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Optron #21
27 ноября 1998 |
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Coding - The test of memory available. Manage memory banks. Adapting programs for Miko.
Miko-Best: a STS'om in the hands of
Ivan Buhay, 1998
In this article we have with you, dear readers "OPTRON",
inspired by Joan Scalp, try to find out more
with pathogenic phenomenon known as "Miko-Best 256kB".
(Immediately, I note that "-Best" - this is probably a
terminological error. It would be "Miko-Suxx". How else to
explain the relationship manufacturers to the child: no
information to support or programs.)
Although this phenomenon has already been covered (see
Rooms 7 and 8 "Optron"), the question requires
further study.
For a start - a small clarification
I have a Miko-Best 256kB v1.5 with
two modifications:
- OUT (# FD), A - works fine (treated pereshivaniem ROM,
performed on RT4, these things were doing at the firm Miko);
- Switch Miko-Pentagon (these things did
Rasp, he was inordinately blagodaren).
And now - the smallness of demagogy
(Or my assumptions)
ROM 64Kb, it:
1 Manager
2 TR-DOS 5.03
3 Basic 128
4 Basic 1948
At startup or reset, control passes to the Manager, is blocked
Magic, interviewed key "R" and "T".
"R" - run a full memory test.
"T" - teletest: test content
# DB00 in the bank # 0D. If it is not equal
# AA55, it is a test AY, Printer, Memory, and
with his success, exits the menu.
Otherwise, check that you have pressed
gap. If yes, Miko Basic (48-th and
128-s) runs from ROM. If not pressed, the
Miko Basic reloaded into RAM - the bank # 0C
The 128 th and # 0E to 48 th. These banks
forbidden to write, and they are projected to
address # 0000.
Let us get to the point
Management of computer resources through the port # DC:
- BIT 0-3 - number of the projected page
to address # 8000;
- BIT 4 - Room "ruler" of the eight banks that are projected
from the address # C000;
- BIT 5 - if "0", instead of the projected ROM RAM - Bank #
0C or 0E #, depending on the condition of the fourth discharge
port # FD ("1" - # 0E, "0" - # 0C);
- BIT 6 - if "0", the entry in the segment 0 is allowed
(provided that the reset BIT 5);
- BIT 7 - If the "1", starting at address
# 4000, the bank projected # 0D, screen 0, and with
Address # C000 - screen 1, Bank # 0F.
Port # FD (it is believed that this port
not to speak of, its track is
hardware, and he emulated portom # FC) -
as in a standard SPECCY 128.
Port # FC - # FD emulates, with the difference
that BIT 5 (latch 48K) can switch
48/128 modes.
All three of these ports are available as
recording and for reading.
Practical application
Here is a small excerpt from Miko comander:
LD BC, # FFFC; port analog # FD
IN H, (C); kept current
LD A, # 55; value
OUT (C), A
IN L, (C); checks available
CP L; whether the record?
JR NZ, NO_MIKO
OUT (C), H; restored
LD DE, 768; available memory
IN A, (# DC); ROM instead of RAM?
BIT 5, A
JR NZ, STANDART
LD DE, 704, and if so,
LD A, # FF; removed from the list
LD (TBANK +13), A; available to banks # 0D
BIT 5, H; included Basic 128?
JR NZ, MODE_128
LD DE, 640; if yes - throw
LD A, # FF; Bank # 0C
LD (TBANK +12), A
Here is the test of memory available, and
management of banks is as follows:
LD HL, TBANK
LD E, A; in a virtual
LD D, 0; page number
ADD HL, DE
LD A, (HL)
CP # FF; if not available -
RET Z; output
LD L, A
AND # 08; identified the third bit
RLCA; and transformed it into
LD H, A; room "rule",
IN A, (# DC); which departs
AND% 11101111; the fourth digit
OR H; port # DC
OUT (# DC), A
LD A, L
AND # 07
LD L, A
IN A, (# FC)
AND% 11111000; three junior level in the
OR L; room of the bank - to
OUT (# FC), A; port # FC (# FD)
SCF
RET
...
TBANK
DB 0,1,3,4,6,7,8,9
DB # 0A, # 0B, # 0F, # 0C, # 0E, # FF
Bank # 0D is not used, since there
Manager stores 4-byte identifier start, because of what is lost
16K (in my opinion, do not advisable).
"And what do with all that?" - You ask.
Well, if you want a program adaptiravat Miko, then all the
simple (for example, HC_3.08 - best Commanderie on Speccy, even
to date):
ORG # 6F0F
PUSH BC
LD B, A
LD A, (# 5B75)
EX AF, AF '
LD A, (# 5B90)
ADD A, A
JR C, PENT
LD A, B
AND # 08
RLCA
OR # 62
OUT (# DC), A
PENT
LD A, B
LD (# 5B75), A
AND # 08
RRCA
RRCA
RRCA
LD C, A
LD A, B
AND # 07
ADD A, C
OR # 10
LD BC, # 7FFD
OUT (C), A
EX AF, AF '
POP BC
RET
Option B should ask User page, and
Autoload Overlays - remove (for 256K). Now you have a 160Kb
without RAM-Disk. At some discrepancy information on Memory
(program made for how at least, 512K) do not pay attention.
