TASKING VX-toolset for ARM User Guide

Run-time EnvironmentMain application execution mode (all architectures except M-profile)With the symbol __PROCESSOR_MODE you can define the execution mode in which the processor shouldrun when your application's main program is called. Based on this setting, together with the interruptstatus (FIQ interrupts enabled/disabled, IRQ interrupts enabled/disabled), the linker will generate a symbol(_APPLICATION_MODE_) which value is used in the startup code in the run-time library to set the valueof the CPSR status register before calling your main function. Available values:Value0x100x110x120x130x170x1B0x1FDescriptionUSR modeFIQ modeIRQ modeSVC modeABT modeUND modeSYS mode (default)Interrupt Status (all architectures except M-profile)It is common use to start with interrupts disabled (__IRQ_BIT=0x80 and __FIQ_BIT=0x40) and enableinterrupt during run-time after installing all exception handlers and initializing all peripherals. To enableinterrupts during run-time, use the __setcpsr() intrinsic:__setcpsr (0x00, 0x80); /* Enable IRQ interrupts */__setcpsr (0x00, 0x40); /* Enable FIQ interrupts */If you want to start with interrupts enabled, set the define the symbols __IRQ_BIT=0 and/or __FIQ_BIT=0.Vector tableBy default the linker can generate a vector table, unless you define the symbol __NO_AUTO_VECTORSor __NO_DEFAULT_AUTO_VECTORS.The linker will look for specific symbols designating the start of a handler function. These symbols aregenerated by the compiler when one of the following function qualifiers is used:Function type qualifier__interrupt_und__interrupt_svc__interrupt_iabt__interrupt_dabt__interrupt_irq__interrupt_fiq__interrupt(n)Vector symbol_vector_1_vector_2 (*)_vector_3_vector_4_vector_6_vector_7_vector_n227