Script started on Wed 28 Feb 2024 10:04:18 PM EST
[mweeks@gsuad.gsu.edu@snowball ~]$ cat array_sum.asm 
; Assemble:	  nasm -f elf64 array_sum.asm
; Link:		  gcc array_sum.o -o array_sum

; Based on code from Irvine's chapter 4.
; This is adapted for NASM.  -MCW

    extern  printf      ; We will use this external function
    extern  puts        ; We will use this external function

    section .data       ; Data section, initialized variables

mystr:    db "%x", 10, 0   ; String format to use (decimal), followed by NL

arrayW:  dw 1000h, 2000h, 3000h

mystr1:   db "The array sum is %d", 10, 0
mystr2:   db "Is this the value that you expected?", 10, 0
sum:      dw 0

    section .text
    global main
main:
   xor   rax, rax          ; A = 0

   ; Put the address of array into RSI
   mov   rsi, arrayW
   mov   ax, [rsi]          ; get the first word
   add   rsi, 2             ; increment the "pointer"
   add   ax, [rsi]          ; add the 2nd word
   add   rsi, 2             ; increment the "pointer"
   add   ax, [rsi]          ; add the 3rd word
   mov   [sum], ax          ; store the sum

   mov   rsi, rax
   mov   rax, 0
   mov   rdi, mystr1   ; 
   call  printf

   mov   rdi, mystr2
   call  puts             ; puts adds a newline. So this will print 2 of them.

   mov  rax, 0
   ret
[mweeks@gsuad.gsu.edu@snowball ~]$ nasm -f elf64 array_sum.asm
[mweeks@gsuad.gsu.edu@snowball ~]$ gcc array_sum.o -o array_sum
[mweeks@gsuad.gsu.edu@snowball ~]$ ./array_sum
The array sum is 24576
Is this the value that you expected?

[mweeks@gsuad.gsu.edu@snowball ~]$ echo value is not right...
value is not right...
[mweeks@gsuad.gsu.edu@snowball ~]$ cat array_sum2.asm
; Assemble:	  nasm -f elf64 array_sum2.asm
; Link:		  gcc array_sum2.o -o array_sum2

; Based on code from Irvine's chapter 4.
; This is adapted for NASM.  -MCW

    extern  printf      ; We will use this external function

    section .data       ; Data section, initialized variables

mystr:    db "%x", 10, 0   ; String format to use (decimal), followed by NL

arrayW:  dw 1000h, 2000h, 3000h

mystr1:   db "The array sum is %x (hex)", 10, 0
sum:      dw 0

    section .text
    global main
main:
   xor   rax, rax          ; A = 0

   ; Put the address of array into RSI
   mov   rsi, arrayW
   mov   ax, [rsi]          ; get the first word
   add   rsi, 2             ; increment the "pointer"
   add   ax, [rsi]          ; add the 2nd word
   add   rsi, 2             ; increment the "pointer"
   add   ax, [rsi]          ; add the 3rd word
   mov   [sum], ax          ; store the sum

   mov   rsi, rax
   mov   rax, 0
   mov   rdi, mystr1   ; 
   call  printf

   mov  rax, 0
   ret
[mweeks@gsuad.gsu.edu@snowball ~]$ nasm -f elf64 array_sum2.asm
[mweeks@gsuad.gsu.edu@snowball ~]$ gcc array_sum2.o -o array_sum2
[mweeks@gsuad.gsu.edu@snowball ~]$ ./array_sum2
The array sum is 6000 (hex)
[mweeks@gsuad.gsu.edu@snowball ~]$ echo this works
this works
[mweeks@gsuad.gsu.edu@snowball ~]$ cat array_sum3.asm
; Assemble:	  nasm -f elf64 array_sum3.asm
; Link:		  gcc array_sum3.o -o array_sum3

; Based on code from Irvine's chapter 4.
; This is adapted for NASM.  -MCW

    extern  printf      ; We will use this external function

    section .data       ; Data section, initialized variables

mystr:    db "%x", 10, 0   ; String format to use (decimal), followed by NL

arrayW:  dw 1000h, 2000h, 3000h

mystr1:   db "The array sum is %x (hex)", 10, 0
sum:      dw 0

    section .text
    global main
main:
   xor   rax, rax          ; A = 0

   mov   rsi, 0
   mov   ax, [arrayW + rsi]   ; get the first word (different way to access)
   add   rsi, 2               ; increment the "pointer"
   add   ax, [arrayW + rsi]   ; add the 2nd word
   add   rsi, 2               ; increment the "pointer"
   add   ax, [arrayW + rsi]   ; add the 3rd word
   mov   [sum], ax            ; store the sum

   mov   rsi, rax
   mov   rax, 0
   mov   rdi, mystr1   ; 
   call  printf

   mov  rax, 0
   ret
[mweeks@gsuad.gsu.edu@snowball ~]$ nasm -f elf64 array_sum3.asm
[mweeks@gsuad.gsu.edu@snowball ~]$ gcc array_sum3.o -o array_sum3
[mweeks@gsuad.gsu.edu@snowball ~]$ ./array_sum3
The array sum is 6000 (hex)
[mweeks@gsuad.gsu.edu@snowball ~]$ echo array_sum3 shows another way to access the data
array_sum3 shows another way to access the data
[mweeks@gsuad.gsu.edu@snowball ~]$ exit
exit

Script done on Wed 28 Feb 2024 10:06:17 PM EST