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Night Owl 6
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Night Owl's Shareware - PDSI-006 - Night Owl Corp (1990).iso
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034a
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prons.zip
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PRONS.ASM
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Assembly Source File
|
1991-11-01
|
14KB
|
480 lines
page 66,132
;
; Copyright 1987, 1989 Samuel H. Smith; All rights reserved
;
; This is a component of the ProDoor System.
; Do not distribute modified versions without my permission.
; Do not remove or alter this notice or any other copyright notice.
; If you use this in your own program you must distribute source code.
; Do not use any of this in a commercial product.
;
; ---------------------------------------------------------------------------
; PRONS - NoScroll -
; keep the top half of the screen from scrolling away
; used by ProDOOR during file transfers. it also preserves
; COM port interrupt vectors and will drop carrier after
; a specified number of clock ticks.
;
; This program works under TaskView and other environments that do
; not pass DOS or ANSI outputs to BIOS.
;
; Written: 30-dec-87 (rev. 20-jan-89)
;
; ---------------------------------------------------------------------------
; Macros
;
; set interrupt vector to ds:dx
setdsdx macro vect,src
mov ah,25h
mov al,vect
int 21h
endm
; store vector into dword
getesbx macro vect,dest
mov ah,35h
mov al,vect
int 21h ;changes es
endm
; ---------------------------------------------------------------------------
;
code segment
assume cs:code,ds:nothing,es:nothing,ss:nothing
org 80h
tailLength db ?
tail db ?
org 100h
entryPoint: jmp startup
; ---------------------------------------------------------------------------
; Working storage
;
copyright db 13,10,'ProNS (C) 1988-1991 S.H.Smith; v3.4 11-01-91'
db 13,10,26
old10Vector dd 0 ;chain to original video handler
retp3 dd 0 ;return-to-user pointer, videoTTY
old21Vector dd 0 ;chain to original dos handler
retp2 dd 0 ;return-to-user pointer, dosWrite
retp1 dd 0 ;return-to-user pointer, dosConOut
lastLine db 24 ;last line of screen (0=first)
splitLine db 3 ;18 ;line where the screen is split
;(lastLine-scrollLines-1)
scrollLines db 0 ;lines in scrolling region
defaltLines = 23 ;default lines in scrolling region
scrollColor = 7 ;display attrib in scrolling region
; ---------------------------------------------------------------------------
; New handler for video interrupts
new10: cmp ah,14
jz videoTTY
cmp ah,6
jz videoScroll
; cmp ah,2
; jz videoSetPos
useOld10: jmp old10Vector ;chain to other interrupts
; ---------------------------------------------------------------------------
; we have a set cursor position request; clip it to the scrolling area only
; (just let this happen; makes PCKERMIT and others look better)
;
;videoSetPos: cmp dh,splitLine
; jge useOld10
;
; mov dh,splitLine
; jmp useOld10
; ---------------------------------------------------------------------------
; we have a scroll request; clip it to the scrolling area only
;
videoScroll: cmp ch,splitLine
jge useOld10
mov ch,splitLine
jmp useOld10
; --------------------------------------------------------------------------
; process video TTY calls
;
videoTTY: cmp al,10 ;linefeed?
jnz useOld10
; ---------------------------------------------------------------------------
; we have a linefeed request; if it will cause scrolling,
; make sure the fixed lines stay where they are
;
videoLineFeed: push ax
push bx
push cx
push dx
push ds
push es
push si
push di
mov ah,3 ;get cursor position
mov bh,0
int 10h
cmp dh,lastLine
jz vTrapScroll
;
; won't cause scroll, restore environ and pass back to bios
;
pop di
pop si
pop es
pop ds
pop dx
pop cx
pop bx
pop ax
jmp useOld10
;
; the linefeed will cause scroll - scroll manually instead
;
vTrapScroll: mov ah,6 ;scroll up
mov al,1 ;lines=1
mov bh,scrollColor
mov cl,0
mov ch,splitLine ;top-left of scroll region
mov dl,79
mov dh,lastLine ;bottom-right of scroll region
int 10h
pop di
pop si
pop es
pop ds
pop dx
pop cx
pop bx
pop ax
pop word ptr retp3 ;return to user code
pop word ptr retp3+2
popf
clc
jmp retp3
; ===========================================================================
; New handler for dos interrupts
new21: cmp ah,2
jz dosConOut
cmp ah,40h
jz dosWrite
useOld21: jmp old21Vector ;chain to other interrupts
; ===========================================================================
; we have a write to file handle-1 request. change it into repeated
; calls to dosConOut so linefeeds will be trapped
;
dosWrite: cmp bx,1 ;stdout
jz trapWrite
cmp bx,2 ;stderr
jz trapWrite
jmp useOld21
trapWrite: pop word ptr retp2 ;pointer to user code
pop word ptr retp2+2
popf
push bx
push cx
push dx
push ds
mov bx,dx
writeChar: cmp cx,0
jz endWrite
push bx
push cx
mov dl,[bx]
mov ah,2 ;use dos dosConOut function
int 21h ;on each char in the buffer
pop cx
pop bx
inc bx
dec cx
jmp writeChar
endWrite: pop ds
pop dx
pop cx
pop bx
mov ax,cx ;return as though all bytes written
clc
jmp retp2
; ===========================================================================
; process console output calls
;
dosConOut: cmp dl,10 ;linefeed?
