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Sorting arrays in x86 assembly assignment help

The assignment deals with implementing two different sorting algorithms using x86 assembly. The algorithms are implemented using functions that take the array address and size as stack arguments. The arrays are sorted in place. The arrays are filled with random data using a special function. The result is printed on the screen using a function. This solution has been provided by our x86 assembly assignment experts to demonstrate how to sort arrays.

Sorting Arrays and Processing their Sizes and Addresses as Stack Arguments

Sorting arrays in x86 assembly assignment help

INCLUDE Irvine32.inc .DATA header1 BYTE "Data for Array1 ", 0dh, 0ah, 0 header2 BYTE "Data for Array2", 0dh, 0ah, 0 msg1 BYTE "----------------", 0dh, 0ah, "Initial array:", 0dh, 0ah, 0 msg2 BYTE "Sorted array:", 0dh, 0ah, 0 msg3 BYTE "Number of comparisons: ", 0 msg4 BYTE 0dh, 0ah, "Number of swaps: ", 0 separator BYTE ", ",0 array1 DWORD 20 DUP(0) ; array of pointers to strings array2 DWORD 20 DUP(0) buffer BYTE 300 DUP(0) ; place to save generated strings bufpos DWORD 0 ; current free position in buffer min DWORD 0 ; stats data swaps DWORD 0 comps DWORD 0 .CODE main PROC call Randomize ; initialize random generator ; Fill first arrray mov eax, 20 ; pass size of array to fill push eax mov eax, OFFSET array1 ; pass array to fill push eax call FillRandomArray ; fill the array with random strings add esp, 8 ; remove arguments from stack mov edx, OFFSET header1 ; load header string address call WriteString ; print on screen mov edx, OFFSET msg1 ; load initial array message address call WriteString ; print on screen ; Print first arrray mov eax, 20 ; pass size of array to print push eax mov eax, OFFSET array1 ; pass array to print push eax call PrintArray ; print the array add esp, 8 ; remove arguments from stack mov eax, 20 ; pass size of array to sort push eax mov eax, OFFSET array1 ; pass array to sort push eax call PairBubbleSort ; sort using pair bubble sort add esp, 8 ; remove arguments from stack mov edx, OFFSET msg2 ; load sorted array message address call WriteString ; print on screen ; Print sorted first array mov eax, 20 ; pass size of array to print push eax mov eax, OFFSET array1 ; pass array to print push eax call PrintArray ; print the array add esp, 8 ; remove arguments from stack ; Print statistics for first array mov edx, OFFSET msg3 ; load comparison stats string address call WriteString ; print on screen mov eax, [comps] ; load comparisons call WriteDec ; print on screen mov edx, OFFSET msg4 ; load swap stats string address call WriteString ; print on screen mov eax, [swaps] ; load swaps call WriteDec ; print on screen call CrLF call CrLF ; Fill second arrray mov eax, 20 ; pass size of array to fill push eax mov eax, OFFSET array2 ; pass array to fill push eax call FillRandomArray ; fill the array with random strings add esp, 8 ; remove arguments from stack mov edx, OFFSET header2 ; load header string address call WriteString ; print on screen mov edx, OFFSET msg1 ; load initial array message address call WriteString ; print on screen ; Print second arrray mov eax, 20 ; pass size of array to print push eax mov eax, OFFSET array2 ; pass array to print push eax call PrintArray ; print the array add esp, 8 ; remove arguments from stack mov eax, 20 ; pass size of array to sort push eax mov eax, OFFSET array2 ; pass array to sort push eax call ListBubbleSort ; sort using list bubble sort add esp, 8 ; remove arguments from stack mov edx, OFFSET msg2 ; load sorted array message address call WriteString ; print on screen ; Print sorted second array mov eax, 20 ; pass size of array to print push eax mov eax, OFFSET array2 ; pass array to print push eax call PrintArray ; print the array add esp, 8 ; remove arguments from stack ; Print statistics for second array mov edx, OFFSET msg3 ; load comparison stats string address call WriteString ; print on screen mov eax, [comps] ; load comparisons call WriteDec ; print on screen mov edx, OFFSET msg4 ; load swap stats string address call WriteString ; print on screen mov eax, [swaps] ; load swaps call WriteDec ; print on screen call CrLF exit ; exit the program main ENDP ; Fill an array with random strings ; Prototype: FillRandomArray(array, n) FillRandomArray PROC push ebp ; save frame pointer mov ebp, esp ; create new stack frame push ecx ; save used registers push esi mov esi, [ebp + 8] ; load array pointer mov ecx, [ebp + 12] ; load array size fill_loop: call GenerateRandomStr ; generate a random string mov [esi], eax ; save pointer in array add esi, 4 ; advance to next position loop fill_loop ; repeat for all entries pop esi ; restore used registers pop ecx pop ebp ; restore frame pointer ret FillRandomArray ENDP ; Generates a random string of length 2 to 7 ; Prototype: