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Arm Swi (1)

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Jack Chen
Jack Chen

The document discusses using ARM SWI (Software Interrupt) functions to handle interrupts in an embedded system. It describes a sample program that installs an interrupt handler for SWI 0x08 and then calls the SWI functions 0 through 3. The main.c file contains functions to install the interrupt handler and call the SWI functions from main.

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ARM SWI Stanley.Ho ADS SVC ʽYҪ(1)ahandle.s(2)chandle.c(3)main.c(4)svc.h ҪǽBʹ SVC(SWI)Ĺ܁ܛwД main.c б ʽf: Install_Handler() : ׃ԭ vector SWI 0x08 ă,׃҂Ҫ Branch routine main() : Install_Handler() SWI(0),SWI(1),SWI(2),SWI(3) #include #include svc.h unsigned *svc_vec = (unsigned *)0x08; extern void SVC_Handler(void); unsigned Install_Handler( unsigned routine, unsigned *vector ){ unsigned vec, old_vec; vec = (routine - (unsigned)vector - 8) >> 2; //routinevectorďֵ /* Branch instructions contain a signed 2s complement 24 bit offset. This is shifted left two bits, sign extended to 32 bits, and added to the PC. The instruction can therefore specify a branch of +
Arm Swi (1)
Arm Swi (1)
Arm Swi (1)

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Arm Swi (1)

  • 1. ARM SWI Stanley.Ho ADS SVC ʽYҪ(1)ahandle.s(2)chandle.c(3)main.c(4)svc.h ҪǽBʹ SVC(SWI)Ĺ܁ܛwД main.c б ʽf: Install_Handler() : ׃ԭ vector SWI 0x08 ă,׃҂Ҫ Branch routine main() : Install_Handler() SWI(0),SWI(1),SWI(2),SWI(3) #include #include svc.h unsigned *svc_vec = (unsigned *)0x08; extern void SVC_Handler(void); unsigned Install_Handler( unsigned routine, unsigned *vector ){ unsigned vec, old_vec; vec = (routine - (unsigned)vector - 8) >> 2; //routinevectorďֵ /* Branch instructions contain a signed 2s complement 24 bit offset. This is shifted left two bits, sign extended to 32 bits, and added to the PC. The instruction can therefore specify a branch of +