How to solve this timer interrupt problem

[Xavier Barreto Tomeo]

Hi! 

Im doing a project in RISC-V and im trying to enable timer interrupts and make a simple code running on it. I have this code that is called from a .c file and it returns to it and stays in while(1)

timern:

la t0, timer_handler

csrw mtvec, t0

csrw stvec, t0

csrs mstatus, 0x8

li t0, 0x80

csrs mie, t0

li t0, 500000

li t1, 0x2004000 #mtimecmp address

sd t0, 0(t1)

ret

timer_handler:

li t1, 0x2004000 #mtimecmp address

lw t0, 0(t1)

li t2, 500000

add t0, t0, t2

sd t0, 0(t1)

j writehello

ret

I try to make a program that every 500000 writes hello with a function that works correctly but it only says hello the first time and doesnt return correctly to the execution. 

I have tried to write with 0x00 the register mip in the handler or in the main but it seems it doesnt work

Can some one help me please?

Thanks!