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ZX Club #06
31 декабря 1997 |
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Soft group - Driver input modes consistent and direct access from the file system TR-DOS. How to use driver.
Boris Kuritsyn,
Assistant Department of Computer Engineering
Cherkassy Engineering and Technological
Institute, PhD student
257010 Cherkassy, PO Box 1529
DRIVER INPUT MODE
Sequential and direct access
FROM THE FILES OF TR-DOS
TABLE OF CONTENTS
Introduction ..................................
Calling System Functions TR-DOS ............
Exception Handling ......................
Driver streaming I / O
to / from files TR-DOS ........................
Using the driver from the Assembler .......
Interface Basic ...........................
Literature ................................
The author wrote this driver (or rather,
the first part) as a basic element of a high-level language
compiler. But it is completely standalone program which can
directly use those who write in assembly language, and
developed through the expander BASIC - and those who BASIC
programmers.
In addition, analysis of her acquaint the reader with the
programming of the drivers, channels and streams, the
principles of writing BASIC extenders, syntactic analysis, with
methods of extending the set of errors BASIC.
What is the purpose of writing this driver?
There is a class of programs that Simultaneity
must work with many files (and for writing, and the
conclusion), and themselves at This takes quite a memory
so that the simultaneous loading of all
required files can not be considered.
Opening the system thread for each file,
they can work through this driver, even
10 files, length of, say, 60 KB at a time, at the rate of
memory about 290 bytes per file. Function driver is close to
operators TR-DOS file handling
direct / sequential access, but works with CODE-files and
similar files with non-standard types.
In addition, as shown by the "father of all
Programmers "Niklaus Wirth (the author of languages
Pascal, Modula-2), then the program is simple, correct and
reliable, when the structure PROGRAM MEETS THE STRUCTURE OF THE
DATA. To implement this principle, we need
appropriate means. One of them
is this driver, since it allows
program only work with "abstract"
aspect of the data, ie, in terms of "character", "read the
position."
First, the technical aspects. Author
prefer assembler ZX Turbo Assembler
v2.4 and the listing is presented in its format.
Hopefully, users of other assemblers do not have any problems
with the transfer of program texts.
The author, when writing programs that use two sub-modules:
module access to TR-DOS
and
module to intercept system errors.
Module TR-DOS is very simple. This is the analogue
syscall # 3D13, which is an error
TR-DOS converts exceptions (call
RST 8) codes 100-112, which eliminates the
necessary each time to check code
system error. In addition, the call itself is done through a
vector (dosVector), which allows you to "hang" on call TR-DOS
additional functions at run time program by replacing the value
at dosVector address of the additional processor.
;
; System call TR-DOS v5.0x
;
; (C) B. Kuritsyn, June 1996
;
; File: dosapi.a
; File Format: ZX TASM
;
The exception "error TR-DOS"
excDosError equ 99
; Mistakes TR-DOS
dNoFile equ 1
dFileExists equ 2
dNoSpace equ 3
dDirFull equ 4
dRecOF equ 5
dNoDisk equ 6
dStrmOpened equ 10
dNotDskFile equ 11
dVfyError equ 13
dos db # c3; it jp (dosVector)
dosVector
dw dosIntr
; Call DOS shell functions
dosIntr push af
ld a, c
ld (_fncNo), a
xor a
ld (23823), a
ld (23824), a
pop af
call # 3d13
push af
ld a, (_fncNo)
Wed # a; if performed function 10
, (File search)
jr z, dosOk; return code - it is not
; Error code
ld a, (23823)
or a
jr z, dosOk; if there was a bug ini
; Tsiirovat exception
; Initiation exception DOS
dosError
add a, excDosError
ld (_errNo), a
rst 8
_errNo db 0
_fncNo db 0
dosOk pop af
ret
Interested Exception Handling
can refer to [1]. Here
I say briefly: exception - it is extremely
convenient programming technology, which allows implicit
conversions of handling errors or exceptional situations
without the need for regular checks flags and return codes,
etc. When This ensures the conservation status
Some elements of the system and programs
(At least the stack). The following module supports the
processing of multilevel Exceptions to the possibility of
dynamic changing the set of conserved elements
and the exception handler. Interested
can simply review the text of the program. Briefly as we can
say this: if beginning any program try to call
(See listing) including the address of your
error-handling routine, then, in the case of a call RST 8
anywhere in the program management be passed to your handler.
