Source Code 1992 March/Source_Code_CD-ROM_Walnut_Creek_March_1992.iso/msdos/asmutl/a86cnvrt.arc/S2.8

Text File | 1987-05-24 | 19KB | 523 lines

  jmp initialize               ; goto initialization routine

interrupts    EQU 0h           ; interrupt table segment
keyboard_int  EQU (9*4) W      ; interrupt 9 vector

rom_bios_data EQU 40h          ; ROM BIOS data area segment
cursor_mode   EQU W[60H]       ; starting and ending cursor scan lines

rom           EQU 0F000h       ; ROM segment
machine_id    EQU B[0FFFEh]    ; ID byte identifies machine as PCjr or other

 db '(C) Copyright 1986, Ziff-Davis Publishing Company ', 1Ah

column_count  dw ?             ; width of window in columns
cursor_type   dw ?             ; cursor scan line definition
setup_status  db 0             ; indicates if printer window is already active
display_mode  dw ?             ; current crt display mode
page_no       dw ?             ; current displayed page
attribute1    db 4Fh           ; window attribute bytes
attribute2    db 70h

display_table db 2Dh,29h       ; display re-enable values for modes 2 and 3
video         dw 0B800h,0B900h,0BA00h,0BB00h     ; starting addresses of video
                                                 ; memory for CGA pages 0 - 3

mono_video    dw 0B000h        ; video segment address for
                               ; monochrome adapter

old_kb_int    DD
old_keyboard_int        dw 2 dup (?)             ; storage for old keyboard
                                                 ; interrupt vector


; Text of the Printer Setup Menu window.
; After initialization, text and attribute bytes are combined and stored
; in the WINDOW_TEXT area, and this area is used to store the contents of
; the screen that underlie the window when the window is called up.

window_buffer   DW
buffer_text:
  db 201,26 dup (205),187
  db 186,'    PRINTER SETUP MENU    ',186
  db 186,'   EPSON RX/FX PRINTERS   ',186
  db 199,26 dup (196),182
  db 186,' F1    Compressed Mode    ',186
  db 186,' F2    Expanded Mode      ',186
  db 186,' F3    Emphasized Mode    ',186
  db 186,' F4    Double-Strike Mode ',186
  db 186,' F5    Elite Mode         ',186
  db 186,' F6    Miniature Mode     ',186
  db 186,' F7    Skip Perforation   ',186
  db 186,' F8    Indent Left Margin ',186
  db 186,' F9    Reset Top-of-Form  ',186
  db 186,' F10   Reset Print Modes  ',186
  db 186,' ESC   Exit               ',186
  db 199,26 dup (196),182
  db 186,' Unshifted:   Toggle ON   ',186
  db 186,' Shifted:     Toggle OFF  ',186
  db 200,26 dup (205),188
  db 532 dup (?)

; Storage area for the combination of text and attribute bytes that
; form the window image.

window_bytes  label byte
window_text   dw 532 dup (?)

; Control code strings for all of the printer setup options.

code_table:
  db 15,255,14 dup (0)                 ; compressed mode on
  db 27,87,1,255,12 dup (0)            ; expanded mode on
  db 27,69,255,13 dup (0)              ; emphasized mode on
  db 27,71,255,13 dup (0)              ; double-strike mode on
  db 27,77,255,13 dup (0)              ; elite mode on
  db 15,27,83,0,27,65,6,255,8 dup (0)  ; miniature mode on
  db 27,78,12,255,12 dup (0)           ; perfskip on
  db 27,108,10,255,12 dup (0)          ; indent left margin
  db 27,67,66,255,12 dup (0)                         ; reset top-of-form
  db 18,27,87,0,27,70,27,72,27,80,27,84,27,50,255,0  ; reset print modes
  db 18,255,14 dup (0)                               ; compress off
  db 27,87,0,255,12 dup (0)            ; expand off
  db 27,70,255,13 dup (0)              ; emphasize off
  db 27,72,255,13 dup (0)              ; double-strike off
  db 27,80,255,13 dup (0)              ; elite off
  db 18,27,84,27,50,255,10 dup (0)     ; miniature off
  db 27,79,255,13 dup (0)              ; perfskip off
  db 27,108,0,255,12 dup (0)           ; indent off



; Execution comes here, to the main body of the program, when an interrupt 9
; is generated from the keyboard. Registers are saved, then the keypress is
; checked and compared to the key combination that activates the menu window.

