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Text File | 1994-04-12 | 40.0 KB | 1,251 lines

******************************* DATA ************************************* ASMLIB data manipulation subroutines Copyright (C) 1991 - 1993 Douglas Herr all rights reserved ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ CHRDEL: deletes a character from a string CHRNDEL: deletes a character from a string of known length The resulting space is closed by moving the remaining characters forward Source: chrdel.asm (strlen.asm) Call with: DS:[BX] pointing to an ASCIIZ string (chrndel only) CX = current string length AX = offset from DS:[BX] to character to delete Returns: CX = new string length Uses: CX Example: lea bx,string ; DS:[BX] points to string mov ax,3 ; delete character at DS:[BX+3] call chrdel ; delete the character, shorten string ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ COLORATTR: calculate a color attribute for ASMLIB'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 asm.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: ES:[DI] = address of field string DS:[SI] = 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: mov ax,@data ; in this case, both strings mov ds,ax ; are in DGROUP mov es,ax assume es:@data, ds:@data lea di,field ; field string lea si,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, Sunday = 1) Returns: ES:[BX] = pointer to day name string CX = length of new string Note that the day name string is not zero-terminated strndup may be used to copy the string to the near heap Uses: ES, BX, CX Example: mov ax,day call dayname ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ FILL4, FILL4b: fill a buffer with specified 4-byte data Source: tiny, small & medium: fill4.asm huge: fill4.asm (lowES2hi.asm) Call with: DS:[SI] pointing to 4-byte data (integer, float or other) ES:[DI] pointing to buffer CX = number of 4-byte data blocks to fill in buffer Fill4b: BX = byte increment between data blocks Returns: nothing Uses: nothing Example: include asm.inc extrn fill4:proc .data wonowon dd 101. ; float4 value farseg dw ? ; program allocates buffer, stores seg address here .code program fragment assumes DS:@data . . . mov es,farseg xor di,di ; start at beginning of far segment lea si,wonowon ; fill every other 4-byte block in far segment mov bx,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: tiny, small & medium: fill8.asm huge: fill8.asm (lowES2hi.asm) Call with: DS:[SI] pointing to 8-byte data (integer, float or other) ES:[DI] pointing to buffer CX = number of 8-byte data blocks to fill in buffer Fill8b: BX = 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 (strlen.asm, $strstr.asm, strnupr.asm) FSTRSTR: search for a string in a disk file, case sensetive Source: fstrstr.asm (strlen.asm, $strstr.asm) Call with: BX = file handle, DS:[SI] points to string to find The file must have been opened with read access, and at least 64k DOS memory must be free. See STARTUP.ASM and ENDPROG.ASM. Returns: if CF = 0, DX:AX is the offset of the string in the file if CF = 1: memory not available if AX = DX = 0 string not found if AX = DX = -1 error reading file if AX = DX = -2 Uses: AX, DX, flags Example: extrn fstrstr:proc .data string db 'A String In The File',0 filename db 'anyold.fil',0 .code yoursub proc mov dx,offset filename mov ax,3D00h ; open the file with read access int 21h jc no_good mov bx,ax mov si,offset string ; DS:[SI] points to the string call fstrstr jc no_good ; returns with DX = high word of ; string position, AX = low word ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ GETCMD: isolates command line parameters GetCMD assumes that parameters are separated by one or more spaces Source: getcmd.asm Call with: ES = PSP segment (see STARTUP.ASM; not requried with TINY model) AX = parameter number (first command line parameter = 0) Returns: ES:[BX] pointing to command line parameter CX = length of parameter string CX = 0 if no command parameter(AX) Note: the string at ES:[BX] is not zero-terminated Uses: BX Example: include asm.inc extrn getcmd:proc .data extrn pspseg:word ; PSP segment saved by startup code .code . . . mov es,pspseg mov ax,0 ; get first parameter call getcmd ; returns with ES:[BX] pointing to parameter ; and CX = length of parameter jcxz