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Simtel MSDOS 1993 May
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SIMTEL_0593.ISO
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msdos
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screen
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scrncolr.asm
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Assembly Source File
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1986-07-16
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10KB
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254 lines
16-Jul-86 14:08:30-PDT,9473;000000000001
Return-Path: <SY.FDC@CU20B.COLUMBIA.EDU>
Received: FROM CU20B.COLUMBIA.EDU BY B.ISI.EDU WITH TCP ; 16 Jul 86 14:04:53 PDT
Date: Wed 16 Jul 86 15:41:15-EDT
From: Frank da Cruz <SY.FDC@CU20B.COLUMBIA.EDU>
Subject: SCRNCOLR.ASM
To: info-ibmpc@B.ISI.EDU
Message-ID: <12223203329.166.SY.FDC@CU20B.COLUMBIA.EDU>
Here's a version of SCRNCOLR.ASM that, unlike the version in your library,
will assemble and run.
page 64,132
title scrncolr - Change display screen from white to color attrib
.radix 10
;***************************************************************
; Adapted from "SCREEN.ASM" by H. Fischer - HFischer@eclb 12/83
; SCREEN was Typed in by Glass - gjg@cmu-cs-cad from Byte Nov. 1983
;
; NOTE: only meaningful with color card, and does not look at
; keyboard (which makes it easywriter, etc. compatible)
;
; To build this program:
; 1> masm scrncolr; /* assemble the code */
; 2> link scrncolr; /* link it - will get no stack seg. message */
; 3> exe2bin scrncolr.exe scrncolr.com /* make executable */
; 4> del scrncolr.exe /* don't need this anymore */
;
; To use program: run it or place in autoexec.bat as follows:
;
; scrncolr nn rr
;
; where nn are screen attributes to replace
; normal white (attr=07h) video, and rr are
; attributes for reversed white (attr=70h)
; (intensity and blink are preserved).
;
; for example, to change calls for white to white on blue
; and to change calls for reverse white to magenta on white,
; issue the call: "scrncolr 17 75"
;
; Only 80x25 screen calls are affected and only in text mode,
; (this makes it LOGO and APL compatible)
;
; COMMANDS:
; none -- you reassemble to change the color assignment
;***************************************************************
;
; Define interrupt vectors for
; screen interrupt 10H, in segment 0.
;
;***************************************************************
scrvect segment at 0 ; define screen interrupt vector
org 10h*4
SCRINT label word ; fixed. was dword. [jrd]
scrvect ends
;***************************************************************
;
; define constants
;
;***************************************************************
bw_val equ 07h ; standard b&w attibute sent to monitor
;***************************************************************
;
; start code area
;
;***************************************************************
code segment para
assume cs:code
org 82h ; parameters
PARM label word ; normal & rev attribs "nn rr"
org 100h ; start code offset 100h from starting segment
; (this leaves room for DOS's work areas)
KEY proc far
START:
; Initialization code...used only once, on system startup
jmp init_code ; call initialization routine
even
validchk db 'FCP!' ; used by INSTALL to check for valid SCREEN
; program
;***************************************************************
;
; SCR_RTNE - Replaces SCREEN interrupt so that it can intercept
; B&W character writes and change attributes
;
;***************************************************************
SCR_RTNE:
assume ds:code
sti
push ds ; get cs into ds the funny way
push cs
pop ds
cmp ah,0 ; Spot mode change call
jne NOT_MODE
mov savemod,al ; Save mode input
NOT_MODE:
cmp ah,6 ; Spot SCROLL UP and SCROLL DOWN calls
jl NORMAL_SCR ;
push ax ; check if in 80x25 modes
mov al,savemod
cmp al,2
pop ax
jl NORMAL_SCR ; no-ignore attribs (keep LOGO straight)
push ax ; check if in 80x25 modes
mov al,savemod
cmp al,3
pop ax
jg NORMAL_SCR ; no-ignore attribs (keep LOGO straight)
cmp ah,6
jg NOT_SCROLL ;
SCROLL:
call GET_CH ; for scrolling, update attribute
jmp NORMAL_SCR ; now, execute scroll
NOT_SCROLL:
cmp ah,9 ; check for "WRITE ATTRIBUTE/CHAR" cmd
jne NORMAL_SCR ; send out any other command as normal
xchg bh,bl ; get attribute for command
call GET_CH ; update attribute for command
xchg bh,bl ; move attribute back to bh for cmd
NORMAL_SCR:
pop ds ; restore ds reg
;
; NOTE: We are now ready to invoke the BIOS screen interrupt.
; Since the ROM code includes an IRET interrupt return call,
; all we need to do is to jump to the start of the ROM code
; and all will be well. Since the initialization code set
; up the address to the screen interrupt code below, we can
; set up a forced jump to that address.
JMP_SCR: ; Address to SCREEN interrupt
db 0EAh ; force a FAR JMP but do not set up dest-
dw 0,0 ; ination address at assembly time.
; (INIT routine will set this address)
savemod db 3 ; default to 80x24 color mode
KEY endp ;done with main routine
;***************************************************************
;
; GET_CH - subroutine replaces B&W character with current replacement
; attributes and allows for intensity bit setting
;
; Inputs : bh contains attribute to be modified
;
;***************************************************************
GET_CH proc near
mov savech,bh ; save character
and bh,77h ; Remove intensity and blink bits
cmp bh,07h ; see if currently defined B&W value
jne ISITREV ; exit if not
mov bh,savech ; otherwise, modify to current attribute
and bh,88h ; get rid of B&W part
or bh,normvid ; move in current attribute part
jmp OUT
ISITREV:
cmp bh,70h ; see if currently defined W&B value
mov bh,savech ; otherwise, modify to current attribute
jne OUT
and bh,88h
or bh,revrvid
OUT:
ret ; done
savech db 0 ; temporary character store
normvid db 05h ; replacement for white norml video
revrvid db 50h ; replacement for reverse white video
GET_CH endp
LASTONE: ; all code after this label is freed to DOS use after
; initialization of the program.
;***************************************************************
;
; INIT_CODE - Code to load and initialize the SCREEN program..
; sets up DOS to keep all code before "LASTONE" label
; safe from overlaying during system operation.
;
;***************************************************************
INIT_CODE proc near
; initialize SCREEN intercept code
assume es:scrvect ;'vectors' is interrupt segment 0
mov ax,scrvect ; get address to interrupt vector
mov es,ax ; save in es
mov ax,es:scrint ; get address to interrupt
mov bx,offset jmp_scr+1 ; address to place to save vector
mov [bx],ax ; save interrupt address
mov ax,es:scrint[2] ; get interrupt segment for rtne
mov [bx+2],ax ; save it too
mov es:scrint,offset scr_rtne ; now replace with own address
mov ax,cs ; save segment in interrupt vector
mov es:scrint[2],ax ;
mov ax,cs ; make parameters for color
mov ds,ax ; addressable
mov dx,PARM
test dx,0040h ; fix hex a-f
jz IT2
sub dx,0007h
IT2: test dx,4000h
jz IT3
sub dx,0700h
IT3:
and dx,0f0fh ; strip and jamb nibbles
mov cl,4
shl dl,cl
or dh,dl
mov normvid,dh ; save parameter
mov dx,PARM+3
test dx,0040h ; fix hex a-f
jz IT4
sub dx,0007h
IT4: test dx,4000h
jz IT5
sub dx,0700h
IT5:
and dx,0f0fh
mov cl,4
shl dl,cl
or dh,dl
mov revrvid,dh
mov dx,offset lastone ; save all code up to "LASTONE" label
int 27h ; no return needed
INIT_CODE endp
code ends
end start
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