main:
  sti                       ; enable software interrupts
  push ax,bx,cx,dx,si,di    ; save all registers
  push ds,es
  push ax                   ; save ax for call to old routine
  in al,0A0h                ; re-enable NMI on PCjr
  pop ax                    ; restore ax
  pushf                     ; simulate interrupt call to old keyboard routine
  CS call old_kb_int        ; call old routine
  mov ah,2                  ; check status of the shift keys
  int 16h
  and al,5                  ; Ctrl and Rt-Shift depressed?
  cmp al,5
  je >L1                    ; yes, then skip exit routine
EXIT:                       ;  common exit point
  pop es,ds
  pop di,si,dx,cx,bx,ax
  iret

; Execution comes here when the proper key combination, Ctrl/Rt-Shift, is
; pressed. First task is to check whether or not the window is already open.

L1:
  MOV DS,ES,CS           ;  set es and ds to the code segment
  cmp setup_status,0     ; is the window already open?
  jne exit               ; yes, then ignore request

; Check current video mode. If it's mode 2, 3, or 7, then set the window
; status flag, store the mode number and page number, save the cursor type,
; and hide the cursor. If any other display mode is active instead, ignore
; the request and exit.

  mov ah,15            ; get page and mode numbers
  int 10h              ; al=mode, bh=page
  cmp al,2             ; is crt now in an acceptable mode?
  je >L0               ; yes, then continue
  cmp al,3
  je >L0
  cmp al,7
  je >L0
  jmp exit

L0:
  mov setup_status,1      ; set status flag to indicate that window is active
  mov ah,0                ; save mode number
  mov display_mode,ax
  push bx
  mov bl,bh               ; save page number for color displays
  mov bh,0
  mov page_no,bx
  pop bx
  mov ah,3                ; get cursor type
  int 10h
  mov cursor_type,cx      ; save it
  mov ah,1                ; hide the cursor until later
  mov ch,20h
  int 10h

; Preparatory routines are completed. Now open the window by first saving the
; contents of video memory beneath the window and then writing the window text
; directly to memory.

  mov bx,page_no           ; use bx as index into video segment address table
  cmp display_mode,7       ; manually adjust index for monochrome adapter
  IF E mov bx,4
  shl bx,1                 ; multiply bx by two since table is made up of words
  mov ax,video[bx]         ; read segment from table
  mov ds,ax                ; ds set to video memory
  CS cmp display_mode,7    ; skip disable if in mode 7
  IF NE call video_disable ; turn display off for snow-free writing
  lea di,window_buffer     ; set di to buffer area to save screen contents
  mov ch,28                ; define window dimensions and location
  mov cl,19
  mov dh,2
  mov dl,26
  call video2mem           ; then transfer screen contents to buffer
  MOV ES,DS                ; set es to video memory
  MOV DS,CS                ; reset ds to code segment
  lea si,window_text       ; point si to window image
  mov ch,28                ; define window region
  mov cl,19
  mov dh,2
  mov dl,26
  call mem2video           ; and write the window to the display
  cmp display_mode,7       ; skip enable if in mode 7
  IF NE call video_enable  ; re-enable the video display

; Window is now present on the screen, so wait for a keypress.

getkey:
  mov ah,0                 ; get a keypress
  int 16h
  cmp al,0                 ; is it an extended code?
  je extended_code         ; yes, go interpret it
  cmp al,27                ; is it the ESC key?
  jne getkey1              ; no, then signal illegal keypress



; Execution comes here when the ESC key is pressed. The window is refilled
; with its original contents, the cursor is restored, and control is handed
; back to the application program.

  cmp display_mode,7       ; skip disable if in mode 7
  IF NE call video_disable ; turn off the display
  lea si,window_buffer     ; point si to the buffer area
  mov ch,28                ; define the window
  mov cl,19
  mov dh,2
  mov dl,26
  call mem2video           ; and write the buffer contents to the display
  cmp display_mode,7       ; skip enable if in mode 7
  IF NE call video_enable  ; turn display back on
  mov ah,1                 ; restore cursor
  mov cx,cursor_type
  int 10h
  mov setup_status,0       ; reset window status
  jmp exit                 ; and exit

; Getkey1 routine handles an illegal keypress by beeping and returning
; for another.

getkey1:
  call beep                ; beep and return for another keypress
  jmp getkey

; An extended code has been entered...check its validity and goto the
; appropriate routine.

