Studies - The program sort the array in ascending order. The procedure for filling the screen specified attribute. Procedure display pictures. The effect of moving towards the stars. "Shower", coming from the upper left corner of the screen. The procedure of "shedding" pictures on the pixel lines. The program of "pulling" the picture at an angle of 45 degrees. Three procedures "Scroll".

<b>Studies</b> - The program sort the array in ascending order. The procedure for filling the screen specified attribute. Procedure display pictures. The effect of moving towards the stars.

(C) Komandin I., Kaluga


   1. I'll start with the easiest.
Once upon a time Sergei Kolotov
proposed to make the program ascending sort array
starting at memory address
specified in the HL, and the length specified in BC.
144.
1910; (c) ZX-MANIACS
20 ORG 40000
30 ENT
1940 50000 START EQU
50 LENGTH EQU 500
60 AGAIN LD HL, START
70 LD BC, LENGTH
80 DEC BC
90 LD D, 0
100 LOOP LD E, (HL)
110 INC HL
120 LD A, (HL)
130 CP E
140 JR NC, CONT
150 LD (HL), E
160 DEC HL
170 LD (HL), A
180 LD D, 1
190 INC HL
200 CONT DEC BC
210 LD A, B
220 OR C
230 JR NZ, LOOP
240 LD A, D
250 OR A
260 JR NZ, AGAIN
270 RET
2

   2. Next the program is done again, "commissioned by Sergei 
Kolotova. This procedure of filling the screen specified 
attribute. Fill is on the swirling clockwise spiral. Speed of 
the program regulated within wide limits.

144.
1910; (c) ZX-MANIACS
20 ORG 40000
30 ENT
40 COLOUR EQU 23
50 PAUSE EQU 1000
60 LD HL, 22528
70 LD B, 12
1980 LOOP PUSH HL
90 LD A, B
100 ADD A, A
110 ADD A, 8
120 L1 LD (HL), COLOUR
130 INC HL
140 DEC A
150 CALL WAIT
160 JR NZ, L1
170 LD A, B
180 ADD A, A
190 DEC HL
200 LD DE, 32
210 L2 LD (HL), COLOUR
220 ADD HL, DE
230 DEC A
240 CALL WAIT
250 JR NZ, L2
260 SBC HL, DE
270 LD A, B
280 ADD A, A
290 ADD A, 8
300 L3 LD (HL), COLOUR
310 DEC HL
320 DEC A
330 CALL WAIT
340 JR NZ, L3
350 INC HL
360 LD A, B
370 ADD A, A
380 L4 LD (HL), COLOUR
390 SBC HL, DE
400 DEC A
410 CALL WAIT
420 JR NZ, L4
430 POP HL
440 LD DE, 33
450 ADD HL, DE
460 DJNZ LOOP
470 RET
480 WAIT PUSH BC
490 PUSH AF
500 LD BC, PAUSE
510 WAIT1 DEC BC
520 LD A, B
530 OR C
540 JR NZ, WAIT1
550 POP AF
560 POP BC
570 RET


   3. It is possible that reading the abstract to the previous
procedure, you will think: "Is not
bad it would make the program
display pictures in this way. "Do not bother
this issue! It's as fruitless as to dream of the periodic 
table. Why? Yes, because all this has long been thought out and 
done. Please. 144.

