assembly - Fill an array with random values -
i'm in assembly language class , doing exercise need pass parameters on stack in order generate n random numbers in specific range.
the problems i'm having:
1. random numbers not in range specifying.
2. when return array , attempt sort , display again, array populated different values.
i'm thinking these problems somehow related way i'm passing parameters.
title program 4 (project04.asm) include irvine32.inc .data intro_1 byte "composite numbers programmed ",0 prompt_1 byte "this program generates random numbers in range [100 .. 999],",0 prompt_2 byte "displays original list, sorts list, , calculates ",0 prompt_3 byte "median value. finally, displays list sorted in descending order.",0 prompt_4 byte "how many numbers should generated? [10 .. 200]: ",0 space3 byte " ",0 errormessage byte "invalid input ",0 usernum dword ? min = 10 max = 200 lo = 100 hi = 999 array dword max dup(?) .code main proc call introduction push offset usernum call getdata ;call randomize push offset array push usernum call fillarray1 push offset array push usernum call displaylist call crlf call crlf push offset array push usernum call sortlist push offset array push usernum call displaylist exit main endp introduction proc mov edx, offset intro_1 call writestring call crlf mov edx, offset prompt_1 call writestring call crlf mov edx, offset prompt_2 call writestring call crlf mov edx, offset prompt_3 call writestring call crlf call crlf ret introduction endp ;get data getdata proc getuserdata: push ebp mov ebp, esp mov edx, offset prompt_4 call writestring call readint mov usernum, eax ;call crlf ;validate cmp eax, max ja error1 cmp eax, min jb error1 pop ebp ret error1: mov edx, offset errormessage call writestring call crlf jmp getuserdata getdata endp ;fill array fillarray1 proc fillarray: push ebp mov ebp,esp pushad ; save registers mov esi,[ebp+12] ; offset of array mov ecx,[ebp+8] ; array size cmp ecx,0 ; ecx == 0? je l2 ; yes: skip on loop mov edx, hi sub edx, lo l1: mov eax, edx call randomrange ; link library add eax, lo mov [esi], eax add esi, 4 loop l1 l2: popad ; restore registers pop ebp ret 8 ; clean stack fillarray1 endp ;sort list sortlist proc push ebp mov ebp, esp mov ecx, [ebp + 8] dec ecx ; decrement count 1 l1: push ecx ; save outer loop count mov esi, [ebp + 12] ; point first value l2: mov eax,[esi] ; array value cmp [esi+4],eax ; compare pair of values jge l3 ; if [esi] <= [edi], don't exch xchg eax,[esi+4] ; exchange pair mov [esi],eax l3: add esi,4 ; move both pointers forward loop l2 ; inner loop pop ecx ; retrieve outer loop count loop l1 ; else repeat outer loop l4 : pop ebp ret 8 sortlist endp ;display median displaymedian proc displaymedian endp i think return value may off in fillarray procedure?
the displaylist procedure:
;display list displaylist proc push ebp mov ebp, esp mov ecx, [ebp + 8] jecxz farewell mov esi, [ebp + 12] ;set counter linebreak print: mov eax, [ebx] call writedec dec esi jnz spaces linebreak: call crlf mov esi, 10 jmp next spaces: cmp esi, 0 ;if there has been ten elements, go next line je linebreak mov edx, offset space3 call writestring next: add ebx, 4 loop print pop ebp ret 8 displaylist endp the getdata procedure accepts reference param:
;get data getdata proc push ebp mov ebp, esp pushad mov esi, [ebp + 8] ;move address of usernum getuserdata: mov edx, offset prompt_4 call writestring call readint mov usernum, eax mov esi, usernum ;move usernum address ;call crlf ;validate cmp eax, max ja error1 cmp eax, min jb error1 pop ebp ret error1: mov edx, offset errormessage call writestring call crlf jmp getuserdata getdata endp when made change, after enter number of random numbers printed, program crashes.
fillarray , sortlist working properly, have tested them.
getdata has bug (big 1 indeed) in error1 path, after printing error message jump getuserdata again creates stack frame.
move creation above getuserdata label, below getdata.
introduction should work (not tested tough).
the main procedure has issues:
call introduction ;ok push offset usernum call getdata ;getdata takes no params ;either update getdata (don't forget ret 04h) ;or remove push ;call randomize push offset array push usernum call fillarray1 ;this should work push offset array push usernum call displaylist ;don't know, no code displaylist call crlf call crlf push offset array push usernum call sortlist ;this should work ;push offset array ;<-- commented push usernum call displaylist ;!! not passing array display ;that's why see different values it seems forget update main after refactoring others functions.
follow up
the displaylist procedure seems wrong because:
- you never initialize
ebx esiholds array pointer seems use counterfarewellnot defined anywhere
i think new displaylist may work (please, please, please, note haven't compiled it, don't have nasm, nor planning installing it)
;array ;number of elements ;elements per line displaylist proc push ebp mov ebp, esp push esi push ecx push edx mov esi, [ebp + 16] ;array mov ecx, [ebp + 12] ;items in array preprint: mov edx, [ebp + 8] ;counter linebreaks print: jecxz end lodsd call writedec ;print items mov edx, offset space3 call writestring ;print space dec ecx dec edx jnz print call crlf jmp preprint end: pop edx pop ecx pop esi pop ebp ret 12 displaylist endp note new displaylist takes 3 arguments:
push offset array push usernum push 10 ;items per line call displaylist if want hardcode items per line , remove past parameters, edit function, remember update ret 12 , [ebp + xx] references!
in new getdata forget popad before pop ebp , replace ret ret 04h.
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