Cream of the Crop 22

home *** CD-ROM | disk | FTP | other *** search

/ Cream of the Crop 22 / Cream of the Crop 22.iso / program / asm32.zip / DATA.DOC < prev next >

Wrap

Text File | 1995-11-30 | 38.6 KB | 1,275 lines

******************************* DATA ************************************* ASM32 data manipulation subroutines Copyright (C) 1993 - 1995 Douglas Herr all rights reserved ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ $SSORT: generic Shell sort engine; calling program supplies Compare and Exchange code Source: $ssort.asm Call with: [ESI] = address of first item to sort [EDI] = address of last item to sort EAX = length of each item EBX = address of compare routine EDX = address of exchange routine $SSORT can be used to sort data of any fixed size, including user-defined records. The calling program specifies the near address of the comparison code, and the near address of the exchange code. The compare code must save all registers except EAX, and is called with ESI = near address of first record to compare, and EDI = near address of the second record to compare. $SSORT expects integer comparisons to be signed. $SSORT calls the exchange subroutine with ES:[EDI] and DS:[ESI] pointing to the records to be exchanged, and ECX = number of bytes to exchange. ASM32's SWAPB subroutine may be used as the exchange code. Returns: nothing Uses: nothing; all flags and registers are saved Example on next page $SSORT Example: extrn $ssort:near, swapb:near include dataseg.inc intdata dw 12,13,120,160 dw 12,13 dw 60,110,120,13 dw 120,160 dw 100,90 dw 20,150,12,100 dw 118 lastint dw 25 nosort dw ? ; anything past lastint not sorted ; in this example @curseg ends include codeseg.inc . . . lea esi,intdata ; point to first integer lea edi,lastint ; point to last integer to sort mov eax,2 ; size of data record lea ebx,compare ; point EBX to comparison code lea edx,swapb ; use ASM32 subroutine for exchange call $ssort ret ; ; For some unexplained reason I want to base the sort on ; only the lower byte of each integer record. ; $SSORT expects this to be a signed comparison, but my bytes are ; unsigned so I'll convert each one to a signed dword. ; I'm using DWORDS instead of WORDS because DWORDS in a 32-bit segment ; are faster and produce smaller code. ; ; Your data will be sorted low-to-high or high-to-low depending on ; your comparison. ; compare: push ebx ; need to save this register movzx eax,byte ptr [esi] movzx ebx,byte ptr [edi] cmp ebx,eax ; do the comparison pop ebx ; restore register ret ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ CHRDEL: deletes a character from a string The resulting space is closed by moving the remaining characters forward Source: chrdel.asm (strlen.asm) Call with: EBX pointing to an ASCIIZ string EAX = offset from EBX to character to delete Returns: ECX = new string length Uses: ECX Example: lea ebx,string ; EBX points to string mov eax,3 ; delete character at [EBX+3] call chrdel ; delete the character, shorten string ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ COLORATTR: calculate a color attribute for ASM32's text-mode subroutines. Intended for 16-color text modes. Source: coloratt.asm Call with: AL = foreground color (0 - 15) AH = background color (0 - 15) Returns: AH = color attribute Uses: AX Example: include codeseg.inc . . . mov al,hired ; bright red mov ah,blue ; blue call colorattr ; this should get their attention mov warning,ah ; save the attribute ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ CSET: centers a string in a fixed field Source: cset.asm (strlen.asm) Call with: EDI pointing to address of field string ESI pointing address of string to be centered in the field Both strings must be zero-terminated (ASCIIZ). The field string may not contain any nul characters except for the terminator. Returns: CF = 0 if no error CF = 1 if string was truncated to fit in the field Uses: CF; all other flags and registers are saved Example: lea edi,field ; field string lea esi,source ; string to be centered in field call cset ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ DAYNAME: returns a pointer to an ASCII string for specified day of the week Source: dname.asm ($mname.asm) Call with: AX = day of week (1 - 7, Monday = 1) Returns: [EBX] = pointer to day name string ECX = length of new string Note that the day name string is not zero-terminated strndup may be used to copy the string to near data. Uses: EBX, ECX Example: mov ax,day call dayname ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ FILL4, FILL4b: fill a buffer with specified 4-byte data Source: fill4.asm Call with: ESI pointing to 4-byte data (integer, float or other) EDI pointing to buffer ECX = number of 4-byte data blocks to fill in buffer Fill4b: EBX = byte increment between data blocks Returns: nothing Uses: nothing Example: include codeseg.inc extrn fill4:near ; data wonowon dd 101. ; float4 value buffer dd ? ; program allocates buffer, stores address here ; code . . . lea edi,buffer lea esi,wonowon ; fill every other 4-byte block in far segment mov ebx,8 ; skip 4 bytes between data blocks mov cx,25 ; do it 25 times cal fill4 ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ FILL8, FILL8b: fill a buffer with specified 8-byte data Source: fill8.asm Call with: ESI pointing to 8-byte data (integer, float or other) EDI pointing to buffer ECX = number of 8-byte data blocks to fill in buffer Fill8b: EBX = byte increment between data blocks Returns: nothing Uses: nothing Example: see Fill4 ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ FSTRISTR: search for a string in a disk file, case insensetive Source: fstristr.asm (mload.asm, $strstr.asm, strnlwr.asm) FSTRSTR: search for a string in a disk file, case sensetive Source: fstrstr.asm (mload.asm, strlen.asm, $strstr.asm) Call with: EDX pointing to file name ESI pointing to string to find EAX = initial offset in file CAUTION: Prior to ASM32 version 3.4, FSTRSTR and FSTRISTR required different parameters. If you are upgrading from an earlier version of ASM32 and have used either of these subroutines, you will need to change parameters. Returns: if CF = 0, EAX is the offset of the string in the file if CF = 1, EAX = DOS or other error code EAX = -1 if insufficient memory (unlikely) Uses: EAX, flags Example: include codeseg.inc extrn fstrstr:near ; data string db 'A String In The File',0 filename db 'anyold.fil',0 ; code yoursub proc near mov edx,offset filename mov esi,offset string ; ESI points to the string xor eax,eax ; shearch entire file call fstrstr ; returns with EAX = string offset jc short no_good ; or error code ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ GETCMD: isolates command line parameters GetCMD assumes that parameters are separated by one or more spaces Source: getcmd.asm Call with: AL = parameter number (first command line parameter = 0) Returns: if ECX = 0, no command parameter(AL) if ECX <> 0, ECX = length of parameter string (CauseWay FLAT model) [EBX] = near pointer to command line parameter (all except CauseWay FLAT model) ES:[EBX] = far pointer to command line parameter Version 2.0: Note that GETCMD does not copy the command parameter string to near data. It returns a far address to the command string which you may copy to near data with STRNDUP if you wish. Uses: ES (except CW FLAT model), EBX, ECX, flags Example: extrn getcmd:near include codeseg.inc . . . mov al,0 ; get first parameter call getcmd ; returns with ES:[EBX] pointing to parameter ; and ECX = length of parameter jecxz no_parameters IFNDEF FLATMODEL call strndup ; copy to near data ENDIF . . . ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ I2TOSTR: convert an integer value to an ASCIIZ string Source: i2tostr.asm (i4tostr.asm) I4TOSTR: convert a long integer value to an ASCIIZ string Source: i4tostr.asm ASM32's TPrint, GPrint and other 'print' subroutines require a string argument. Numeric data must be converted to a string before printing. Call with: [ESI] pointing to a buffer space; must be 12 bytes or bigger (i2tostr) AX = integer value (i4tostr) EAX = long integer value Returns: ASCIIZ string at [ESI]; numerals are right-justified Uses: nothing; all registers and flags are saved Supports: (i2tostr) signed 2-byte integers (i4tostr) signed 4-byte integers Example: include codeseg.inc extrn i2tostr:near ; data nbuffer db 12 dup(?) ; code . . . lea esi,nbuffer