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Adventurer #06
28 февраля 1997 |
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Exchange of experience - How to make a disc version? ..
(C) RAY
(C) Music PHANTOM LORD / ACCEPT CORP.
HOW TO MAKE A disk version
You certainly know this situation: when loading a program
(No matter the game or sistemka) receive the message "Disked by
...", a then when you try to, say, download something, you see
the blinking Border. What words will be spoken against the very
"disketizatora" I hope you can guess. In general, I think so:
You can write to loader, the program disketirovana
only if done full disk version. If you just prilyapan Thesis
kovy loader, then it is better to write nothing, or note that
is not fully de- prog disketirovana. True latest version of the
very few people can organize, so I share with you some
information about how to make a full disc version
program.
So, you have a code block,
in which you want to change the up / downloading
any data from tape to disk. First, consider the load address of
the block. Usually one less than the address set stack. (NOTE:
Make sure that after running the program does not change its
position in memory, in particular, throws himself whether the
address below!) Typically, the minimum address is 24500.
If you block this address or greater -
All DC, 90%, that problems with the alteration
under the disc does not arise. If not - the situation is
slightly more complicated and we consider later (in this
article the disketizatsiya standard methods of TR-DOS).
Before you look for entry points
tape loading procedure and write, it is useful to view the
entire memory for finding unoccupied space program.
As shown, in any prog
there is always a byte 150 .. 200 free
places (you can chunks, byte 45). And that is more than enough
for our purposes. If not - you can use a place that is
BASIC-loader.
Now start looking for an entry point.
Here, too, can be two options:
1) the program uses its own pro
procedure for loading / writing;
2) the benefits of the procedure of
Rom.
In the first case to look for entry points
difficult, but it will not have to then find space in the
program, because new routines just them across the
site of the old.
In the second case, you can try
find challenges ROM.
I recommend to first find the entry point
in SAVE, because it is easier to define the parameters of the
delivered units (starting address / Usually in register IX /
length and / Reg. DE /).
I will cite some entry points for
tape routines in ROM, pulled
from different programs:
mnemonic bytes to search
SAVE: CALL 1218 CD C2 04
CALL 1222 CD C6 04
LOAD: CALL 1366 CD 56 05
CALL 2050 CD February 2008
CALL 1378 CD 62 05
CALL 1889 CD 61 07
In addition, there are also exotic
ways:
CALL # 0605
where the SAVE or LOAD is defined
on the cell 23688 0 - SAVE
1 - LOAD
Even more interesting way:
SAVE: CALL 2416,
where
IX - the first 17 bytes - header
then the data;
length is given as follows:
LD DE, length
LD (IX +11), D
LD (IX +12), E.
If you have a suspicion that
programs use their own procedures for working with tape, then
you can do following. Because Typically, these procedures
are based on PZU'shnyh, then look for
the following sequence:
mnemonic code
08 EX AF, AF '
13 INC DE
DD 2B DEC IX
F3 DI
This piece from the procedure, located in
ROM at 1222 (# 04C6). If you have found
something like that, then this is the beginning (almost)
routines on the tape. Left
only to find out where by calling it
and define the parameters of the delivered unit.
If none of the above are not
help - try searching for messages,
that the program issues when working with
tape. Typically, these messages are
next to the relevant procedures.
So, all we found. Substitute address
call routines found below. However, there is one more thing:
could be three options for shipping (for
BitTorrent - the same way):
1) in the same file;
2) in the same place on disk or
"A";
3) in different files (the most preferable
respect).
In the first case, the file name is fixed. In the second
it is generally not necessary. And in third to it as a type
(such usually occurs in adventyurnyh games).
Consider these cases ...
1. In one file:
SAVE
CALL SET_NAME; ready systems.
; Variables
LD C, 10, look for a file
CALL 15635
LD A, C
BIT 7, C
JR NZ, SAV_BL; it is not
LD DE, (23878) found, rewrite
LD BC, # nn06
LD HL, address
CALL 15635
RET
SAV_BL; create a new
LD HL, address
LD DE, size
LD C, 11
CALL 15635
RET
where the address - the address of the beginning of the
delivered
block;
size - the size in bytes;
nn = the size in sectors.
