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Assembly Source File | 1989-09-25 | 25.3 KB | 509 lines

PAGE ,132 TITLE String manipulation -- LARGE MEM (FAR) NAME StrPackL ; Use this file in any way that pleases you. DOSSEG .MODEL LARGE .XLIST XchgSeg MACRO Seg1,Seg2 Push Seg1 ; Save the Segment register Push Seg2 ; Save the Segment register Pop Seg1 ; Put Segment here Pop Seg2 ; The same for the first ENDM .LIST .DATA? TempW DW ? ; Temporary Word size VAR TempW2 DW ? ; Another temporary word if needed TempB DB ? ; Temporary Byte .CODE PUBLIC Length, Append, Concat, Extract, PUBLIC Split, LowerCase, UpperCase, Proper PUBLIC Trim, Checksum, Compare Length Proc ;-----------------------------------------------------------------------------; ; Returns the length of an asciiz string. ; ; INPUT: ; ; DS:SI = Address of ASCIIZ string ; ; OUTPUT: ; ; AX = Length of string (Not including the NULL char at end ; ;-----------------------------------------------------------------------------; Push Di ; Push Cx ; Save them Push Es ; ; Xor Cx,Cx ; Clear to 0 Not Cx ; And flip the bits Cld ; Mov Di,Si ; Push Ds ; Pop Es ; Mov Al,0 ; Search Repnz Scasb ; Scan for the 0 Not Cx ; Flip the bits back Mov Ax,Cx ; Put count Here Dec Ax ; And take one out -- do not include 0 ; Pop Es ; Pop Cx ; Get the old Cx Pop Di ; Get the ols si Ret ; And exit Length Endp Append Proc ;-----------------------------------------------------------------------------; ; Appends Second string onto the first string in memory. ; ; INPUT: ; ; DS:SI = Address of First string. ; ; ES:DI = Address of Second string (one to be appedned ; ; OUTPUT: ; ; Nothing changed except first string is now Firststring+Secondstring ; ;-----------------------------------------------------------------------------; Push Ax ; Save all the registers Used Push Cx ; Push Si ; Push Di ; Pushf ; And the flags ; Call Length ; Get the length of first string Add Si,Ax ; Add to get to end of first Xchg Si,Di ; Switch to XchgSeg Ds,Es ; Exchange these segment registers Call Length ; Get the length of the second string Mov Cx,Ax ; Count Inc Cx ; Snag the ASCIIZ byte also Cld ; Up Rep Movsb ; Transfer ; Popf ; Pop everything used Pop Di ; Pop Si ; Pop Cx ; Pop Ax ; Ret ; And return Append Endp ; Concat Proc ;-----------------------------------------------------------------------------; ; Works like Append except neither of the two orugunal strings are touched, ; ; but the result is placed in another location all together (C := A+B) ; ; INPUT: ; ; DS:SI = Address of First String ; ; DS:BX = Address of Second String ; ; ES:DI = Address to place (First String + Second String) ; ; OUTPUT: ; ; AX = Length of resulting string ; ;-----------------------------------------------------------------------------; Push Bx ; Push Cx ; Push Dx ; Push Si ; Push Di ; ; Cld ; Dest is ES:DI ; Get some string lengths Call Length ; String 1 Mov Cx,Ax ; Length of string 1 in CX Xchg Bx,Si ; Call Length ; Xchg Bx,Si ; Mov Dx,Ax ; Length of String 2 in DX Add Ax,Cx ; Get resulting length Mov TempW,Ax ; Save it for temp ; Now, Rep Movsb ; Transfer part one Xchg Dx,Cx ; Switch Xchg Bx,Si ; Switch Inc Cx ; Include the ASCIIZ NULL Rep Movsb ; Move this ; We