Topic "How is it done?" No 2
Eliseev
Monitor command-line IS-DOS
and restart the line editor # 6E smbgt
Hello, dear readers ZX
Format! I hope that those of you who have decided to try their
hand at programming in the IS-DOS, it was interesting to read
about the internal structure of system Utilities gmen.com, the
work described in the first issue.
Today we continue the study of
restarts IS-DOS, so to speak, to live
examples we consider in general terms the use of the restart
line editor # 6E smbgt the example of the utility mon.com.
Utility mon.com well known to each user IS-DOS, because
with the help of organized dialogue with the user system and
introduces all the basic commands. It allows you to take the
keyboard and edit the text input commands and
pressing ENTER sends his system, causing the performance of the
command specified in text. To enter and edit text command is
used to monitor restart # 6E smbgt, which is a functionally
complete unit string editor, with a maximum of string
256 bytes. Consider the text of the program:
;****************************************
; Example of string
; Editor IS-DOS # 6E smbgt
; Monitor command line mon.com
; Source code with comments
ORG # 5D64
;****************************************
, The beginning of the program, the finding by
; Restart # 45 g_com buffer address coma; ne line - a special
area of memory; Tee, which is used to send commands ; System
and putting it on the stack
START LD C, # 45; definition addresses
RST # 10; buffer command
EXX; line (HL)
PUSH HL; address - stack
;****************************************
, Initialize the program, preparation of the working window,
buffer, etc.
; Routine cleaning of the buffer
CLBUF LD B, # 7F; buffer length
CLBUF1 LD (HL), # 20; initialization
INC HL; buffer
DJNZ CLBUF1; command line
, Opens a window to the editor
; Pre-determined according to the contents; Therefore, system
variables, the current color , So that the window does not
stand out and ; Put them into the vector window.
LD IX, WIND; address vector window
; Editor
LD C, # 72; determine the address
RST # 10; vector screen
EXX; (in HL)
LD A, (HL); consider color
; The current screen
LD (IX +4), A; enter the current
; Color vector
; Editor
, Draw a box
LD C, # 61; initialization window
RST # 10
; Initialize pointer
CURINI SBC HL, HL; zeroing HL
LD C, # 6B; installation
RST # 10; cursor coordinates
POP HL; in HL - Address
; Buffer command
; Line
;****************************************
, Entering and editing commands
, Sets the parameters for the editor - width
The windows and byte of the state - and vyzy; Vai Editor
LD A, # 2A; width of the window red.
LD DE, # 0B00; status register
; Byte status register determines the mouth; Novki default
editor:
; Byte 0 = 0 - lowercase
, 1 - uppercase
, B 1 = 0 - Latin register
, 1 - Russian Register
, B 2 = 0 - text mode
; 1 - mode pseudographics
; Byte 3 must equal 1
LD BC, # 036E; call smbgt # 6E
RST # 10
; Restart smbgt accepts any keyboard; bye characters, as well
as independently of; rabatyvaet control keys displacement, of
the cursor and Delete, by pressing ENTER ; Are finished editing
and ; Output, while in case A is contained
The length of the input string. Output is possible
, Also on the piano CS +9, CS + SS, SS + A,
; SS + SPACE, SS + ENTER, while in case
; A return code of the key that caused the
; Exit from the editor
RET C; out by mistake
, I / O
And if pressed CS +9, CS + SS, SS + A,
; SS + SPACE, SS + ENTER, then
JR NZ, EXIT; out of denial
; Test - whether the buffer is not empty?
AND A; check flag
; ZERO
JR Z, START; go to top
, With an empty buffer
;***************************************
, The processing of clipboard contents
PUSH HL; remember the address
; Buffer com. line
LD D, E; reset D
LD E, A; in E - the length of the line
ADD HL, DE; determine the address
, The first free
; Cell buffer
LD (HL), # 0D; add ENTER
EX (SP), HL; placed in a stack
; Address end of the buffer
; Command line
, And HL - start
PUSH HL; put the address
; Start command
; Line in the stack over
; Address end
LD B, (HL); save the first
PUSH BC; symbol com. line
PUSH IX; save the address
; Vector window
; Transfer name and parameters imposed by the
; Command interpreter IS-DOS
XOR A; set A = 0
LD C, # 44; call exebat # 44
RST # 10
; Restoring register contents
POP IX; vector window
POP BC; the first character cc
POP HL; start address cc
POP DE; address of the end of the sg
;***************************************
, The processing result of the command
; And restore the buffer contents to
; Editing error
RET C; out of a serious
; Error exebat
LD A, # 20, in A - the code space
LD (DE), A; "score" ENTER to
; Buffer com. line
LD (HL), B; recover
; The first character in
; Buffer com. line
PUSH HL; remember the stack
; Buffer address cc
JR NZ, CURINI; error in cc
, Return to the conservation
; Niemi text strings
; Correction
JR CLBUF; correct return
, With purification buffer
; To the execution of
; Line
;****************************************
; Out of denial
EXIT LD (HL), # 0D; put the ENTER
; Beginning of the buffer sg
XOR A; set flags
; Output:
; Z = 1, C = 0
LD A, # F4; install code
; Internal team
; Shell (similar to
; Shel1 # 81 with preserved
; Neniem positions
; Cursor on both
; Panels)
RET
;****************************************
; The data area of the program
And the vector window:
WIND DEFB # 00; X-coordinate of window
DEFB # 00; Y-coordinate of window
DEFB # 03; window height
DEFB # 20, window width
DEFB% 00101000; color box
DEFB% 11111111; shadow color # FF -
That the shadow does not appear
DEFB # 00; X-print position
DEFB # 00; Y-print position
;****************************************
Author - Leontiev
Comments - Eliseev
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