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ZX Review #3-4
22 июля 1997 |
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Retro - Dzh.Hardman, E. Hyuzon. Top 40 procedures.
RETRO
Dzh.Hardman, E. Hyuzon.
40 best PROCEDURES.
(Continued see ZX REVIEW
97/1-2)
SECTION B
4. INTRODUCTION
Section B presents the program in machine code. For
simplicity and ease of use they are in standard format.
The introduction describes this
format and provides a program for
BASIC'e, which can be used for loading programs into memory.
Length: This is the length of the program
in bytes.
Doing some number of
variables: the program may,
require changes
value of one or
more variables
transmitted to the prog
Rummy buffered
printer.
Check each program so
sum: for in the form of a sequence
sequence of integers
positive numbers,
placed in the following
successive cell
memory. Verification
amount (ie, the sum
all the numbers entered
routines) is given by
to you
were confident in the right
regularity downloads.
Function: A short description
description of the tasks fulfilled
equate with
program.
Variables: We define the name,
length and address in the bu
Fere printer each
each variable. Ne
Belt length
one byte (a whole by
positive number in
ranging from 0 to
255) passed in
program from the BASIC
or keyboard Th
Res POKE.
POKE cell value
Two-byte variable
passed by a 2-x
commands:
POKE cell, the value of-256 *
INT (znachenie/256):
POKE a cell,
INT (znachenie/256)
Cells are used
Buffer memories
printer.
Calling Program vyzyvapodprogrammy: are used to
Niemi function USR,
which should
be included in the
command. If space
grams in the machine
dimensional code is not re
gives some values
chenie back
BASIC for completion
NII, then use
is the command:
RANDOMIZE USR address
If you need to
result was returned as a result
gistrovoy pair BC, then the call
done as follows:
LET A = USR address
or
PRINT USR address
depending on whether
whether the data returned
saved in the variable
BASIC or output
on the screen.
Explains control verification
Error: Key performed about
grams for illogical
GOVERNMENTAL or contradictory
O values of the variables
variables, parameters, and
etc.
Comments: Explains the possible
nye options prog
Rummy.
Listing in the program representation
Lena native language Assem
code: Blair. To download
in memory uses
Xia third column -
"The numbers for input."
All numbers here are
decimal system
IU.
As she explained the principle of
works: the program.
LOADER machine code
Almost all programs of this
books conveyed, ie, they will work correctly regardless of
where in the RAM, we their estates. If the program does not
traveling, in the comments
explains how it should be
changed if it is saved in a different area of memory. In
Section A (Part 2) we have seen,
that the ZX-SPECTRUM uses a variety of RAM for various
fukntsii and that the region between
cells, these systemic
variables RAMTOP and UDG, is designed to store routines in
machine code.
Program BP can be used to download, edit and move the program
in native. With the help of
the user can reset the pointer RAMTOP, which will
more space
for machine code, enter the program with the keyboard to move
forward or backward to adjust Error; insert or delete
part of the program.
Program BP. Loader
Machine Code (MC LOADER)