are done Pop Di ; Pop Si ; Pop Dx ; Pop Cx ; Pop Bx ; Mov Ax,TempW ; Get the resulting count Ret ; And return Concat Endp Extract Proc ;-----------------------------------------------------------------------------; ; EXtracts a number of chars from a given string and puts in dest. ; ; INPUT ; ; DS:SI = The address of string to be extracted from (source) ; ; ES:DI = Destination address of the new string ; ; AX = Number of chars to extract ; ; OUTPUT ; ; ES:DI = address of first char of new string. ; ; everything else is actually unchanged. ; ;-----------------------------------------------------------------------------; Push Ax ; Push Cx ; Push Si ; ; Mov Cx,Ax ; Put this here Add Si,Ax ; Add offset Mov Al,0 ; Cld ; Rep Movsb ; Move it -- HA and bingo Stosb ; Save an ASCIIZ char ; Pop Si ; Pop Cx ; Pop Ax ; Ret ; Extract Endp Split Proc ;-----------------------------------------------------------------------------; ; Splits a given ASCIIZ string into 2 distinct ASCIIZ string. ; ; INPUT ; ; DS:SI = Address of string to be split. ; ; BX = Offset into DS:SI where the start of split occurs. ; ; ES:DI = OFfset of the second half of DS:SI (split) is to be placed. ; ; OUTPUT ; ; ES:DI = Address of string that came from string one. ; ; AX = New Length of string that was DS:SI ; ; BX = Length of the string that is found in ES:DI ; ; Thus... ; ; "The green roof on the lawn",0 split at r of roof ; ; BECOMES... ; ; "The green ",0 (DS:SI) [New Length in AX] AND ; ; "roof on the lawn",0 (ES:DI) [New Length in BX] ; ;-----------------------------------------------------------------------------; Push Cx ; Push Dx ; Push Si ; Push Di ; Push Bp ; Cld ; ; Push Si ; Call Length ; Get the length Mov Dx,Ax ; Add Si,Bx ; Add this Call Length ; Get the length of second string Mov Bp,Ax ; Save length of new string for later Mov Cx,Ax ; Grab that length Inc Cx ; Include the null Rep Movsb ; Move it including the null Pop Si ; Get the offset back ; Mov BYTE PTR [Bx+Si],0 ; Make it null ; Sub Dx,Bp ; Get difference Mov Ax,Dx ; Mov Bx,Bp ; ; Pop Bp ; Pop Di ; Pop Si ; Pop Dx ; Pop Cx ; Ret ; Split Endp LowerCase Proc ;-----------------------------------------------------------------------------; ; Converts entire input string to lowercase. ; ; INPUT : ; ; DS:SI = Address of source string. ; ; ES:DI = Address of new string exactly like first exept all lc. ; ; OUTPUT : ; ; ES:DI = Address of New string all in lowercase. ; ;-----------------------------------------------------------------------------; Push Ax ; Push Cx ; Push Si ; Push Di ; ; Cld ; Yep Call Length ; Get the Length Mov Cx,Ax ; Put it for the count _UtoLtop: Lodsb ; Get it Cmp Al,'A' ; Well Jb @F ; Nope Cmp Al,'Z' ; Well... Ja @F ; Nope skip add Add Al,20h ; Convert to lower case @@: Stosb ; Loop _UtoLtop ; Back ; Pop Di ; Pop Si ; Pop Cx ; Pop Ax ; Ret ; LowerCase Endp UpperCase Proc ;-----------------------------------------------------------------------------; ; Converts entire input string to uppercase. ; ; INPUT : ; ; DS:SI = Source string. ; ; ES:DI = Address to place new string. ; ; OUTPUT: ; ; ES:DI = address of new string like souce but all to uppercase. ; ;-----------------------------------------------------------------------------; Push