mov ax,32750 ; integer value call i2tostr ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ LSET: left-justifies a string in a fixed field Source: lset.asm (strlen.asm) Call with: EDI = address of field string ESI = address of string to be justified in the field Both strings must be zero-terminated (ASCIIZ). The field string may not contain any NUL characters except for the terminator. Returns: CF = 0 if no error CF = 1 if string was truncated to fit in the field Uses: CF all other flags and registers saved Example: lea edi,field ; field string lea esi,source ; string to be justified in field call lset ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ LTRIM: remove leading blanks from an ASCIIZ string Source: ltrim.asm (strlen.asm) Call with: EBX pointing to string Returns: ECX = new string length Uses: ECX Example: lea ebx,string call ltrim ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ MAXI2, MAXI2b: find maximum value in a signed integer array Source: maxi2.asm MINI2, MINI2b: find minimum value in a signed integer array Source: mini2.asm MAXU2, MINU2b: find maximum value in an unsigned integer array Source: maxu2.asm MINU2, MINU2b: find minimum value in an unsigned integer array Source: minu2.asm Call with: EDI pointing to the array ECX = number of array elements For max/min?2b, call with EBX = byte increment between array elements. Max/min?2 assume increment = 2. Returns: EAX = array element number with maximum value see example to calculate address of maximum value if subroutine was called with ECX = 0, CF = 1 Uses: EAX, CF Example: include codeseg.inc extrn maxi2:near ; data integers dw 140 dup(0) ; code . ; program establishes array values . . lea edi,integers mov ecx,140 ; search the entire array call maxi2 shl eax,1 ; convert word offset to byte offsest add edi,eax ; EDI points to the maximum value ; With max/min?2b, the offset of the ; value is EDI + (EAX * EBX). ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ MAXI4, MAXI4b: find maximum value in a signed 4-byte integer array Source: maxi4.asm MINI4, MINI4b: find minimum value in a signed 4-byte integer array Source: mini4.asm MAXU4, MAXU4b: find maximum value in an unsigned 4-byte integer array Source: maxu4.asm MINU4, MINU4b: find minimum value in an unsigned 4-byte integer array Source: minu4.asm Call with: EDI pointing to the array ECX = number of array elements For max/min?4b, call with EBX = byte increment between array elements. Max/min?4 assume increment = 4. Returns: EAX = array element number with maximum value see example to calculate address of maximum value. if subroutine was called with ECX = 0, CF = 1 Uses: EAX, CF Example: include codeseg.inc extrn maxi4:near ; data int4 dd 140 dup(0) ; code . ; program establishes array values . . lea edi,int4 mov ecx,140 ; search the entire array call maxi4 shl eax,2 ; convert dword offset to byte offset add edi,eax ; EDI points to the maximum value ; With max/min?4b, the offset of the ; value is EDI + (EAX * EBX). ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ MEMCOPY: copy data, checking for overlap if ES = DS Source: memcopy.asm Call with: DS:[ESI] = source address ES:[EDI] = destination address ECX = bytes to move Returns: nothing Uses: nothing Example: extrn memcopy:near include dataseg.inc farmem dw ? ; selector of far memory block source dd ? ; offset in far memory block destination dd ? ; destination offset @curseg ends include codeseg.inc . . . push ds push es mov esi,source mov edi,destination mov ax,farmem mov ds,ax mov es,ax call memcopy pop es pop ds ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ MONTHNAME: returns a pointer to an ASCII string for specified month Source: mname.asm ($mname.asm) Call with: AX = month (1 - 12, January = 1) Returns: [EBX] = pointer to month name string ECX = length of month string Note that the month name string is not zero-terminated strndup may be used to copy the string to near data. Uses: EBX, ECX Example: mov ax,month call monthname ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ PATH: finds path strings in program enviornment isolates each path in "PATH=" part of enviornment Source: path.asm (strlen.asm) Call with: EAX = path number Returns: if ECX =0, path(EAX) does not exist. if ECX <> 0, ECX = length of path string, and (CauseWay FLAT model) [EBX] = near pointer to path(EAX). (all except CauseWay FLAT model) ES:[EBX] = far pointer to path(EAX). The path string is located in the program's environment block. The first path in the enviornment is path(0). Note that the path string is NOT zero-terminated. (all except CauseWay FLAT model) Version 2.0: Note that PATH does not copy the path string to near data. It returns a far address to the path string which you may copy to near data with STRNDUP if you wish. Uses: ES (except CW FLAT model), EBX, ECX, flags Example: extrn path:near include codeseg.inc . . . xor eax,eax ; start with the first path find_path: call path jecxz no_path ; exit if no more paths IFNDEF FLATMODEL call strndup ; copy to near data ENDIF . . . inc eax ; look for next path jmp find_path no_path: . . ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ RANDOM: generates a near-random number Source: random.asm Call with: no parameters Returns: AX = near-random number between 0 and 65535 you may notice repeating patterns every few thousand calls to Random. Uses: AX Example: call random ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ RSET: right-justifies a string in a fixed field Source: rset.asm (strlen.asm) Call with: EDI = address of field string ESI = address of string to be justified in the field Both strings must be zero-terminated (ASCIIZ). The field string may not contain any nul characters except for the terminator. Returns: CF = 0 if no error CF = 1 if string was truncated to fit in the field Uses: CF; all other flags and registers saved Example: lea edi,field ; field string lea esi,source ; string to be justified in field call rset ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ RTRIM: removes trailing blanks from an ASCIIZ string Source: rtrim.asm (strlen.asm) Call with: EBX pointing to string Returns: ECX = new string length Uses: ECX Example: lea ebx,string call rtrim ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ SORTI2HI: sort an array of 2-byte signed integers, highest first Source: sorti2hi.asm SORTI4HI: sort an array of 4-byte signed integers, highest first Source: sorti4hi.asm SORTI2LO: sort an array of 2-byte signed integers, lowest first Source: sorti2lo.asm SORTI4LO: sort an array of 4-byte signed integers, lowest first Source: sorti4lo.asm Call with: ES:[EDI] = address of first element of array to sort ECX = number of array elements SortI4 assumes ECX < 1 Gigabyte SortI2 assumes ECX < 2 Gigabytes Returns: nothing Uses: nothing; all registers and flags are saved Example: extrn sorti4hi:near include dataseg.inc i4data dd 1500 dup(0) @curseg ends include codeseg.inc . ; program establishes data values . . lea edi,i4data push ds pop es mov ecx,1500 call sorti4hi ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ SORTU2HI: sort an array of 2-byte unsigned integers, highest first Source: sortu2hi.asm SORTU4HI: sort an array of 4-byte unsigned integers, highest first Source: sortu4hi.asm SORTU2LO: sort an array of 2-byte unsigned integers, lowest first Source: sortu2lo.asm SORTU4LO: sort an array of 4-byte unsigned integers, lowest first Source: sortu4lo.asm Call with: ES:[EDI] = address of first element of array to sort ECX = number of array elements SortI4 assumes ECX < 1 Gigabyte SortI2 assumes ECX < 2 Gigabytes Returns: nothing Uses: nothing; all registers and flags are saved Example: extrn sortu4hi:near include dataseg.inc u4data dd 1500 dup(0) @curseg ends include codeseg.inc . ; program establishes data values . . lea edi,u4data push ds pop es mov ecx,1500 call sortu4hi ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ STRTOI4: converts an ASCII string to an integer value STRNTOI4: converts n bytes of an ASCII string to an integer value Source: strtoi4.asm Call with: ESI = address of string strntoi4 only: ECX = number of bytes to read Returns: EAX = integer value strtoi4: ESI points to character past terminating byte strntoi4: if ECX = 0, ESI points to next character if ECX <> 0, ESI points to character past terminating byte BL = error code bit 0 if set = CR read before reading