Vlákno názorů k článku Jak probíhal vývoj pro osmibitová Atari před 45 lety? od judovana - 1 ; ============================================ 2 ; SNAKE GAME...
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1 ; ============================================ 2 ; SNAKE GAME — Atari 8-bit (XL/XE) 3 ; Assembler: MADS (mads snake.asm -o:snake.xex) 4 ; Input: Joystick port 1 5 ; ============================================ 6 7 ; --- OS / Hardware Equates --- 8 RTCLOK = $0014 ; jiffy clock (~60 Hz NTSC) 9 SAVMSC = $0058 ; screen memory pointer 10 STICK0 = $0278 ; joystick 0 11 COLOR1 = $02C5 ; text luminance 12 COLOR2 = $02C6 ; background 13 COLOR4 = $02C8 ; border 14 RANDOM = $D20A ; hardware RNG 15 CH = $02FC ; last key pressed 16 ATRACT = $004D ; attract-mode timer 17 CRSINH = $02F0 ; cursor inhibit (1=off) 18 NMIEN = $D40E ; NMI enable 19 20 ; Screen geometry (Graphics 0 = ANTIC mode 2) 21 SCRW = 40 22 SCRH = 24 23 24 ; Internal screen character codes 25 CH_SPACE = $00 26 CH_WALL = $E0 ; inverse space (solid block) 27 CH_BODY = $14 ; diamond body segment 28 CH_FOOD = $00+$80 ; inverse space for food pellet 29 CH_HEAD = $13+$80 ; inverse 'S' 30 31 ; Joystick bit patterns 32 JOY_UP = 14 33 JOY_DOWN = 13 34 JOY_LEFT = 11 35 JOY_RIGHT = 7 36 37 ; --- Zero-page variables --- 38 ZPTMP = $80 ; 2-byte pointer 39 ZPTMP2 = $82 ; 2-byte pointer 40 HEADIDX = $84 ; ring-buffer head index 41 TAILIDX = $85 ; ring-buffer tail index 42 DIRX = $86 ; direction X: $FF / $00 / $01 43 DIRY = $87 ; direction Y: $FF / $00 / $01 44 HEADX = $88 ; current head column 45 HEADY = $89 ; current head row 46 FOODX = $8A ; food column 47 FOODY = $8B ; food row 48 SCORE = $8C ; 2-byte BCD score 49 SPEED = $8E ; frames between moves 50 GROW = $8F ; segments left to grow 51 NEWX = $90 ; candidate head column 52 NEWY = $91 ; candidate head row 53 FOODCNT = $92 ; food-eaten counter (for speed ramp) 54 DEAD = $93 ; nonzero = game over 55 56 ; Ring buffers — 256 entries each, page-aligned 57 RING_X = $0600 58 RING_Y = $0700 59 60 ; ============================================ 61 org $2000 62 ; ============================================ 63 64 ; ---------- ENTRY ---------- 65 Start 66 lda #0 67 sta NMIEN ; blank screen during setup 68 69 lda #$0E ; bright white text 70 sta COLOR1 71 lda #$94 ; dark blue playfield 72 sta COLOR2 73 lda #$00 ; black border 74 sta COLOR4 75 76 lda #$40 77 sta NMIEN ; VBI on, DLI off 78 79 lda #1 80 sta CRSINH ; hide cursor 81 82 ; ---------- NEW GAME ---------- 83 NewGame 84 lda #0 85 sta SCORE 86 sta SCORE+1 87 sta DEAD 88 sta HEADIDX 89 sta TAILIDX 90 sta FOODCNT 91 92 lda #8 ; ~7.5 moves/s (NTSC) 93 sta SPEED 94 lda #3 ; snake starts at length 4 95 sta GROW 96 97 lda #1 ; initial direction: right 98 sta DIRX 99 lda #0 100 sta DIRY 101 102 jsr ClearScreen 103 jsr DrawBorder 104 jsr DrawScore 105 106 lda #SCRW/2 ; place head at center 107 sta HEADX 108 sta RING_X 109 lda #SCRH/2 110 sta HEADY 111 sta RING_Y 112 113 ldx HEADX 114 ldy HEADY 115 lda #CH_HEAD 116 jsr PlotChar 117 118 jsr PlaceFood 119 120 ; "PRESS