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Assembly Source File | 1986-10-07 | 12.6 KB | 417 lines

CGROUP GROUP CODE_SEG, DATA_SEG ;Group together two segments ASSUME CS:CGROUP, DS:CGROUP ;-----------------------------------------------------------------------; ; This file contains various procedures that write to the screen: ; ; ; ; WRITE_CHAR Writes a character on the screen ; ; WRITE_CHAR_N_TIMES Writes N copies of one character ; ; WRITE_STRING Writes a string to the screen ; ; WRITE_PATTERN Writes a pattern on the screen ; ; WRITE_HEX_DIGIT Writes a single hexadecimal digit ; ; WRITE_HEX Writes a two-digit hex number ; ; WRITE_DECIMAL Writes a decimal number on the screen ; ; WRITE_ATTRIBUTE_N_TIMES Writes just the attribute to the screen ; ; ; ; WRITE_HEADER Writes the header on the screen ; ; WRITE_PROMPT_LINE Writes the prompt line to the screen ; ; WRITE_EDITOR_PROMPT Displays the editor prompt ; ; WRITE_FUNCTION_KEYS Display the function key line ; ;-----------------------------------------------------------------------; CODE_SEG SEGMENT PUBLIC PUBLIC WRITE_CHAR EXTRN CURSOR_RIGHT:NEAR ;-----------------------------------------------------------------------; ; This procedure outputs a character to the screen using the ROM BIOS ; ; routines so that characters such as backspace, etc., are treated as ; ; any other character and displayed. ; ; This procedure must do a bit of work to update the cursor position. ; ; ; ; DL byte to print on screen. ; ; ; ; Uses: CURSOR_RIGHT ; ;-----------------------------------------------------------------------; WRITE_CHAR PROC NEAR PUSH AX PUSH BX PUSH CX PUSH DX MOV AH,9 ;Call for output of character/attribute MOV BH,0 ;Set to display page 0 MOV CX,1 ;Write only one character MOV AL,DL ;Character to write MOV BL,7 ;Normal attribute INT 10H ;Write character and attribute CALL CURSOR_RIGHT ;Now move the cursor to the next position POP DX POP CX POP BX POP AX RET WRITE_CHAR ENDP PUBLIC WRITE_CHAR_N_TIMES ;-----------------------------------------------------------------------; ; This procedure writes more than one copy of a character ; ; ; ; DL Character code ; ; CX Number of times to write the character ; ; ; ; Uses: WRITE_CHAR ; ;-----------------------------------------------------------------------; WRITE_CHAR_N_TIMES PROC NEAR PUSH CX N_TIMES: CALL WRITE_CHAR ;Write one copy of the character LOOP N_TIMES ;Keep writing for N times POP CX RET WRITE_CHAR_N_TIMES ENDP PUBLIC WRITE_STRING ;-----------------------------------------------------------------------; ; This procedure writes a string of characters to the screen. The ; ; string must end with DB 0 ; ; ; ; DS:DX address of the string ; ; ; ; Uses: WRITE_CHAR ; ;-----------------------------------------------------------------------; WRITE_STRING PROC NEAR PUSH AX PUSH DX PUSH SI PUSHF ;Save direction flag CLD ;Set direction for increment (forward) MOV SI,DX ;Place address into SI for LODSB STRING_LOOP: LODSB ;Get a character into the AL register OR AL,AL ;Have we found the zero yet? JZ END_OF_STRING ;Yes, we are done writing the string MOV DL,AL ;No, write character CALL WRITE_CHAR ;Write the character JMP STRING_LOOP ;Read in the next character END_OF_STRING: POPF ;Restore direction flag POP SI POP DX POP AX RET WRITE_STRING ENDP PUBLIC WRITE_PATTERN ;-----------------------------------------------------------------------; ; This procedure writes a line to the screen, based on data in the ; ; form ; ; ; ; DB {character, number of times to write character}, 0 ; ; Where '{x}' means that x can be repeated any number of times ; ; DS:DX address of above data statement ; ; ; ; Uses: WRITE_CHAR_N_TIMES ; ;-----------------------------------------------------------------------; WRITE_PATTERN PROC NEAR PUSH AX PUSH CX PUSH DX PUSH SI PUSHF ;Save the direction flag CLD ;Set direction flag for increment MOV SI,DX ;Move offset into SI register for LODSB