100 GO SUB 8100
200 REM ***** Calculation of available memory
210 LET min = 1 + PEEK 23730 +256 * PEEK 23731
220 LET p = PEEK 23732 +256 * PEEK 23733
230 LET t = p - min + 1
400 REM ***** determining the starting address
410 PRINT "Lowest possible start ="; min ... "Maximum space
avalible = "; t
420 INPUT "Do you wish to change the lowest start address
(Y or N)? "; Z $
430 IF z $ = "Y" OR z $ = "y" THEN GO TO 7000
440 INPUT "Enter address at which to start loading machine
code "; a
450 IF a <min OR a> p THEN BEEP .2,24: GO TO 440
500 GO SUB 8100
510 LET t = t-a + min
520 PRINT "You can use up to"; t "bytes" ...
530 LET u = PEEK 23675 +256 * PEEK 23676
540 IF a <u AND u = U THEN PRINT "You will overwrite the user defined
graphics area. "
560 INPUT "Is that OK (Y or N)?"; Z $
570 IF z $ = "N" OR z $ = "n" THEN GO TO 7000
580 IF z $ <> "Y" AND z $ <> "y" THEN BEEP .2,24: GO TO 560
700 REM *** GO AHEAD AND LOAD
710 LET l = a
750 GOSUB 8200
760 INPUT "Enter number, b, f, i, d or t"; z $
770 IF z $ = "" THEN BEEP .2,24: GO TO 760
780 LET a $ = CHR $ (CODE z $ (1) - 32 * (z $ (a )>"@"))
790 GO TO 800 +200 * (a $ = "B") +300 * (a $ = "F") +400 * (a
$ = "I") +500 * (a $ =
"D") +600 * (a $ = "T")
800 LET x = VAL z $
810 IF l> p THEN BEEP .2,24: GO TO 750
820 IF x <0 OR x> 256 OR x <> INT x THEN BEEP .2,24: GO TO 760
830 POKE l, x
840 LET l = l +1
850 GO TO 740
1000 REM *** Move forward
1010 LET l = l-1
1020 IF LEN z $> 1 THEN LET l = l +1- VAL z $ (2 TO)
1030 IF l 1 THEN LET l = l-1 + VAL z $ (2 TO)
1130 IF l> p THEN LET l = p
1140 GO TO 740
1200 REM *** Insert
1210 IF LEN z $ = 1 THEN LET n = 1: GO TO 1225
1220 LET n = VAL z $ (2 TO): IF n <1 OR n> p-1 OR n <> INT n
THEN
BEEP .2,24: GO TO 740
1225 CLS: GOSUB 8100: PRINT TAB 6; "Inserting in progress"
1230 FOR j = p TO l + n STEP -1
1240 POKE j, PEEK (j-n)
1250 NEXT j
1260 FOR j = l TO l + n-1
1270 POKE j, 0
1280 NEXT j
1290 GO TO 740
1300 REM *** Delete
1310 IF LEN z $ = 1 THEN LET n = 1: GO TO 1330
1320 LET n = VAL z $ (2 TO): IF n <1 OR n> pl OR n <> INT n THEN
BEEP .2,24: GO TO 740
1330 IF n <0 OR n> p-l THEN BEEP .2,24: GO TO 1320
1340 CLS: GOSUB 8100: PRINT TAB 6; "DELETING IN PROGRESS"
1350 FOR j = l TO p-n
1360 POKE j, PEEK (j + n)
1370 NEXT j
1380 GO TO 740
1400 STOP
1401 PRINT AT 21,7; "PROGRAM TERMINATED"
1410 STOP
7000 REM *** Change RAMTOP
7010 INPUT "ENTER NEW START ADDRESS"; a
7020 IF a <27000 OR a> p THEN BEEP .2,24: GO TO 710
7030 CLEAR a-1
7040 RUN
7999 STOP
8100 CLS
8110 PRINT TAB 6; "MACHINE CODE LOADER" ...
8120 RETURN
8200 REM *** Display the contents of memory
8210 GOSUB 8100
8220 PRINT "ADDRESS DECIMAL CHECK SUM"
8230 LET c = 0
8240 LET s = l-8: IF s p THEN LET f = p
8290 FOR j = s TO f
8300 LET c = c + PEEK j
8310 PRINT AT j-s +3,1; j; TAB 12; PEEK j; TAB 22; c
8320 NEXT j
8400 LET pos = a-s +3
8410 PRINT AT pos, 1912; FLASH 1; PEEK l
8420 RETURN
When the program BP starts, it prints the lowest address,
with which the program in machine
Codes can be entered and stored, ie, one greater
than RAMTOP.
In the car with 48K memory Jr.
address of 65368 if a user
to update the system variable RAMTOP.
At the end of RAM is usually reserved for the 168 bytes of
UDG, but program allows the user to use this area
if he wishes. It may also be possible to choose a new junior
address that the program then puts in a system environment
variable RAMTOP, using the command CLEAR. Data can not be
introduced to address less than 27000, as otherwise violated
boundaries of the region required for
the program BP. Program BP
asks for the address from which
should start the program in
native. Thus,
user can reserve
area for several procedures
and then download them each separately.
Figure shows the format of BP1
display after a cell has been loaded 32000 Program "Screen
Invert". The first column - the address, the second - the
contents of memory at this address, the third - the checksum.
The program "Screen Invert" has 18 bytes in length and checksum
is 1613. Consequently, it takes a cell with 32000 to 32017 and
the control the amount given to 32,017 cells,
ie amount of cell contents
(32000 ... 32017) is equal to 1613.
MACHINE CODE LOADER
ADDRESS DECIMAL CHECK SUM
32000 33 33
32001 0 33
32002 64 97
32003 1 98
32004 0 98
32005 24 122
..... ... ...