1910; (c) ZX-MANIACS
20 ORG 40000
30 ENT
40 BUFF EQU 50000
50 PAUSE EQU 1000
60 LD HL, 22528
70 LD DE, 22529
80 LD (HL), 0
90 LD BC, 767
100 LDIR
110 LD HL, BUFF
120 LD DE, 16384
130 LD BC, 6144
140 LDIR
150 LD HL, 22528
160 LD B, 12
170 LOOP PUSH HL
180 LD A, B
190 ADD A, A
200 ADD A, 8
210 L1 CALL PUT
220 INC HL
230 DEC A
240 CALL WAIT
250 JR NZ, L1
260 LD A, B
270 ADD A, A
290 LD DE, 32
300 L2 CALL PUT
310 ADD HL, DE
320 DEC A
330 CALL WAIT
340 JR NZ, L2
350 SBC HL, DE
360 LD A, B
370 ADD A, A
380 ADD A, 8
390 L3 CALL PUT
400 DEC HL
410 DEC A
420 CALL WAIT
430 JR NZ, L3
440 INC HL
450 LD A, B
460 ADD A, A
470 L4 CALL PUT
480 SBC HL, DE
490 DEC A
500 CALL WAIT
510 JR NZ, L4
520 POP HL
530 LD DE, 33
540 ADD HL, DE
550 DJNZ LOOP
560 RET
570 WAIT PUSH BC
580 PUSH AF
590 LD BC, PAUSE
600 WAIT1 DEC BC
610 LD A, B
620 OR C
630 JR NZ, WAIT1
640 POP AF
650 POP BC
660 RET
670 PUT PUSH AF
680 PUSH DE
690 PUSH HL
700 LD DE, BUFF-16384
710 ADD HL, DE
720 LD A, (HL)
730 POP HL
740 LD (HL), A
750 POP DE
760 POP AF
770 RET
2

   4. I turn now, perhaps,
by pixel effects (after
creating a "fountain" I am very
like this type of program).
After reviewing all of the ZX-REVIEW 94-96
years, I am a great surprise, not found a program,
creates the effect of moving towards the stars (and it should 
agree that the effect is extremely well known). I think this 
should be corrected. 144.

1910; (c) ZX-MANIACS
20 ORG 40000
30 ENT
40 INIT LD HL, COORDS
50 LD B, 70
60 L1 LD (HL), 128
70 INC HL
80 LD (HL), 96
90 INC HL
100 CALL RND
110 LD (HL), A
120 INC HL
130 CALL RND
140 LD (HL), A
150 INC HL
160 DJNZ L1
170 MAIN LD HL, COORDS
180 LD B, 70
190 L2 PUSH BC
200 PUSH HL
210 LD C, (HL)
220 INC HL
230 LD B, (HL)
240 LD A, 191
250 SUB B
260 PUSH HL
270 CALL 8880
280 LD B, A
290 LD A, 7
300 SUB B
310 ADD A, A
320 ADD A, A
330 ADD A, A
340 ADD A, 134
350 LD (RPX), A
360 DEFB # CB
370 RPX NOP
380 POP HL
390 INC HL
400 LD B, (HL)
410 DEC HL
420 LD A, (HL)
430 ADD A, B
440 CP 191
450 JR NZ, NEW
460 LD (HL), A
470 INC HL
480 INC HL
490 LD B, (HL)
500 DEC HL
510 DEC HL
520 DEC HL
530 LD A, (HL)
540 ADD A, B
550 CP 4
560 JR C, NEW1
570 CP 252
580 JR NC, NEW1
590 LD (HL), A
600 LD C, (HL)
610 INC HL
620 LD B, (HL)
630 LD A, 191
640 SUB B
650 PUSH HL
660 CALL 8880
670 LD B, A
680 LD A, 7
690 SUB B
700 ADD A, A
710 ADD A, A
720 ADD A, A
730 ADD A, 198
740 LD (SPX), A
750 DEFB # CB
760 SPX NOP
770 POP HL
780 INC HL
790 LD A, (HL)
800 OR A
810 JR NZ, PASS
820 INC HL
830 LD A, (HL)
840 OR A
850 JR NZ, PASS
860 DEC HL
870 DEC HL
880 NEW DEC HL
890 NEW1 LD (HL), 128
900 INC HL
910 LD (HL), 96
920 INC HL
930 CALL RND
940 LD (HL), A
950 INC HL
960 CALL RND
970 LD (HL), A
980 PASS POP HL
990 POP BC
1000 INC HL
1010 INC HL
1020 INC HL
1030 INC HL
1040 DJNZ L2
1050 RET
1060 RND LD DE, 0
1070 LD A, D
1080 ADD A, # 77
1090 LD D, A
1100 RLE E
1110 ADD A, E
1120 LD E, A
1130 LD (RND +1), DE
1140 AND 1915
1150 SUB 7
1160 RET
1170 COORDS DEFS 280
2

   The procedure is a step by step, ie each of its launch
produces a shift of the points. Program is run fairly standard:
144.

