ARM/Thumb Mode Interworking in Keil
2005-02-07 by Richard
I am using the macros:
#define IENABLE /* Nested Interrupts Entry */ \
__asm { MRS LR, SPSR } /* Copy SPSR_irq to LR */ \
__asm { STMFD SP!, {LR} } /* Save SPSR_irq */ \
__asm { MSR CPSR_c, #0x1F } /* Enable IRQ (Sys Mode) */ \
__asm { STMFD SP!, {LR} } /* Save LR */
#define IDISABLE /* Nested Interrupts Exit */ \
__asm { LDMFD SP!, {LR} } /* Restore LR */ \
__asm { MSR CPSR_c, #0x92 } /* Disable IRQ (IRQ Mode) */ \
__asm { LDMFD SP!, {LR} } /* Restore SPSR_irq to LR */ \
__asm { MSR SPSR_cxsf, LR } /* Copy LR to SPSR_irq */
which work fine until I switch to thumb mode. Does anyone know of a
thumb/ARM mode interworking switch which will allow these to work?
The MSR op-code in particular seems to be the sticky wicket.
Richard