ARM interrupt vector program example

ARM interrupt handlers generally handle various exception situations through the exception vector table. Interrupts are also an abnormal event. When an exception occurs, ARM will automatically jump to the address specified by the vector table to execute the corresponding processing function.

/Create vector table file vector_table.S/ 

/First create an exception vector table and map the vector table address to 0x00000000 or 0xffff0000/ 

.text 

.align 2 

.global vector_start 

vector_start: 

ldr pc, __reset //Reset 0x00000000 

ldr pc, __undef //Undefined instruction 0x00000004 

ldr pc, __svc //Administrator mode 0x00000008 

ldr pc, __pabort //Instruction exception 0x0000000c 

ldr pc, __dabort //Data exception 0x0000010 

nop 

ldr pc, __irp //Normal interrupt 0x00000018 

ldr pc, __firp //fast interrupt 0x00000020 

/Because the ldr instruction can only jump to the 4KB range starting from the current PC, the B instruction can jump to the 32MB instruction starting from the current PC, so in the vector table, a byte is called, this byte stores the first address of the corresponding processing function, and then jumps to the address within the byte/ 

__reset: 

.word reset // allocate a byte of space to store the first address of the corresponding processing function, the same below 

__undef: 

.word undef 

__undef: 

.word svc 

__undef: 

.word pabort 

__undef: 

.word dabort 

__undef: 

.word irp 

__undef: 

.word irp

.text 

.align 2 

.global vector_end 

vector_end: /No specific content, just indicates the end of the vector table/

/The following are specific exception handling functions, such as reset_handler(), which can be written directly in C program/ 

reset: 

ldr sp, =0xfffffffc /allocation stack/same below 

stmfd sp!, {r0-r12, lr} /Save the current state and address/same below 

b reset_handler /Call processing function/same below 

ldmfd sp!, {r0-r12, lr} /Return after exception handling/same below 

undef: 

b undef_handler 

svc: 

b svc_handler 

favor: 

b pabort_handler 

dabort: 

b dabort_handler 

irp: 

b irp_handler 

firp: 

b firp_handler