          CALL INIT
LOOP HALT

          CALL MAIN

          LD A, # 7F

          IN A, (# FE)

          RRA

          JR C, LOOP

          RET
2

   If you think that the speed with which the fly points
too large, then replace
lines 1140 and 1150 to the following:

1140 AND 7
1150 SUB 3


   If you need to
the duration of the program fits into one interrupt, I want to
to warn that the maximum number of points at
where possible, is 85
(On my computer.) Quite
it is possible that you have it will be
slightly different. Number
points recorded in the register B in
Lines 50 and 180. Buffer Size
coordinates given by the line
1170, should be four times
greater than the number of points.


   5. The following procedure - processing the previous one. It 
creates a "shower", coming from the upper left corner of the 
screen. 144.

1910; (c) ZX-MANIACS
20 ORG 40000
30 ENT
40 INIT LD HL, COORDS
50 LD B, 60
60 L1 LD (HL), 0
70 INC HL
80 LD (HL), 0
90 INC HL
100 CALL RND
110 LD (HL), A
120 INC HL
130 CALL RND
140 LD (HL), A
150 INC HL
160 DJNZ L1
170 MAIN LD HL, COORDS
180 LD B, 60
190 L2 PUSH BC
200 PUSH HL
210 LD C, (HL)
220 INC HL
230 LD A, (HL)
240 PUSH HL
250 CALL 8880
260 LD B, A
270 LD A, 7
280 SUB B
290 ADD A, A
300 ADD A, A
310 ADD A, A
320 ADD A, 134
330 LD (RPX), A
340 DEFB # CB
350 RPX NOP
360 POP HL
370 INC HL
380 LD B, (HL)
390 DEC HL
400 LD A, (HL)
410 ADD A, B
420 CP 191
430 JR NC, NEW
440 LD HL, A
450 INC HL
460 INC HL
470 LD B, HL
480 DEC HL
490 DEC HL
500 DEC HL
510 LD A, (HL)
520 ADD A, B
530 JR C, NEW1
540 LD (HL), A
550 LD C, (HL)
560 INC HL
570 LD A, (HL)
580 PUSH HL
590 CALL 8880
600 LD B, A
610 LD A, 7
620 SUB B
630 ADD A, A
640 ADD A, A
650 ADD A, A
660 ADD A, 198
670 LD (SPX), A
680 DEFB # CB
690 SPX NOP
700 POP HL
710 INC HL
720 LD A, (HL)
730 OR A
740 JR NZ, PASS
750 INC HL
760 LD A, (HL)
770 OR A
780 JR NZ, PASS
790 DEC HL
800 DEC HL
810 NEW DEC HL
820 NEW1 LD (HL), 0
830 INC HL
840 LD (HL), 0
850 INC HL
860 CALL RND
870 LD (HL), A
880 INC HL
890 CALL RND
900 LD (HL), A
910 PASS POP HL
920 POP BC
930 INC HL
940 INC HL
950 INC HL
960 INC HL
970 DJNZ L2
980 RET
990 RND LD DE, 0
1000 LD A, D
1010 ADD A, # 77
1020 LD D, A
1030 RLE E
1040 ADD A, E
1050 LD E, A
1060 LD (RND +1), DE
1070 AND 7
1080 INC A
1090 RET
1100 COORDS DEFS 24
2

   Called program similar to the previous one. Number of points 
recorded in the register B in Lines 50 and 180. Speed points

can be reduced by changing the line
1070 to:

1070 AND 3


   The maximum number of points at
which time the program fits into one interrupt
is 90.