Ax ; Push Si ; Push Di ; ; Cld ; Call Length ; Get the length Mov Cx,Ax ; For the count _LtoUtop: Lodsb ; Grab Cmp Al,'a' ; Well Jb @F ; Foreward Cmp Al,'z' ; Well,/// Ja @F ; skip the subtract Sub Al,20h ; Take it out @@: Stosb ; Save it Loop _LtoUtop ; Hmm... ; Pop Di ; Pop Si ; Pop Ax ; Ret ; UpperCase Endp Proper Proc ;-----------------------------------------------------------------------------; ; Make a given input string to proper format. i. e. ; ; "THIS IS A STRING",0 made proper would look like... ; ; "This Is A String",0 ; ; INPUT : ; ; DS:SI = Source input string. ; ; ES:DI = Destination address. ; ; OUTPUT: ; ; ES:DI = address of output proper string. ; ;-----------------------------------------------------------------------------; Push Ax ; Push Si ; Push Di ; ; Cld ; ; First convert to lowercase Call LowerCase ; Make it all like lower case ; Now search and do. Mov Si,Di ; Neww source address XchgSeg Ds,Es ; Mov Ah,0 ; Clear our flag _FindWord: Lodsb ; Cmp Al,0 ; Are we done Je _ProperDone ; Cmp Al,'a' ; well? Jb @F ; Cmp Al,'z' ; Ja @F ; Add Al,-20h ; Ok Dec Ah ; @@: Stosb ; Or Ah,Ah ; Jns _FindWord ; Not negative then keep finding ; Found word and converted _FindDelim: Lodsb ; Grab Cmp Al,0 ; Je _ProperDone ; Cmp Al,'a' ; Well Jae _Pt2xx ; Jmp SHORT _DFp; _Pt2xx: Cmp Al,'z' ; Ok? Jbe @F ; Skip the flag reset _DFp: Inc Ah ; Back to 0 @@: Stosb ; Or Ah,Ah ; Js _FindDelim ; While negative keep searching Jmp _FindWord ; Back to word search _ProperDone: Stosb ; Save the ASCIIZ ; XchgSeg Ds,Es ; Back to what these were ; Pop Di ; Pop Si ; Pop Ax ; Ret ; Proper Endp Trim PROC ;-----------------------------------------------------------------------------; ; Trims an input string by removing all the leading and trailing spaces. ; ; also leaves one space in between each word and if comma then it goes ; ; the comma then space, if period then . and if not at end then 2 spaces ; ; INPUT: ; ; DS:SI = address of string to be trimmed. ; ; ES:DI = destination of new string. ; ; OUTPUT: ; ; AX = length of resulting new sentence and of course.. ; ; ES:DI = address of new string. NOTE THAT the original string is intact. ; ;-----------------------------------------------------------------------------; Push Cx ; Push Dx ; Push Si ; Push Di ; ; Cld ; Upper Call Length ; Get the length of the monstocity Mov Cx,Ax ; This is our count down counter Xor Dx,Dx ; This is our count up counter Mov Ah,' ' ; Start the flag with a space _TrimTlop: Jcxz _TrimBlop ; If we are done then exit Lodsb ; Get a char Dec Cx ; Down one Cmp Al,' ' ; Are we pointing to a space Jne @F ; Forweward Cmp Ah,' ' ; If we find a space and we had a space Je _TrimTlop ; Then ignore it and we continue Cmp Ah,'.' ; But if we had a period Jne _lastwaschar; --- Stosb ; Store the space and Inc Dx ; _lastwaschar: Stosb ; Otherwise we store the space Xchg Ah,Al ; And switch the bytes Inc Dx ; Add one for our length Jmp _TrimTlop ; And back we go @@: Cmp Al,',' ; Are we pinting to a comma Jne @F ; Nope so we jump to next test Stosb ; Save the comma Inc Dx ; Counter + 1 Mov Al,' ' ; and one space Stosb ; After the comma Inc Dx ; Counter + 1 Xchg Ah,Al ; Switch to tell our