32012 11 836
32013 120 956
32014 177 1133
32015 32 1165
32016 247 1412
32017 201 1613
Fig. BP1. Submitted Screen
during boot
machine code. Program
"Screen Invert" is loaded with
address 32000.
The main screen of attention
Users attracted to one cell - the contents of this
cell flickers. This cell is the current and original
is chosen start address
program. The user enters
integer between 0 and 255 inclusive, that the program MC
LOADER fits into the current cell. Then the next address
becomes the current cell. The user can not enter a number, and
instead choose to adjust the options described in the Table BT1.
Code Option
B Back One
Address ago
B n (number) Go to n
Address ago
F Back One
mail forward
F n (number) Go to n
Address forward
I n (integer) Insert n bytes
each of which
contains 0
D n (number) Delete n bytes
current area
T End program
Table BT1.
Possible options
editing the machine code.
5. SUB-shift.
5.1. Shift attributes to the left.
Length: 23
Number of variables: 1
Checksum: 1574
Purpose: This program
shifts the attributes of all symbols
screen left one familiarity.
Variables:
Name: new attr
Length: 1
Cell: 23296
Comment: This attribute is introduced in the rightmost column.
Calling the program:
RANDOMIZE USR address
Error Checking: None.
Comment: This program is useful for highlighting areas of
text or graphics. To scroll through only 22 of upper row 24 *
should be changed to 22.
LISTING machine code
Assembly label NUMBER FOR INPUT
147.
LD HL, 22 528 33 0 88
LD A, (23296) 58 0 91
LD C, 24 14 24 *
NEXT_L LD B, 31 June 1931
NEXT_C INC HL 35
LD E, (HL) 94
DEC HL 1943
LD (HL), E 115
INC HL 35
DJNZ NEXT_C 16249
LD (HL), A 119
INC HL 35
DEC C 13
JR NZ, NEXT_L 32242
2
How it works:
In a couple of registers loaded HL address field attributes.
Battery load values attribute, enter in the right hand column.
The register C is loaded number of lines to shift - he
can now be used
as the row count. In case B
recorded the number 1 less
than the number of characters per line,
that it be used as a counter. HL is increased to
specify the following attribute
which is loaded into the E-register.
HL decreases, and at HL
fit value of E-register. HL increases again
to indicate the following attribute. Register B is reduced and
if it is not equal to 0, the transition to NEXT_C. HL now
points to the right column, and
at HL fit value
from the battery. HL is increased to indicate the following
string - NEXT_L. Row Count
(Case C) is reduced. If
result value is not 0,
subroutine returns
to NEXT_L.
Upon completion of the program
returns to BASIC.
5.2. Shift to the right attributes.
Length: 23
Number of variables: 1
Checksum: 1847
Purpose: This program
shifts the attributes of all symbols
screen to the right by one familiarity.
Variables:
Name: new attr
Length: 1
Cell: 23296
Comment: This attribute is entered in the leftmost column.
Calling the program:
RANDOMIZE USR address
Error Checking: None.
Comment: This program is useful for highlighting areas of
text or graphics. To scroll through only 22 of upper row 24 *
should be changed to 22.
LISTING machine code
Assembly label NUMBER FOR INPUT
147.
LD HL, 23295 33 255 1988
LD A, (23296) 58 0 91
LD C, 24 14 24 *
NEXT_L LD B, 31 June 1931
NEXT_C DEC HL 1943
LD E, (HL) 94
INC HL 35
LD (HL), E 115
DEC HL 1943
DJNZ NEXT_C 16249
LD (HL), A 119
DEC HL 1943
DEC C 13
JR NZ, NEXT_L 32242
RET 201
2
How it works:
In a couple of registers HL loaded the last byte of the
address attributes. Battery is loaded attribute value for input
into the left kololnku. In the case of C loaded lines for the
shift - it is used as row count. The register recorded the
number of B 1 less than the number of characters in
line for use in
as a counter.
HL increases to specify the following attribute. The value of
this attribute is loaded into E-register. HL increases, and
at HL fit value
of E-register. HL decreases
again to specify the address of the next attribute. Counter in
the register B is reduced, and if he does not is 0, then -
return back to NEXT_C. HL now points to the
leftmost column, and in a cell with the address of HL puts the
value of the battery. HL decreases to indicate the right end of
the next line. Row count is reduced, and if he is not 0 -
return back to NEXT_L.
The program returns to BASIC.
