_cpsr, NewState, LSL #7 /* reset IRQ bit with new value */ MSR CPSR_c, my_cpsr /* store updated program status */ } } void main(void) { __asm{MSR CPSR_c, #0x13} //Go into Supervisor Mode ChangeIRQ(0); while(1) { } }