last thing Jmp _TrimTlop ; Back to do another @@: Stosb ; Save the char (period or otherwise) Inc Dx ; Hmm Xchg Ah,Al ; Specify the last char taken Jmp _TrimTlop ; _TrimBlop: Mov Al,0 ; Put a null here Stosb ; Save the null Mov TempW,Dx ; ; Pop Di ; Pop Si ; Pop Dx ; Pop Cx ; Mov Ax,TempW ; Get this Ret ; Trim Endp Checksum Proc ;-----------------------------------------------------------------------------; ; Retruns the checksum of a string (including the asciiz -- as if ) ; ; INPUT : ; ; DS:SI = address of string ; ; OUTPUT: ; ; AX = Word Checksum of string (by bytes) -- flags modified ; ;-----------------------------------------------------------------------------; Push Si ; Save what we use Push Bx ; Push Cx ; ; Call Length ; Get the length Mov Cx,Ax ; Put it here Xor Bx,Bx ; Xor Ax,Ax ; This too @@: Add Ax,[Bx+Si] ; So add Inc Bx ; By one Loop @B ; Loop Baxk ; Pop Cx ; Pop Bx ; Pop Si ; Test Ax,Ax ; Set the flags Ret ; Checksum Endp Compare Proc ;-----------------------------------------------------------------------------; ; Compares 2 input string and returns the compare result as follows... ; ; If CF reset then the strings were exactly equal. ; ; Otherwise AX returns sevral values.. see below ; ; INPUT : ; ; DS:SI = Address of first string. ; ; ES:DI = Address of second string. ; ; OUTPUT: ; ; If CF=0 AND AX = 0 Then the Strings are Identical. ; ; If CF=0 AND AX > 0 Then Str2 = Str1 Upto(AX offset in Str1)... ; ; LengthOfStr2 < LengthOfStr1. ; ; IF CF=0 AND AX < 0 Then Str1 = Str2 (AX NegativeOffset in Str2) ; ; LengthOfStr1 < LengthOfStr2. ; ; Note above that strings are equal to a point and AX holds dif. ; ; If CF=1 AND AX > 0 Then Str1>Str2 and AX = Offset of Mismatch ; ; If CF=1 AND AX < 0 Then Str1<Str2 and AX = NegativeOffset Mismatch ; ; Just a note that Negative offset if the numerical negative of the offset ; ; for that given number. To find the actual offset, absolute value the num. ; ;-----------------------------------------------------------------------------; Push Bx ; Push Cx ; Push Si ; Push Di ; ; Call Length ; Get length of Number 1 Xchg Ax,Bx ; Flip to save XchgSeg Ds,Es ; Exchange the segments Call Length ; And get length of string 2 XchgSeg Ds,Es ; Switch them back Xchg Ax,Bx ; LENGTH1 in AX, LENGTH2 in BX Cmp Ax,Bx ; Check Ax vs. Bx Je sameLength ; The strings are the same length. ; ; sameLength: Mov TempW,Ax ; Save the length that we got Mov Cx,Ax ; Put the count for the test here Clc ; Clear for fun! Repe Cmpsb ; Keep comparing the things Je slEqual ; Same length strings are equal Pushf ; Save the flags Mov Ax,TempW ; Get that saved length Sub Ax,Cx ; Which char erred Dec Ax ; One more for the offset Popf ; Get the flags to see WHICH is bigger Jnb str1Bigger ; If not below then 1 is bigger than 2 Neg Ax ; Send back the negative offset str1Bigger: Stc ; Set the carry Jmp short compExit; Exit out of here slEqual: Clc ; Clear the carry Xor Ax,Ax ; Clear AX Jmp short compExit; Exit out of here ; ; compExit: Mov TempW,Ax ; Save this Lahf ; Save thew flags Mov TempB,Ah ; Put this here Pop Di ; Pop Si ; Pop Cx ; Pop Bx ; Mov Ah,TempB ; Get the flags Sahf ; Set the flags Mov Ax,TempW ; Get AX Back Ret ; Say by bye Compare Endp END