5.3. Shift attributes up.
Length: 21
Number of variables: 1
Checksum: 1591
Purpose: This program
shifts the attributes of all symbols
the screen up to one familiarity.
Variables:
Name: new attr
Length: 1
Cell: 23296
Comment: This attribute is introduced into the bottom line.
Calling the program:
RANDOMIZE USR address
Error Checking: None.
Comment: This program is useful for highlighting areas of
text or graphics. To scroll through only 22 of upper row 224 *
should be changed to 160.
LISTING machine code
Assembly label NUMBER FOR INPUT
147.
LD HL, 22560 33 32 88
LD DE, 22 528 17 0 88
LD BC, 736 1224 * 2
LDIR 237,176
LD A, (23296) 58 0 91
LD B, 32 June 1932
NEXT_C LD (DE), A 18
INC DE 1919
DJNZ NEXT_C 16252
RET 201
2
How it works:
In a couple of registers HL loaded address of the second row
attributes, DE loads the address of the first row and the BC
number of bytes loaded for the move.
The number of bytes specified in the register pair BC, is
copied to a memory address, located in the DE of the cells
starting from the address in HL, using the instructions LDIR.
These results indicate a DE on the bottom line attributes.
Battery is loaded code attribute to put in the bottom line.
B-register is loaded number of characters on one line - it is
used as a counter.
DE is placed at the value of the battery, and then DE
increases to indicate
next byte. Counter is decremented, and if it is not 0, the
routine returns to NEXT_C.
The program then returns to
BASIC.
5.4. The shift of attributes down.
Length: 21
Number of variables: 1
Checksum: 2057
Purpose: This program
shifts the attributes of all symbols
screen down one familiarity.
Variables:
Name: new attr
Length: 1
Cell: 23296
Comment: This attribute is introduced into the top line.
Calling the program:
RANDOMIZE USR address
Error Checking: None.
Comment: This program is useful for highlighting areas of
text or graphics. To scroll through only 22 top rows must be
changed: 223 * to 159, 255 * to 191, 224 * 160.
LISTING machine code
Assembly label NUMBER FOR INPUT
147.
LD HL, 23263 33 223 * 90
LD DE, 23295 17 255 * 90
LD BC, 736 1224 * 2
LDDR 237,184
LD A, (23296) 58 0 91
LD B, 32 June 1932
NEXT_C LD (DE), A 18
DEC DE 1927
DJNZ NEXT_C 16252
RET 201
2
How it works:
In HL load address of the last attribute of the twenty-third
row. In DE load address of the last attribute of the 24 th row.
In BC the number of bytes loaded for the move. The team then
moves LDDR bytes (the number indicated in the register pair BC)
of the address in HL at a DE. These
results in the DE store address
the last attribute of the first row.
As the battery is loaded attribute value to put in the top
row. The B-register the number of bytes loaded at the top line
- it is used as counter. In a cell with address DE
puts the value of the battery, and DE reduced to indicate the
next byte. Counter is decremented, and if he does not is equal
to 0, the routine returns to NEXT_C.
The program then returns to
BASIC.
5.5 The shift to the left by one character.
Length: 21
Number of variables: 0
Checksum: 1745
Purpose: This program scrolls the graphics screen for one
character to the left.
Subroutine call:
RANDOMIZE USR address
Error Checking: None.
Comment: This program is helpful in organizing the screen
as a "window" that shows a
Currently a minority of
large area of the display. This
"Window" is moved using
sub shift.
LISTING machine code
Assembly label NUMBER FOR INPUT
147.
LD HL, 16 384 33 0 64
LD D, L 85
LD A, 192 62 192
NEXT_L LD B, 31 June 1931
NEXT_B INC HL 35
LD E, (HL) 94
DEC HL 1943
LD (HL), E 115
INC HL 35
DJNZ NEXT_B 16249
LD (HL), D 114
INC HL 35
DEC A 61
JR NZ, NEXT_L 32242
RET 201
2
How it works:
In a couple of registers loaded HL address display file, and
D-register is set to 0. In
battery is loaded number
lines on the screen. The B-register
load value to 1
less than the number of characters in
line - it is the number of
bytes to copy.
HL increases to indicate
to the following address and the contents
of this cell is loaded into
E-register. HL decreases, and
cell loaded with the address of HL
value of E-register. HL increases to address the next byte and
a counter in the B-register is reduced. If it is not 0, the
routine returns to NEXT_B.