   If you want to shower rained
from the upper right corner of the screen,
then replace the line 60, 520 and 820
the following:
144.
60 L1 LD (HL), 255
520 SUB B
820 NEW1 LD (HL), 255
2

   Neither this nor the previous program did not save image
on the screen, but I think it is
is not necessary. Indeed, in DEMO and
INTRO to toys (and where else can use these programs?) Dynamic 
image, and damaging several points are not be noticeable. 
Saving the same screen image will mean, first, the slowdown of 
the program, and, secondly, damage to entire bytes (after all, 
to time when the procedure is to restore the image,

picture is likely to change).


   6. Well, now I will return to
his favorite subject - drawing and clean images on the screen. 
Nizheprevedennaya procedure designed to clean monochrome image. 
She seemed to be overwhelms the image on a pixel

lines. I think it would be nice to use in conjunction with
I wrote earlier procedure of "spraying" pictures on the pixel 
lines. 144.

1910; (c) ZX-MANIACS
20 ORG 40000
30 ENT
40 PAUSE EQU 50
50 LD B, 191
1960 LOOP PUSH BC
70 LD A, B
80 DEC A
1990 PUSH AF
100 LD A, 192
110 SUB B
120 LD B, A
130 POP AF
140 LOOP1 PUSH BC
150 PUSH AF
160 LD C, 0
170 CALL 8880
180 POP AF
190 PUSH AF
144.200 PUSH HL
210 INC A
220 LD C, 0
230 CALL 8880
240 EX DE, HL
250 LD BC, 32
260 POP HL
270 PUSH HL
280 LDIR
290 POP HL
300 LD D, H
310 LD E, L
320 LD (HL), 0
330 INC DE
340 LD BC, 31
350 LDIR
360 POP AF
370 INC A
380 LD B, PAUSE
390 WAIT DJNZ WAIT
400 POP BC
410 DJNZ LOOP1
420 LD HL, 22496
430 LD DE, 22497
440 LD BC, 31
450 LD (HL), 0
460 LDIR
470 POP BC
480 DJNZ LOOP
490 RET
2

   Speed of the program
can be changed by changing the value
delay in line 40.


   7. The following program draws a picture, pulling her
from the left edge of the screen at an angle
45 degrees. Effect is quite
interesting, but the procedure, all
as a drawback - it's a bit
sluggish (image shakes because the step of drawing is not
fit into one interrupt).
144.
1910; (c) ZX-MANIACS
20 ORG 40000
30 ENT
40 BUFF EQU 50000
50 LD A, 1
1960 LOOP PUSH AF
1970 CP 193
80 JR C, CONT
90 LD A, 192
100 CONT LD B, A
110 XOR A
120 LOOP1 PUSH BC
130 PUSH AF
140 LD C, 0
150 CALL 8880
160 LD DE, BUFF-16384
170 PUSH HL
180 ADD HL, DE
190 LD B, 32
200 L1 RR (HL)
210 INC HL
220 DJNZ L1
230 POP HL
240 LD B, 32
250 L2 RR (HL)
260 INC HL
270 DJNZ L2
280 POP AF
290 INC A
300 POP BC
310 DJNZ LOOP1
320 POP AF
330 INC A
340 JR NZ, LOOP
350 LD B, 192
360 LOOP2 PUSH BC
370 LD A, 191
380 LOOP3 PUSH BC
390 PUSH AF
400 LD C, 0
410 CALL 8880
420 PUSH HL
430 LD DE, BUFF-16384
440 ADD HL, DE
450 LD B, 32
460 L3 RR (HL)
470 INC HL
480 DJNZ L3
490 POP HL
500 LD B, 32
510 L4 RR (HL)
520 INC HL
530 DJNZ L4
540 POP AF
550 DEC A
560 POP BC
570 DJNZ LOOP3
580 POP BC
590 DJNZ LOOP2
600 LD HL, BUFF +6144
610 LD DE, 22528
620 LD BC, 768
630 LDIR
640 RET
2

   During operation, the procedure
erases the image stored in memory at BUFF.


   8. Another program theme, which I've always liked - is, of 
course, SCROLL'y. So this time I decided not to leave it 
unattended, and therefore offer some of their New programs from 
this area. 

