Created
March 14, 2015 04:53
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.syntax unified | |
.arch armv7-a | |
.text | |
.align 2 | |
.thumb | |
.thumb_func | |
.global fibonacci | |
.type fibonacci, function | |
fibonacci: | |
@ ADD/MODIFY CODE BELOW | |
@ PROLOG | |
push {r3, r4, r5, lr} | |
@ R4 = R0 - 0 (update flags) | |
@subs r4, r0, #0 -> cmp r0, #0 | |
subs r4, r0, #0 | |
@ if(R0 <= 0) goto .L3 (which returns 0) | |
ble .L3 | |
@ Compare R4 wtih 1 | |
cmp r4, #1 | |
@ If R4 == 1 goto .L4 (which returns 1) | |
beq .L4 | |
@ R0 = R4 - 1 | |
sub r0, r4, #1 | |
@ Recursive call to fibonacci with R4 - 1 as parameter | |
bl fibonacci | |
@ R5 = R0 | |
mov r5, r0 | |
@ R0 = R4 - 2 | |
sub r0, r4, #2 | |
@ Recursive call to fibonacci with R4 - 2 as parameter | |
bl fibonacci | |
@ R0 = R5 + R0 (update flags) | |
adds r0, r5, r0 | |
pop {r3, r4, r5, pc} @EPILOG | |
@ END CODE MODIFICATION | |
.L3: | |
mov r0, #0 @ R0 = 0 | |
pop {r3, r4, r5, pc} @ EPILOG | |
.L4: | |
mov r0, #1 @ R0 = 1 | |
pop {r3, r4, r5, pc} @ EPILOG | |
.size fibonacci, .-fibonacci | |
.end |
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