If the register B is 0, that
means that the last byte
line copied and HL points to the extreme right bytes. By
this address in the register pair
HL placed 0, and HL increased, pointing to the next
line. Row Count - the battery - is reduced, and if he
is not zero, a transition to NEXT_L.
The program returns to BASIC.
5.6.Sdvig right one character.
Length: 22
Number of variables: 0
Checksum: 1976
Purpose: This program
scrolls the contents of the display file, one character to the
right.
Subroutine call:
RANDOMIZE USR address
Error Checking: None.
Comment: This program is helpful in organizing the screen
as a "window" that shows a
Currently a minority of
large area of the display. This
"Window" is moved using
sub shift.
LISTING machine code
Assembly label NUMBER FOR INPUT
147.
LD HL, 22527 33 255 1987
LD D, 0 22 0
LD A, 192 62 192
NEXT_L LD B, 31 June 1931
NEXT_B DEC HL 1943
LD E, (HL) 94
INC HL 35
LD (HL), E 115
DEC HL 1943
DJNZ NEXT_B 16249
LD (HL), D 114
DEC HL 1935
DEC A 61
JR NZ, NEXT_L 32242
RET 201
2
How it works:
In a couple of registers HL loaded the last byte address of
the display file, and the D-register is set to 0. As the
battery is loaded on the number of rows screen. The B-register
is loaded value of 1 less than the number of characters per
line - it is used as a counter.
HL decreases, indicating
next byte, and its value
loaded into the E-register. HL then increases in cell
address value is loaded HL
E-sensitive. HL decreases, pointing to the next byte, and
counter (B-register) is reduced. If it is not 0, the routine
returns to NEXT_B.
If the register B is 0, that
means that the HL indicates
leftmost byte of the string. Then, at a register pair
HL placed 0, and HL decreases, pointing to the next line. Row
Count (battery) decreases and if it is not equal
0, a transition to NEXT_L.
The program returns to BASIC.
5.7. Upward shift by one character.
Length: 68
Number of variables: 0
Checksum: 6328
Purpose: The program shifts
display file contents
Up to eight pixels.
Calling the program:
RANDOMIZE USR address
Error Checking: None.
Comment: None.
LISTING machine code
Assembly label NUMBER FOR INPUT
147.
LD HL, 16 384 33 0 64
LD DE, 16 416 17 32 64
SAVE PUSH HL 229
PUSH DE 213
LD C, 23 14 23
NEXT_L LD B, 32 June 1932
COPY_B LD A, (DE) 26
LD (HL), A 119
LD A, C 121
AND 7230 7
CP 1 254 1
JR NZ, NEXT_B 32 2
SUB A 151
LD (DE), A 18
NEXT_B INC HL 35
INC DE 1919
DJNZ COPY_B 16241
DEC C 13
JR Z, REST 40 19
LD A, C 121
AND 7230 7
CP 0254 0
JR Z, N_BLOCK 40 22
CP 7254 7
JR NZ, NEXT_L 32225
PUSH DE 213
LD DE, 1792 17 0 7
ADD HL, DE 25
POP DE 209
JR NEXT_L 24217
REST POP DE 209
POP HL 225
INC D 20
36 INC H
LD A, H 124
CP 72254 1972
JR NZ, SAVE 32,204
RET 201
N_BLOCK PUSH HL 229
LD HL, 1792 33 0
ADD HL, DE 25
EX DE, HL 235
POP HL 225
JR NEXT_L 24198
2
How it works:
In a couple of registers HL loaded starting address of
display file, and loads the address in DE byte of eight lines
down. HL and DE are stored in the stack. In
C-register is loaded on a number of
less than the number of lines on the screen. The B-register is
loaded the number of bytes on one line of the display - it is
used as a counter.
As the battery is loaded
byte addressed by DE, and this
value is loaded into the cell by
at HL. As the battery is loaded content, C-register and
if it is 1, 9 or 17, in
cell is placed at DE
0. HL and DE are increasing, pointing to the next byte. Counter
in B-register is reduced, and if
it is not 0, the transition to 'COPY_B'.
Row count in register C and then decreases. If it is
0, a transition to
'RESTORE'. If C contains 8 or
16, the transition to
'N_BLOCK'. If C does not contain 7
or 15, the routine goes to
'NEXT_L'. Then 1792 is added to the HL - HL now points to the
the next block of the screen. Subroutine goes to 'NEXT_L'.