any numeric characters bit 1 if set = CR was the terminating character bit 6 if set = overflow; result in EAX is unusable bit 7 if set = result is unsigned; result is unusable if the value represented by the string was negative Uses: EAX, EBX, ECX, ESI, flags Example: include codeseg.inc ; data number_string db '1234567',0 ; code . . . lea esi,number_string ; point to '1234567' mov ecx,7 ; 7-byte field call strntoi4 ; return result as an integer in EAX ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ STRCAT: catenates (combines) two ASCIIZ strings Source: strcat.asm (strdup.asm, strlen.asm) Call with: ESI = address of first string EBX = address of second string Returns: if CF = 0, EBX = address of combined ASCIIZ string if CF = 1, insufficient memory available (not likely) Uses: EBX, ECX, CF Example: include codeseg.inc extrn strcat:near ; data string0 db 'this string goes first',0 string1 db ' this one is added at the end of the first',0 ; code . . . lea esi,string0 ; address of first string lea ebx,string1 ; address of second string call strcat ; result returned at EBX jc no_memory ; original strings are undisturbed ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ STRCHR: search an ASCIIZ string for a specified character STRNCHR: search n bytes of an ASCII string for a specified character Source: strchr.asm (strlen.asm) Call with: EBX = pointer to ASCIIZ string AL = character to find ECX = number of bytes to search (strnchr only) Returns: ECX = string length if CF = 0, EAX is the offset from EBX to matching character in the source string if CF = 1, no matching character found Uses: ECX, EAX, CF Example on next page ; use STRNCHR to determine if a key pressed was a legal key include codeseg.inc extrn strnchr:proc, getkey:proc, toupper:proc ; data valid_string db 'ABC123',27 ; keys 1,2,3,A,B,C and Esc valid_len equ $-valid_string ; number of valid keys dispatch_table label word dd akey, bkey, ckey, onekey, twokey, threekey, esckey ; code . . . get_another: lea ebx,valid_string ; EBX points to a string of valid keys call getkey ; keycode returned in EAX shr ah,1 ; test for extended keycode jc get_another ; I'm not interested in extended keycodes today call toupper ; convert keycode to upper case mov ecx,valid_len call strnchr jc get_another ; CF = 1 if key pressed is not among the ; keys in the validation string mov ebx,eax shl ebx,1 ; convert byte offset to word offset jmp dispatch_table[ebx] akey: . . . bkey: . . . ckey: . . . ; etc ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ STRCMP: compare strings, case-sensetive Source: strcmp.asm (strlen.asm) Call with: DS:[ESI] pointing to string1 ES:[EDI] pointing to string2 Returns: if string1 < string2, SF = 1 if string1 = string2, ZF = 1 if string1 > string2, SF = 0, ZF = 0 Note that 'A' < 'a', and that 'a' < 'z'. Both strings must be NUL-terminated ASCII strings. Uses: flags; all registers are saved See also: STRICMP, case-insensetive string comparison Example: include model.inc extrn strcmp:near include dataseg.inc string1 db 'Maple',0 string2 db 'Oak',0 @curseg ends include codeseg.inc . . . ; make sure ES = DS mov ax,ds mov es,ax lea esi,string1 ; DS:[SI] points to string1 lea edi,string2 ; ES:[DI] points to string2 call strcmp je short they_are_the_same jns short string2_GT_string1 ; string1 < string2 . . ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ STRCPY: copy an ASCIIZ string to existing buffer Source: strcpy.asm (strlen.asm, strncpy.asm) Call with: ES:[EBX] pointing to ASCIIZ string DS:[ESI] pointing to destination buffer STRCPY assumes that the buffer is long enough to hold the entire string. The string's terminating NUL byte is not copied to the buffer. Returns: ECX = string length Uses: ECX ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ STRNCPY: copy ECX bytes to an existing buffer Source: strncpy.asm Call with: ES:[EBX] pointing to ASCII string DS:[ESI] pointing to destination buffer ECX = number of bytes to copy STRNCPY assumes that the buffer is long enough to hold the entire string Returns: nothing Uses: nothing; all registers and flags are saved Example: ; I want to copy a command line parameter to DGROUP include asm.inc extrn