The handler must first of all cause endTry to restore the stack
and withdrawal for themselves. The same call should be made
before the command RET program.
;
; Exceptions handle
; Exception Handling
; (C) 1994-96 B. Kuritsyn
; Version: 2.0 06/18/1996
; File: except.a
;
err_SP equ 23613
; External Treatment
try db # C3; a JP (tryAd)
tryAd dw mark
endTry db # C3
eTryAd dw unmark
; Continue the current exception
, (Just call the exception handler
; Team JP)
; New exception code in the A
putErr ld (iy), a
; The same exception
contErr ld sp, (err_SP)
ret
; Change marking stack
; Entry: @ HL-new handler Try, @ DE-new
; Handler EndTry
, Output: @ HL-old handler, Try, @ DE-hundred; ry handler EndTry
chMarking ld bc, (tryAd)
ld (tryAd), hl
ld h, b
ld l, c
ld bc, (eTryAd)
ld (eTryAd), de
ld d, b
ld e, c
ret
; SALE
; Mark stack entry: @ DE-handler
; Exceptions
; Destroyed: HL, IX
mark POP IX
LD HL, (err_SP)
PUSH HL
PUSH DE
LD (err_SP), SP
JP (IX)
; Demarcate the stack are destroyed: HL, IX
unmark POP IX
LD SP, (err_SP)
POP HL
POP HL
LD (err_SP), HL
JP (IX)
Necessary to stipulate that those who
do not know what a "channel" and "flow", before continuing
reading this article should read the chapter on canals and
streams in the famous three volumes Inforkoma Programming for
the ZX Spectrum or an annex to user manual for a text editor BK
Write, is spread by the author.
And now for the driver itself. Which set of functions it
should perform?
Firstly, it is opening the file: creating a channel that
is associated with the file and the connection of a flow to the
channel.
Secondly, the driver let dozhen
Reads a byte file, not only sequentially but also rearrange the
index of reading directly to any position in the file.
Thirdly, it is closing a file: the destruction of the
channel, closing the stream.
And how, indeed, entering information, you ask?
It's very simple - the system procedure
WaitKey (address # 15D4).
Next, we consider the annotated
Text driver (note: in the driver
there are moments associated with the output to a file -
This part of the driver is not finished yet, but
order to include it in the article is not possible due to the
large volume).
Immediately turn to the main idea
Driver: we must give byte file, which is offset in the file
determined by the current position. Position can be arbitrarily
changed at any time. When reading
byte pointer is moved to
next byte. Trying to read
anything beyond the end of the file is generated
the exemption.
