PsL Monthly 1993 December

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Assembly Source File | 1991-05-23 | 21.9 KB | 544 lines

;«RM92»«TS8,16,24,32,40,48» ; updated 5/21/91 DOSSEG .MODEL MEDIUM, BASIC .DATA EXTRN B$TEMPDATA:WORD ;inside FDATA, 128 byte buffer EXTRN B$STRINGLEN:WORD ;inside FDATA, empty string descriptor EXTRN B$STRINGOFF:WORD ;inside FDATA .CODE EXTRN B$ASSN:FAR ;This allows QBASIC to manipulate fixed length string EXTRN B$STDL:FAR ;This creates null strings ; Please do not remove Copyright DB 13,10,'Copyright Copr. (C) 1991 Sidney J. Kelly',13,10 Copyright1 DB 'All Rights Reserved',13,10,26 COPY_STRING_BUFFER macro ;;Copies user input string to a buffer (FDATA.ASM) ;;Does not test length of string! ;;Uses SI,DI,ES,AX,CX,BX ;;Assumes BX = address of string descriptor ;; CX = length of string ;; DS = segment of string ;; ES = DGROUP ;; Direction Flag clear, CLD ;;Trashes AX, SI, DI and CX Mov SI,[BX+2] ;; put offset of string in SI Mov DI,OFFSET B$TEMPDATA ;; put address of buffer in DI ;;Rep MOVSB ;; copy the string to buffer ;;The following is faster than a MOVSB routine Shr CX,1 ;; convert bytes to word Rep MOVSW ;; move DS:SI to ES:DI ADC CX,CX ;; CX=1 if bytes were odd, 0 if even Rep MOVSB ;; copy the odd byte if there was one endm ASCII_Space EQU 32 EVEN ;memory rather than stack used allow deep nesting of routine ;prevents use under OS/2 or protected mode Right_Edge dw 0 ; right edge of Buffer Max_Cursor dw 0 ; dimension of max cursor Min_Cursor dw 0 ; dimension of min cursor Orig_Cursor dw 0 ; original cursor shape Exit_Key dw 0 ; key hit to exit routine Old_BP dw 0 ; temp storage for BP, to correct ; for bug in early PC video bios ; that changes BP Max_Len db 0 ; max length of Result$ Curr_Page db 0 ; current video page Insert_State db 0 ; -1 = insert on, 0 = insert off Start_Row db 0 ; Starting Row Start_Col db 0 ; Starting Column Curr_Row db 0 ; (never really used) Curr_Col db 0 ; Current column location Max_Right db 0 ; rightmost column Curr_V_Mode db 0 ; fix for rom BIOS error ; in AST 386/AMI 386 BIOS ;======================================================================= ; DECLARE FUNCTION EDITOR$ (BYVAL ROW%, BYVAL COL%, BYVAL LENGTH%, _ ; BYVAL ATTR%, INPUT$, FILTER$, EXITKEY%) ; Result$ = EDITOR$ (ROW%, COL%, LENGTH%, ATTR%, FILTER$, EXITKEY%) ; Compatible input editor, allowed keystrokes limited by Filter$. ; Extended keys not recognized, primarily for alpha-numeric input only ; Allows editing using any video page supported by the video system ; ; Editing keys recognized; ; Home: move cursor to beginning of window ; Insert; toggle insert mode, default mode is insert on ; End; move cursor to end of window ; Del: moves string left, deletes character under cursor ; Backspace: moves string left, deletes character to left of cursor ; Currently ESC, ENTER, TAB, and SHIFT-TAB will end the routine ; ; Input: ; Row: Row on screen 1 to 50, no range check is performed ; Col: Starting Column 1 to 80, no range check is performed ; Length: Length of editing window, no range check performed ; If extends past right border, then wraps to lower line. ; Attr: Color attribute for window (back * 16 + foreground color) ; Input$: allows programmer to feed routine an existing string ; for editing. The Input$ is not changed, only