jnz useOld21
; ---------------------------------------------------------------------------
; we have a linefeed request; if it will cause scrolling,
; make sure the fixed lines stay where they are
;
dosLineFeed: push ax
push bx
push cx
push dx
push ds
push es
push si
push di
mov ah,3 ;get cursor position
mov bh,0
int 10h
cmp dh,lastLine
jz dTrapScroll
;
; won't cause scroll, restore environ and pass back to dos
;
pop di
pop si
pop es
pop ds
pop dx
pop cx
pop bx
pop ax
jmp useOld21
;
; the linefeed will cause scroll - scroll manually instead
;
dTrapScroll: mov ah,6 ;scroll up
mov al,1 ;lines=1
mov bh,scrollColor
mov cl,0
mov ch,splitLine ;top-left of scroll region
mov dl,79
mov dh,lastLine ;bottom-right of scroll region
int 10h
pop di
pop si
pop es
pop ds
pop dx
pop cx
pop bx
pop ax
pop word ptr retp1 ;return to user code
pop word ptr retp1+2
popf
clc
jmp retp1
; ===========================================================================
; startup entry point
; is noScroll already in memory?
;
startup: getesbx 10h ;es:bx <- original cs
mov bx,offset copyright
checkPresent: mov al,cs:[bx] ;get next byte from copyright message
cmp al,26 ;end of message?
jz unInstall ;already present if so
cmp al,es:[bx] ;compare next byte to handler in chain
jz checkNext
jmp newInstall ;new installation if mismatch
checkNext: inc bx ;got a match, try the next char
jmp checkPresent
; ---------------------------------------------------------------------------
; already in memory - uninstall and exit
;
assume ds:nothing
unInstall:
lds dx,es:old10Vector
setdsdx 10h
lds dx,es:old21Vector
setdsdx 21h
;
; deAllocate the memory used by ProNS
;
push es
mov es,es:2ch ;dealloc the tsr's environment segment
mov ah,49h
int 21h
pop es ;dealloc the tsr's code segment
mov ah,49h
int 21h
mov ax,4ch ;terminate process
int 21h
; ---------------------------------------------------------------------------
; install noScroll
;
newInstall:
xor ch,ch
mov cl,tailLength
lea si,tail
nextTail:
jcxz checkEga
lodsb
dec cx
cmp al,'0'
jl nextTail
cmp al,'9'
jg nextTail
sub al,'0'
mov ah,scrollLines
add ah,ah ;*2
add ah,ah ;*4
add ah,scrollLines ;*5
add ah,ah ;*10
add al,ah
mov scrollLines,al
jmp nextTail
checkEga:
mov ax,40h
mov es,ax ;is ega present and active?
test byte ptr es:[87h],8
jnz notEga
mov ax,01130h
xor bx,bx ;get last screen line
mov dl,lastLine ;default to normal setting
int 10h
mov lastLine,dl
notEga:
;verify that scrollLines is in range, use default if not
mov ah,scrollLines
cmp ah,lastLine
jg defaultScroll
cmp ah,2
jle defaultScroll
jmp scrollOK
defaultScroll:
mov ah,defaltLines
scrollOK:
mov scrollLines,ah
mov al,lastLine
sub al,ah
inc al
mov splitLine,al
getesbx 10h
mov word ptr [old10Vector+0],bx
mov word ptr [old10Vector+2],es
getesbx 21h
mov word ptr [old21Vector+0],bx
mov word ptr [old21Vector+2],es
;
; prepare screen
; make sure the original cursor is below the split line
;
prepare_scr: mov ah,2 ;linefeed once
mov dl,10
int 21h
mov ah,3 ;get cursor position
mov bh,0
int 10h
cmp dh,splitLine
jl prepare_scr
;
; make sure the original cursor line is above the split line
;
xor ch,ch
mov cl,scrollLines
dec cl
dec cl
moveDown: mov ah,2
mov dl,10
push cx
int 21h
pop cx
loop moveDown
mov ah,2 ;set cursor position
mov bh,0
mov dh,splitLine
mov dl,0
int 10h
;
; vector in the new handler
;
assume ds:code
push cs
pop ds
mov dx,offset new10
setdsdx 10h
mov dx,offset new21
setdsdx 21h
mov dx,offset startup ;last resident byte
int 27h ;terminate and stay resident
code ends
end entryPoint