To implement this in a leader tape channel
provides space for one sector
file. At any point in that buffer is loaded sector
corresponding to the current file position. With any change in
position number of the sector is monitored and, if necessary,
the sector is overloaded. ;
**************************************** * *
; * DISK STREAMABLE I / O DRIVER v1.05 *
* *
* Driver streaming I / O *
* To / from files TR-DOS. *
* *
; * (C) B. Kuritsyn, June 1996 *
* *
* File: stream.a *
* File Format: ZX Turbo Assembler *
; ****************************************
include "dosapi.a"
The length of the sector
sectLen equ 256
; System variables
chans equ 23631; pointer to
; Channels
curChl equ 23633; pointer to the current
; Channel
prog equ 23635; pointer to prog; Rummy (at the end of channels)
; System variables TR-DOS
dfDrive equ # 5d19; drive by default
searchCh equ 23814; number of characters for
; Name Search
; System protsedury,
And details regarding the procedures
, See [2]
makeRoom equ # 1655
reclaim2 equ # 19E8
strData equ # 171E +3
chOpen equ # 1601
callJp equ # 162C
; Channel input and output is named "F",
; That they can be distinguished,
; Established leader tape of the signature:
readSign equ # 5678
writeSign equ # 6789
; Throwing exceptions
invStream
rst 8
db 23, "is used incorrectly
; Stream
invFileName
rst 8
db 14, "invalid name"
invDevice
rst 8
db 18, "invalid device"
endOfFile
rst 8
db 7, 'end of file "
; Shift in the leader tape, about
; Unique structure of the leader tape see [3]
oPrint equ 0; address inference procedures
oInput equ 2; address of a procedure entry
oName equ 4; channel name
oSign equ 5; the signature of the channel
oClose equ 7; address closing procedures
; File
oLength equ 9; length of leader tape
oIntern equ 11; More
; Image of the leader tape channel for reading
readRecord
DW invStream
DW inputIn
DB "F"
DW readSign, noOp
DW 1930 + sectLen; length of leader tape
DB 0; device
; (Offset oIntern +0)
DB "C"
DS 7; directory entry (...+ 1)
DW # FFFF; file position (...+ 17)
; Here: DS sectLen - buffer sector
; File (...+ 19)
rdRecLen equ $-readRecord + sectLen
; Procedure for entering characters from a file;
; Next byte of the file is returned to A.
; Byte is always returned, so
; State INKEY $ # 5 = "does not happen.
inputIn ld ix, (curChl); address of the leader tape
ld l, (ix + oIntern +17); current
; Position in the file
ld h, (ix + oIntern +18)
ld c, l
ld b, 0
add ix, bc
ld a, (ix + oIntern +19); Picks
; Bytes from the current sector
scf; Flag: Byte received
C unit
push af
inc hl
call _seekRead; transition to
; The following position
pop af
noOp ret
; Positioning in the current file
; Reading
; Input: HL-position
; --- External version, verify that the current
; Channel - F and is opened for reading, if
, No - wrong thread)
seekRead
push hl
call testChl
ld l, (ix + oSign)
ld h, (ix + oSign +1)
ld bc, readSign
and a
sbc hl, bc
jp nz, invStream
pop hl
; --- Internal version
_seekRead
ld ix, (curChl)
, Check to see whether an end of file
ld c, l
ld b, h
ld e, (ix + oIntern +12); compared with the
The length of the file
ld d, (ix + oIntern +13)
and a
sbc hl, de
; Position just after the last byte of the file,
, The buffer is not overloaded
jr z, atEOF
jp nc, endOfFile
; Establish a new position
ld a, b
cp (ix + oIntern +18); in the same
; Sector?
atEOF ld (ix + oIntern +17), c
ld (ix + oIntern +18), b
ret z; yes - complete
; Not - the new position of the corresponding byte
; From another sector of the file, download a new
; Sector to clipboard
ld l, (ix + oIntern +15)
ld h, (ix + oIntern +16); position
; Beginning of the file on disk
call makeLog; transformation
, The logical sector
ld e, b
ld d, 0
add hl, de; this logical number
; Sector
; You want to download
call makePhis; reverse
; Transformation
ex de, hl
push ix
pop hl
ld bc, oIntern +19
add hl, bc
push hl
push de
ld a, (ix + oIntern)
ld c, a
call dos; drive select
pop de
pop hl
ld bc, # 105; boot sector
jp dos
; Convert options
, "Sector L - track H"
; A "logical sector HL"
Remark: the transformation
; A "logical sector" makes it easy
; Calculate the position of the sector on the disk,
; As the logical sector can be
; Add and subtract like normal numbers.