no_parameters ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ I2TOSTR: convert an integer value to an ASCIIZ string Source: i2tostr.asm I4TOSTR: convert a long integer value to an ASCIIZ string Source: i4tostr.asm ASMLIB's TPrint, GPrint and other 'print' subroutines require a string argument. Numeric data must be converted to a string before printing. Call with: DS:[SI] pointing to a buffer space (i2tostr) AX = integer value (i4tostr) DX:AX = long integer value i2tostr requires a 7-byte (or greater) buffer; i4tostr requires a 12-byte (or greater) buffer Returns: ASCIIZ string at DS:[SI]; 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 asm.inc extrn i2tostr:proc .data nbuffer db 7 dup(?) .code . . . mov ax,@data mov ds,ax ; numeric buffer is in DGROUP assume ds:@data lea si,nbuffer mov ax,32750 ; integer value call i2tostr ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ LOWDS2HI: converts low DS:high SI address to high DS:low SI this is handy for data structures over 64k Source: lowds2hi.asm Call with: DS:[SI] = address to convert Returns: DS:[SI] = converted address; SI <= 15 Uses: DS, SI; all other registers and flags are saved Example: extrn lowDS2hi:proc .code . . . mov ds,hugeseg mov si,next_data call lowDS2hi ; ready to address next (65535-15) bytes ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ LOWES2HI: converts low ES:high DI address to high ES:low DI this is handy for data structures over 64k Source: lowes2hi.asm Call with: ES:[DI] = address to convert Returns: ES:[DI] = converted address; DI <= 15 Uses: ES, DI; all other registers and flags are saved Example: extrn lowES2hi:proc .code . . . mov es,hugeseg mov di,next_data call lowES2hi ; ready to address next (65535-15) bytes ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ LSET: left-justifies a string in a fixed field Source: lset.asm (strlen.asm) Call with: ES:[DI] = address of field string DS:[SI] = 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: mov ax,@data ; in this case, both strings mov ds,ax ; are in DGROUP mov es,ax assume es:@data, ds:@data lea di,field ; field string lea si,source ; string to be justified in field call lset ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ LTRIM: remove leading blanks from an ASCIIZ string Source: ltrim.asm (strlen.asm) Call with: DS:[BX] pointing to string Returns: CX = new string length Uses: CX Example: lea bx,string call ltrim ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ MAXI2, MAXI2b: find maximum value in a signed integer array Source: tiny, small & medium models: maxi2.asm huge model: maxi2.asm (lowDS2hi.asm) MINI2, MINI2b: find minimum value in a signed integer array Source: tiny, small & medium models: mini2.asm huge model: mini2.asm (lowDS2hi.asm) MAXU2, MINU2b: find maximum value in an unsigned integer array Source: tiny, small & medium models: maxu2.asm huge model: maxu2.asm (lowDS2hi.asm) MINU2, MINU2b: find minimum value in an unsigned integer array Source: tiny, small & medium models: minu2.asm huge model: minu2.asm (lowDS2hi.asm) Call with: ES:[DI] pointing to the array CX = number of array elements For max/min?2b, call with BX = byte increment between array elements. Max/min?2 assume increment = 2. Returns: AX = array element number with maximum value see example to calculate address of maximum value if subroutine was called with CX = 0, CF = 1 Uses: AX, CF Example: include asm.inc extrn maxi2:proc .data integers dw 140 dup(0) .code . ; program establishes array values . . mov ax,@data mov es,ax assume es:@data lea di,integers mov cx,140 ; search the entire array call maxi2 shl ax,1 ; convert word offset to byte offsest add di,ax ; ES:[DI] points to the maximum value ; With max/min?2b, the offset of the ; value is DI + (AX * BX). ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ MAXI4, MAXI4b: find maximum value in a signed 4-byte integer array Source: tiny, small & medium models: maxi4.asm huge model: maxi4.asm (lowDS2hi.asm) MINI4, MINI4b: find minimum value in a signed 4-byte integer array Source: tiny, small & medium models: mini4.asm huge model: mini4.asm (lowDS2hi.asm) MAXU4, MAXU4b: find maximum value in an unsigned 4-byte integer array Source: tiny, small & medium models: maxu4.asm huge model: maxu4.asm (lowDS2hi.asm) MINU4, MINU4b: find minimum value in an unsigned 4-byte integer array Source: tiny, small & medium models: minu4.asm huge model: minu4.asm (lowDS2hi.asm) Call with: ES:[DI] pointing to the array CX = number of array elements For max/min?4b, call with BX = byte increment between array elements. Max/min?4 assume increment = 4. Returns: AX = array element number with maximum value see example to calculate address of maximum value. if subroutine was called with CX = 0, CF = 1 Uses: AX, CF Example: include asm.inc extrn maxi4:proc .data int4 dd 140 dup(0) .code . ; program establishes array values . . mov ax,@data mov es,ax assume es:@data lea di,int4 mov cx,140 ; search the entire array call maxi4 shl ax,1 ; convert dword offset to word offset shl ax,1 ; convert word offset to byte offset add di,ax ; ES:[DI] points to the maximum value ; With max/min?4b, the offset of the ; value is DI + (AX * BX). ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ 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: ES:[BX] = pointer to month name string CX = length of month string Note that the month name string is not zero-terminated strndup may be used to copy the string to the near heap Uses: ES, BX, CX Example: mov ax,month call monthname jc no_memory ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ NFORMAT: formats a numeric string Source: nformat.asm (ltrim.asm, strspace.asm, heap.asm) Call with: DS:[SI] pointing to a numeric string (such as one produced by i4tostr or i2tostr) AL = number of decimal places in output string BL = option code where option 1 = negative numbers enclosed with parentheses option 2 = commas between thousands option 4 = decimals truncated (instead of rounded) assumes DS @data Note: you must initialize the near heap with HINIT before using NFORMAT. See STARTUP.ASM. Returns: DS:[BX] pointing to formatted ASCIIZ string Uses: BX, CF Example: include asm.inc extrn nformat:proc, i2tostr:proc extrn hinit:proc .data ; reserve space for the heap heapsize equ 3000 ; should be plenty hbuffer db heapsize dup (0) ; I'll use this numeric buffer nbuffer db 12 dup(0) .code ; program fragment assumes DS:@data . . . lea bx,hbuffer mov ax,heapsize call hinit mov ax,-12345 lea si,nbuffer call i2tostr mov al,2 ; 2 decimal places mov bl,1 OR 2 ; I want parentheses and commas call nformat ; result returned at DS:[BX] ; remember to release the formatted ; string space with HFREE when you're ; done with the string ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ PATH: finds paths in program enviornment isolates each path in "PATH=" part of enviornment Source: path.asm (strlen.asm) Call with: ES = PSP segment, AX = path number. See STARTUP.ASM. Returns: ES:[BX] -> path(AX) in enviornment block, CX = length of path If CX = 0, path(AX) does not exist. The first path in the enviornment is path(0). Note that the path string at ES:[BX] is NOT zero-terminated. Uses: BX, CX, ES; flags and all other registers are saved Example: ; program startup code saves PSP segment include asm.inc extrn path:proc stacksize equ 1024 .stack stacksize .data public pspseg pspseg dw ? ; storage for PSP segment .code includelib asmlib start: ; start by pointing DS to DGROUP mov ax,@data mov ds,ax assume ds:@data ; save PSP segment mov pspseg,es . . . ; sometime later in the program xor ax,ax ; start with the first path find_path: mov es,pspseg call path jcxz no_path ; exit if no more paths, or else copy CX bytes ; at ES:[BX] to some useful location (try ; strndup). inc ax ; look for next path jmp find_path no_path: ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ QFNAME: qualifies a filename Source: qfname.asm Call with: DS:[BX] pointing to a filename; the filename may contain drive specification and/or complete or partial path name. Drive specification and path name not required. Returns: DS:[SI] pointing to the full DRIVESPEC:\PATH\FILENAME CX = length of full filename Note that DS:[SI] points to QFName's buffer space; the next call to QFName will return a new filename at the same address. Uses: SI, CX, flags Example: include asm.inc .data docs db '*.doc',0 ; search for .DOC files in current directory .code . . . mov ax,@data mov ds,ax lea bx,docs call qfname ; returns 'drive:\path\*.doc' ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ 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: ES:[DI] = address of field string DS:[SI] = 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: mov ax,@data ; in this case, both strings mov ds,ax ; are in DGROUP mov es,ax assume es:@data, ds:@data lea di,field ; field string lea si,source ; string to be justified in field call rset ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ RTRIM: removes trailing blanks from an ASCIIZ string Source: rtrim.asm (strlen.asm) Call with: DS:[BX] pointing to string Returns: CX = new string length Uses: CX Example: lea bx,string call rtrim ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ SORTI2HI: sort a signed array of 2-byte integers, highest first Source: sorti2hi.asm SORTI2LO: sort a signed array of 2-byte integers, lowest first Source: sorti2lo.asm Call with: ES:[DI] = address of first element of array to sort CX = number of array elements Returns: nothing Uses: nothing; all registers and flags are saved Example: include asm.inc extrn sorti2hi:proc .data i2data dw 1500 dup(0) .code . ; program establishes data values . . mov ax,@data mov es,ax assume es:@data lea di,i2data mov cx,1500 call sorti2hi ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ SORTI4HI: sort a signed array of 4-byte integers, highest first Source: tiny, small & medium: sorti4hi.asm huge: sorti4hi.asm (lowES2hi.asm) SORTI4LO: sort a signed array of 4-byte integers, lowest first Source: tiny, small & medium: sorti4lo.asm huge: sorti4lo.asm (lowES2hi.asm) Call with: ES:[DI] = address of first element of array to sort CX = number of array elements Returns: nothing Uses: nothing; all registers and flags are saved Example: include asm.inc extrn sorti4hi:proc .data i4data dd 1500 dup(0) .code . ; program establishes data values . . mov ax,@data mov es,ax assume es:@data lea di,i4data mov cx,1500 call sorti4hi ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ STRTOI2: converts an ASCII string to equivalent integer value STRNTOI2: converts n bytes of an ASCII string to equivalent integer value strtoi2 and strntoi2 ignore leading blanks and tabs, then read the string until a non-numeric character is read. strntoi2 reads a maximum of CX characters or until a non-numeric character is read, whichever comes first. Source: strtoi2.asm STRTOI4: converts an ASCII string to a long integer value STRNTOI4: converts n bytes of an ASCII string to a long integer value similar to strtoi2 and strntoi2, but returning a long integer value in DX:AX. Source: strtoi4.asm Call with: DS:[SI] = address of string strntoi2/strntoi4 only: CX = number of bytes to read Returns: AX = integer value, or DX:AX = long integer value strtoix: DS:[SI] points to character past terminating byte strntoix: if CX = 0, DS:[SI] points to next character if CX <> 0, DS:[SI] 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 DX:AX is unusable bit 7 if set = result is unsigned; result is unusable if the value represented by the string was negative Uses: AX, BX, CX, SI, flags Example: lea si,long_integer ; near address of ASCII string mov cx,7 ; 7-byte field call strntoi2 ; return result as an integer in AX ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ STRCAT: catenates (combines) two ASCIIZ strings Source: strcat.asm (strdup.asm, strlen.asm, heap.asm) Call with: DS:[SI] = address of first string DS:[BX] = address of second string assumes DS:@data Returns: if CF = 0, DS:[BX] = address of combined ASCIIZ string if CF = 1, insufficient memory available in near heap Note: you must initialize the near heap with HINIT before using STRCAT. See STARTUP.ASM. Uses: BX, CX, CF Example: include asm.inc extrn strcat:proc .data string0 db 'this string goes first',0 string1 db ' this one is added at the end of the first',0 .code ; program fragment assumes DS:@data . . . lea si,string0 ; address of first string lea bx,string1 ; address of second string call strcat ; result returned at DS:[BX] jc heap_is_full ; 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: DS:[BX] = pointer to ASCIIZ string AL = character to find CX = number of bytes to search (strnchr only) Returns: CX = string length if CF = 0, AX is the offset from DS:[BX] to matching character in the source string if CF = 1, no matching character found Uses: CX, AX, CF Example on next page ; use STRNCHR to determine if a key pressed was a legal key include asm.