Subversion Repositories neorv32

.file   "blink_led_in_asm.S"

.section .text

.balign 4

.global blink_led_asm

blink_led_asm:

  /* base address of GPIO controller's output port is passed as argument (in a0)*/

  sw   zero, 0(a0) /* clear output port */

  li   t1, 0 /* initialize counter */

blink_loop:

  andi t1, t1, 255 /* apply 8-bit mask */

  sw   t1, 0(a0)   /* output current counter value */

  addi t1, t1, 1   /* increment counter */

  jal  ra, blink_delay /* call delay function */

  j    blink_loop

blink_delay:

  li   t2, 0xfffff /* delay time */

blink_delay_loop:

  beq  t2, zero, blink_delay_end

  addi t2, t2, -1

  nop

  nop

  j    blink_delay_loop

blink_delay_end:

  ret

.end