extended_code:
  cmp ah,59                ; less than F1?
  jb getkey1               ; yes, then don't accept it
  cmp ah,91                ; greater than Shft-F8?
  ja getkey1               ; yes, then don't accept it
  cmp ah,68                ; between F1 and F10?
  jbe unshifted            ; yes
  cmp ah,84                ; between Shft-F1 and Shft-F9?
  jae shifted              ; yes
  jmp getkey1              ; if all tests failed, then keypress was illegal



; If a legal function key was pressed, its scan code is translated here to the
; starting address of the string of bytes to be sent to the printer. The
; string is then sent to LPT1: provided it's powered on and on-line.

shifted:
  sub ah,15                ; adjustment for shifted function keys
unshifted:
  sub ah,59                ; adjustment for unshifted function keys
  mov al,ah                ; convert index to word in ax
  xor ah,ah
  mov cl,4                 ; multiply ax by 16
  shl ax,cl
  add ax,code_table        ; convert ax to full offset address
  mov si,ax                ; and transfer it to si
  call lpt1stat            ; check for printer ready
  jc getkey1               ; beep if printer not ready
  mov bl,255               ; specify delimiter for call to LPRINTZ
  call lprintz             ; send control code string to printer
  jmp getkey               ; return for another keypress



; VIDEO_ENABLE and VIDEO_DISABLE routines manipulate bit 3 of port 3D8h,
; the CGA Mode Control Register, to temporarily turn the display on or off.
; Since these routines write directly to hardware, they have no effect on
; other video adapters.

video_disable:
  mov dx,3DAh              ; read CGA status port
L1:
  in al,dx                 ; wait for vertical retrace to occur
  test al,8                ; is bit 3 set?
  je L1                    ; no, wait until it is
  mov dx,3D8h              ; now disable the display
  mov al,25h               ; by clearing bit 3 of the Mode Control Register
  out dx,al
  ret

video_enable:
  mov dx,3D8h              ; CGA Mode Control Register
  mov bx,display_mode      ; get value to re-enable display
  sub bx,2
  mov al,display_table[bx]
  out dx,al                ; and send it to the port
  ret



; VIDEO2MEM routine transfers the contents of a portion of video memory
; to a memory buffer for storage.
; Entry:      DS    - video segment
;             ES:DI - memory buffer
;             DH,DL - row and column of upper left corner of window
;             CH    - width of window in columns
;             CL    - number of lines in window

video2mem:
  mov al,ch                ; store number of columns
  mov ah,0
  mov column_count,ax
  mov ch,0                 ; cx = number of lines
  push di                  ; save di
  call video_offset        ; get cell address of first character
  mov si,di                ; put it in si
  pop di                   ; restore di
L1:
  push si,cx               ; save next line pointer and line count
  mov cx,column_count      ; set cx for call to WRITELN
  call writeln             ; transfer one line
  pop cx,si                ; restore saved registers
  add si,160               ; set si for next line address
  loop L1                  ; loop until all lines are done
  ret



; MEM2VIDEO writes a selected area of memory to the video display.
; Entry:      DS:SI - memory buffer
;             ES    - video segment
;             DH,DL - row and column of upper left corner of window
;             CH    - width of window in columns
;             CL    - number of lines in window

mem2video:
  mov al,ch                ; save number of columns
  mov ah,0
  mov column_count,ax
  mov ch,0                 ; cx = number of lines
  call video_offset        ; get offset into video memory
L1:
  push di,cx               ; save video starting address and line count
  mov cx,column_count      ; set cx for call to WRITELN
  call writeln             ; transfer one line
  pop cx,di                ; restore registers
  add di,160               ; set di for next display line
  loop L1                  ; loop until done
  ret



; VIDEO_OFFSET calculates the offset into video memory of a character cell.
; Entry:      DH,DL - row and column of cell (0-24,0-79)
; Exit:       DI    - offset address

video_offset:
  mov al,160
  mul dh                   ; row * 160
  shl dl,1                 ; column * 2
  mov dh,0                 ; byte to word
  add ax,dx                ; (row *160)+(column*2)
  mov di,ax                ; set offset in di
  ret



; WRITELN subroutine copies a string of words from one memory location to
; another. The CGA status port is not checked for vertical retrace status
; before transfer.
; Entry:      DS:SI - source
;             ES:DI - destination
;             CX    - number of words

writeln:
  cld                      ; clear for string instructions
L1:
  movsw                    ; move one word
  loop L1                  ; loop until done
  ret