PATTERN_LOOP: LODSB ;Get character data into AL OR AL,AL ;Is it he end of data (0H)? JZ END_PATTERN ;Yes, return MOV DL,AL ;No, set up to write character N times LODSB ;Get the repeat count in AL MOV CL,AL ;And put in CX for WRITE_CHAR_N_TIMES XOR CH,CH ;Zero upper byte of CX CALL WRITE_CHAR_N_TIMES ;Write N copies of this character JMP PATTERN_LOOP ;Get next part of the pattern END_PATTERN: POPF ;Restore direction flag POP SI POP DX POP CX POP AX RET WRITE_PATTERN ENDP PUBLIC WRITE_HEX_DIGIT ;-----------------------------------------------------------------------; ; This procedure converts the lower 4 bits of DL to a hex digit and ; ; writes it to the screen. ; ; ; ; DL Lower 4 bits contain number to be printed in hex. ; ; ; ; Uses: WRITE_CHAR ; ;-----------------------------------------------------------------------; WRITE_HEX_DIGIT PROC NEAR PUSH DX ;Save registers used CMP DL,10 ;Is this nibble <10? JAE HEX_LETTER ;No, convert to a letter ADD DL,"0" ;Yes, convert to a digit JMP SHORT WRITE_DIGIT HEX_LETTER: ADD DL,"A"-10 ;Convert to hex letter WRITE_DIGIT: CALL WRITE_CHAR POP DX ;Restore old value of AX RET WRITE_HEX_DIGIT ENDP PUBLIC WRITE_HEX ;-----------------------------------------------------------------------; ; This procedure converts the byte in the AL register to hex and writes ; ; the two hex digits at the current cursor position. ; ; ; ; DL byte to be converted to hex. ; ; ; ; Uses: WRITE_HEX_DIGIT ; ;-----------------------------------------------------------------------; WRITE_HEX PROC NEAR ;Entry point. PUSH CX ;Save registers used in this procedure PUSH DX MOV DH,DL ;Make a copy of byte MOV CX,4 ;Get the upper nibble in DL SHR DL,CL CALL WRITE_HEX_DIGIT ;Convert the nibble in DL to hex and print MOV DL,DH ;Get lower nibble into DL AND DL,0FH CALL WRITE_HEX_DIGIT POP DX POP CX RET WRITE_HEX ENDP PUBLIC WRITE_DECIMAL ;-----------------------------------------------------------------------; ; This procedure writes a 16-bit, unsigned number in decimal notation. ; ; ; ; DX N : 16-bit, unsigned number ; ; ; ; Uses: WRITE_CHAR, WRITE_HEX_DIGIT ; ;-----------------------------------------------------------------------; WRITE_DECIMAL PROC NEAR PUSH AX ;Save registers used here PUSH CX PUSH DX PUSH SI MOV AX,DX ;Put the number into AX MOV SI,10 ;Will divide by 10 using SI XOR CX,CX ;Count of digits placed on stack NON_ZERO: XOR DX,DX ;Set upper word of N to 0 DIV SI ;Calculate N/10 and (N mod 10) PUSH DX ;Push one digit onto the stack INC CX ;One more digit added OR AX,AX ;N = 0 yet? JNE NON_ZERO ;Nope, continue WRITE_DIGIT_LOOP: POP DX ;Get the digits in reverse order CALL WRITE_HEX_DIGIT ;Write a single digit LOOP WRITE_DIGIT_LOOP ;Get the next digit END_DECIMAL: POP SI POP DX POP CX POP AX RET WRITE_DECIMAL ENDP PUBLIC WRITE_ATTRIBUTE_N_TIMES EXTRN CURSOR_RIGHT:NEAR ;-----------------------------------------------------------------------; ; This procedure sets the attribute for N characters starting at the ; ; current cursor position. ; ; ; ; CX Number of characters to set attribute for ; ; DL New attribute for characters ; ; ; ; Uses: CURSOR_RIGHT ; ;-----------------------------------------------------------------------; WRITE_ATTRIBUTE_N_TIMES PROC NEAR PUSH AX PUSH BX PUSH CX PUSH DX MOV BL,DL ;Set attribute to new attribute XOR BH,BH ;Set display page to zero MOV DX,CX ;CX is used by the BIOS routines MOV CX,1 ;Set attribute for one character ATTR_LOOP: MOV AH,8 ;Read character under cursor INT 10H MOV AH,9 ;Write attribute/character INT 10H CALL CURSOR_RIGHT DEC DX ;Set attribute for N characters? JNZ ATTR_LOOP ;No, continue POP DX POP CX POP BX POP AX RET WRITE_ATTRIBUTE_N_TIMES ENDP PUBLIC WRITE_HEADER DATA_SEG SEGMENT PUBLIC EXTRN HEADER_LINE_NO:BYTE EXTRN HEADER_PART_1:BYTE EXTRN HEADER_PART_2:BYTE EXTRN DISK_DRIVE_NO:BYTE EXTRN CURRENT_SECTOR_NO:WORD EXTRN FILE_FLAG:BYTE EXTRN FILE_HEADER:BYTE EXTRN FILE_NAME:BYTE DATA_SEG ENDS EXTRN