Inserting values into array in assembly MASM32

Question

I'm having trouble figuring out how to put a value I currently have in register EAX into an array.

The basic function of this program is to take the dates array, convert them to unique numbers, BubbleSort them, and convert them back.

I put the values I find with "datetonum" into EAX, and I want to store those values I find into my array named ra .

I can't seem to figure out how to do something that.
Seems like it should be fairly simple?

Thanks in advance!

include \masm32\include\masm32rt.inc
.data
  dates  BYTE "23-JUL-2010", 0, "23-JAN-2010", 0, "23-JUL-2009", 0, "31-JUL-2012", 0, "05-MAR-2010", 0
  months BYTE "JAN",0,"FEB",0,"MAR",0,"APR",0,"MAY",0,"JUN",0,"JUL",0,"AUG",0,"SEP",0,"OCT",0,"NOV",0,"DEC",0
  nDates DWORD 4
  ra     DWORD 1,0,0,0,0

.code
start:
    lea  EAX, dates     ; create pointer to beginning of dates array
    push EAX
    call datetonum

    ;-------------------
    ;put value currently in EAX into array to be sorted
    ;-------------------
    print "Array to be sorted contents: "
    print chr$(13,10)


    lea ECX, ra
    mov [ECX + nDates], EAX
    print ra
    print chr$(13,10)

Here's the datetonum function

;param1 (date string) = address of 12 byte date
datetonum:
    enter 4, 0                    ; [EBP - 4] holds 4 byte temp variable
    mov  EBX, [EBP + 8]           ; pointer to entire date string
    lea  ESI, [EBX]               ; pointing to day part of date
    lea  EDI, [EBP - 4]           ; pointing to address of local variable to store day string
    mov  ECX, 2
    cld
    rep  movsb
    mov  EDX, 0
    mov  [EDI], EDX               ; add null terminator

    lea  EDX, [EBP - 4]
    mov  EAX, sval(EDX)           ; convert day string to int
    push EAX                      ; push EAX to stack


    ; extract month from date
    lea  ESI, [EBX + 3]           ; pointing to month part of date
    lea  EDI, [EBP - 4]           ; pointing to address of local variable to store month string
    mov  ECX, 3
    cld
    rep  movsb
    mov  EDX, 0
    mov  [EDI], EDX               ; add null terminator



    ; debug print of month string
    pushad
    lea  EDX, [EBP - 4]
    print EDX
    print chr$(9)                 ; print a tab character
    print chr$(13,10)
    popad

    ; find month number
    sub ESI, ESI
    lea EDX, [EBP - 4]
    mov EAX, [EDX]
    mov ECX, 12
search_top:
    lea EDX, [months + ESI * 4]
    mov EBX, [EDX]
    inc ESI
    cmp EAX, EBX
    loopne search_top

    mov EDX, ESI                    ; result is in ESI

    pop EAX                         ; pop EAX off the stack
    mov AH, DL                      ; copy the month int into AH
    push EAX                        ; push EAX to stack

    ; convert year chars to 2 byte int
    mov EBX, [EBP + 8]
    lea ESI, [EBX + 7]              ; pointing to year part of date
    lea EDI, [EBP - 4]              ; pointing to address of local variable to store year string
    mov ECX, 4
    cld
    rep movsb
    mov EDX, 0
    mov [EDI], EDX                  ; add null terminator

    lea EDX, [EBP - 4]
    mov EDX, sval(EDX)              ; convert year string to int

    pop EAX                         ; pop EAX off the stack
    mov EBX, EAX                    ; copy EAX (contains month in AH and day in AL) to EBX
    mov EAX, EDX                    ; copy year to EAX
    shl EAX, 16                     ; shift the year over to high 16 bits in EAX
    mov AX, BX                      ; copy the month and day into low 16 bits in EAX

    ;print EAX ; this crashes the proc
    print str$(EAX)
    print chr$(13,10)

    leave
    ret 4
    exit

Answer 1

If your dates are stored in an array, and you want to use another array to store the dates converted to numbers, you will need at least one loop. You can use index registers (ESI, EDI) to point to both arrays, then use one register to read the value from one array, and the other register to move the value into the other array.

Let's imagine you already have next 3 procedures :

• num2date : converts a num in EAX back into a date (the opposite of datetonum ). This date is stored in a variable date that is declared like this : date BYTE "DD-MMM-AAAA" .
• bubble_sort : sorts the numbers in array ra .
• transfer_date : takes the 11 bytes of variable date and move them into the position pointed by ESI ( ESI is pointing somewhere inside array dates ).

This could be the logic of your code :

start:
;▼ NEXT LOOP CONVERTS ALL DATES TO NUMBERS ▼
    lea ESI, dates      ;POINTER TO ARRAY "DATES".
    lea EDI, ra         ;POINTER TO ARRAY "RA".
    mov ECX, 5          ;LENGTH OF ARRAY "DATES".
dates2numbers:
    push ECX ESI EDI    ;PRESERVE REGISTERS.
    mov  EAX, [ESI]     ;CURRENT DATE.
    push EAX
    call datetonum      ;CONVERT CURRENT DATE TO A NUMBER.
    pop  EAX            ;GET THE NUMBER.
    pop  EDI ESI ECX    ;RESTORE REGISTERS.
    mov  [EDI], EAX     ;STORE NUMBER IN "RA".
    add  ESI, 12        ;NEXT ITEM IN ARRAY "DATES" (12 BYTES EACH).
    add  EDI, 4         ;NEXT ITEM IN ARRAY "RA" (4 BYTES EACH).
    loop dates2numbers

    call bubble_sort    ;◄■■■ SORT ARRAY "RA".

;▼ NEXT LOOP CONVERTS ALL NUMBERS TO DATES ▼
    lea ESI, dates      ;POINTER TO ARRAY "DATES".
    lea EDI, ra         ;POINTER TO ARRAY "RA".
    mov ECX, 5          ;LENGTH OF ARRAY "RA".
numbers2dates:
    push ECX ESI EDI    ;PRESERVE REGISTERS.
    mov  EAX, [EDI]     ;CURRENT NUMBER.
    call num2date       ;CONVERTS EAX TO A DATE IN VARIABLE "DATE".
                        ;VARIABLE "DATE" LOOKS LIKE THIS : DATE BYTE "DD-MMM-AAAA"
                        ;"NUM2DATE" SHOULD PRESERVE ESI AND RESTORE IT
                        ;BECAUSE "TRANSFER_DATE" WILL NEED IT.
    call transfer_date  ;TRANSFER CONTENT OF VARIABLE "DATE" INTO THE
                        ;ARRAY "DATES" AT THE POSITION ESI IS POINTING TO.
    pop  EDI ESI ECX    ;RESTORE REGISTERS.
    add  ESI, 12        ;NEXT ITEM IN ARRAY "DATES" (12 BYTES EACH).
    add  EDI, 4         ;NEXT ITEM IN ARRAY "RA" (4 BYTES EACH).
    loop numbers2dates