bytecode.mem

// BALL_IMAGE    EQU 0x031E
// BALL_X        EQU 0x00
// BALL_Y        EQU 0x01
// BALL_ZOOM     EQU 0x02
// SPEED         EQU 0x03
// BALL_VX       EQU 0x04
// BALL_VY       EQU 0x05
// PAUSE_SLICES  EQU 0xFF

// init: (0000)
00 FF 00 02           // mov [PAUSE_SLICES], 2 ; 2*20ms = 40ms per frame = 25 frames / sec
00 03 00 01           // mov [SPEED], 1
00 00 00 A0           // mov [BALL_X], 160
00 01 00 64           // mov [BALL_Y], 100
00 02 00 40           // mov [BALL_ZOOM], 0x40
01 04 03              // mov [BALL_VX], [SPEED]
02 04 03              // add [BALL_VX], [SPEED]
01 05 03              // mov [BALL_VY], [SPEED]
02 05 03              // add [BALL_VY], [SPEED]
0b 03 FF              // setPalette 0x03
0D 00                 // selectVideoPage 0x00

// mainloop: (0025)
0E 00 07              // fill page=0x00, color=0x07
55 01 8F 00 01 02     // video offset=BALL_IMAGE, x=[BALL_X], y=[BALL_Y], zoom=[BALL_ZOOM]
10 00                 // blitFramebuffer 0x00
01 00 00              // mov [0x00], [0x00] // 3 byte nop (to avoid re-calculating all addresses below)
13 00 03              // sub [BALL_X], [SPEED]
02 00 04              // add [BALL_X], [BALL_VX]
13 01 03              // sub [BALL_Y], [SPEED]
02 01 05              // add [BALL_Y], [BALL_VY]

0A 44 00 01 40 00 4A  // jl [BALL_X], 320, _1
00 04 00 00           // mov [BALL_VX], 0

// _1: (004A)
0A 02 00 00 00 56     // jg [BALL_X], 0, _2
01 04 03              // mov [BALL_VX], [SPEED]
02 04 03              // add [BALL_VX], [SPEED]

// _2: (0056)
0A 04 01 C8 00 60     // jl [BALL_Y], 200, _3
00 05 00 00           // mov [BALL_VY], 0

// _3: (0060)
0A 02 01 00 00 6C    // jg [BALL_Y], 0, _4
01 05 03             // mov [BALL_VY], [SPEED]
02 05 03             // add [BALL_VY], [SPEED]

// _4: (006C)
07 00 25             // jmp mainloop