Result$ is. ; Filter$: the input filter string, if LEN(Filter$) = 0 then ; every key is o.k. ; Exitkey%: the scan code of the key used to exit the routine ; currently ESC, ENTER, TAB, and SHIFT-TAB recognized ;======================================================================= EVEN EDITOR PROC FAR BASIC USES SI DI, ROW:WORD, COL:WORD, \ LENGTHH:WORD, ATTR:WORD, INPUT:WORD, FILTER:WORD, EXITKEY:WORD Assume DS:@data Setup: Mov Old_BP,BP ; store it because bios may change BP ; and we need it to access stack correctly Mov AX,@data ; this is a pointer to DGROUP Mov ES,AX ; move near data seg to ES Assume ES:@data ; tell assembler CLD ; clear direction flag for safety Mov AX,2020h ; load spaces in AX Mov CX,44 ; count 44 words, 88 bytes to be safe Mov DI,OFFSET B$TEMPDATA ; load offset of buffer in DI Rep STOSW ; fill buffer (ES:DI) with spaces Mov AL,0FFh ; make AL = -1 to record using insert mode Mov Insert_State,AL Mov AX,LENGTHH ; get length of output string into AX (BYVAL) Or AX,AX ; make sure not 0 JNZ Setup1 ; not 0, so jump ahead Mov AX,1 ; make AX = 1, so can read one character Jmp Short Setup2 ; jump ahead Setup1: Cmp AL,80 ; make sure LENGTHH < than size of buffer JBE Setup2 ; range o.k. so continue Mov AL,80 ; else make it 80 character max Setup2: Mov Max_Len,AL ; store in CSEG Mov BL,AL ; store temporarily in BL Dec BL ; make length 0 biased Mov AX,ROW ; get starting row into AX (BYVAL) Dec AL ; make 0 bias Mov Start_Row,AL ; store value Mov Curr_Row,AL ; put cursor at beginning Mov AX,COL ; get starting column into AX (BYVAL) Dec AL ; make 0 bias Mov Start_Col,AL ; store value Mov Curr_Col,AL ; put cursor at beginning Add AL,BL ; add Curr_Col+(Max_Len-1) Mov Max_Right,AL ; store in Max_Right Mov AX,OFFSET B$TEMPDATA ; load offset of buffer in AX Add AL,BL ; add 0 biased length to buffer offset Mov Right_Edge,AX ; store in memory for fast access Get_Video_Info: Mov AH,0Fh ; get current page number in BH Int 10h Mov Curr_Page,BH ; save current page number Mov Curr_V_Mode,AL ; save current video mode Cmp AL,7 ; mono mode? JNE Try_Color ; nope, try color Mov AH,3 ; get current default size Int 10h Mov Orig_Cursor,CX ; save current cursor shape Mov CX,000Ch ; use mono sizing Mov Max_Cursor,CX ; set max cursor size Mov AH,1 ; to model insert mode Int 10h Mov CH,0Bh ; set min cursor size for mono Mov Min_Cursor,CX ; save it Jmp Short Other_Info ; skip over color sections Try_Color: Mov AH,3 ; BH must contain current page number Int 10h ; returns current cursor in CX Mov Orig_Cursor,CX ; save current cursor shape Mov DX,CX ; copy value in DX too for temporary storage Xor CH,CH ; clear top value so it is 0 Mov Max_Cursor,CX ; store maximum size in CSEG Mov AH,1 ; AL contains current video mode Int 10h ; set cursor to maximum size Mov CL,DL ; get back temporary value from DX Mov CH,DL Dec CH ; reduce top scan value by one Mov Min_Cursor,CX ; store in Min value Other_Info: Call Near Ptr Mov_Cursor ; move cursor where desired Mov BP,Old_BP ; restore BP in case bios changed it Mov AX,ATTR ; get attribute in AX (BYVAL) Or AX,AX ; see if it is zero JNZ @f Mov AL,7 ; use default of White on Black @@: Mov BL,AL ; put display attribute in BL ; BH already contains current page Mov AX,0920h ; get ready to print spaces Mov CL,Max_Len ; write spaces