FIRE" prompt — row 10, col 14 121 lda SAVMSC 122 clc 123 adc #<(10*SCRW+14) 124 sta ZPTMP 125 lda SAVMSC+1 126 adc #>(10*SCRW+14) 127 sta ZPTMP+1 128 ldy #0 129 @title lda TitleMsg,y 130 beq @twait 131 sta (ZPTMP),y 132 iny 133 bne @title 134 135 @twait lda #0 136 sta ATRACT 137 lda $D010 ; TRIG0 hardware 138 bne @twait 139 140 ; erase prompt 141 lda SAVMSC 142 clc 143 adc #<(10*SCRW+14) 144 sta ZPTMP 145 lda SAVMSC+1 146 adc #>(10*SCRW+14) 147 sta ZPTMP+1 148 ldy #11 149 lda #CH_SPACE 150 @eclr sta (ZPTMP),y 151 dey 152 bpl @eclr 153 154 lda RTCLOK 155 sta DEAD ; reuse as last-clock seed 156 ; (DEAD is cleared below before loop) 157 158 lda #0 159 sta DEAD 160 161 lda RTCLOK 162 sta FOODCNT ; (reuse byte briefly; reset below) 163 lda #0 164 sta FOODCNT 165 166 ; ---------- MAIN LOOP ---------- 167 GameLoop 168 lda #0 169 sta ATRACT 170 171 ; --- speed gate --- 172 @wait lda RTCLOK 173 sec 174 sbc FOODCNT ; FOODCNT doubles as "last tick" here 175 ; Oops — I'm reusing FOODCNT. Let me use a proper variable. 176 ; Actually let me just use the Y-indirect trick with RTCLOK. 177 ; I'll track "last clock" in a separate place. 178 ; Fix: use DEAD as temp... no. Let me just compare directly. 179 jmp @wait2 180 @wait2 181 ; Simple timing: busy-wait until SPEED jiffies have passed 182 ; since last move. Store last-move-clock at $94. 183 LASTCLK = $94 184 lda RTCLOK 185 sec 186 sbc LASTCLK 187 cmp SPEED 188 bcc @wait2 189 190 lda RTCLOK 191 sta LASTCLK 192 193 ; --- read joystick --- 194 jsr ReadJoy 195 196 ; --- compute candidate position --- 197 lda HEADX 198 clc 199 adc DIRX 200 sta NEWX 201 202 lda HEADY 203 clc 204 adc DIRY 205 sta NEWY 206 207 ; --- wall collision --- 208 lda NEWX 209 beq HitWall ; column 0 210 cmp #SCRW-1 211 beq HitWall ; column 39 212 lda NEWY 213 beq HitWall ; row 0 214 cmp #SCRH-2 215 bcs HitWall ; row >= 22 216 217 ; --- self collision (read screen) --- 218 ldx NEWX 219 ldy NEWY 220 jsr ReadChar 221 cmp #CH_BODY 222 beq HitSelf 223 224 ; --- food? --- 225 lda NEWX 226 cmp FOODX 227 bne NoFood 228 lda NEWY 229 cmp FOODY 230 bne NoFood 231 232 ; ate food 233 lda GROW 234 clc 235 adc #3 236 sta GROW 237 238 sed 239 lda SCORE 240 clc 241 adc #$10 ; +10 pts 242 sta SCORE 243 lda SCORE+1 244 adc #0 245 sta SCORE+1 246 cld 247 248 jsr DrawScore 249 250 ; speed ramp: every 5 pellets, decrease delay (min 3) 251 inc FOODCNT 252 lda FOODCNT 253 cmp #5 254 bne @noramp 255 lda #0 256 sta FOODCNT 257 lda SPEED 258 cmp #3 259 beq @noramp 260 dec SPEED 261 @noramp 262 jsr PlaceFood 263 264 NoFood 265 ; --- move snake --- 266 ; old head -> body 267 ldx HEADX 268 ldy HEADY 269 lda #CH_BODY 270 jsr PlotChar 271 272 ; update head coords 273 lda NEWX 274 sta HEADX 275 lda NEWY 276 sta HEADY 277 278 ; push into ring buffer 279 inc HEADIDX 280 ldx HEADIDX 281 lda HEADX 282 sta RING_X,x 283 lda HEADY 284 sta RING_Y,x 285 286 ; draw head 287 ldx HEADX 288 ldy HEADY 289 lda #CH_HEAD 290 jsr PlotChar 291 292 ; grow or trim tail 293 lda GROW 294 beq @trim 295 dec GROW 296 jmp GameLoop 297 298 @trim ; erase