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I am stuck on problem 7 that is outlined clearly. I am trying to create a process that changes all of the non-prime number elements of a 65,000 element array to 1. Then I would like to verify that array was marked correctly so that only prime numbers have 0's at their location in the array. The displayArray process should display 1,3,5,7,11,13 etc. up to 65,000.


There is an include file also
Thanks for your help

TITLE MASM Template						(main.asm)

; Program: Chapter 9 Problems 1,2,7
; Author: Jon Wayman
; Created Date: July 11th,2008
; Revision date:

INCLUDE Irvine32.inc
.data
intVal DWORD ?
sString BYTE "This string is 34 characters long.",0
tString BYTE 100 DUP (?)
msgMaxStr BYTE "Enter the maximum string size to copy: ",0
targetStr BYTE "ABCED",10 DUP(0)
sourceStr BYTE "FGH",0

.data?
count = 65000				; 65,000 element array
sieve DWORD count DUP(?)

.code
main PROC

;------------- Problem 1 -----------------
mov	edx,OFFSET msgMaxStr		;move Max String size message
call writestring				;write message to console
call crlf

call readint					;Read an integer value for Str_copyN
mov	intVal,eax
mov	ebx,eax

push	OFFSET tString
push OFFSET sString
call Str_copyN	

mov edx,OFFSET tString
call writestring
call crlf
;------------- Problem 1 -----------------

;------------- Problem 2 -----------------

push OFFSET targetStr			; push the offest of the target
push OFFSET sourceStr			; push the offset of the source
call Str_concat

mov edx,OFFSET targetStr
call writeString
call crlf

;------------- Problem 2 -----------------

;------------- Problem 7 -----------------

push count
push OFFSET sieve
call initArray

push count
push OFFSET sieve
call findSieve

push count
push OFFSET sieve
call displayArray


;------------- Problem 7 -----------------
exit
main ENDP

;--------------------------------------------------
Str_copyN	PROC USES eax ebx ecx esi edi,
	source: PTR BYTE,
	target: PTR BYTE,
	 maxSz: DWORD
;
;Copy a string from a source to target.
;The user defines the maximum string size to copy.
;Requires: the target string must contain enough
;		 space to hold a copy of the source string.
;--------------------------------------------------

	mov    maxSz,ebx
	INVOKE Str_length,source			; EAX = length of source
	cmp	  maxSz,eax
	jge	  L1
	mov	  ecx,maxSz
	dec	  ecx
	jne	  L2

L1:	mov	  ecx,eax					; REP count
L2:	inc	  ecx
	mov	  esi,source
	mov	  edi,target
	cld
	rep	  movsb
	ret
Str_copyN	ENDP

;--------------------------------------------------
Str_concat PROC USES eax ecx esi edi,
	source2: PTR BYTE,
	target2: PTR BYTE,
;
;Append the source string to the target string
;Requires: the target string must contain enough
;		 space to hold a copy of the source string.
;--------------------------------------------------

	INVOKE Str_length,source2			; EAX = length of source
	mov	ecx,eax						; REP count
	inc	ecx							; add 1 for null byte
	mov	esi,source2

	INVOKE Str_length,target2			; EAX = length of targte
	mov	edi,target2
	add	edi,eax						; EDI = end of target
	cld
	rep	movsb
	ret
Str_concat ENDP

;--------------------------------------------------
initArray PROC USES eax ecx edi,
	pArray: PTR DWORD,
   CountTmp: PTR DWORD
;
; This procedure initializes an array with zeros
;--------------------------------------------------

	mov   al,0					; AL = 0
	mov	edi,pArray				; EDI points to array
	mov	ecx,CountTmp				; loop counter
	cld
	rep	stosb					; fill with zeros
	ret
initArray ENDP

;--------------------------------------------------
findSieve PROC uses ebx ecx edi,
	pArray: PTR DWORD,
   CountTmp2: PTR DWORD
;
; Mark all non-primes with 1
;--------------------------------------------------
	mov edx, pArray
	push 2
	pop eax         
iLOOP:
	mov ecx, eax
	shl ecx, 1
jLOOP:
	mov ebx, CountTmp2
	cmp ecx, ebx                
ja @F
	mov DWORD PTR [edx+ecx-1], 4 
	add ecx, eax 
	jmp jLOOP
@@:
	inc eax                
	shr ebx, 1
	cmp eax, ebx               
	jb iLOOP
	RET
findSieve ENDP

;--------------------------------------------------
displayArray PROC USES eax ecx edi esi,
	pArray: PTR DWORD,
   CountTmp: PTR DWORD
;
; This procedure displays the array
;--------------------------------------------------

	cld
	mov	esi,pArray
	mov	edi,esi
	mov	ecx,CountTmp
	mov	al,0
zLOOP:
	cmp	[edi],al
	je	J1

	lodsd
	call writeInt					;display integer
	mov	al,','
	call writeChar
J1:
	loop	zLOOP

	ret
displayArray ENDP





END main
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