on screen Xor CH,CH ; print spaces using function 9 Int 10h ; as this allows us to set attributes ; but it does not move cursor ; so this is the only time we use it Mov DL,CL ; store Max_Len in DL Xor DH,DH ; clear DH Mov BP,Old_BP ; restore BP in case bios changed it Mov BX,INPUT ; get address of input string Mov CX,[BX] ; get length in CX JCXZ Clear_Keyb ; if LEN=0 then skip ahead Cmp CX,DX ; is LEN > Max_Len JBE @f ; it is less than or equal so jump ahead Mov CX,DX ; make LEN of Imput$ = Max_Len @@: Mov DX,CX ; store LEN in DX, because CX will be trashed COPY_STRING_BUFFER ; copy Input$ to buffer MACRO Mov AL,Curr_Col ; get starting column Add AL,DL ; add LEN to Start_Row Mov BL,Max_Right ; get address of right side Cmp AL,BL ; see if AL > Max_Right JBE @f ; if less than or equal, skip ahead Mov AL,BL ; limit cursor to right side of buffer @@: Mov Curr_Col,AL ; move cursor to end of string Call Near Ptr Show_String ; show input string EVEN Clear_Keyb: ; make sure buffer is empty when we start ; there are faster ways, but this is the most compatible way ; faster way will be incompatible with Tandy machines Mov AH,1 ; clear keyboard buffer Int 16h JZ Main ; no key waiting so quit Xor AH,AH ; get key into AX Int 16h Jmp Short Clear_Keyb ; loop until buffer is empty EVEN Main: ; this is the main loop, most everything returns here Xor AH,AH ; this will wait until a key is pressed Int 16h ; use BIOS so CTRL-C, CTRL-BREAK wont ; kill program Or AL,AL ; is it an extended key? JZ Parse_Extended ; yes Cmp AL,ASCII_Space ; below ASCII 32 (space character) JB Parse_Control ; yes, treat as control key Mov BP,Old_BP ; restore BP in case bios changed it Mov BX,FILTER ; check if an allowed key Mov CX,[BX] ; move length ito CX, if LEN(FILTER$) = 0 Jcxz Add_String ; then, by definition, got the right key Mov DI,ES:[BX+2] ; move address of FILTER$ to DI Repne Scasb ; search for match JNE Err_Beep ; did we search entire string?, if yes Beep Add_String: Jmp Add_Char ; add AL to string buffer & display it EVEN Err_Beep: Mov AX, 0E07h ; Write ASCII 7 character Int 10h ; (bell) to console (BEEP) ; this makes the beep CPU speed independent Jmp Short Clear_Keyb; clear KBD buffer to prevent excess keys EVEN Parse_Control: ; parse control keys Mov Exit_Key,AX ; store exit key in CSEG buffer Cmp AL,9 ; Is it a tab key? JE Quit1 ; yes, so quit Cmp AL,13 ; Is it a carriage return key? JE Quit1 ; yes, so quit Cmp AL,27 ; Is it an escape key? JE Quit1 ; yes, so quit Cmp AL,8 ; Is it backspace? JNE Main ; not any of the above so reloop ; Send BackSpace ; else, send backspace Mov AL,Curr_Col ; get current column Cmp AL,Start_Col ; see > starting column JA Back_S ; it is, so o.k. Jmp Err_Beep ; else, at left margin can go no more Back_S: Dec AL ; reduce current column by one Mov Curr_Col,AL ; store result Call Near Ptr Mov_Buff_Left ; move buffer left Call Near Ptr Show_String ; display changes Jmp Main EVEN Quit1: ; lilly pad Jmp Quit EVEN Parse_Extended: ; parse extended keys Mov Exit_Key,AX ; store exit key in CSEG buffer Cmp AH,15 ; is it shift-tab JE Quit1 ; yes, so quit Cmp AH,52h ; is it Insert JNE @f ; nope, so jump ahead Toggle_Insert: ; Toggle Insert mode Mov AL,Insert_State ; get current state Not AL ; flip all bits 0 to FFh, or FFh to 0 Mov Insert_State,AL ; store