   I will not describe the action
first SCROLL'a. Let me just say
it has a drawback, opposite the previous
program - it's too fast. In
as a counter can
advise on insert a space between letters in each word
text ticker and 2-3
spaces between words.
144.
1910; (c) ZX-MANIACS
20 ORG 40000
30 ENT
40 INIT LD HL, TEXT
50 LD (TEXTP), HL
60 SCROLL LD HL, (TEXTP)
70 LD A, (HL)
80 OR A
90 JR NZ, CONT
100 LD HL, TEXT
110 LD (TEXTP), HL
120 LD A, (HL)
130 CONT INC HL
140 LD (TEXTP), HL
150 LD H, 0
160 LD L, A
170 ADD HL, HL
180 ADD HL, HL
190 ADD HL, HL
200 LD DE, (23606)
210 ADD HL, DE
220 LD DE, # 50DF
230 LD B, 8
240 LOOP LD A, (HL)
250 LD (DE), A
260 INC HL
270 INC D
280 DJNZ LOOP
290 LD HL, # 50C1
300 LD B, 2
310 LOOP2 PUSH BC
320 PUSH HL
330 LD B, 8
340 LOOP1 PUSH BC
350 PUSH HL
360 LD D, H
370 LD E, L
380 DEC DE
390 LD BC, 31
400 LDIR
410 POP HL
420 INC H
430 POP BC
440 DJNZ LOOP1
450 POP HL
460 LD DE, 32
470 ADD HL, DE
480 POP BC
490 DJNZ LOOP2
500 LD A, 176
510 LD (CH +1), A
520 LD A, 60
530 LD (CH3), A
540 LD (CH4), A
550 XOR A
560 LD (CH2 +1), A
570 LD (CH5 +1), A
580 CALL UPDOWN
590 LD A, 128
600 LD (CH2 +1), A
610 LD (CH5 +1), A
620 CALL UPDOWN
630 LD A, 191
640 LD (CH +1), A
650 LD A, 61
660 LD (CH3), A
670 LD (CH4), A
680 LD A, 64
690 LD (CH2 +1), A
700 LD (CH5 +1), A
710 CALL UPDOWN
720 LD A, 192
730 LD (CH2 +1), A
740 LD (CH5 +1), A
750 CALL UPDOWN
760 RET
770 UPDOWN LD B, 15
780 CH1 LD A, 0
790 LOOP5 PUSH BC
800 PUSH AF
810 CH2 LD C, 0
820 PUSH BC
830 CALL 8880
840 POP BC
850 POP AF
860 PUSH AF
870 EX DE, HL
880 CH3 NOP
890 CALL 8880
900 LD BC, 8
910 LDIR
920 POP AF
930 CH4 NOP
940 POP BC
950 DJNZ LOOP5
960 CH5 LD C, 0
970 CALL 8880
980 LD D, H
990 LD E, L
1000 INC DE
1010 LD (HL), 0
1020 LD BC, 7
1030 LDIR
1040 RET
1050 TEXTP DEFW TEXT
1060 TEXT DEFM "(C) ZX -"
1070 DEFM "M A N I A C S"
1080 DEFM "K A L U"
1090 DEFM "G A '1 9 9"
1100 DEFM "7"
1110 DEFM ""
1120 DEFB 0
2

   9. Next SCROLL is rather unusual. It takes a whole
third of the screen, although it does not use attributes. It is 
quite possible that someone will not like,

as seem too "liquid".
But this SCROLL'a has also a very good thing - it takes very 
little CPU time. 144.

