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.section .text
.align 2
.global delay
.include "memory_map.inc"
# a0 is delay in milliseconds argument
delay:
addi sp, sp, -16 # Allocate stack frame
sw ra, 12(sp) # save return address to the stack
li t0, MTIME # load the timer register
lw t1, 0(t0) # load value of the timer
li t2, MTIME_FREQUENCY # get clock freq (approx.)
mul t2, t2, a0 # multiply milliseconds with freq
add t2, t1, t2 # target mtime is now in t2
1:
lw t1, 0(t0) # load value of the timer
blt t1, t2, 1b # keep looping until target mtime has been reached
lw ra, 12(sp) # load return address
addi sp, sp, 16 # deallocate stack frame
ret
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