GOTO_XY:NEAR, CLEAR_TO_END_OF_LINE:NEAR ;-----------------------------------------------------------------------; ; This procedure writes the header with disk drive and sector number. ; ; ; ; Uses: GOTO_XY, WRITE_STRING, WRITE_CHAR, WRITE_DECIMAL ; ; CLEAR_TO_END_OF_LINE ; ; Reads: HEADER_LINE_NO, HEADER_PART_1, HEADER_PART_2 ; ; DISK_DRIVE_NO, CURRENT_SECTOR_NO, FILE_FLAG ; ; FILE_HEADER, FILE_NAME ; ;-----------------------------------------------------------------------; WRITE_HEADER PROC NEAR PUSH DX XOR DL,DL ;Move cursor to header line number MOV DH,HEADER_LINE_NO CALL GOTO_XY CMP FILE_FLAG,1 ;Are we in file mode? JE WRITE_OFFSET ;Yes, then don't write drive number LEA DX,HEADER_PART_1 ;Display "Disk " CALL WRITE_STRING MOV DL,DISK_DRIVE_NO ;Display the disk drive number ADD DL,'A' ;Print drives A, B, ... CALL WRITE_CHAR WRITE_OFFSET: LEA DX,HEADER_PART_2 ;Display " Sector " CALL WRITE_STRING MOV DX,CURRENT_SECTOR_NO ;Display the sector number CALL WRITE_DECIMAL CMP FILE_FLAG,1 ;Are we in file mode? JNE DONT_WRITE_FILE_HEADER ;No, then don't write the file header LEA DX,FILE_HEADER ;Yes, display the file header CALL WRITE_STRING LEA DX,FILE_NAME ;Write the name of the file CALL WRITE_STRING DONT_WRITE_FILE_HEADER: CALL CLEAR_TO_END_OF_LINE ;Clear rest of sector number POP DX RET WRITE_HEADER ENDP PUBLIC WRITE_PROMPT_LINE EXTRN CLEAR_TO_END_OF_LINE:NEAR EXTRN GOTO_XY:NEAR DATA_SEG SEGMENT PUBLIC EXTRN PROMPT_LINE_NO:BYTE DATA_SEG ENDS ;-----------------------------------------------------------------------; ; This procedure writes the prompt line to the screen and clears the ; ; end of the line. ; ; ; ; DS:DX Address of the prompt-line message ; ; ; ; Uses: WRITE_STRING, CLEAR_TO_END_OF_LINE, GOTO_XY ; ; Reads: PROMPT_LINE_NO ; ;-----------------------------------------------------------------------; WRITE_PROMPT_LINE PROC NEAR PUSH DX XOR DL,DL ;Write the prompt line and MOV DH,PROMPT_LINE_NO ; the cursor there CALL GOTO_XY POP DX CALL WRITE_STRING CALL CLEAR_TO_END_OF_LINE RET WRITE_PROMPT_LINE ENDP PUBLIC WRITE_EDITOR_PROMPT DATA_SEG SEGMENT PUBLIC EXTRN EDITOR_PROMPT:BYTE DATA_SEG ENDS ;-----------------------------------------------------------------------; ; This procedure writes the editor prompt line. We've defined it as ; ; a procedure since we need to switch to the Edit prompt in so many ; ; places. ; ; ; ; Uses: WRITE_PROMPT_LINE ; ; Reads: EDITOR_PROMPT ; ;-----------------------------------------------------------------------; WRITE_EDITOR_PROMPT PROC NEAR PUSH DX LEA DX,EDITOR_PROMPT CALL WRITE_PROMPT_LINE POP DX RET WRITE_EDITOR_PROMPT ENDP DATA_SEG SEGMENT PUBLIC EXTRN FUNCTION_KEY_LINE_NO:BYTE EXTRN FUNCTION_KEY_LINE:BYTE DATA_SEG ENDS EXTRN GOTO_XY:NEAR, CURSOR_RIGHT:NEAR PUBLIC WRITE_FUNCTION_KEYS ;-----------------------------------------------------------------------; ; This procedure writes the function-key line in inverse video, with ; ; the key numbers in normal video. ; ; ; ; Uses: GOTO_XY, WRITE_STRING, WRITE_ATTRIBUTE_N_TIMES ; ; CURSOR_RIGHT ; ; Reads: FUNCTION_KEY_LINE ; ;-----------------------------------------------------------------------; WRITE_FUNCTION_KEYS PROC NEAR PUSH AX PUSH BX PUSH CX PUSH DX XOR DL,DL ;Start a left of screen MOV DH,FUNCTION_KEY_LINE_NO ;And the bottom CALL GOTO_XY PUSH DX ;Save start of line LEA DX,FUNCTION_KEY_LINE CALL WRITE_STRING POP DX ;Restore start of line CALL GOTO_XY ;Return to the start of this line MOV AX,9 ;Use as a counter MOV DL,70H ;Attribute for inverse video MOV CX,6 ;Write 6 characters in inverse FUNCTION_KEY_LOOP: CALL CURSOR_RIGHT ;Skip over the number CALL WRITE_ATTRIBUTE_N_TIMES ;Write inverse video for 6 characters CALL CURSOR_RIGHT ;Skip gap DEC AX ;Done yet? JNZ FUNCTION_KEY_LOOP ;No, invert another word CALL CURSOR_RIGHT ;Skip the last gap CALL WRITE_ATTRIBUTE_N_TIMES ;Invert the 10th word POP DX POP CX POP BX POP AX RET WRITE_FUNCTION_KEYS ENDP CODE_SEG ENDS END