; LPRINTZ routine sends a string of bytes delimited by a user-specified byte to
; LPT1: thru INT 17h.
; Entry:       DS:SI - string address
;              BL    - delimiter (0-255)

lprintz:
  cld                      ; for 8088 string instructions
L1:
  lodsb                    ; get one byte
  cmp al,bl                ; is it the delimiter?
  je RET                   ; yes, then exit
  mov dx,0                 ; printer no. 0 (LPT1:)
  mov ah,0
  int 17h                  ; send byte to printer
  jmp L1                   ; return for next byte

  ret



; LPT1STAT checks the current status of printer LPT1:.  If it's either
; powered off or off-line, then an error condition is signalled upon return
; thru the carry flag.
; Exit:        Carry clear - no error
;              Carry set   - error

lpt1stat:
  mov dx,0                 ; printer no. 0
  mov ah,2                 ; use ROM BIOS 'get status' function
  int 17h
  test ah,8                ; test bit 3, I/O error indicator
  je >L1                   ; if clear, then no error
  stc                      ; raise error flag
  ret

L1:
  clc                      ; clear error flag
  ret



; BEEP uses the 8253 timer chip to emit a short beep thru the PC's speaker.

beep:
  mov al,182               ; notify 8253 that frequency data is coming
  out 67,al
  mov al,0                 ; send frequency (776.8 Hz)
  out 66,al
  mov al,6
  out 66,al
  in al,97                 ; activate speaker
  or al,3
  out 97,al
  mov cx,6000h             ; time delay for sound duration
L1:
  loop L1
  in al,97                 ; deactivate speaker
  and al,252
  out 97,al
  ret



; MEM2MEM subroutine transfers a non-overlapping block of memory one byte
; at a time.
; Entry:       DS:SI - source
;              ES:DI - destination
;              CX    - number of bytes

mem2mem:
  cld
L1:
  movsb                    ; transfer one byte
  loop L1                  ; and loop until done
  ret



; Initialization routine sets up the window image in the WINDOW_TEXT area,
; resets the CURSOR_MODE word if this is a PCjr, and saves and replaces the
; old keyboard interrupt vector.

initialize:

; Initialize the window text area by combining the text data with the attribute
; bytes and placing the conglomeration in the WINDOW_TEXT area.

  mov ah,15            ; check the current video mode
  int 10h
  cmp al,7             ; if it's mode 7, then replace the attribute
  jne >L0              ; bytes with ones appropriate for mono adapter
  mov attribute1,70h
  mov attribute2,07h
L0:
  cld                  ; now combine the text and attribute bytes
  lea si,buffer_text   ; point si to table of text
  lea di,window_bytes  ; and di to storage area
  mov cx,112           ; create first four lines by combining
  mov al,attribute1    ; text with attribute1 (112 words)
L1:
  movsb                ; text byte
  stosb                ; attribute byte
  loop L1              ; loop until all 112 words are done
  mov cx,11            ; now do the next 11 lines
L2:
  push cx              ; first attribute in each line is attribute1
  movsb
  stosb
  mov cx,26            ; next 26 attributes are attribute2
  mov al,attribute2
L3:
  movsb
  stosb
  loop L3
  movsb
  mov al,attribute1    ; and the last in each line is attribute1
  stosb
  pop cx
  loop L2              ; loop until all 11 lines are done
  mov cx,112           ; create the last four lines just like
L4:
  movsb                ; the first four
  stosb
  loop L4

; Check the machine ID byte in ROM and if this is a PCjr, then reset the
; cursor and correct the CURSOR_MODE word at 0040:0060.

  mov ax,rom            ; set ds to rom
  mov ds,ax
  cmp machine_id,0FDh   ; is this a PCjr?
  jne >L5               ; no, then skip this routine
  mov ax,rom_bios_data  ; set ds to ROM BIOS data area
  mov ds,ax
  mov cursor_mode,0607h ; reset the cursor mode indicator
  mov ah,1              ; then physically reset the cursor
  mov cx,0607h
  int 10h

; Now save the old keyboard interrupt vector and replace it with the new one.

L5:
  mov ax,interrupts             ; set ds to the interrupt vector area
  mov ds,ax
  mov ax,keyboard_int           ; save old vector
  CS mov old_keyboard_int,ax
  mov ax,keyboard_int[2]
  CS mov old_keyboard_int[2],ax
  cli                           ; disable all interrupts but NMI
  mov keyboard_int,main         ; and install new vector
  mov keyboard_int[2],cs
  sti                           ; re-enable interrupts
  mov dx,initialize             ; point dx to end of resident section
  int 27h                       ; terminate-but-stay-resident