Question

[8 pts] We want to create the multiplication operation, using the ARM LEGv8 operations we already know (without using the MUL-variant instructions). Notice, by taking the a number and adding it to itself max times, performs the operation of number * max, or simply multiplication. Note, in this case number equals 5, so our work with 5. Prove this formula yourself by setting max to different values, stepping through the code and comparing to number *max 4. multiplications will always The value for max is stored at the address given in X14. After you load the value for max, this problem only requires you to translate the pseudo-code given into ARM/ LEGV8 in order to complete your solution. total number 5 = for n = 0; n < max; n++ total + number; total

Answer 1

ARM64 GCC 8.2 code:

main:

sub sp, sp, #16

str wzr, [sp, 12]

mov w0, 5

str w0, [sp, 4]

str wzr, [sp, 8]

.L3:

ldr w1, [sp, 8]

ldr w0, [sp]

cmp w1, w0

bge .L2

ldr w1, [sp, 12]

ldr w0, [sp, 4]

add w0, w1, w0

str w0, [sp, 12]

ldr w0, [sp, 8]

add w0, w0, 1

str w0, [sp, 8]

b .L3

.L2:

mov w0, 0

add sp, sp, 16

ret

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