Write a procedure labeled merge: that will merge two sorted arrays in memory into a single sorted array. Arguments are as follows:

x$0$: length of first array

x$1$: address of first element of the first array

x$2$: length of the second array

x$3$: address of first element of the second array

x$4$: address at which to write the sorted array. Guaranteed to be able to hold x$0+$x$2$ elements.

Note: all elements are unsigned $64-$bit values. Sorting is from smallest to largest.

Hints:

You should write this function first in Python or C to figure out the process before trying to write it in assembly.

It's a bit easier to write assembly loops that have the index count down.

x$1($and x$3,$ and x$4)$ is not just the base of an array, it's also a pointer to the first address in the array. "add x$1,$x$1,8"$ will change the pointer to the next location in the array if your code doesn't need to "remember" the base.

Don't forget that you may run out of values in one or the other of the lists, and you'll need to continue copying the rest of the other list. Feel free to use code you've figured out from the previous question.

My code:merge:

MOV x$5,$ #$0$

MOV x$6,$ #$0$

MOV x$7,$ x$1$

MOV x$8,$ x$3$

MOV x$9,$ x$4$

ADD x$10,$ x$0,$ x$2$

merge$\_$loop:

CMP x$5,$ x$0$

B$.$EQ arr$2$

CMP x$6,$ x$2$

B$.$EQ arr$1$

LDR x$11,[$x$7]$

LDR x$12,[$x$8]$

CMP x$11,$ x$12$

BLE arr$1\_$sm

STR x$12,[$x$9],$ #$8$

ADD x$6,$ x$6,$ #$1$

ADD x$8,$ x$8,$ #$8$

B merge$\_$loop

arr$1\_$sm:

STR x$11,[$x$9],$ #$8$

ADD x$5,$ x$5,$ #$1$

ADD x$7,$ x$7,$ #$8$

B merge$\_$loop

arr$2$:

SUBS x$12,$ x$2,$ x$6$

B$.$LE end

ADD x$12,$ x$12,$ #$1$

ADD x$12,$ x$12,$ x$6,$ LSL #$3$

ADD x$8,$ x$8,$ x$12$

B cp$\_$arr$2$

arr$1$:

SUBS x$12,$ x$0,$ x$5$

B$.$LE end

ADD x$12,$ x$12,$ #$1$

ADD x$12,$ x$12,$ x$5,$ LSL #$3$

ADD x$7,$ x$7,$ x$12$

cp$\_$arr$1$:

LDR x$11,[$x$7],$ #$-8$

STR x$11,[$x$9],$ #$8$

SUBS x$12,$ x$12,$ #$8$

B$.$NE cp$\_$arr$1$

cp$\_$arr$2$:

LDR x$11,[$x$8],$ #$-8$

STR x$11,[$x$9],$ #$8$

SUBS x$12,$ x$12,$ #$8$

B$.$NE cp$\_$arr$2$

end:

RET

Test:

array$0=[1,3,7]$

array$1=[9,10,11,12,13]$

Expected:

$[1,3,7,9,10,11,12,13]$

Got:

$***$Run error$***$

Traceback $($most recent call last$)$:

File $"\_\_$tester$\_\_.$python$3",$ line $107,$ in

armsim.run$()$

File $"/$usr$/$local$/$lib$/$python$3\mathrm{.}6/$site$-$packages$/$armsim$.$py$",$ line $1268,$ in run

execute$($line$)$

File $"/$usr$/$local$/$lib$/$python$3\mathrm{.}6/$site$-$packages$/$armsim$.$py$",$ line $1101,$ in execute

raise ValueError$("$Unsupported instruction or syntax error: $"+$line$)$

ValueError: Unsupported instruction or syntax error: add x$12,$x$12,$x$6,$lsl $3$