In the process of 'REST' DE and HL are taken from the stack,
and 256 is added to each of them. Thus, DE and HL points to a
string, the position which is lower than what was
previous cycle. If HL contains the value 18432, the subroutine
returns to BASIC, otherwise the transition to a procedure
'SAVE'. The procedure 'N_BLOCK'
1972 added to the DE - such
read DE points to the next block of the screen. Subroutine
then returns to 'NEXT_L'.
Upon completion of the work going on
return to BASIC.
5.8. Shift down by one character.
Length: 73
Number of variables: 0
Checksum: 7987
Purpose: This program
shifts the contents of the display
file down to eight pixels.
Calling the program:
RANDOMIZE USR address
Error Checking: None.
Comment: None.
LISTING machine code
Assembly label NUMBER FOR INPUT
147.
LD HL, 22527 33 255 1987
LD DE, 22495 17 223 1987
SAVE PUSH HL 229
PUSH DE 213
LD C, 23 14 23
NEXT_L LD B, 32 June 1932
CORY_B LD A, (DE) 26
LD (HL), A 119
LD A, C 121
AND 7230 7
CP 1 254 1
JR NZ, NEXT_B 32 2
SUB A 151
LD (DE), A 18
NEXT_B DEC HL 1943
DEC DE 1927
DJNZ COPY_B 16241
DEC C 13
JR Z, REST 40 21
LD A, C 121
AND 7230 7
CP 0254 0
JR Z, N_BLOCK 40 24
CP 7254 7
JR NZ, NEXT_L 32225
PUSH DE 213
LD DE, 1792 17 0 7
AND A 167
SBC HL, DE 237 82
POP DE 209
JR NEXT_L 24215
REST POP DE 209
POP HL 225
DEC D 21
DEC H 37
LD A, H 124
CP 79254 1979
RET Z 200
JR SAVE 24,201
N_BLOCK PUSH HL 229
LD HL, 1792 33 0 7
EX DE, HL 235
AND A 167
SBC HL, DE 237 82
EX DE, HL 235
POP HL 225
JR NEXT_L 24193
2
How it works:
In a couple of registers HL loaded the last byte address of
the display file, and DE is loaded a byte address that
corresponds to the image, separated by eight lines up. HL and
DE stored on the stack. The C-register is loaded on a number of
less than the number of lines on the screen. Then, in the
B-register is loaded the number of bytes on one line of the
display - it is used as a counter.
As the battery is loaded bytes
address DE, and this value is sent to the cell at HL.
As the battery is loaded (for
test) the contents of register C
and if it is 1, 9 or 17,
then the cell is placed at DE 0. HL and DE is reduced by
unit, pointing to the next
byte display. Byte count in
register B decreases and if
it is not 0, the transition to 'COPY_B'.
Further decrements
rows in register C. If it is 0, the transition to the procedure
of 'REST'. If C contains 8 or 16, then a transition to
procedure 'N_BLOCK'. Unless C
contains 7 or 15, the subroutine
moves to 'NEXT_L'. Then, from
HL subtracted 1792 - now HL
points to the next third of the screen and the routine goes to
'NEXT_L'.
In the process of 'REST' values of DE
and HL are taken from the stack, and from them
subtracted the number 256. As a result, DE
HL and points to a string, a position which is higher than that
was in the previous cycle. If HL
contains the value 20479, the subroutine returns to BASIC,
otherwise there is a transition to a procedure 'SAVE'.
The procedure 'N_BLOCK' 1972 is subtracted from the DE, ie,
then DE points to the next block
screen. Subroutine then proceeds to 'NEXT_L'.
5.9. Shift left by one pixel.
Length: 17
Number of variables: 0
Checksum: 1828
Purpose: The shift in the content
display a file on one pixel
left.
Calling the program:
RANDOMIZE USR address
Error Checking: None.
Comment: This program
provides a smoother movement than a shift left by one
symbol, but you need to call it
eight times to move
display one complete character.
LISTING machine code
Assembly label NUMBER FOR INPUT
147.
LD HL, 22527 33 255 1987
LD C, 192 14 192
NEXT_L LD B, 32 June 1932
OR A 183
NEXT_B RL (HL) 203 1922
DEC HL 1943
DJNZ NEXT_B 16251
DEC C 13
JR NZ, NEXT_L 32245
RET 201
2
How it works:
In a couple of registers HL loaded the last byte address of
the display file, and register C load number of lines in
file system on display (it's used as a counter lines). The
register B is loaded amount bytes on one line (it is used as
the byte count). Carry flag is set to
0.
