;------------------------------------------------------------------------- ;The Ball by Emir Sakic ;saka@hotmail.com ;Examples on sprites and self modifying code ;(c) 2001. ;------------------------------------------------------------------------- .nolist #include "ion.inc" .list #ifdef TI83P COORD .equ 8A3Ah .org progstart-2 .db $BB,$6D #else COORD = STATVARS .org progstart #endif ret jr nc,START ;jumps to the label START .db "The Ball By Emir Sakic",0 ;The title displayed by ION START: LD HL,$0000 LD (COORD),HL bcall(_GRBUFCLR) SET_SCREEN1: LD HL,PLOTSSCREEN ;sets half LCD black LD DE,PLOTSSCREEN+1 LD (HL),$FF LD BC,383 LDIR LD H,08h LD L,0Ch LD IX,TEXT SET_TEXT: LD A,H ADD A,8 LD H,A PUSH HL CALL XORSPR POP HL LD A,1 CP (IX) JR NZ,SET_TEXT XOR A LD L,38h LD IX,CPYRGHT CALL XORSPR LD A,08h LD L,38h LD IX,CPYRGHT+8 CALL XORSPR LD A,10h LD L,38h LD IX,CPYRGHT+16 CALL XORSPR LD A,18h LD L,38h LD IX,CPYRGHT+24 CALL XORSPR LD HL,PLOTSSCREEN ;save whole screen as background LD DE,SAVESSCREEN LD BC,768 LDIR MAIN_LOOP: CALL SP_PUT ;put the sprite on (X,Y) CALL ionFastCopy ;put the picture on the LCD CALL DELAY ;delay to slow down the ball CALL RESET_SCREEN ;recall the background in PLOTSSCREEN Go_x: LD HL,COORD LD A,(HL) Bounder_x: CP 88 Jump_x: CALL Z,Ch_to_left Direction_x: INC (HL) Go_y: LD HL,COORD+1 LD A,(HL) Bounder_y: CP 56 Jump_y: CALL Z,Ch_to_up Direction_y: INC (HL) LD A,$FF ;reset the keypad OUT ($01),A DEC A ;enable Group 2 (with clear key) DEC A OUT ($01),A IN A,($01) BIT 6,A ;if Clear key pressed (bit #6=0) return RET Z JR MAIN_LOOP Ch_to_left: ;self modifying code XOR A LD (Bounder_x+1),A ;now Bounder line gets: CP 0 LD DE,Ch_to_right LD (Jump_x+1),DE ;now gets JP Z,Ch_to_right LD A,35h ;INC (HL) gets DEC (HL) LD (Direction_x),A RET ;go back to modified code Ch_to_right: LD A,88 LD (Bounder_x+1),A LD DE,Ch_to_left LD (Jump_x+1),DE LD A,34h LD (Direction_x),A RET Ch_to_up: XOR A LD (Bounder_y+1),A LD DE,Ch_to_down LD (Jump_y+1),DE LD A,35h LD (Direction_y),A RET Ch_to_down: LD A,56 LD (Bounder_y+1),A LD DE,Ch_to_up LD (Jump_y+1),DE LD A,34h LD (Direction_y),A RET SP_PUT: LD HL,COORD LD A,(HL) INC HL LD L,(HL) LD IX,Pic ;-----> Draw a sprite ; b=size of sprite ; l=yc ; a=xc ; ix holds pointer XORSPR: LD B,8 ;size of the sprite CALL ionPutSprite RET ;------ Reset_Screen: LD HL,SAVESSCREEN LD DE,PLOTSSCREEN LD BC,768 LDIR RET DELAY: LD B,20 LOOP1: PUSH BC LD B,255 LOOP2: DJNZ LOOP2 POP BC DJNZ LOOP1 RET TEXT: .db %00001000 .db %00010000 .db %01111110 .db %00100000 .db %01000000 .db %10000000 .db %10000000 .db %01100000 .db %00001000 .db %00010000 .db %00100000 .db %01110000 .db %01001000 .db %10001000 .db %10001000 .db %10010000 .db %00000000 .db %01111000 .db %11000100 .db %11000100 .db %10111000 .db %10000000 .db %01000100 .db %00111000 .db %00000000 .db %00000000 .db %00000000 .db %00000000 .db %00000000 .db %00000000 .db %00000000 .db %00000000 .db %11111100 .db %11000110 .db %11000010 .db %11111100 .db %11000010 .db %11000010 .db %11111110 .db %11111110 .db %01111100 .db %11111110 .db %11000110 .db %11000110 .db %11111110 .db %11111110 .db %11000110 .db %11000110 .db %11000000 .db %11000000 .db %11000000 .db %11000000 .db %11000000 .db %11000010 .db %11111110 .db %11111110 .db %11000000 .db %11000000 .db %11000000 .db %11000000 .db %11000000 .db %11000010 .db %11111110 .db %11111110 .db %00000001 CPYRGHT: .db %00000000 .db %00000000 .db %00100000 .db %01010000 .db %01010101 .db %00100110 .db %01011000 .db %10000000 .db %00000000 .db %00000000 .db %01001000 .db %11000100 .db %01000100 .db %00101000 .db %00010000 .db %01100000 .db %00000000 .db %01110011 .db %10000101 .db %01000101 .db %00100111 .db %00010101 .db %00010101 .db %11100101 .db %00000000 .db %01010011 .db %01010101 .db %01010101 .db %01100111 .db %01010101 .db %01010101 .db %01010101 PIC: .db %00111100 .db %01111110 .db %11111111 .db %11111111 .db %11111111 .db %11111111 .db %01111110 .db %00111100 .end END