Draconland

Today I did a sprite moving.

I think I'll explode by happiness....

Nope.

 

Here's the code, for sake the curiosity

 

; ---- Sprite movement ---

OPTION BINARY

ALIGN OFF

 

;Registers I'm using

; V0 Temp

; V1 player X

; V2 player Y

 

; keys:

; #2 = up

; #4 = left

; #5 = space

; #6 = right

; #8 = down

; #A = Ctrl

; #B = shift

; #C = Z

; #F = Space

 

;-----------------------------

Gamestart

 

cls ;CleanScreen

 

ld v1,32 ;Load X to initial position 32 on the screen (half of the 64)

ld v2,16 ;Load Y to position 16 (half of the 32 Y resolution)

;-----------------------------

GameLoop

 

ld v0,#2 ;Load Up to V0 register

skp v0 ;Check if pressed (v0 != 0)

jp CheckDown ;No, jump to "CheckDown"

add v2,#FF ;Yes, add -1 to Y (V2) (#FF = -1)

 

CheckDown

ld v0,#8 ;Load Down

skp v0 ;Pressed?

jp CheckRight ;No, jump

add v2,1 ;yes, +1 to Y

 

CheckRight

ld v0,#6

skp v0

jp CheckLeft

add v1,1

 

CheckLeft

ld v0,#4

skp v0

jp Reset

add v1,#FF

 

Reset

ld v0,#C

skp v0

jp DrawingCode

jp Gamestart

 

;-----------------------------

DrawingCode

 

cls ;Clear Screen

 

ld I,Sprite0 ;Point I (indexer) to Sprite0 Table

drw v1,v2,9 ;Draw Sprite0 using v1 and v2 as X and Y. 9 is the height of the sprite table

 

;TimeDelay

 

ld v0,1 ;Load 5 to v0

ld dt,v0 ;Set V0 as timmer (DT)

 

WaitDelay

ld v0,dt ;Decrement V0 using DT

se v0,0 ;If 0, go to jp GameLoop

jp WaitDelay ;If Non-zero, repeat

 

jp Gameloop ;End of the code. Jump to GameLoop and repeat process.

 

;------------------------------

 

Sprite0 ;Sprite Data

DB $...11...

DB $..1111..

DB $...11...

DB $.111111.

DB $1..11..1

DB $1..11..1

DB $..1..1..

DB $..1..1..

DB $.11..11.

 

 

There are 16 registers, V0 to V9 and VA to VF. They are general pourpose less VF wich is set when colision happens, also VF hang the carry.Chip8 support subroutine by 16 levels. There is one indexer named I.Skp is a short branch, skip 2 bytes (next instruction) if Vx is non-zero.Well, see ya.