getcmd:near extrn strncpy:near include dataseg.inc extrn pspseg:word ; PSP segment address was saved by STARTUP string_buffer db 128 dup (?) @curseg ends include codeseg.inc . . . xor eax,eax ; first command line parameter call getcmd ; returns parameter at ES:[EBX], length as ECX jcxz no_parameters lea esi,string_buffer call strncpy ; make it zero-terminated add esi,ecx mov byte ptr [esi],0 ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ STRICMP: compare strings, case-insensetive Source: strcmp.asm (strlen.asm) Call with: DS:[ESI] pointing to string1 ES:[EDI] pointing to string2 Returns: if string1 < string2, SF = 1 if string1 = string2, ZF = 1 if string1 > string2, SF = 0, ZF = 0 Note that 'A' = 'a', and that 'a' < 'z'. Both strings must be NUL-terminated ASCII strings. Uses: flags; all registers are saved See also: STRCMP, case-sensetive string comparison Example: include model.inc extrn stricmp:near include dataseg.inc string1 db 'Maple',0 string2 db 'Oak',0 @curseg ends include codeseg.inc . . . ; make sure ES = DS mov ax,ds mov es,ax lea esi,string1 ; DS:[SI] points to string1 lea edi,string2 ; ES:[DI] points to string2 call strcmp je short they_are_the_same jns short string2_GT_string1 ; string1 < string2 . . ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ STRINS: inserts string1 in string0 at specified offset. Creates new string in near memory; first part of new string is n bytes of string0; middle of new string is string1; end of new string is remainder of string0. Source: strins.asm (strlen.asm) Call with: ESI pointing to string0 EBX pointing to string1 EAX = offset in string0 to insert string1 Returns: if CF = 1, insufficient memory (not likely) if CF = 0, EBX points to new string Uses: EBX, CF Example: include codeseg.inc extrn strins:near ; data string0 db '1234567890',0 string1 db 'abcdefghij',0 ; code . . . lea esi,string0 ; address of first string lea ebx,string1 ; address of second string mov eax,3 ; string1 inserted after '123' call strins ; result returned at EBX jc no_memory ; original strings are undisturbed ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ STRDUP: duplicates an ASCIIZ string Source: strdup.asm (strlen.asm) STRNDUP: duplicates n bytes of a string Source: strdup.asm Call with: ES:[EBX] = address of source string (strndup) ECX = number of bytes to duplicate assumes DS:dataseg strdup requires an ASCIIZ string; strndup duplicates ECX characters at ES:[EBX] whether zero-terminated or not. The duplicate created by strdup or strndup will be an ASCIIZ string. Version 2.0: Note that ES is not nessesarily = DS. STRNDUP may be used to copy a string returned by EXENAME, PATH, or GETCMD to near data. Returns: if CF = 0, EBX = address of string copy in near memory ECX = string length if CF = 1, insufficient memory in near memory (not likely) Uses: EBX, ECX, flags Example: call exename ; get name of this program ; returns ES:[EBX] pointing to ; program name in environment call strdup ; copy program name to near data jc oops ; not enough memory if CF = 1 ; otherwise, EBX = address ; of string copy ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ STRIPCHR: remove all occurances of a character from an ASCIIZ string. Source: stripchr.asm (strlen.asm) Call with: EBX = string address AL = character to remove from the string Returns: ECX = new string length Uses: ECX Example: lea ebx,string ; EBX -> string mov al,'$' ; remove "$" character from string call stripchr ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ STRLEN: finds length of an ASCIIZ string Source: strlen.asm Call with: EBX = address of the string Returns: ECX = length of string excluding the terminating NUL Uses: ECX Example: lea ebx,string call strlen ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ STRLWR: changes upper-case characters in a string to lower case Source: strlwr.asm STRNLWR: changes a string of known length to lower case Source: strnlwr.asm Call with: EBX = address of an ASCIIZ string ECX = number of bytes (strnlwr only) Returns: nothing Uses: nothing Example: lea ebx,string call strlwr ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ STRRCHR: find the last byte in a string matching AL STRNRCHR: find the last byte in n bytes matching AL Source: strrchr.asm (strlen.asm) Call with: EBX pointing to the first character of the string AL = byte to find (strnrchr only) ECX = number of bytes to search Returns: if CF = 1, no match if CF = 0, EAX = offset of the last matching byte from EBX Uses: EAX, CF; all other flags and registers are saved Example: include model.inc extrn strrchr:near dataseg.inc string db 'my old computer was a real slug',0 @curseg ends include codeseg.inc . . . mov al,'w' ; look for the lower-case "w" lea ebx,string call strrchr jc oops ; cut outta here if not in the string ; else go on ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ STRREV: reverses all characters in a string STRNREV: reverses n characters in a string Source: strrev.asm (strlen.asm) Call with: EBX pointing to the first character of the string ECX = number of bytes in string to reverse (strnrev only) Returns: ECX = string length Uses: ECX; all other registers and flags saved Example: lea ebx,string ; EBX points to ASCIIZ string call strrev ; also returns ECX = string length ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ STRSPACE: creates an ASCIIZ string filled with the space character, terminated with NUL Source: strspace.asm Call with: EAX = string length (not including terminating NUL) Returns: if CF = 1, insufficient memory (not likely) if CF = 0, EBX points to the new string ECX = string length (should be same as EAX) Uses: ECX, EBX, CF Example: mov eax,14 ; make a new string 14 characters long call strspace jc short oops ; not enough memory if CF = 1 mov string14,ebx ; else save pointer to string ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ STRSET: sets all bytes of an ASCIIZ string to a specified character STRNSET: sets n bytes of an ASCIIZ string to a specified character Source: strset.asm (strlen.asm) Call with: EBX pointing to a valid ASCIIZ string AL = character ECX = number of bytes to set (strnset only) Returns: ECX = string length Uses: ECX Example: lea ebx,string ; EBX points to an ASCIIZ string mov al,'*' call strset ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ STRSTR: finds the first match with a target string in a source string case sensetive Source: strstr.asm ($strstr.asm, strlen.asm) STRISTR: finds the first match with a target string in a source string case insensetive Source: stristr.asm (strstr.asm, strdup.asm, strupr.asm) STRRSTR: finds the last match with a target string in a source string case sensetive Source: strrstr.asm (strrev.asm, $strstr.asm) Call with: DS:[EDI] pointing to source string DS:[ESI] pointing to target string. Returns: if CF = 0, EAX = offset of target in source string. if CF = 1, no match Uses: EAX, CF; all other flags and registers are saved Example: include model.inc include dataseg.inc string db 'Monday',0 substring db 'day',0 @curseg ends include codeseg.inc . . . lea edi,string ; source = 'monday',0 lea esi,substring ; target = 'day',0 ; find the offset of 'day' in 'Monday' call strstr ; in this example, strstr returns EAX = 3 ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ STRUPR: changes lower-case characters in an ASCIIZ string to upper case Source: strupr.asm STRNUPR: changes lower-case characters in an n-length string to upper case Source: strnupr.asm Call with: EBX pointing to string (strnupr only) ECX = number of bytes in string Returns: nothing Uses: nothing Example: mov ebx,offset string mov ecx,bytes call strnupr ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ SWAPB: swaps ECX bytes at DS:[ESI] with the bytes at ES:[EDI] Source: swapb.asm Call with: ESI pointing to one of the data areas, EDI pointing to the other ECX = number of bytes to swap Returns: nothing Uses: nothing; all registers and flags are saved Example: include model.inc extrn swapb:near include dataseg.inc string1 db 'this is string 1',0 string2 db 'this is string 2',0 strings dw string1, string2 ; addresses of the strings ; this trivial example will swap ; the string pointers @curseg ends include codeseg.inc public stringswap stringswap proc near . . . lea esi,strings mov edi,esi mov eax,2 ; each string pointer is 2 bytes add edi,eax ; point to 2nd pointer call swapb