LOAD
CALL SET_NAME; ready systems.
; Variables
LD C, 10, look for a file
CALL 15635
LD A, C
BIT 7, C
JR Z, LD_1
; Message "file not found" or ...
RET
LD_1; Georgia ...
LD A, C
LD C, 8
CALL 15635
XOR A
LD (23801), A
LD (23824), A
LD C, 14
CALL 15635
RET
; Sub-install sist.peremennyh
SET_NAME
LD HL, NAME; toss
LD DE, 23773, file name
LD BC, 8
LDIR
LD A, "C"; type MB
LD (23781), A; any, except
; "#"," D "," B "
LD A, 9; file search
LD (23814), A; to 9 characters
RET
NAME DEFM "filename"
2. In the same place ("a"):
SAVE
LD HL, address
LD DE, (T_S)
LD BC, # nn06
CALL 15635
RET
LOAD
LD HL, address
LD DE, (T_S)
LD BC, # nn05
CALL 15635
RET
T_S DEFW # SSTT; track and sector,
; To write / read
3. In different files:
Case similar to 1, only the procedure
SET_NAME must be replaced by INP_NAME.
* If you disketiruete adventyuru, then
better to find a program input procedure
line and use it to enter the name
file. How to use it - is shown below. Otherwise you have to
write it yourself.
NAME EQU; address to read
; Line
INPUT EQU; address of the procedure read
; Line
FROM EQU; the "address"
LEN EQU; the "length" (BYTES)
INP_NAME
LD HL, NAME; clear the name of
LD DE, NAME +1; file
LD BC, 7
LD (HL), # 20
LDIR
CALL INPUT; see *
LD A, "C"; type MB
LD (23781), A; any, except
; "#"," D "," B "
LD A, 9; file search
LD (23814), A; to 9 characters
LD HL, NAME
LD B, 8
CHECK LD A, (HL)
CP NN; terminator
JR NZ, NEXTS; line code NN
LD A, # 20, is replaced by
LD (HL), A; gap
NEXTS INC HL
DJNZ CHECK
LD HL, NAME
LD DE, 23773
LD BC, 8
LDIR
RET
And in conclusion, I want to share one
podprogrammkoy, which allows you to change
Drive:
call: LD D, n; n-number of the disk
CALL CNG_D; 0-A, 1-B, 2-C
....
CNG_D DI
LD A, # C9; disabled because of
LD (# 5CC2), A; processing errors
; (See ADV # 5)
LD (IY +0), # FF; reset
XOR A; all codes
LD (23824), A; error
LD A, D; set
LD (23833), A; system ne
LD (23798), A; belt TRDOS
LD C, 1; choice
CALL # 3D13; drive
LD C, # 18; tuning
CALL # 3D13; drive
EI
RET
P.S. If you do not configure the disk, then
by changing the drive could happen
that he will read only the zero track.
P.P.S. Listed in ADV # 5, and this issue
procedures are not perfect, though
fully operational. If someone knows how to do better (or better
yet - the driver with direct programming SH and processing
errors, for example: a standard call, and upon completion of
work A registry error code), then we are happy to publish his
achievements. Be bold, virtuoso keyboard!
On this let me finish. If
something is not clear - write.
We continue a series of articles devoted to the disc
loader. Word of our correspondent.
(C) Nicolas Viper
"The lazy person, so
more than any of his act
similar to the deed. "
Folk wisdom
Delay velikovata, well, who now
easy? Reach for their brains out jars
Solutions with a wipe, someone dusty, and delve.
First of all, it should be noted
that the statement that in checking the correctness of reading
(hereinafter: CFR), DOS can not help us was wrong. Only In
turn, we must help him.