Bytes, addressed to HL, is shifted by one bit to the left, bit
transfer is copied to the extreme
rightmost bit, and the leftmost bit
copied into the carry flag. HL register pair is reduced to
guidance to the next byte and
meter (B-register) is reduced.
If it is not 0, the routine makes a transition to
NEXT_B, otherwise reduce the number of processed lines, and
if it is not 0, the routine returns to the procedure
NEXT_L.
Upon completion of the program
returns to BASIC.
5.10. Shift to the right by one peak
villages.
Length: 17
Number of variables: 0
Checksum: 1550
Purpose: The shift in the content
display a file on one pixel
right.
Subroutine call:
RANDOMIZE USR address
Error Checking: None.
Comment: This program
provides a smoother movement than the right shift on
one character, but it takes eight
times cause the program to move the display to one
complete symbol.
LISTING machine code
Assembly label NUMBER FOR INPUT
147.
LD HL, 16 384 33 0 64
LD C, 192 14 192
NEXT_L LD B, 32 June 1932
OR A 183
NEXT_B RR (HL) 203 30
INC HL 35
DJNZ NEXT_B 16251
DEC C 13
JR NZ, NEXT_L 32245
RET 201
2
How it works:
In a couple of registers loaded HL address display file, and
C-register is loaded the number of lines on the screen (it's
used as a counter lines). In Register B is loaded the number of
bytes on one line (it used as a counter
bytes). Carry flag set to 0. Bytes at HL
shifted by one bit to the right,
carry bit is copied into the leftmost bit and the rightmost
bit is copied into the carry flag.
HL register pair increases,
pointing to the next byte and
meter (B-register) is reduced.
If it is not 0, the routine makes a transition to
NEXT_B, otherwise reduce the number of processed lines, and
if it is not 0, the routine returns to NEXT_L.
When you are finished, the procedure
returns to BASIC.
5.11.Sdvig up one pixel.
Length: 91
Number of variables: 0
Checksum: 9228
Purpose: The shift in the content
display a file up one
pixel.
Calling the program:
RANDOMIZE USR address
Error Checking: None.
Comment: None.
LISTING machine code
Assembly label NUMBER FOR INPUT
147.
LD HL, 16 384 33 0 64
LD DE, 16 640 17 0 65
LD C, 192 14 192
NEXT_L LD B, 32 June 1932
CORY_B LD A, (DE) 26
LD (HL), A 119
LD A, C 121
CP 2 254 2
JR NZ, NEXT_B 32 2
SUB A 151
LD (DE), A 18
NEXT_B INC DE 1919
INC HL 35
DJNZ COPY_B 16243
PUSH DE 213
LD DE, 224 17 224 0
ADD HL, DE 25
EX (SP), HL 227
ADD HL, DE 25
EX DE, HL 235
POP HL 225
DEC C 13
LD A, C 121
AND 7230 7
CP 0254 0
JR NZ, SUBTR 32 10
PUSH DE 213
LD DE, 2016 17 224 7
AND A 167
SBC HL, DE 237 82
POP DE 209
JR N_BLOCK 24 14
SUBTR CP 1254 1
JR NZ, N_BLOCK 32 10
PUSH HL 229
EX DE, HL 235
LD DE, 2016 17 224 7
AND A 167
SBC HL, DE 237 82
EX DE, HL 235
POP HL 225
N_BLOCK LD A, C 121
AND 63 230 63
CP 0254 0
JR NZ, ADD 32 6
LD A, 7 July 1962
ADD A, H 132
LD H, A 103
JR NEXT_L 24187
ADD CP 1254 1
JR NZ, NEXT_L 32183
LD A, 7 July 1962
ADD A, 7130
LD D, A 87
LD A, C 121
CP 1 254 1
JR NZ, NEXT_L 32174
RET 201
2
How it works:
In a couple of registers loaded HL address display file, and
DE address of first byte of the second
lines of the display. The register C is loaded the number of
lines on the screen. The register B is loaded the number of
bytes on one line - it used as a counter.
As the battery is loaded bytes
address in DE, and this value
transferred into the cell at
HL. As the battery is stored the contents of register C. If it
is 2, the DE indicates the bottom of the screen and the address
is written 0. HL and DE increase, to indicate
next byte. Counter in the register B decreases and if it does
not is 0, the transition to
COPY_B.