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 dw akey, bkey, ckey, onekey, twokey, threekey, esckey .code ; program fragment assumes DS:@data . . . get_another: lea bx,valid_string ; DS:[BX] points to a string of valid keys call getkey ; keycode returned in AX 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 cx,valid_len call strnchr jc get_another ; CF = 1 if key pressed is not among the ; keys in the validation string mov bx,ax shl bx,1 ; convert byte offset to word offset jmp dispatch_table[bx] akey: . . . bkey: . . . ckey: . . . ; etc ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ STRCPY: copy an ASCIIZ string to existing buffer Source: strcpy.asm (strlen.asm, strncpy.asm) Call with: ES:[BX] pointing to ASCIIZ string DS:[SI] 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: CX = string length Uses: CX Example: include asm.inc extrn strcpy:proc .fardata fstring db 'a far string',0 .data string_buffer db 128 dup (?) .code ; code fragment assumes DS:@data . . . ; copy far string to DGROUP for convenient manipulation mov ax,@fardata mov es,ax assume es:@fardata mov bx,offset @fardata:fstring mov si,offset @data:string_buffer call strcpy ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ STRNCPY: copy CX bytes to an existing buffer Source: strncpy.asm Call with: ES:[BX] pointing to ASCII string DS:[SI] pointing to destination buffer CX = 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:proc extrn strncpy:proc .data extrn pspseg:word ; PSP segment address was saved by STARTUP string_buffer db 128 dup (?) .code ; code fragment assumes DS:@data . . . mov es,pspseg xor ax,ax ; first command line parameter call getcmd ; returns parameter at ES:[BX], length as CX jcxz no_parameters lea si,string_buffer call strncpy ; make it zero-terminated add si,cx mov byte ptr [si],0 ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ STRINS: inserts string1 in string0 at specified offset. Creates new string in near heap; 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, heap.asm) Call with: DS:[SI] pointing to string0 DS:[BX] pointing to string1 AX = offset in string0 to insert string1 (0 >= AX >= 32767) Assumes DS:@data Returns: if CF = 1, insufficient memory in hear heap if CF = 0, DS:[BX] points to new string Note: you must initialize the near heap with HINIT before using STRINS. See STARTUP.ASM. Uses: BX, CF Example: include asm.inc extrn strins:proc .data string0 db '1234567890',0 string1 db 'abcdefghij',0 .code . . . mov ax,@data mov ds,ax ; dgroup assume ds:@data ; tell MASM about it lea si,string0 ; address of first string lea bx,string1 ; address of second string mov ax,3 ; string1 inserted after '123' call strins ; result returned at DS:[BX] jc heap_is_full ; original strings are undisturbed ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ STRDUP: duplicates a string at ES:[BX] Source: strdup.asm (strlen.asm, heap.asm) STRNDUP: duplicates n bytes of a string at ES:[BX] Source: strndup (strdup.asm, heap.asm) Call with: ES:[BX] = address of source string assumes DS:@data (strndup) CX = number of bytes to duplicate String copied to near heap Source string need not be in same segment as heap strdup requires an ASCIIZ string; strndup duplicates CX characters at ES:[BX] whether zero-terminated or not. The duplicate created by strdup or strndup will be an ASCIIZ string. Returns: if CF = 0, DS:[BX] = address of string copy CX = string length if CF = 1, insufficient memory in near heap Note: you must initialize the near heap with HINIT before using STRDUP. See STARTUP.ASM. Uses: BX, CX, CF; all other flags and registers are saved Example: mov ax,@data mov ds,ax mov es,ax ; in this case, the source string ; is in the data segment lea bx,source ; ES:[BX] = source address call strdup jc oops ; not enough memory if CF = 1 ; otherwise, DS:[BX] = address ; of string copy ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ STRIPCHR: remove all occurances of a character from an ASCIIZ string. Source: stripchr.asm (strlen.asm) Call with: DS:[BX] = string address AL = character to remove from the string Returns: CX = new string length Uses: CX Example: lea bx,string ; DS:[BX] -> string mov al,'$' ; remove "$" character from string call stripchr ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ STRLEN: finds length of an ASCIIZ string Source: strlen.asm Call with: DS:[BX] = address of the string Returns: CX = length of string excluding the terminating NUL Uses: CX Example: lea bx,string call strlen ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ STRLWR: changes upper-case characters in a string to lower case Source: strlwr.asm STRNLWR: changes n bytes of a string to lower case Source: strnlwr.asm Call with: DS:[BX] = address of an ASCIIZ string CX = number of bytes (strnlwr only) Returns: nothing Uses: nothing Example: lea bx,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: DS:[BX] pointing to the first character of the string AL = byte to find (strnrchr only) CX = number of bytes to search Returns: if CF = 1, no match if CF = 0, AX = offset from DS:[BX] of the last matching byte Uses: AX, CF; all other flags and registers are saved Example: .data string db 'my old computer was a real slug',0 .code . . . mov ax,@data mov ds,ax assume ds:@data mov al,'w' ; look for the lower-case "w" lea bx,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: DS:[BX] pointing to the first character of the string CX = number of bytes in string to reverse (strnrev only) Returns: CX = string length Uses: CX; all other registers and flags saved Example: lea bx,string ; DS:[BX] points to ASCIIZ string call strrev ; also returns CX = string length ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ STRSPACE: creates an ASCIIZ string filled with the space character, terminated with NUL Source: strspace.asm (heap.asm) Call with: AX = string length (not including terminating NUL) Assumes DS:@data Returns: if CF = 1, insufficient memory in near heap if CF = 0, DS:[BX] points to the new string CX = string length (should be same as AX) Note: you must initialize the near heap with HINIT before using STRSPACE. See STARTUP.ASM. Uses: CX, BX, CF Example: mov ax,14 ; make a new string 14 characters long call strspace jc oops ; not enough memory if CF = 1 mov string14,bx ; 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: DS:[BX] pointing to a valid ASCIIZ string AL = character CX = number of bytes to set (strnset only) Returns: CX = string length Uses: CX Example: lea bx,string ; DS:[BX] 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, strlwr.asm, heap.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: ES:[DI] pointing to source string, DS:[SI] pointing to target string. STRISTR assumes DS:@data Returns: if CF = 0, AX = offset of target in source string. if CF = 1, no match Note: you must initialize the near heap with HINIT before using STRISTR. See STARTUP.ASM. Uses: AX, CF; all other flags and registers are saved Example: mov ax,@fardata mov es,ax assume es:@fardata ; source string is in far data area mov ax,@data mov ds,ax assume ds:@data lea di,string ; source = 'monday',0 lea si,substring ; target = 'day',0 call strstr ; in this example, strstr returns ax = 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: DS:[BX] pointing to string (strnupr only) CX = number of bytes in string Returns: nothing Uses: nothing Example: mov bx,offset string mov cx,bytes call strnupr ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ SWAPB: swaps AX bytes at DS:[SI] with the same number at ES:[DI] Source: swapb.asm Call with: DS:[SI] pointing to one of the data areas, ES:[DI] pointing to the other AX = number of bytes to swap Returns: nothing Uses: nothing; all registers and flags are saved Example: include asm.inc extrn swapb:proc .data string1 db 'this is string 1',0 string2 db 'this is string 2',0 strings dw string1, string2 ; addresses of the strings ; this example will swap ; the string pointers .code public stringswap stringswap proc ; program fragment assumes DS:@data . . . lea si,strings push ds pop es ; ES = DS mov di,si mov ax,2 ; each string pointer is 2 bytes add di,ax ; point to 2nd pointer call swapb ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ WORDTOHEX: Converts word data to hex (base 16) ASCIIZ string Source: wtohex.asm Call with: AX = word data DS:[SI] pointing to string buffer buffer must be at least 6 bytes Returns: DS:[SI] points to ASCIIZ string, hex format Uses: nothing Example: extrn word2hex:proc .data hexbuf db 6 dup(?) .code . . . mov ax,hexnumber call wordtohex