; Transformation formula:
; Log. sector = track * 16 + sector
makeLog xor a
srl h
rr a
srl h
rr a
srl h
rr a
srl h
rr a
or l
ld l, a
ret
; Convert options
, A "logical sector HL"
; In the sector L - track H "
makePhis
ld a, l
sla a
rl h
sla a
rl h
sla a
rl h
sla a
rl h
ld a, # F
and l
ld l, a
ret
; Type of file to open, changing it
; Value before calling openRead
Or you can open a non-standard files
fileType db "C"
; Opening file for reading;
; Entry:
; A-number flow, @ DE/BC- name string
; (As usual: the address of DE, the length of BC)
; Specified thread will be opened on the file.
openRead
exx
ld (stream), a; verify that
; Specified stream is closed
call strData
ld a, b
or c
ld a, dStrmOpened; if not -
; Error DOS
, "Stream is already open"
jp nz, dosError
call newRdRecord; create a leader tape
; Channel
ld (record), hl
push hl
exx
pop hl
call parseName; syntactic
; Parse name
ld hl, (record)
inc hl
ld bc, (chans); find the offset
; Leader tape in (Chans) ...
and a
sbc hl, bc
push hl
ld a, (stream)
call strData
pop bc
ld (hl), c; ... and discover
; The requested stream to the channel
inc hl
ld (hl), b
ld ix, (record)
ld a, (ix + oIntern)
ld c, a
call dos; drive select
ld c, # 18
call dos; setting a floppy disk
ld hl, (record)
ld bc, oIntern +1
add hl, bc
push hl
ld c, # 13
call dos
ld hl, searchCh
ld (hl), 9
ld c, # a
call dos; search for the file, which
; Open
bit 7, c
jr nz, noFile; if the file does not exist -
; Everything back to its original state
ld a, c
ld c, 8
call dos; if the file is,
; Obtain its directory entry
pop hl
ld c, # 14
call dos; and copy it to the leader tape
; Channel
ld a, (stream)
call chOpen
ld hl, 0
jp _seekRead; set
; Position at top of file
, In the absence of a file all returns
, The initial state
noFile ld ix, (record)
call freeRecord; remove the leader tape
; Channel
ld a, (stream)
call strData
ld (hl), 0; close of thread
inc hl
ld (hl), 0
ld a, dNoFile; an error DOS
, "No such file"
jp dosError
stream db 0
record dw 0
; Parsing the file name
, As "[drive:] name". If the drive
; Not specified, the drive is taken by default.
And the name and the drive is transferred to the region
; OIntern leader tape.
; Input: HL-mail leader tape to open
; Channel, @ DE/BC- name string
parseName
push hl
pop ix
ld a, b; empty string name -
, Error
or c
jp z, invFileName
ld a, (dfDrive); until the drive
By default
ld (ix + oIntern), a
ld a, (fileType); set
; Type
ld (ix + oIntern +9), a
ld hl, -3; name is longer than
; Three characters?
and a
adc hl, bc
jp m, nameOnly; not - hence,
; Drive in a name is not specified exactly
inc de; check the relative
; Drive ...
ld a, (de)
dec de
cp ":"; if the second character -
; Colon ...
jr nz, nameOnly
ld a, (de); ... then the first - the drive
res 5, a; leads to an upper
; Register
sub "A"; separate the correct
; Names: A, B, C, D.
jp c, invDevice
cp 4
jp nc, invDevice
ld (ix + oIntern), a; drive
; Found and installed in the leader tape
inc de; shifts
, To name ... (2 characters)
inc de
dec bc
dec bc
nameOnly
ld a, b
or a
jp nz, invFileName
ld a, c; if the name is longer than
; 8 characters - a mistake
cp 9
jp nc, invFileName
ld b, c; if everything is in order -
; Copy the name of leader tape
copyName
ld a, (de)
inc de
ld (ix + oIntern +1), a
inc ix
djnz copyName
ret
; Creating leader tape read channel
; Output: HL-mail created by the leader tape
newRdRecord
ld hl, (prog); at the end of
; Chans ...
dec hl
ld bc, rdRecLen; ... allocate memory
; For the leader tape ...
call makeRoom
inc hl
push hl
ex de, hl
ld hl, readRecord; ... and copy
; There way of leader tape
ld bc, rdRecLen-sectLen
ldir
pop hl
ret
; Removing leader tape read / write channel
; Entry: IX-mail leader tape
freeRecord
ld c, (ix + oLength); of the leader tape
; Obtain its length ...
