screen effects - "pouring" the screen of the game Rockstar.

   Another absolutely "stunning" effect from the program
ROCKSTAR. This so-called
"Pouring" the screen. As is known, it is better to see once
so look at the monitor.
The screen turns from
the lowest pixel line.
Thus there is a kind of "waterfall effect": top-down "falls" 
image and gradually "fills" the screen from top to bottom. 
Moreover, in contrast to the folding screen in COMANDO TRACER, 
everything here occurs in color, creating a quite stunning 
effect. 

   Listing procedure that performs the effect of "pouring" 
screen. 1420.

62AC 21E0BE LD HL, # BEE0
62AF 7D LD A, L
62B0 32439C LD (# 9C43), A
62B3 7C LD A, H
62B4 32449C LD (# 9C44), A
62B7 3EC0 LD A, # C0
62B9 32459C LD (# 9C45), A
62BC 21E0BB LD HL, # BBE0
62BF 7D LD A, L
62C0 32499C LD (# 9C49), A
62C3 7C LD A, H
62C4 324A9C LD (# 9C4A), A
62C7 3E18 LD A, # 18
62C9 32409C LD (# 9C40), A
62CC CDFA62 CALL # 62FA
62CF CD6763 CALL # 6367
62D2 3A4A9C LD A, (# 9C4A)
62D5 3D DEC A
62D6 324A9C LD (# 9C4A), A
62D9 0E0C LD C, # 0C
62DB 3A459C LD A, (# 9C45)
62DE 2F CPL
62DF 47 LD B, A
62E0 10FE DJNZ # 62E0
62E2 0D DEC C
62E3 79 LD A, C
62E4 FE00 CP # 00
62E6 C2DB62 JP NZ, # 62DB
62E9 3A459C LD A, (# 9C45)
62EC 3D DEC A
62ED 32459C LD (# 9C45), A
62F0 E607 AND # 07
62F2 FE00 CP # 00
62F4 CA2D63 JP Z, # 632D
62F7 C3CF62 JP # 62CF
----------------------------- 62FA 3A409C LD A, (# 9C40)
62FD 32549C LD (# 9C54), A
6300 110058 LD DE, # 5800
6303 2A439C LD HL, (# 9C43)
6306 012000 LD BC, # 0020
6309 E5 PUSH HL
630A EDB0 LDIR
630C E1 POP HL
630D EB EX DE, HL
630E 09 ADD HL, BC
630F EB EX DE, HL
6310 3A549C LD A, (# 9C54)
6313 3D DEC A
6314 32549C LD (# 9C54), A
6317 FE00 CP # 00
6319 C20363 JP NZ, # 6303
631C 012000 LD BC, # 0020
631F 2A439C LD HL, (# 9C43)
6322 ED42 SBC HL, BC
6324 7D LD A, L
6325 32439C LD (# 9C43), A
6328 7C LD A, H
6329 32449C LD (# 9C44), A
632C C9 RET
----------------------------- 632D 21409C LD HL, # 9C40
6330 1935 DEC (HL)
6331 3A459C LD A, (# 9C45)
6334 E63F AND # 3F
6336 FE00 CP # 00
6338 CA4D63 JP Z, # 634D
633B 2A499C LD HL, (# 9C49)
633E 11E007 LD DE, # 07E0
6341 1919 ADD HL, DE
6342 7D LD A, L
6343 32499C LD (# 9C49), A
6346 7C LD A, H
6347 324A9C LD (# 9C4A), A
634A C3CC62 JP # 62CC
----------------------------- 634D 3A459C LD A, (# 9C45)
6350 FE00 CP # 00
6352 C8 RET Z
6353 2000 NOP
6354 2000 NOP
6355 01E000 LD BC, # 00E0
6358 2A499C LD HL, (# 9C49)
635B 09 ADD HL, BC
635C 7D LD A, L
635D 32499C LD (# 9C49), A
6360 7C LD A, H
6361 324A9C LD (# 9C4A), A
6364 C3CC62 JP # 62CC
----------------------------- 6367 3E00 LD A, # 00
6369 32469C LD (# 9C46), A
636C 110040 LD DE, # 4000
636F 2A499C LD HL, (# 9C49)
6372 012000 LD BC, # 0020
6375 D5 PUSH DE
6376 EDB0 LDIR
6378 D1 POP DE
6379 1914 INC D
637A 3A469C LD A, (# 9C46)
637D 3C INC A
637E 32469C LD (# 9C46), A
6381 1947 LD B, A
6382 3A459C LD A, (# 9C45)
6385 B8 CP B
6386 C8 RET Z
6387 3A469C LD A, (# 9C46)
638A E607 AND # 07
638C FE00 CP # 00
638E C26F63 JP NZ, # 636F
6391 3A469C LD A, (# 9C46)
6394 E63F AND # 3F
6396 FE00 CP # 00
6398 CAA563 JP Z, # 63A5
639B 01E007 LD BC, # 07E0
639E EB EX DE, HL
639F ED42 SBC HL, BC
63A1 EB EX DE, HL
63A2 C36F63 JP # 636F
63A5 01E000 LD BC, # 00E0
63A8 EB EX DE, HL
63A9 ED42 SBC HL, BC
63AB EB EX DE, HL
63AC C36F63 JP # 636F
2

