Array Help

[utcguy]

I am trying to get this program to work but all i get is a blank result and would like to know what I am doing wrong. Can you please point out what is wrong with it? Any help would be greatly appreciated.


i have created these subroutines to find the min & max elements in an array. i am not sure if it is correct.

include pcmac.inc
.model small
.586

.code 


	public amax

amax	proc
	push ebx
	push ecx
	mov  eax, [ebx]; the first one

mx:
	cmp eax, [ebx]; compare it with the current
	jge cont ; its not the maximum
	mov eax, [ebx] ; its a new maximum value

cont:
	add ebx, 4 ; go to next element
	dec ecx ; subtract 1 from count 
	jnz mx  ; continue if its not zero
	pop ecx
	pop ebx
	ret

amax	endp


	public amin

amin	proc
	push ebx
	push ecx
	mov  eax, [ebx]; first one in array

mn:
	cmp  eax,[ebx]; compare with current min value
	jle  cont2; its not the minimum value
	mov  eax, [ebx]; its the new minimum value

cont2:
	add  ebx, 4 ; go to next element
	dec  ecx ; subtract 1  from count
	jnz  mn  ; continue if its not zero
	pop  ecx
	pop  ebx
	ret

amin	endp
	end

this is the main program that i created to utilize the subroutines, again I dont know if it is correct.

include pcmac.inc
.model small
.586
.stack 200h


	.data

list	dd	-100, 7565, 380, -9866, 452, 1295, 626, -1128, 459
	dd	-762, 4722, 1369, 489, 8988, -23321, 6675, 4239
	dd	5677, -999, 24863

lsize	dd	20
arrmax	dd	?
arrmin	dd	?
maxmsg	db	'Maximum element is: $'
minmsg	db	'Minimum element is: $'

	.code

extrn	getddec:near, putddec:near
extrn	amax:near, amin:near

lab6	proc
	_begin
	

	mov ebx,[list]
mov ecx, lsize
	call amax
	mov  arrmax, eax
	call amin
	mov  arrmin, eax

	_putstr maxmsg
	mov 	eax, arrmax
	call	putddec
	_putch	13,10
	_putstr minmsg
	mov 	eax, arrmin
	call	putddec
	_putch	13,10

	
lab6	endp
	end lab6

[Hobson]

Look here:
http://www.codeguru.com/forum/showthread.php?t=328170

Edit:
your searching routines work ok for signed numbers, I checked this.
In main program you need to change line
mov bx,[list] to mov bx,offset list
This may be the reaon of malfuncion in your program. I changed only this line and it worked. If thee is still something wrong, check printing macros.

Hob

[svenhag]

Here's a nasm example

bits 32

global _start

array	dd	-100, 7565, 380, -9866, 452, 1295, 626, -1128, 459
	dd	-762, 4722, 1369, 489, 8988, -23321, 6675, 4239
	dd	5677, -999, 24863

len	dd	20

%define array_arg	ebp+8
%define len_arg		ebp+12

arr_max:
	enter 0,0

	xor eax, eax
	mov ebx, [array_arg]
	mov ecx, [len_arg]
	dec ecx

for:
	mov edx, [ebx+4*ecx]
	cmp edx, eax
	jle not_bigger
	mov eax, edx

not_bigger:
	loop for

	leave
	ret


_start:
	push dword [len] ; push array length
	push array ; push array address
	call arr_max
	add esp, 0x8

	mov eax, 0x1 ; exit
	int 0x80 ; make syscall

[utcguy]

Thank you both. Hobson, i added the "offset" before and it worked. I am unsure as to why though. If its not too much trouble, can you give me an explanation as to why it is significant?

[Hobson]

The main reason it worked is not adding word 'offset', but changing '[list]' to 'list'.
mov bx,[list] means: take a memory cell named list, look inside, and put its value in bx register,
mov bx, offset list means: take a memory cell named list, and put its address in bx register. In this case word 'offset' can be ommited with some assemblers. Check if yours require it or not. Word offset means, that we want to know, how far from the beginning of data segment our memory cell is located. With newer versions of assemblers use of this word is not necessary.

Hob