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ZX Review #5-6
04 ноября 1997 |
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Studies - The procedure for searching text files.
It may be worth based on
studies and the deceased in a Bose section for beginners to
create a corner of the programmer in which systematically cover
the practical programming techniques. Level began to take place
quite quickly, and between novice and master -
large range of intermediate
levels, whose representatives and
constitute the majority of readers of the Revue. "
To improve the overall
Literacy would not hurt to systematize ways to reduce
the size of standard procedures and improve their performance,
especially for procedures to copy blocks of memory. In
principle, it is all already given, but scattered
for different numbers. But lately the program starts
meet the fragments of type:
LOOP LDI; 16 bars
JP PE, LOOP; 10 cycles
(Information about the run-time commands taken from the
three-volume programming in machine code. "Inforkom, 1993).
Obviously, the author read somewhere that LDI faster LDIR
(21 cycle). As a result, the length of more
three bytes, and performance
below 5 cycles in each cycle
displacement bytes.
It seems that someone has offered to do collaborative
programming. Leave this way to a game that has great
commercial value, it is unlikely, not least because it was
unlikely Does anyone have the strength to manually fill a huge
number of sprites. But write another
variant of TETRIS or BALL BREAKER
with a minimum number of sprites is quite possible. The game
itself not of paramount importance. Importantly - show all
the process of creating a complete
program. A designed for
this time, the procedure can be
continue to use their own developed programs.
If the result will be
More at least several tens of
programmers who write for
SPECTRUM, it would be better all because the software market
software can not satisfy
increasing number of programs we offer. The more
programs, the more users and greater demand for other
program. A number of topics for
programming indefinitely.
The search
TEXT FILE
I have not met yet not a single disk doctor that supports
alternative character set, which became the de facto standard
for text files ZX-SPECTRUM. To simplify the process of recovery
discs containing text files ZX-WORD, ZX / IBM EDITOR, ZX-ASM and
etc., the proposed procedure show discs destroyed catalog.
The initial track and sector
set in the variable TRACK. On
displays the contents of three
related sectors. At the top of the screen printed track number
and sector, which begins with a conclusion. Sectors are
highlighted in color.
When you press BREAK exits from the procedure by pressing
any other key dumps the following three sectors.
At FONT during
compilation is loaded decoder contains images of 256
character codes 0-255.
LOADCODE - assembler directives
XAS, retrieves the block
codes. If you're using another assembler, replace it
A similar directive to your
assembler. For ZEUS this PLACE,
for TASM, ALASM - INGBIN, ZX-ASM
3 - INSERT.
Decoder can make their own, but much
easier to retrieve it with the help of
program's FIND EDIT FONT, from any text editor that uses a
matrix of 6x8 pixels. Even easier to use one of character sets,
attached to the ZX-ASM assembler 3.
Procedure PRIN_42, used for printing in the format 42
character in the string is taken
Review of the ZX-N4-5/96 p.101 ((c)
A. Matyushev).
140.
INIT LD HL, # 0100; H-TRK, L-SEC.
TRACK EQU $ -2
LD (# 5CF4), HL
XOR A
OUT (# FE), A
LD A, # 45
LD (# 5C8D), A
START LD HL, # 4000
LD DE, # 4001
LD (HL), L
LD BC, # 1840
LDIR
LD A, # 30
LOOP1 LD C, # E0; B = 0
LD (HL), A
LDIR
SUB 8
CP # 18
JR NZ, LOOP1
LD C, 31
LD (HL), B
LDIR
LD A, 2
CALL # 1601
LD DE, MES1
LD C, MES2-MES1
CALL # 203C
LD HL, # 5CF5
PUSH HL
CALL NUMBER
LD DE, MES2
LD BC, FONT-MES2
CALL # 203C
POP HL
DEC HL
CALL NUMBER
LD HL, # 0200
LD (XTXT), HL
LD HL, BUFF
PUSH HL
LD DE, (# 5CF4)
LD BC, # 0305
CALL # 3D13
POP HL
LD C, # 03; B = 0
LOOP LD A, (HL)
CALL PRIN_42
INC HL
DJNZ LOOP
PUSH HL
LD HL, YTXT
INC (HL)
POP HL
DEC C
JR NZ, LOOP
KEY XOR A
IN A, (# FE)
OR% 11100000
INC A
JR Z, KEY
CALL # 1F54; BREAK?
RET NC
JR START
NUMBER LD C, (HL)
LD B, 0
CALL # 2D2B
JP # 2DE3
MES1 DEFB 22,00,6
DEFM "TRACK:"
MES2 DEFB 6
DEFM "SECTOR:"
FONT LOADCODE "Font"
PRIN_42 PUSH HL
LD HL, XTXT
LD A, 41
CP (HL)
JR NC, WR2
XOR A
LD (HL), A
INC HL
INC (HL)
WR2 POP HL
LD A, (HL)
PRSYM EXX
PUSH HL
LD L, A
LD H, 0
ADD HL, HL
ADD HL, HL
ADD HL, HL
LD DE, FONT
ADD HL, DE
PUSH HL
LD DE, (XTXT)
LD A, E
ADD A, A
LD E, A
ADD A, A
ADD A, E
LD E, 255
LD L, 8
CHPL1 INC E
SUB L
JR NC, CHPL1
ADD A, L
LD H, A
LD A, L
SUB H
LD (SL1-1), A
LD (SL2-1), A
LD A, D; AADR
AND # 18
ADD A, # 40
LD H, A
LD A, D
AND 7
RRCA
RRCA
RRCA
ADD A, E
LD L, A
POP DE
LD C, 8
SCRL LD A, (DE)
LD B, 0
SL1 SRL (HL)
DJNZ SL1
AND A
LD B, 0
SL2 RL A
RL (HL)
DJNZ SL2
INC HL
LD (HL), A
DEC HL
INC H
INC DE
DEC C
JR NZ, SCRL
LD HL, XTXT
INC (HL)
POP HL
EXX
RET
XTXT DEFB 0
YTXT DEFB 0
BUFF; buffer for loading of 3 sectors
2
Besides restoring the damaged disc, the above
procedure can be used for
translation of the text contained in the HELP-programs to note
printable.
Monitors, debuggers, unfortunately, also not yet understood
porusski and faster may prove the following method: runs HELP,
insert a blank disk and pushed MAGIC. The program can then hang
up, but the text will be stored in uncompressed form. (Protect
from MAGIC your ad product will be only a madman). It remains
to crawl disk, extract the text and using
text editor to remove trash code at the beginning and end of
file.
*
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