   Routine starts with a load address 62ACH. But before this
screen, which will be subjected to
such an effect, must be loaded into the address A400H.

   When working procedure uses 11 system cells from an address
9C40H (40000) on 9C4AH (40010)
inclusive.

   Output from the procedure occurs at 6352H command RET
Z. You can, depending on the
specific circumstances, to substitute for RET Z and the two 
teams NOP another option: JP Z, ADDR.



   To obtain the code block
"Pouring screen, you can use BASIC program:


   1 READ ram: CLEAR ram: READ f
$: READ st: READ len: FOR a = st T
O st + len-1: READ b: POKE a, b: NE
XT a: SAVE f $ CODE st, len

  1910 DATA 25259, "roc", 25260,259
 100 DATA
033,224,190,125,050,067,156,124,
050,068,156,062,192,050,069,156,
033,224,187,125,050,073,156,124,
050,074,156,062,024,050,064,156
 110 DATA
205,250,098,205,103,099,058,074,
156,061,050,074,156,014,012,058,
069,156,047,071,016,254,013,121,
254,000,194,219,098,058,069,156
 120 DATA
061,050,069,156,230,007,254,000,
202,045,099,195,207,098,058,064,
156,050,084,156,017,000,088,042,
067,156,001,032,000,229,237,176
 130 DATA
225,235,009,235,058,084,156,061,
050,084,156,254,000,194,003,099,
001,032,000,042,067,156,237,066,
125,050,067,156,124,050,068,156
 140 DATA
201,033,064,156,053,058,069,156,
230,063,254,000,202,077,099,042,
073,156,017,224,007,025,125,050,
073,156,124,050,074,156,195,204
 150 DATA
098,058,069,156,254,000,200,000,
000,001,224,000,042,073,156,009,
125,050,073,156,124,050,074,156,
195,204,098,062,000,050,070,156
 160 DATA
017,000,064,042,073,156,001,032,
000,213,237,176,209,020,058,070,
156,060,050,070,156,071,058,069,
156,184,200,058,070,156,230,007
 170 DATA
254,000,194,111,099,058,070,156,
230,063,254,000,202,165,099,001,
224,007,235,237,066,235,195,111,
099,001,224,000,235,237,066,235,
195,111,099


   Below is a BASIC program that demonstrates "pouring screen. 
Here on line 30 is preloading screen-saver program from 
ROCKSTAR (or any) under the address A400H (41,984). The 
procedure starts immediately After the download is complete.



  10 BORDER 0: PAPER 0: INK 7: C
LEAR 25259

  20 LOAD "roc" CODE

  30 LOAD "rockst $" CODE 41984

  40 RANDOMIZE USR 25260

  1950 BEEP .1,26: BEEP .1,20: PAU
SE 0