Take a look at Listing:
ORG 40000
DI; Installation:
LD HL, # FD00;-Prés
LD A, H; algebra
LD DE, # FD01; Islands
LD BC, 256; equations
LD (HL), # FE
LDIR
LD I, A
IM 2
CALL MUSRUN;-Music
EI
LD DE, # 0100;-Location,
LD HL, 16384; where and
LD B, 27; how much we
CALL LOADER; shipping
JP MUSRUN; Music off + RET
*************** ***************** GEORGIA
LOADER
LD IX, # 2F65; Promotion
CALL DOS
L1
PUSH DE
PUSH BC
LD A, D
OR A
RRA
LD C, A
LD A, # 3C
JR NC, L2
LD A, # 2C
L2
LD IX, # 2F4D; Put the skull on
CALL DOS; road
POP BC
POP DE
PUSH HL
PUSH DE
PUSH BC
CALL LOA_COM
POP BC
POP DE
POP HL
; Translation:
INC H; - Address
LD A, E; - sec
INC A; then
AND 15; pa
LD E, A
JR NZ, L5; - roads
INC D
L5
DJNZ L1; new sector
DI; Output
IM 1
EI
RET
This part has not changed since the first
Coming. But most important:
LOA_COM
LD C, # 5F; Conversion rates
LD A, E; sector zasyl
INC A; ka in the register
LD IX, # 2A53; sector VG-shki
CALL GODOS
TRY1
PUSH HL; on the stack
PUSH DE
TRYMET
XOR A; No error
LD (ERRFLG +1), A; (yet:)
LD B, A; B = 0
LD C, # 1F; Team
LD A, # 80, "read
LD IX, # 2A53; Sector
CALL DOS
LD C, # 7F; Reading sector
LD IX, # 3FE5
CALL GODOS
POP DE; picked up a stack
POP HL
ERRFLG
LD A, 0; Check
OR A; time errors
JR NZ, TRY1; reading. (Under
LD D, 1; more details described
LD IX, # 2F2F; below)
JP GODOS
DOS
HALT
GODOS
PUSH IX
JP # 3D2F
IMCOM; caught the interrupt
LD (STACK), SP; tion
PUSH IX
PUSH HL; Here, too, in
PUSH DE; nutshell
PUSH AF; not describe:)
PUSH BC; Look for more details
CALL MUSIC; surface below.
LD HL, (STACK)
LD E, (HL)
INC HL
LD D, (HL)
LD A, D
CP # 40
JR NC, RETOS
CP # 3F
JR NZ, PA_CNT
POP BC
PUSH BC
LD A, B
LD (ERRFLG +1), A
PA_CNT
LD HL, 0 - # 2F3A
OR A
ADC HL, DE
JR Z, RTBR
LD A, # C3
POPALL
LD (CHANGE), A
POP BC
POP AF
POP DE
POP HL
POP IX
EI
CHANGE
JP # 3D2F
RETOS
LD A, # C9
JR POPALL
RTBR
LD SP, (STACK)
POP AF
EI
JP TRYMET
STACK DW 0
ORG # C000
INSERT "MUSIC"
ORG # FEFE
JP IMCOM
MUSRUN EQU # C000
MUSIC EQU # C006
At # 2F2F in TR-DOS:
# 2F2F IN A, (# 1F)
AND # 7F
RET Z
DEC D
PUSH HL
PUSH DE
JR NZ, # 2EXX; No matter where
HALT;) We catch!
Kratenko:
About IMCOM: the problem of this procedure -
check when it was interrupted.
The options are:
- In RAM. Then it all on the drum - m
paradise music and vertaemsya.
- The ROM (assuming that it is DOS! On-the idea
we do not find ourselves in SOS). Then, too, wa
variants:
- Grab addresses with a # 2F3A - this value
This means that we caught the HALT (see above)
which, in turn, suggests that
occurred while reading one of the "mill
dard "error - loss of data, not
match the checksums, etc.
- ... From the address # 3FXX (XX - any value
tion) - again, in theory, there we can
We show the procedure to intercept only reading
of the sector. This means that, alas,
we are uncertain situation - should be
complete the procedure, but due to delays
to play tunes, etc. we
lost time and have read Brokers
torit.
When an error occurs, we put
at (ERRFLG + 1) is not zero - it says that we need to reread
the sector (See label ERRFLG).
Everything else is not so difficult and it was
painted before. E-mail if that is not
so, the editors or mylte me:
nicky@univ.uniyar.ac.ru
Although, judging by previous publications, you, dear
readers, is still not paid for this procedure is no
Spotlight - glitches in it was full, and
nobody wrote: "... because of this
Your #@$'$- of prog myself floppy spoiled, beloved! "
(C) Kotov AV (CAV Inc.)
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