224 is added to the register
pairs HL and DE, to point to the next line screen.
Then decreases register C,
counter lines. If the contents
Register C is not a multiple of 8, a transition to SUBTR,
otherwise 2016 subtracted from the HL and is
transition to N_BLOCK. Now HL
points to the following 8 lines.
The procedure SUBTR, if the value of (C-1) is not a multiple
of 8, a transition to N_BLOCK, otherwise 2016 is subtracted
from the DE, ie, DE now points to the following 8 lines. The
procedure N_BLOCK, if the value of C-register multiply 64, 1792
added to the HL and made the transition to NEXT_LINE - HL now
points to the next block of 64 lines. The procedure
ADD, if the value of (C-1)
multiple of 64, 1792 added to the
DE, DE to a pair of points to
the next block of 64 lines. If
C-register does not contain 1, then
the program returns to N_LINE,
otherwise return to BASIC.
5.12. Shift down by one pixel.
Length: 90
Number of variables: 0
Checksum: 9862
Purpose: The shift in the content
display the file down to one
pixel.
Calling the program:
RANDOMIZE USR address
Error Checking: None.
Comment: None.
LISTING machine code
Assembly label NUMBER FOR INPUT
147.
LD HL, 22527 33 255 1987
LD DE, 22271 17 255 1986
LD C, 192 14 192
NEXT_L LD B, 32 June 1932
CORY_B LD A, (DE) 26
LD (HL), A 119
LD A, C 121
CP 2 254 2
JR NZ, NEXT_B 32 2
SUB A 151
LD (DE), A 18
NEXT_B DEC DE 1927
DEC HL 1943
DJNZ COPY_B 16243
PUSH DE 213
LD DE, 224 17 224 0
ADD A 167
SBC HL, DE 237 82
EX (SP), HL 227
AND A 167
SBC HL, DE 237 82
EX DE, HL 235
POP HL 225
DEC C 13
LD A, C 121
AND 7230 7
CP 0254 0
JR NZ, ADD 32 8
PUSH DE 213
LD DE, 2016 17 224 7
ADD HL, DE 25
POP DE 209
JR N_BLOCK November 24
ADD CP 1254 1
JR NZ, N_BLOCK 32 7
PUSH HL 229
LD HL, 2016 33 224 7
ADD HL, DE 25
EX DE, HL 235
POP HL 225
N_BLOCK LD A, C 121
AND 63 230 63
CP 0254 0
JR NZ, SUBTR 32 6
LD A, H 124
SUB 7214 7
LD H, A 103
JR NEXT_L 24188
SUBTR CP 1254 1
JR NZ, NEXT_L 32184
LD A, D 122
SUB 7214 7
LD D, A 87
LD A, C 121
CP 1 254 1
JR NZ, NEXT_L 32175
RET 201
2
How it works:
In a couple of registers HL loaded the last byte address of
the display file, and a pair of registers DE loaded byte
address line, which is located directly above this byte. In
register C is loaded the number of lines the screen. The
register B is loaded the number of bytes on one line of the
display - it is used as a counter.
As the battery is loaded bytes
from a cell with an address in DE, and this
value is loaded into the cell by
at HL. As the battery is loaded the contents of register C.
If it is 2, the DE indicates that the top line of the screen,
address of which was brought 0. HL and
DE decreased to indicate
The following bytes. Meter (B-register) decreases and if it
does not is 0, the transition to
COPY_B.
224 is subtracted from the register
pairs HL and DE - now they point to the next line of the screen.
Register C (row count)
decreases. If the contents of register C is a multiple of 8, ie
with 8 cycles for one line the transition to a procedure
ADD, otherwise the 2016 is added to the HL
and a transition to N_BLOCK -
HL now points to the next 8 lines.
The procedure ADD, if the value of (C-1) is not evenly
divisible by 8, a transition to N_BLOCK, otherwise 2016
added to the DE, a pair of registers DE points to the following
8 lines. The procedure N_BLOCK, if the value of C-register is
divisible by 64, subtracted from HL 1792. HL now points to the
next block of 64 lines, and a transition to NEXT_L. The
procedure SUBTR, if the value of (C-1) is not divisible
64, is subtracted from DE 1792 - in
finally DE points to the next
block of 64 lines.
If the C-register does not contain 1,
then returns to the subroutine
NEXT_LINE, except in BASIC.