It's an astounding thought, but true, that three of the most original and best selling games of the last 12 months, Tau Ceti, Room Ten and Micronaut One were all programmed by the same bloke. This talented 3Dologist is none other than Pete Cooke, our Pitstop special guest. Pete has spent a lot of time programming computer games, his first products coming out on the Richard Shepherd Software label between 1983-85. First Invincible Island, then Urban Upstart, Inferno and finally Ski Star 2000. Moving over to CRL in 1985, he produced Juggernaut, and the Tau Ceti range of games (applause). Pete now works for Nexus and, having recently wowed us all with the excellent Micronaut One, is currently working on a top secret project. Coo-er-gosh.
The routine Pete has contributed to Pitstop is the fab keyboard scanning routine from both the Tau Ceti games and Micronaut One. It is an assembly routine, printed as such because it's easier to make out whats happening that way. So now you will be able to incorporate Pete's routines into your games, as the first step to implementing the sort of Windows, Icons, Mouse and Pointer type controls. This is just the first step, the rest is up to you.
10 org 60000 20 ent 60000 30 ; 40 ; 50 ; YS_KEYS 60 ; 70 ;prog for Your Sinclair 80 ; 90 ;file for Hisoft GENS 100 ;assembler but should 110 ;be suitable for most 120 ;assemblers on the market 130 ; 140 ;Reads the keyboard 150 ;Returns with C 160 ;holding L/R/U/D/F 170 ; 180 ;bit 4,C left 190 ;bit 3,C right 200 ;bit 2,C up 210 ;bit 1,C down 220 ;bit 0,C fire 230 ; 240 ;bit set to 1 if pressed 250 ; 260 ;keys are chosen by 270 ;values in KEYTAB 280 ; 290 readke ld hl,keytab 300 ld bc,#0500 310 ; 320 ;5 keys to read 330 ; 340 read_1 ld a,(hl) 350 rra 360 rra 370 and #1e 380 ld e,a 390 ld d,0 400 ; 410 ;2*the row number 420 ; 430 ld a,(hl) 440 inc hl 450 push hl 460 ; 470 ;save place in KEYTAB 480 ; 490 ld hl,keyadd 500 add hl,de 510 ld d,a 520 ; 530 ;index port addresses 540 ; 550 push bc 560 ld c,(hl) 570 inc hl 580 ld b,(hl) 590 in a,(c) 600 inc b 610 dec b 620 jr z,read_2 630 cpl 640 read_2 ld e,a 650 ; 660 ;read the port 670 ;and flip bits if not 680 ;Kempston 690 ; 700 pop bc 710 pop hl 720 ; 730 ;and get back BC+HL 740 ; 750 ld a,d 760 and #07 770 jr z,read_4 780 ; 790 read_3 rr e 800 dec a 810 jr nz,read_3 820 ; 830 ;rotate L so bit needed 840 ;is in bit 0 850 ; 860 read_4 rr e 870 rl c 880 ; 890 ;rotate the bit into C 900 ; 910 djnz read_1 920 ret 930 ; 940 ;exit B=0 950 ; C=keys 960 ; 970 ;A,HL,DE corrupt 980 ; 990 ; 1000 ;port addresses of 1010 ;the keyboard rows 1020 ; 1030 keyadd defw 63486,64510,65022,65278,61438,57342,49150,32766 1040 defw 31 ;*Kempston* 1050 ; 1060 ; 1070 ;KEYTAB holds the position 1080 ;of each key as 1090 ;1/2 row number*8 plus 1100 ;distance from the edge 1110 ;eg. P = 5*8+0 1120 ; O = 5*8+1 1130 ; Q = 1*8+0 1140 ; 4 = 0*8+3 1150 ; 1160 keytab defb 5*8+1,5*8+0,2*8+1,3*8+2,7*8+0 1170 ; 1180 ;set for O,P,S,X,space 1190 ; 1200 ;for a Kempston joystick 1210 ;substitute 1220 ; 1230 defb 8*8+1,8*8+0,8*8+3,8*8+2,8*8+4 1240 ; |