Topic questions
1. ASCII is the American Standard Code for Information Interchange. Though TI uses a different standard than the currently accepted computer standard, it functions in a similar function: data represented by numbers point to an offset that holds a representation of the character.
2. GetKey will wait for a key to be pressed to return a value, and GetCSC will check to see if a key has been pressed, and if so, return that value. Also, GetKey utilizes the shift operators ([2nd] and [Alpha]) while getCSC returns a scan code for those two keys.
Code Fragments
3. Write a short program to display "HELLO WORLD" diagonally
;here's one that looks decent
ld hl,0
ld (pencol),hl
ld hl,txt
loop:
ld a,(hl)
or a
jr z,stop
bcall(_vPutmap)
inc hl
push hl
ld hl,(pencol)
inc h
inc h
inc h
ld (pencol),hl
pop hl
jr loop
stop:
bcall(_GetKey)
ret
txt:
.db "HELLO WORLD",0
4. Write a program that moves a dot around the screen when the user presses an arrow key. (hint: Use the _IPoint, or see sprites for a better method)
;sorry, no comments
bcall(_ClrLCDFull)
set fullScrnDraw, (IY + apiFlg4)
bcall(_runindicoff)
ld bc,$3232
ld d,1
push bc
bcall(_IPoint)
keyloop:
bcall(_GetCSC)
cp skup
jr z,moveUp
cp skdown
jr z,movedown
cp skleft
jr z,moveleft
cp skright
jr z,moveright
cp skclear
jr z,quit
jr keyloop
quit:
pop bc
bcall(_ClrLCDFull)
ret
movedown:
ld d,0
pop bc
push bc
bcall(_IPoint)
pop bc
ld a,c
or a
jr z,$+3
dec a
ld c,a
push bc
ld d,1
bcall(_IPoint)
jr keyloop
moveup:
ld d,0
pop bc
push bc
bcall(_IPoint)
pop bc
ld a,c
cp 63
jr z,$+3
inc a
ld c,a
push bc
ld d,1
bcall(_IPoint)
jr keyloop
moveleft:
ld d,0
pop bc
push bc
bcall(_IPoint)
pop bc
ld a,b
or a
jr z,$+3
dec a
ld b,a
push bc
ld d,1
bcall(_IPoint)
jr keyloop
moveright:
ld d,0
pop bc
push bc
bcall(_IPoint)
pop bc
ld a,b
cp 95
jr z,$+3
inc a
ld b,a
push bc
ld d,1
bcall(_IPoint)
jr keyloop
Programming Errors
5. Completely correct
6. Two errors: First of all, ionfastcopy uses plotsscreen instead of appbackupscreen, and the way it defines the buffer is running through the rows, as opposed to the columns. Even if plotsscreen was used, you would have an interesting line pattern drawn instead of an 8*8 box (feel free to try it).
