Question

2. Given the following data declarations:

.DATA Alpha WORD 1Ah, 2Bh, 3Ch, 4CH, 5C00, 6D03, 7F1A SUM WORD ?

.CODE

;Write instructions that sum the odd elements of the array into AX and then save the resultant sum in the location SUM.

This needs to be done using Assembly.

Answer 1

Alpha:
        dw 1Ah, 2Bh, 3Ch, 4CH, 5C00h, 6D03h, 7F1Ah
SUM:
        dw   0
s(dw*):
        push    rbp
        mov     rbp, rsp
        mov     QWORD PTR [rbp-24], rdi
        mov     WORD PTR [rbp-2], 0
.L3:
        cmp     WORD PTR [rbp-2], 6
        ja      .L2
        movzx   eax, WORD PTR [rbp-2]
        lea     rdx, [rax+rax]
        mov     rax, QWORD PTR [rbp-24]
        add     rax, rdx
        movzx   edx, WORD PTR [rax]
        movzx   eax, WORD PTR SUM[rip]
        add     eax, edx
        mov     WORD PTR SUM[rip], ax
        add     WORD PTR [rbp-2], 2
        jmp     .L3
.L2:
        movzx   eax, WORD PTR SUM[rip]
        pop     rbp
        ret
main:
        push    rbp
        mov     rbp, rsp
        sub     rsp, 16
        mov     edi, OFFSET FLAT:Alpha
        call    s(unsigned short*)
        mov     WORD PTR [rbp-2], ax
        movzx   eax, WORD PTR [rbp-2]
        mov     WORD PTR SUM[rip], ax
        mov     eax, 0
        leave
        ret