ld b, (ix + oLength +1)
ld (recLen), bc
push ix
pop hl
jp reclaim2; ... and release
; Area they occupied
recLen dw 0
, Check that the current channel -
And this channel is "F"
, Output: IX = (curChl)
testChl
ld ix, (curChl); if the name of the current
; Channel ...
ld a, "F"
cp (ix + oName); ... not "F" ...
ld a, dNotDskFile
jp nz, dosError; ... mistake DOS
, "Is not a disk file"
ret
, Close the file read / write stream A
close push af
call chOpen; makes the channel current
call testChl; verify that this
; Flow associated with our channel
, Perform the procedure closing the channel
ld l, (ix + oClose)
ld h, (ix + oClose +1)
call callJp; transition to execution
; Free memory
ld ix, (curChl)
call freeRecord; delete the current
; Channel from memory
, Close the stream
pop af
call strData
ld (hl), 0, 0 - stream closed
inc hl
ld (hl), 0
; Adjust variables to Streams
; Flows 0-15.
; The fact that after the opening of the SC; signal could be
discovered, and others. Their pa; cords are located in memory
after our ; Leader tape.
; With the removal of our leader tape bias
; Of Streams on a channel one hundred, if invalid, and must be
fast; rektirovat on the length of the remote ; Leader tape.
ld d, b; offset the already remote
; Leader tape
ld e, c
ld b, 16; scan the 16 streams
strmLoop
push bc
ld a, b
dec a
call strData; choose a value for
; Flow
push hl
pop ix
ld h, d
ld l, e
and a
sbc hl, bc; if its offset
; No more of our ...
jr nc, noCorrt; ... correction
; Not required
ld h, b
ld l, c
ld bc, (recLen); otherwise reduce
, Offset by the length of leader tape
and a
sbc hl, bc
ld (ix), l; and save
ld (ix +1), h
noCorrt
pop bc
djnz strmLoop; cycle for all streams
ret
Thus, the driver is written. And how to use it?
Elementary. First, any free flow (say, # 5) Open on file:
org 60000
jp start
include "stream.a"; inclusion
; Driver ...
include "except.a"; ... and form
; Processing exceptions
name db "textfile"; to name
; File ...
nameLen equ $-name; ... and its length
start ld de, name
ld bc, nameLen
ld a, 5
call openRead
File is opened. Now, for example, print it on the screen.
We will, character by character read the file and send bytes
channel "S". Because the process is completed except for "end
of file", catch the exception:
ld de, endOfPrint; address
; Handler
call try
Now you can display the file in the "infinite" loop.
waitKey equ # 15D4
process ld a, 5; file stream
call chOpen; chOpen = # 1601
call waitKey; introduce the symbol
push af
ld a, 2; flow screen
call chOpen
pop af
rst 16; derive symbol
jr process
At the end of a file or other exceptions, control is
passed to here:
endOfPrint
call endTry; remove handler
ld a, 7
cp (iy); current fault -
And this "end of file"?
jp nz, contErr; if not -
; Continue her spread the word, and if so -
; Everything is in order, the withdrawal is completed
ld a, 5
call close; close
; Disk file
ret
What about BASIC? I would like to have
the ability to open files directly from the operators BASIC.
Nothing could be easier. Below
BASIC interface to the driver implements it
and one more thing: it converts new DOSovskie exceptions to the
new error BASIC, that appear in the same way as conventional.
In addition, it displays the status of the flow system on the
screen or in any other thread. New BASIC statements are as
follows:
LET d = 64000
REM opening <flow> on <filename>
RANDOMIZE USR d: OPEN # stream, filename $
REM closing disk file associated
c <thread>
RANDOMIZE USR d: CLOSE # stream
REM transition to in the file
associated with <thread>
PRINT # thread;: RANDOMIZE USR d
GO TO position
REM output information
about the state of flux at <thread>
REM to display flow = 2
RANDOMIZE USR d: LIST # stream
A small remark about the operator GO TO: operator PRINT, you
see ahead, only makes the current flow, since GO TO work with
the current thread. Note the ";" at the end operator PRINT.
