diff options
Diffstat (limited to 'tb/sim/irq.S')
| -rw-r--r-- | tb/sim/irq.S | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/tb/sim/irq.S b/tb/sim/irq.S new file mode 100644 index 0000000..35ce2c9 --- /dev/null +++ b/tb/sim/irq.S @@ -0,0 +1,44 @@ +.global reset +reset: + # Stop and reset timer + ldr r2, =0x30020000 + mov r1, #(1 << 3) + str r1, [r2, #4] + mov r1, #0 + str r1, [r2, #0] + + # Enable timer interrupts + ldr r3, =0x30070000 + ldr r1, =(1 << 0) + str r1, [r3, #4] + + # Enable IRQs + mov r0, #0 + mrs r1, cpsr + and r1, #~(1 << 7) + msr cpsr_c, r1 + + # Program timer with timeout value of 128 cycles + mov r1, #4 + str r1, [r2, #8] + mov r1, #0 + str r1, [r2, #12] + + # Start timer + mov r1, #(1 << 0 | 1 << 2) + str r1, [r2, #4] + + .wfi: + tst r0, r0 + beq .wfi + + mov r2, #2 + mov pc, lr + +.global irq +irq: + mov r0, #1 + ldr r1, [r2, #0] + mov r4, #0 + str r4, [r2, #0] + subs pc, lr, #4 |