current result Mov CX,Max_Cursor ; assume max cursor size Or AL,AL ; is AL = 0, want min size? JNZ Tog_1 ; nope, wanted max size Mov CX,Min_Cursor ; else get min cursor Tog_1: Mov AH,1 ; set current scan lines Mov AL,Curr_V_Mode ; fix AST/AMI 386 Rom BIOS error Int 10h Jmp Main ; hop back to main loop @@: Cmp AH,4Dh ; is it right arrow JNE @f ; not a special key so continue Mov_Right: ; Move cursor right Mov AL,Curr_Col ; get current column Cmp AL,Max_Right ; get right border JB Mov_R ; are we left of right border Jmp Err_Beep ; nope, so beep Mov_R: Inc AL ; move current column right Mov Curr_Col,AL ; update memory variable Call Near Ptr Mov_Cursor ; move cursor where desired Jmp Main @@: Cmp AH,4Bh ; is it a left arrow JNE @f ; not that key so continue Mov_Left: ; Move cursor left Mov AL,Curr_Col Cmp AL,Start_Col ; are we right of left border JA Mov_L Jmp Err_Beep ; nope, so beep Mov_L: Dec AL Mov Curr_Col,AL Call Near Ptr Mov_Cursor ; move cursor where desired Jmp Main @@: Cmp AH,47h ; is it the home key JNE @f ; not that key so continue Mov_Home: ; Cursor Home, to start of string Mov AL,Start_Col ; get starting column Mov Curr_Col,AL ; make current column = starting Call Near Ptr Mov_Cursor ; move cursor where desired Jmp Main ; hop back into main loop @@: Cmp AH,53h ; is it Del key JNE @f ; not that key so continue Del_Char: ; else, delete current character Call Near Ptr Mov_Buff_Left ; move string at right of cursor, left Call Near Ptr Show_String ; but don't move cursor Jmp Main @@: Cmp AH,4Fh ; is it the end key? JE Mov_End ; yes Jmp Main ; nope so start again Mov_End: ; Move to End of buffer Mov AL,Max_Right Mov Curr_Col,AL Call Near Ptr Mov_Cursor ; move cursor where desired Jmp Main EVEN Quit: Mov AH,1 ; reset cursor to original size Mov AL,Curr_V_Mode ; fix AST/AMI 386 Rom BIOS error Mov CX,Orig_Cursor Int 10h Mov BP,Old_BP ; restore BP in case bios changed it Mov BX,EXITKEY ; get address of EXITKEY Mov AX,Exit_Key ; save ExitKey Or AL,AL ; make sure return value in AL JNZ @f Mov AL,AH ; if not then move to AL @@: Xor AH,AH ; and make sure that AH = 0 Mov [BX],AX ; store in EXITKEY CopyString: Mov AL,Max_Len ; get length of string in AX Xor AH,AH ; clear high byte Mov CX,AX ; put length in CX Mov DI,OFFSET B$TEMPDATA ; move address of string to DI Dec AX ; make Max_Len zero biased Add DI,AX ; get last byte (beginning + length) Mov AL,20h ; look for trailing spaces STD ; set direction down, scan backwards Repz Scasb ; search for non match (ES:DI w/ AL) CLD ; clear direction flag JZ Err_Quit ; all spaces so quit Inc CX ; remove 1 byte overrun of SCASB ; standard way to return a string to QBASIC Push DS ; Store the Data Segment Mov AX, OFFSET B$TEMPDATA Push AX ; Store offset of string Push CX ; Store LENGTH of string Push DS ; Store the Data Segment Mov AX, OFFSET B$STRINGLEN Push AX ; Store Descriptor of string Xor AX,AX ; tell Basic it is a variable string Push AX ; Store a 0 Call B$ASSN ; copy string into BASIC space Mov AX, OFFSET B$STRINGLEN ; address of descriptor Ret EVEN Err_Quit: ; this returns a null string if have an error Mov AH,1 ; reset cursor to original size Mov CX,Orig_Cursor Mov AL,Curr_V_Mode ; fix AST/AMI 386 Rom BIOS error Int 10h Err_Quit1: Mov BP,Old_BP ; restore BP in case bios changed it Mov BX,EXITKEY Xor