1910; (c) ZX-MANIACS
20 ORG 40000
30 ENT
40 INIT LD HL, TEXT
50 LD (TEXTP), HL
60 XOR A
70 LD (COL), A
80 LD HL, # 5000
90 LD DE, # 5001
100 LD (HL), 0
110 LD BC, 2047
120 LDIR
130 SCROLL LD HL, # 5401
140 LD D, H
150 LD E, L
160 DEC DE
170 LD BC, 255
180 LDIR
190 LD A, (COL)
200 OR A
210 JR NZ, CONT
220 LD A, 8
230 LD (COL), A
240 LD HL, (TEXTP)
250 LD A, (HL)
260 OR A
270 JR NZ, PASS
280 LD HL, TEXT
290 LD (TEXTP), HL
300 LD A, (HL)
310 PASS INC HL
320 LD (TEXTP), HL
330 LD H, 0
340 LD L, A
350 ADD HL, HL
360 ADD HL, HL
370 ADD HL, HL
380 LD DE, (23606)
390 ADD HL, DE
400 LD DE, BUFF
410 LD BC, 8
420 LDIR
430 CONT LD DE, # 541F
440 LD HL, BUFF
450 LD B, 8
460 LOOP PUSH BC
470 RL (HL)
480 JR C, CONT1
490 LD A, 68
500 LD (DE), A
510 JR CONT2
520 CONT1 XOR A
530 LD (DE), A
540 CONT2 INC HL
550 EX DE, HL
560 LD BC, 32
570 ADD HL, BC
580 EX DE, HL
590 POP BC
600 DJNZ LOOP
610 LD A, (COL)
620 DEC A
630 LD (COL), A
640 RET
650 COL DEFB 0
660 BUFF DEFS 8
670 TEXTP DEFW TEXT
680 TEXT DEFM "(C) ZX-MANIACS"
690 DEFM ", KALUGA'1997"
700 DEFM ""
710 DEFB 0
2

   10. Finally the last
SCROLL is, in my opinion,
the most interesting of all the above. It is not chemto 
particularly steep, but its originality will surely attract 
your attention. 144.

1910; (c) ZX-MANIACS
20 ORG 40000
30 ENT
40 INIT LD HL, TEXT
50 LD (TEXTP), HL
60 XOR A
70 LD (COL), A
80 SCROLL LD A, (COL)
90 OR A
100 JR NZ, CONT
110 LD HL, (TEXTP)
120 LD A, (HL)
130 OR A
140 JR NZ, PASS
150 LD HL, TEXT
160 LD A, (HL)
170 PASS INC HL
180 LD (TEXTP), HL
190 LD H, 0
200 LD L, A
210 ADD HL, HL
220 ADD HL, HL
230 ADD HL, HL
240 LD DE, (23606)
250 ADD HL, DE
260 LD DE, BUFF
270 LD BC, 8
280 LDIR
290 LD A, 8
300 LD (COL), A
310 CONT LD B, 8
320 LD HL, # 401F
330 LD DE, BUFF
340 LOOP PUSH BC
350 PUSH HL
360 XOR A
370 EX DE, HL
380 RL (HL)
390 EX DE, HL
400 LD B, 8
410 LOOP1 RL (HL)
420 DEC HL
430 DJNZ LOOP1
440 LD B, 2
450 LOOP5 PUSH BC
460 PUSH AF
470 PUSH HL
480 LD B, 10
490 LOOP2 RL (HL)
500 DEC HL
510 DJNZ LOOP2
520 LD B, 2
530 LOOP4 PUSH BC
550 PUSH HL
560 LD B, 14
570 LOOP3 RL (HL)
580 DEC HL
590 DJNZ LOOP3
600 POP HL
610 POP AF
620 POP BC
630 DJNZ LOOP4
640 POP HL
650 POP AF
660 POP BC
670 DJNZ LOOP5
680 POP HL
690 INC H
700 INC DE
710 POP BC
720 DJNZ LOOP
730 LD A, (COL)
740 DEC A
750 LD (COL), A
760 RET
770 COL DEFB 0
780 BUFF DEFS 8
790 TEXTP DEFW TEXT
800 TEXT DEFM "(C) ZX-MANIACS"
810 DEFM ", KALUGA'1997"
820 DEFM ""
830 DEFB 0
2

   All SCROLL'y are step by step and calls the standard:
144.

          CALL INIT
LOOP HALT

          CALL SCROLL

          LD A, # 7F

          IN A, (# FE)

          RRA

          JR C, LOOP

          RET
2
 At the end of each
SCROLL'ov should be 0 - end mark.


          *