Operator LIST lists all open streams with an indication of
the channels that they are open.
Direct input from a file in the usual way: the operator
INPUT # thread; simv_peremennaya $
to enter a character string, or an operator
LET simv_peremennaya $ = INKEY $ # stream
to enter a single character.
The second way is preferable, since
as in the ZX Spectrum has a special feature: it is assumed that
the operator INPUT data is entered only from the streams,
associated with the keyboard and the sound of keyboard
processed in a statement INPUT. Therefore,
input from the file, you will hear a sequence of squeaks
"keystroke" when you enter each character. In addition, input
line will only be completed upon receipt of symbol with a key
code <Enter> (# 0D) and itself is a character in the string
will not be included.
Throughout the program, show how
BASIC extender not only performs
actions, but also analyzes sintasis program.
;*****************************************
* *
; * BASIC INTERFACE TO *
; * DISK STREAMABLE I / O DRIVER, v1.05 *
* *
* The interface to the BASIC *
* Download streaming I / O *
* To / from files TR-DOS. *
* *
; * (C) B. Kuritsyn, June 1996 *
* *
* File: basint.a *
* File Format: ZX Turbo Assembler *
;*****************************************
; Codes tokens
t_open equ # d3
t_close equ # d4
t_goto equ # ec
t_list equ # f0
; System variables (or bias)
oFlags equ 1
oTVFlag equ 2
oFlags2 equ 48
oFlagX equ 55
oXPtrHi equ 37
defAdd equ 23563
strms_6 equ 23574
; Used semiconductor ROM.
; Details, see [2].
class06 equ # 1C82; syntax. analyzer
- Must be
; Numeric expression
class0A equ # 1C8C; syntax. analyzer
- Must be
; String of characters
separator equ # 1B6F; syntax. analyzer
- Must be
; Token
stkToA equ # 1E94; stack calculator -
, In A
stkToBC equ # 1E99; stack calculator -
; In BC
stkFetch equ # 2BF1; stack calculator -
; In the A / BC / DE
clsLower equ # 0D6E
setMin equ # 16B0
copyBuff equ # 0ECD
stackA equ # 2D28; A - on the stack
; Calculator
printFP equ # 2DE3; print the number of
; Stack calculator
po_mess equ # 0C0A; display a message A
; From the table (DE)
org 64000
; Entry point
startUp ld de, newErrors; new
; Handler issklyucheny
call try
ld c, ":"; this is a separator
; After USR 64000
; Separator verify that the current interval; pretiruenmy
symbol is gone. And if not - error "nonsense in BASIC"
call separator
ld c, a
rst # 20; take the name of the operator ...
ld hl, statms; ... and look for it
; Table Statms
jr compare
nextSearch inc hl
inc hl
compare ld a, (hl)
inc hl
or a
jr nz, cont_comp; if the table
; Ended - error
rst 8
db # b; Nonsense in Basic
cont_comp cp c
jr nz, nextSearch
ld a, (hl); found
; Choose the address of the handler ...
inc hl
ld h, (hl)
ld l, a
call callJp; ... and run it
call endTry; remove handler
; Exceptions
ret
; Table description operators.
; Format: token, the address of the handler
; Token, the address of the handler ,..., 0.
statms db t_open
dw _open
db t_close
dw _close
db t_goto
dw _goto
db t_list
dw _list
db 0
listStrm db 0
The text for cinematography LIST
listMess db # 80, "Streams status:", 13 + # 80
db ": opened to", 34 + # 80
db 34,13 + # 80
; Operator LIST # stream
_list ld c, "#"; check symbol
; Flow
call separator
call class06; should follow
; Numeric expression
call stkToA; it -
; In the battery
call chOpen; open channel
; For output
ld de, listMess
sub a
ld (listStrm), a
call po_mess; output header
listNext ld a, (listStrm); for the flow ...