AX,AX ; return no exit key Mov [BX],AX Mov AX, OFFSET B$STRINGLEN ; put address of Push AX ; descriptor in AX Call B$STDL ; make it a null string Mov AX, OFFSET B$STRINGLEN ; put address of descriptor in AX Ret EDITOR ENDP ;--------------------------- Jump Section------------------------- ;simple procedures with local labels so that they will not have public names ;and take up space in the .OBJ file with use full PROC directives EVEN Mov_Cursor Label Near ; this is a common routine Mov DH,Curr_Row ; move cursor to that location Mov DL,Curr_Col ; Row at Curr_Row, Col at Curr_Col Mov BH,Curr_Page ; this allows use of any video page Mov AH,2 Int 10h Retn EVEN Show_String Label Near ; turn off cursor until printing is complete Mov BH,Curr_Page ; get current page in BH Mov AH,3 ; read cursro info Int 10h ; Clear cursor by Or CH,20h ; by turning on bit 5 of CH Mov AH,1 ; set Cursor size function Mov AL,Curr_V_Mode ; fix AST/AMI 386 Rom BIOS error Int 10h ; do it Mov AH,2 ; move cursor to beginning of string Mov DH,Start_Row ; note BH contains Curr_Page Mov DL,Start_Col ; load starting Row & Column Int 10h Mov CL,Max_Len ; determine how many bytes to show Xor CH,CH ; clear CH Mov SI,OFFSET B$TEMPDATA ; get the offset of buffer into SI EVEN Looper1: Lodsb ; load DS:SI into AL Mov AH,0Eh ; display AL & move cursor Int 10h ; (now hidden) Loop Looper1 Mov AH,3 ; make cursor visable again Int 10h ; get current cursor And CH,11011111b ; clear bit 5 Mov AH,1 ; reset cursor so it is now displays Mov AL,Curr_V_Mode ; fix AST/AMI 386 Rom BIOS error Int 10h Jmp Mov_Cursor ; move cursor to desired location ; & return from whence we came EVEN Add_Char Label Near Mov CX,AX ; temporarily store AX in CX Mov AL,Insert_State ; see if Insert Mode is on Cmp AL,0 ; i.e. is AL <> 0? JE Add_Char1 ; nope, AL = 0 insert off, skip ahead Mov AL,Curr_Col ; get current location Cmp Max_Right,AL ; are we at right column edge? JE Add_Char1 ; yes so add to buffer, & ignore Insert mode Mov_Buff_Right: ; must preserve CX Mov DX,CX ; store CX in DX to preserve CX Mov BX,Right_Edge ; load BX w/ right side of buffer Mov DI,BX ; set destination in ES:DI Dec BX ; reduce right side by one Mov SI,BX ; set source in DS:SI Mov AL,Curr_Col ; find how many words to Mov CL,Max_Right ; right of cursor Sub CL,AL Inc CL ; remove 0 bias Xor CH,CH ; number of bytes in CX Std ; use STD to count down Rep MovSB Cld ; reset flag Mov CX,DX ; restore CX to original value Add_Char1: Mov SI, OFFSET B$TEMPDATA ; get address of buffer in SI Mov AL,Start_Col Mov BL,Curr_Col Sub BL,AL Xor BH,BH Mov DS:[SI+BX],CL Call Near Ptr Show_String Mov AL,Curr_Col Cmp AL,Max_Right JB Add_Char2 Jmp Main Add_Char2: Inc AL ; increment the cursor location Mov Curr_Col,AL Call Near Ptr Mov_Cursor ; move cursor where desired Jmp Main ; start loop again EVEN Mov_Buff_Left Label Near ; moves the buffer left to erase a character or characters Mov BX,OFFSET B$TEMPDATA Mov AL,Start_Col Mov CL,Curr_Col Sub CL,AL Xor CH,CH Add BX,CX Mov DI,BX ; put destination in ES:DI Inc BX Mov SI,BX ; put source in DS:SI Mov CL,Max_Right Mov AL,Curr_Col Sub CL,AL Inc CL ; find how many words to move Rep MovSB Mov BX,Right_Edge ; get right side of buffer Mov AL,ASCII_Space ; put ASCII space in AL Mov DS:[BX],AL ; add ASCII space to end of string Retn END