A83: Re: help to understand
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A83: Re: help to understand
>Allright, normally I just sit reading your letters and do nothing, but I
>have decided to get off my ass and start programing in assembly. I have
>many-a questions, some you have already answered but I delete e-mail
>often.
>
>For starters what do these do:
>
>call _puts ;seems to be frequently used
Places text w/ large font on home screen.
>call _newline ;does this make a new blank line?
scrolls cursor down to new line, sort of like Disp "" in BASIC
>call _LCD_Busy ;does this add that busy signal up top?
A sort of delay to prevent further calcuations from going on while the LCD
Driver processes the information given to it. Would be useful for making a
game so your calculations don't get too far ahead of the graphics.
>call _runIndicOff ;no clue?
Turns off the the little bar in the upper left hand corner. A tell-tale
sign that a program (or other instruction) is running. Turning off is
useful for progs like shells and "fake mem clear" programs where you don't
want it to be seen.
>call _runIndicOn ;turn whatever it does back on I suppose
exactly
>call lcd_busy ;is this the same as the one I listed above?
yes
>out (LCDINSTPORT),a ;lost on this one
I dunno.
>jp ; is this a jump to whatever variable is listed to the right of it
yes (for the most part)
jp next ; jumps to 'next'
jp z, next ; if a=0, goes to 'next', otherwise ignored.
jp nz, next; if a not = 0, goes to 'next,' otherwise ignored.
>call _putc ;??
not aware of that one
>call _pdspgrph ;what does this do to the graph, and what is the command
>to clear the graph
dunno
>call _saveshadow ;probably has to do with the Last Entry on the Home
>screen
Saves a copy of the home screen. An example is the TI-OS. Say you have a
bunch of calculations of the home screen. On an 83 you hit [2nd] Math, then
decide you don't need anything there. You hit [2nd] quit. After you hit
quit, it restores the numbers and other stuff you had on the homescreen.
That is the text shadow.
>call _rstrshadow ;does this reset the saveshadow?
No; restores the shadow
>call _VPUTS ;??
outputs text in the small, graph screen font (can be used on home-screen).
>
>This is a part of a program I just lost it on:
>
>set write_on_graph,(iy+sgrflags) ;I assume it deals with placing
>something on the graph
I think so.
>1d h1,0 ;does this set h1 as 0
its "ld hl,0" not "1d h1,0" and yes, it does. hl is the 16 bit register,
combining "h" and "L" (l)
>1d (pencol),h1 ;does this set pencol as h1 or 0
it loads hl to pencol, in this case, hl is 0 so both are correct.
>Ld HL, THIS_IS_COOL ;I assume this prints THIS_IS_COOL at pencol
It loads the string "THIS_IS_COOL" to the 16 bit register. It is not
printed on the screen yet, though.
>call _VPUTS ;this is a funny command used alot in the source I read
Prints "THIS_IS_COOL"
>res write_on_graph,(iy+sgrflags) ;Does this disable writing on the
>graph?
yes
>
>Is this how you draw a line:
>
>set write_on_graph(iy+sgrflags)
>1d bc,57 ;store 57 as bc
>1d de,94 ;store 94 as de
>1d h1,bc ;store bc as h1
>1d h,de ;store de as h
>call _iline
can't help you there.
NE
>
>Phelan 'Amen' Wolf
>
>he's comming out of the closet and into the real world of asm
>