char *GenerateRandomStr() ; uses the global buffer and bufpos GenerateRandomStr PROC push ecx ; save used registers push esi push edi mov eax, 6 ; generate number between 0 and 5 for length call RandomRange add eax, 2 ; add 2 to get range 2 to 7 mov edi, OFFSET buffer ; point to start of buffer add edi, [bufpos] ; advance to current position in array mov esi, edi ; save start position in esi mov ecx, eax ; copy to loop counter gen_loop: mov eax, 62 ; generate number between 0 and 61 for character call RandomRange cmp eax, 26 ; if number is between 0 and 26 jl saveLo ; save lowercase cmp eax, 52 ; if number is between 26 and 52 jl saveHi ; save uppercase saveDigit: sub eax, 52 ; subtract 52 to get value 0-9 add eax, 48 ; convert to ascii jmp save saveLo: add eax, 'a' ; convert number to lowercase letter jmp save saveHi: sub eax, 26 ; subtract 26 to get value 0-25 add eax, 'A' ; convert number to lowercase letter jmp save save: mov [edi], al ; save char in string inc edi ; advance to next position in buffer inc [bufpos] ; increment global buffer position loop gen_loop ; loop for the length of the string mov BYTE PTR [edi], 0 ; save end of string inc [bufpos] ; increment global buffer position mov eax, esi ; return the initial pointer pop edi ; restore used registers pop esi pop ecx ret GenerateRandomStr ENDP ; Sorts an array using pairwise bubble sort ; Prototype: PairBubbleSort(array, n) PairBubbleSort PROC push ebp ; save frame pointer mov ebp, esp ; create new stack frame push ebx ; save used registers push ecx push edx push esi mov DWORD PTR [swaps], 0 ; reset swap count mov DWORD PTR [comps], 0 ; reset comparison count mov esi, [ebp + 8] ; load array pointer mov ecx, [ebp + 12] ; load array size n in j index dec ecx ; use j = n - 1 for_j: mov edx, 0 ; load 0 in i index for_i: cmp edx, ecx ; compare i with j jge end_for_i ; if i >= j, end loop inc DWORD PTR [comps] ; increment comparisons mov eax, [esi + edx*4 + 4] ; load array[i + 1] push eax ; pass as second argument mov eax, [esi + edx*4] ; load array[i] push eax ; pass as first argument call Str_compare ; compare strings jle for_i_next ; if array[i] <= array[i + 1], skip inc DWORD PTR [swaps] ; increment swaps ; swap values array[i] and array[i + 1] mov eax, [esi + edx*4 + 4] ; load array[i + 1] mov ebx, [esi + edx*4] ; load array[i] mov [esi + edx*4 + 4], ebx ; save swapped array[i + 1] mov [esi + edx*4], eax ; save swapped array[i] for_i_next: inc edx ; i++ jmp for_i end_for_i: loop for_j ; j--, repeat while j>0 pop esi ; restore used registers pop edx pop ecx pop ebx pop ebp ; restore frame pointer ret PairBubbleSort ENDP ; Sorts an array using listwise bubble sort ; Prototype: ListBubbleSort(array, n) ListBubbleSort PROC push ebp ; save frame pointer mov ebp, esp ; create new stack frame push ebx ; save used registers push ecx push edx push esi mov DWORD PTR [swaps], 0 ; reset swap count mov DWORD PTR [comps], 0 ; reset comparison count mov esi, [ebp + 8] ; load array pointer mov ecx, [ebp + 12] ; load array size n dec ecx ; use n - 1 mov edi, 0 ; load 0 in index i fori: cmp edi, ecx ; compare i with j jge end_fori ; if i >= n-1, end loop mov [min], edi ; min = i mov edx, edi ; j = i+1 inc edx forj: cmp edx, ecx ; compare j with n-1 jg end_forj ; if j > n-1, end loop inc DWORD PTR [comps] ; increment comparisons mov eax, [min] mov eax, [esi + eax*4] ; load array[min] push eax ; pass as second argument mov eax, [esi + edx*4] ; load array[j] push eax ; pass as first argument call Str_compare ; compare strings jge forj_next ; if array[j] >= array[min], skip mov [min], edx ; min = j forj_next: inc edx ; j++ jmp forj end_forj: inc DWORD PTR [swaps] ; increment swaps ; swap values array[min] and array[i] mov edx, [min] mov eax, [esi + edx*4] ; load array[min] mov ebx, [esi + edi*4] ; load array[i] mov [esi + edx*4], ebx ; save swapped array[min] mov [esi + edi*4], eax ; save swapped array[i] inc edi ; i++ jmp fori end_fori: pop esi ; restore used registers pop edx pop ecx pop ebx pop ebp ; restore frame pointer ret ListBubbleSort ENDP ; Prints an array on the screen ; Prototype: PrintArray(array, n) PrintArray PROC push ebp ; save frame pointer mov ebp, esp ; create new stack frame push ecx ; save used registers push esi mov esi, [ebp + 8] ; load array pointer mov ecx, [ebp + 12] ; load array size print_loop: mov edx, [esi] ; load string pointer from array call WriteString ; generate a random string cmp ecx, 1 ; if this is the last entry je print_skip ; don't print separator mov edx, OFFSET separator ; load address of separator string call WriteString ; print separator on screen print_skip: add esi, 4 ; advance to next position loop print_loop ; repeat for all entries call CrLF ; jump to next line call CrLF ; jump to next line pop esi ; restore used registers pop ecx pop ebp ; restore frame pointer ret PrintArray ENDP END main