tail cell on screen 299 ldx TAILIDX 300 lda RING_X,x 301 sta NEWX ; temp reuse 302 lda RING_Y,x 303 sta NEWY 304 305 ldx NEWX 306 ldy NEWY 307 lda #CH_SPACE 308 jsr PlotChar 309 310 inc TAILIDX 311 jmp GameLoop 312 313 ; ---------- COLLISION ---------- 314 HitWall 315 HitSelf 316 ; flash screen 317 ldx #8 318 @flash lda #$34 319 sta COLOR1 320 jsr WaitFrames 321 lda #$0E 322 sta COLOR1 323 jsr WaitFrames 324 dex 325 bne @flash 326 327 ; "GAME OVER" — row 11, col 15 328 lda SAVMSC 329 clc 330 adc #<(11*SCRW+15) 331 sta ZPTMP 332 lda SAVMSC+1 333 adc #>(11*SCRW+15) 334 sta ZPTMP+1 335 ldy #0 336 @gmsg lda GameOverMsg,y 337 beq @gwait 338 sta (ZPTMP),y 339 iny 340 bne @gmsg 341 342 ; "PRESS FIRE" — row 13, col 14 343 @gwait2 344 lda SAVMSC 345 clc 346 adc #<(13*SCRW+14) 347 sta ZPTMP 348 lda SAVMSC+1 349 adc #>(13*SCRW+14) 350 sta ZPTMP+1 351 ldy #0 352 @pmsg lda TitleMsg,y 353 beq @gfire 354 sta (ZPTMP),y 355 iny 356 bne @pmsg 357 358 @gfire lda #0 359 sta ATRACT 360 lda $D010 361 bne @gfire 362 363 jsr WaitFrames ; debounce 364 jsr WaitFrames 365 jmp NewGame 366 367 ; ============================================ 368 ; SUBROUTINES 369 ; ============================================ 370 371 ; --- Read joystick, update direction (prevent reversal) --- 372 ReadJoy 373 lda STICK0 374 375 cmp #JOY_RIGHT 376 bne @nR 377 lda DIRX 378 cmp #$FF 379 beq @done ; block: already going left 380 lda #1 381 sta DIRX 382 lda #0 383 sta DIRY 384 rts 385 @nR cmp #JOY_LEFT 386 bne @nL 387 lda DIRX 388 cmp #1 389 beq @done 390 lda #$FF 391 sta DIRX 392 lda #0 393 sta DIRY 394 rts 395 @nL cmp #JOY_UP 396 bne @nU 397 lda DIRY 398 cmp #1 399 beq @done 400 lda #0 401 sta DIRX 402 lda #$FF 403 sta DIRY 404 rts 405 @nU cmp #JOY_DOWN 406 bne @done 407 lda DIRY 408 cmp #$FF 409 beq @done 410 lda #0 411 sta DIRX 412 lda #1 413 sta DIRY 414 @done rts 415 416 ; --- Clear screen (960 bytes) --- 417 ClearScreen 418 lda SAVMSC 419 sta ZPTMP 420 lda SAVMSC+1 421 sta ZPTMP+1 422 lda #CH_SPACE 423 ldy #0 424 ldx #4 ; 4 full pages = 1024 (> 960) 425 @pg sta (ZPTMP),y 426 iny 427 bne @pg 428 inc ZPTMP+1 429 dex 430 bne @pg 431 rts 432 433 ; --- Draw border walls --- 434 DrawBorder 435 ; top row (row 0) 436 lda SAVMSC 437 sta ZPTMP 438 lda SAVMSC+1 439 sta ZPTMP+1 440 ldy #SCRW-1 441 lda #CH_WALL 442 @top sta (ZPTMP),y 443 dey 444 bpl @top 445 446 ; bottom row (row 22) 447 lda SAVMSC 448 clc 449 adc RowLo+22 450 sta ZPTMP 451 lda SAVMSC+1 452 adc RowHi+22 453 sta ZPTMP+1 454 ldy #SCRW-1 455 lda #CH_WALL 456 @bot sta (ZPTMP),y 457 dey 458 bpl @bot 459 460 ; left + right columns (rows 1-21) 461 ldx #1 462 @side lda SAVMSC 463 clc 464 adc RowLo,x 465 sta ZPTMP 466 lda SAVMSC+1 467 adc RowHi,x 468 sta ZPTMP+1 469 470 ldy #0 471 lda #CH_WALL 472 sta (ZPTMP),y ; col 0 473 ldy #SCRW-1 474 sta (ZPTMP),y ; col 39 475 476 inx 477 cpx #22 478 bne @side 479 rts 480 481 ; --- Plot character (X=col, Y=row, A=char) --- 482 PlotChar 483 pha 484 lda RowLo,y 485 clc 486 adc SAVMSC 487 sta ZPTMP 488 lda RowHi,y 489 adc SAVMSC+1 490 sta ZPTMP+1 491 txa 492 tay ; Y = column for indirect index 493 pla 494 sta (ZPTMP),y 495 rts 496 497 ; --- Read character (X=col, Y=row -> A=char) --- 498 ReadChar 499 lda RowLo,y 500 clc 501 adc SAVMSC 502 sta ZPTMP 503 lda RowHi,y 504 adc SAVMSC+1 505 sta ZPTMP+1 506 txa 507 tay 508 lda (ZPTMP),y 509 rts 510 511 ; --- Place food at a random empty cell --- 512 PlaceFood 513 @retry lda RANDOM 514 and #$3F ; 0-63 515 cmp #38 516 bcs @retry 517 adc #1 ; 1-38 518 sta FOODX 519 tax 520 521 lda RANDOM 522 and #$1F ; 0-31 523 cmp #21 524 bcs @retry 525 adc #1 ; 1-21 526 sta FOODY 527 tay 528 529 jsr ReadChar 530 cmp #CH_SPACE 531 bne @retry ; occupied — try again 532 533 ldx FOODX 534 ldy FOODY 535 lda #CH_FOOD 536 jsr PlotChar 537 rts 538 539 ; --- Draw score on row 23 --- 540 DrawScore 541 lda SAVMSC 542 clc 543 adc RowLo+23 544 sta ZPTMP 545 lda SAVMSC+1 546 adc RowHi+23 547 sta ZPTMP+1 548 549 ; "SCORE:" label 550 ldy #1 551 @lbl lda ScoreLbl-1,y 552 beq @digits 553 sta (ZPTMP),y 554 iny 555 bne @lbl 556 557 @digits ; 4 BCD digits 558 lda SCORE+1 559 lsr 560 lsr 561 lsr 562 lsr 563 ora #$10 ; screen code '0' = $10 564 sta (ZPTMP),y 565 iny 566 567 lda SCORE+1 568 and #$0F 569 ora #$10 570 sta (ZPTMP),y 571 iny 572 573 lda SCORE 574 lsr 575 lsr 576 lsr 577 lsr 578 ora #$10 579 sta (ZPTMP),y 580 iny 581 582 lda SCORE 583 and #$0F 584 ora #$10 585 sta (ZPTMP),y 586 rts 587 588 ; --- Wait ~4 jiffies --- 589 WaitFrames 590 lda RTCLOK 591 clc 592 adc #4 593 sta ZPTMP2 ; temp 594 @wf cmp RTCLOK 595 bne @wf 596 rts 597 598 ; ============================================ 599 ; DATA 600 ; ============================================ 601 602 ; Row-start offsets (row * 40) 603 RowLo 604 .byte $00,$28,$50,$78,$A0,$C8,$F0,$18 605 .byte $40,$68,$90,$B8,$E0,$08,$30,$58 606 .byte $80,$A8,$D0,$F8,$20,$48,$70,$98 607 RowHi 608 .byte $00,$00,$00,$00,$00,$00,$00,$01 609 .byte $01,$01,$01,$01,$01,$02,$02,$02 610 .byte $02,$02,$02,$02,$03,$03,$03,$03 611 612 ; Screen-code strings (null-terminated) 613 ; ATASCII -> internal: chr - $20 (for $20..$5F) 614 ; 'P'=$30 'R'=$32 'E'=$25 'S'=$33 ' '=$00 615 ; 'F'=$26 'I'=$29 !=$01 616 ScoreLbl 617 .byte $33,$23,$2F,$32,$25,$1A,$00 ; "SCORE:" 618 619 ; "PRESS FIRE!" in screen codes 620 TitleMsg 621 .byte $30,$32,$25,$33,$33,$00,$26,$29,$32,$25,$01,$00 622 623 ; "GAME OVER" inverse (add $80) 624 GameOverMsg 625 .byte $A7,$A1,$AD,$A5,$80,$AF,$B6,$A5,$B2,$00 626 627 ; ============================================ 628 ; Run address 629 ; ============================================ 630 org $02E0 631 .word Start
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Toz.. muzete to nekdo zkontrolovat? Psal to samozrejme cloude, ale neslo mu to. Hold toho ma na netu prilis malo k uceni :D A trvalo mu to 30minut... coz je na prumerny maly AI task docela hodne. Na druhou stranu ja bych se to 14dnuiucil a pak tyden psal. POdle zkusenosti "an technologii co znam, to blije obcas hrozny veci, taks e to bnojim pouzit na technlologii co neznam"... Tohle presen spada sem. Ale prekvapil ze zpatlal aspon neco vzheldem k tomu jak malo materialu je na netu