call strData; ... selected
; Data from Streams
ld a, b
or c
jr z, listCont; when closed -
; Next thread
ld a, "#"; print symbol
; Flow ...
push bc
rst 16
ld a, (listStrm)
call stackA
call printFP; ... and its facilities
pop bc
ld hl, (chans)
add hl, bc
inc hl
inc hl
inc hl; definition addresses
; OName bias in the channel
push hl
ld a, 1
ld de, listMess
call po_mess; message
, Is open for ...
pop hl
ld a, (hl)
rst 16; ... such and such a channel
ld a, 2
ld de, listMess
call po_mess
listCont ld hl, listStrm
inc (hl); next thread
ld a, 16
cp (hl)
jr nz, listNext; transition to
; Next thread
ret
; Operator OPEN # stream, name $ -
; Without comments
_open exx
push hl
call openParams
call openRead
pop hl
exx
ret
; Parse OPEN statement
openParams call class06; should be number
; Flow - on the stack
; Calculator
ld c, ","
call separator; then a comma
call class0A; then a character
; Expression -
The name of the file
rst # 28; exchange name and stream
; Places on the stack
db 1, # 38; exchange
call stkToA; stream -
; In the battery
push af
call stkFetch; name - in the DE / BC
pop af
ret
; Operator CLOSE # stream
_close call class06; should be number
; Flow - on the stack
; Calculator
call stkToA; stream -
; In the battery
jp close
; Operator GO TO pos
_goto call class06; number - position
; In the file
call stkToBC; from the stack
; Calculator in BC
ld h, b
ld l, c
jp seekRead
; Error handler:
; Visualizes new errors
newErrors call endTry; remove handler
halt
ld a, (iy); error code
cp excDosError + dNoFile
jp m, contErr; usual errors
; SOLD further
; This part almost repeats
; Of the standard error handler
; From the ROM to output error messages.
; See [3] from the address # 1303
res 5, (iy + oFlags)
bit 1, (iy + oFlags2)
call nz, copyBuff
ld hl, 0
ld (iy + oFlagX), h
ld (iy + oXPtrHi), h
ld (defAdd), hl
ld hl, 1
ld (strms_6), hl
call setMin
res 5, (iy + oFlagX)
call clsLower
set 5, (iy + oTVFlag)
ld a, (iy)
sub excDosError + dNoFile
ld b, a
add a, "a"; new codes Posts
rst 16
ld a, ""; gap
rst 16
ld a, b
ld de, messages; new posts
; In this table
ld (iy), # FF
jp # 1346; further processing
; Standard - in ROM
; Table text messages about new bugs
, (In the format procedure PO_MESS)
messages db # 1980, "No fil", "e" + # 80
db "File exist", "s" + # 80
db "Disk ful", "l" + # 80
db "Dir ful", "l" + # 80
db "RecNo overflo", "w" + # 80
db "No dis", "k" + # 80
db "(7) DOS erro", "r" + # 80
db "(8) DOS erro", "r" + # 80
db "(9) DOS erro", "r" + # 80
db "Stream opene", "d" + # 80
db "Not disk fil", "e" + # 80
db "(1912) DOS erro", "r" + # 80
db "Verify erro", "r" + # 80
; Enable drivers and exception handling
include "stream.a"
include "except.a"
; *** End of basint.a ***
I hope that my brief (due to the large amount of assembly
code) comments given at least a general idea of work program
and the program will useful to you.
If you encounter problems or specific questions, you can
write to the author at the address above.
REFERENCES
1. B. Kuritsyn. Intercepting System Errors
when programming in assembler for
computers "ZX Spectrum".: ham
10'1994, p. 12 - Minsk, 1994.
2. Logan, O'Hare. Full description ZX Rom
Spectrum.: "Program-Ass" - Kharkov, 1992.
3. K. Kurylovich, D. Madej, K. Marasek. Guide to the ZX
Spectrum.: "Program-Ass" - Kharkov, 1992.
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