If the program is made under the Port
Scorpion, then do it even simpler.
And what to do with four screens?
For example, we look tricolor
Pictures:
ORG # 7800
LCODE "PICT"
ORG # 6000
BEGIN
DI
LD A, # 17
LD HL, # 7800
LD BC, # 7FFD
LD DE, # C000
OUT (C), A
PUSH DE, BC
LD BC, 6144
LDIR
PUSH HL
LD HL, # D800
INC DE
LD BC, 767
LD A, (COLOR2)
LD (HL), A
LDIR
POP HL
POP BC, DE
PUSH DE, BC
LD A, # 15
OUT (C), A
LD BC, 6144
LDIR
PUSH HL
LD HL, # D800
INC DE
LD BC, 767
LD A, (COLOR4)
LD (HL), A
LDIR
POP HL
POP BC, DE
LD A, # 72
OUT (# DC), A
LD A, # 17
OUT (C), A
LD BC, 6144
LDIR
LD HL, # D800
INC DE
LD BC, 767
LD A, (COLOR1)
LD (HL), A
LDIR
LD A, # 62
OUT (C), A
LD HL, # BE00
LD DE, # BE01
LD A, H
LD (HL), # BF
LD I, A
LD BC, 257
LDIR
LD A, # C3
LD (# BFBF), A
LD HL, # 8000
LD (# BFC0), HL
EX DE, HL
LD HL, INT
LD BC, COLOR1-INT
LDIR
IM 2
EI
LD A, # 15
OUT (# FD), A
MAIN HALT
CALL 8020
JR C, MAIN
EXIT DI
LD A, # 62
OUT (# DC), A
LD BC, # 7FFD
LD A, 60
LD I, A
IM 1
LD A, # 10
OUT (C), A
EI
RET
INT DI
PUSH AF, BC, DE, HL, IX, IY
EXX
EX AF, AF '
PUSH AF, BC, DE, HL
LD BC, # 7FFD
LD HL, # 151D
LD A, # 62
OUT (# DC), A
LD A, 0
WHO EQU # 8000 + $ 1-INT
OR A
JR NZ, SK0
INC A
SK0 DEC A
JR NZ, SK7
OUT (C), H
INC A
JR QEX
SK7 DEC A
JR NZ, SK5F
OUT (C), L
INC A
INC A
JR QEX
SK5F LD A, # E2
OUT (# DC), A
LD A, # 11
P1 DJNZ $
DEC A
JR NZ, P1
XOR A
DEC A
QEX INC A
LD (WHO), A
LD A, # 62
OUT (# DC), A
POP HL, DE, BC, AF
EX AF, AF '
EXX
POP IY, IX, HL, DE, BC, AF
EI
RET
COLOR2 DEFB # 42
COLOR4 DEFB # 44
COLOR1 DEFB # 41
Here and do not need to be considered: almost all the time
computer - in vashey power. This passage
is taken from the 3C-studio, I wrote a year ago (full-screen
editor tricolor images). In principle, It is already possible
to paint any picture. If someone expresses the desire, then I
Finish it.
By the way, this editor you can write and
for the Speccy 128 (using one-third of the screen to edit), the
problems here no.
Prospect
It would be nice to make the interception Magic'a
or Reset'a: it's real. When a signal instead of NMI TR ROM-DOS
substitute page of RAM, and then choose
Magic, Debuger etc.
Another good thing would be in ROM instead of the Manager's
sew up their program.
In general, you need a programmer. And there -
try that out.
P.S. by rasp
Of course, little use to replace Manager
something more "other" is tempting, but not
Take your time, dear users Miko: "Do not
knowing ford, not poke your nose into the water. "Just because
take and sew up something in the ROM is designed to work in
Miko Best, will not leave!
It turns out that the developers of the computer smart enough
to confuse the data bus, ROM and the CPU! Here is a plate from
which it is clear that to this:
ROM CPU
D0 (11) D2 (12)
D1 (12) D7 (13)
D2 (13) D0 (14)
D3 (1915) D1 (15)
D4 (1916) D5 (9)
D5 (1917) D3 (8)
D6 (18) D4 (7)
D7 (19) D6 (10)
In parentheses, I have pin numbers of the chips.
As seen from the plate, visible
some regularity of this arrangement is the tires. Until this is
likely to hit upon some careless developer who decided to save
a couple of transition holes, dropping all the tracks in
parallel. Or maybe it's because "code" information?
And as a replacement for Manager's, I would suggest to try
the firmware Gluk Reset Service; it can be ordered on the Tree
of Life BBS.
If you do not have the programming, for
flash ROM can contact S. Filimonov. Its coordinates, as well as
the coordinates of the author of this article can be found at
Homepage About.
Other articles:
ZX-waggons - Overview of electronic media: Pilot 1929, CNet Week 17, Born Dead 1-4, Maximum 47, Nicron 104. |
Iron - Many functions in one body (about AON'ah). |
Iron - Overview of quality floppies. |
Coding - The test of memory available. Manage memory banks. Adapting programs for Miko. |
Likbez - Assembler: A look from afar (continued). |
Advertising - Advertisements and announcements ... |
four kilobytes - On the thematic issues Optron: Iron and coding. |
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