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Pavel TišnovskýZlatý podporovatelahoj Jirko. Ze bych si AI slop dotahl i do Atarka, kdyz s tim v praci bojuju 8 hodin denne? No, zkusim tedy
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Já tedy se přiznám, že takhle to tedy ze zásady nezkusím. Ne že bych věřil na to, že se mi do atárka dostane vir a znásilní mi papouška. Ale to je právě ta zásada - copak jsme to tu nečetli už tolikrát, zrovna na root.cz ??? Už o tom proběhlo tolik zpráviček, kolik projektů řeší zaplavení AI slopem, kdy je strašně snadné něco vygenerovat, a pak ti "autoři" (čti: přeposílači) očekávají, že tím zaměstnají skutečné vývojáře. Pardon, ale to podporovat nechci.
Minimálně emulátor Atari je k dispozici všem, na mnoha platformách. Očekávám tady tudíž zaslanou hotovou a odladěnou variantu, a ne za půl hodiny někomu vyrobit práci na několik hodin.
A naopak: jako každý fanda se rád podívám na tu člověkem odladěnou verzi, i kdyby k ní napsal, že se třeba trápí s jedním KONKRÉTNÍM problémem - a pokusím se mu s ním pomoct.
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Pavel TišnovskýZlatý podporovatel
a to plne chapu. Jenze to je Jirka, on je chudak Javista (v lepsich casech jsme byli v jednom tymu), tak proc mu trosku nepomoci ;)
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Jo, je to AI slop. Ja sam nebyl ochoten venovat cas tomu to hodit do emulatoru. Hlavne na tom neplytvej vic cyklu nez "rychle oko". Vzdycky kdyz mam k dispozici nejaky lepsi model, rad zkousim jak moc to neumi resit problemy (nejen programco), ktere nejsou na netu opsane milionkrat. Ted mam na chvili opus 4.neco, ale nemel jsem problem k vyzkouseni, protoze uz mi dosli technologie ktere "to nezna" a "ja dokazu zkontrolovat". Navic kdyz tomu das hada v "normalnim" jazyce, ma to za minutu napsany, a docela hezky. Tak sem chtel zkusit. Ale trvalo mu to tak dlouho ze jsem oddriftoval jinam. Z dnesniho raniho pohledu je to normlani spam.
Kdyz sme u te javy, tak dycky modely nachytam na novych JEPech. Jednoduse z vise zminenych duvodu: protoze je nikdo nerozpitval milionkrat (minimlane v dobe generovani modelu).
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Pavel TišnovskýZlatý podporovatel
takže po přepisu do ca65 (sorry, ale kvůli MADS jsem si Pascal nestahoval :-)
1) nějaká návěští se musela opravit
2) ovšem AI "zapoměla" na to, že cíle skoků jsou jen v rozsahu jednoho (signed) bajtuca65 snake1.asm -t atari -o snake1.o -l snake1_list.asm --list-bytes 100 snake1.asm(209): Error: Range error (158 not in [-128..127]) snake1.asm(211): Error: Range error (154 not in [-128..127]) snake1.asm(213): Error: Range error (150 not in [-128..127]) snake1.asm(215): Error: Range error (146 not in [-128..127]) snake1.asm(222): Error: Range error (135 not in [-128..127])Možná mašinu přesvědčit, ať dodržuje specifikaci MOS 6502? :-)
[kupodivu to nenasekalo žádné syntaktické chyby]
26. 8. 2026, 11:31 editováno autorem komentáře
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