Is anything wrong with this?

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hckr83

Joined: 12 Nov 2006
Posts: 86
Location: usa

hckr83

I have made a super generic putpixel function..
it isn't working however...I am doing this on my emulator, hence my wierd small instruction set things..

is anything wrong with this?

Code:

PutPoint: ;ax=x bx=y cx=count dl=color
push ds
push bp

push di
mov di, 0xb800
mov ds,di
pop di


;nop
;this translates to C as bp=ax(x)+(bx(y)*320)
;mov bp,0
mov bp,ax ;bp=ax
mov ax,320
push dx
mul bx ;(bx*320)
pop dx ;ignore top word..
add bp,ax ;+

;cx is already setup
_drawing_loop:
mov [bp],dl
mov bx,0x500
cmp bp,bx
jg failure
mov ax,1

add bp,ax
loop _drawing_loop

pop bp
pop ds
ret
;;END;;
failure:
nop
nop
hlt


display_test:

mov ax,2
mov bx,0
mov cx,20
mov dl,0xF0
call PutPoint
nop

jmp infinite_loop

_________________
x86 CPU Emulation library: http://sourceforge.net/projects/x86lib

25 Feb 2007, 22:44

Chewy509

Joined: 19 Jun 2003
Posts: 297
Location: Bris-vegas, Australia

Chewy509

2 immediate problems. I assume your in 320x200x256colour graphics mode?

The screen buffer for this mode is located at a0000h not b8000h, (eg mov di, 0a000h).

Also try using a segment override when placing your pixel, eg. mov [ds:bp], dl. As a side note, I highly recommend using ES instead of DS.

Also 320 = 256 + 64... So instead of mul we can use 2 shifts and add the result.

eg.

Code:

mov di, [y] ; di = y
mov bx, di ; bx = y
shl di, 8; di = di * 256
shl bx, 6; bx = bx * 64
add di, bx ; di = di + bx
add di, [x] ; di = di + x
mov bx, 0a000h
mov es, bx
mov [es:di], dl

25 Feb 2007, 23:11

vid
Verbosity in development

Joined: 05 Sep 2003
Posts: 7105
Location: Slovakia

vid

Quote:

I have made a super generic putpixel function..

super-generic = slow
fast = totoally not generic

25 Feb 2007, 23:12

hckr83

Joined: 12 Nov 2006
Posts: 86
Location: usa

hckr83

lol...it's only temporary, and I emulate the device wrong so it is at b8000..I did forget that BP uses SS though..(and it took me so long to implement that right!)
won't use ES...no support for segment overrides(yet)

lol..you'd be suprised how fun you can have coding on an imcomplete instruction set

25 Feb 2007, 23:50

rugxulo

Joined: 09 Aug 2005
Posts: 2341
Location: Usono (aka, USA)

rugxulo

hckr83 wrote:

lol..you'd be suprised how fun you can have coding on an imcomplete instruction set

>++++++++[<+++++++++>-]<++++++.>+++++[<++++++>-]<+++.>++[<++>-]<+.>++
+++++++[<--------->-]<---.>+++++++++[<+++++++++>-]<+.>+++[<---->-]<-.
----.>+++[<+++>-]<++..>+++[<++++>-]<+.>+++++++++[<--------->-]<------
-.-..>+++++[<+++++>-]<+.>+++[<---->-]<-.----.>+++++[<------>-]<-.

26 Feb 2007, 01:07

hckr83

Joined: 12 Nov 2006
Posts: 86
Location: usa

hckr83

not even gonna try to get that joke...

10 Mar 2007, 01:46

Madis731

Joined: 25 Sep 2003
Posts: 2140
Location: Estonia

Madis731

it was BF* if I'm correct, but I don't know enough to translate it Smile

10 Mar 2007, 10:38

Dex4u

Joined: 08 Feb 2005
Posts: 1601
Location: web

Dex4u

You could uses DexOS's BF* interpreter Wink

http://jas2o.forthworks.com/dexforum/index.php?topic=55.msg1651#msg1651

PS: I would say it's " Not really! Smile

10 Mar 2007, 13:47

rugxulo

Joined: 09 Aug 2005
Posts: 2341
Location: Usono (aka, USA)

rugxulo

Yes, I said "Not really", as in "No, I'm not surprised at all, many people enjoy weird things like that from time to time." (Just in case you misunderstood me.) Laughing

EDIT: Check here for TXT2BF.C (worked as expected w/ GCC 4.1.0, aka DJGPP 2.04 beta). Also, a good small! BF compiler (written in NASM) is bfd. Have fun! Smile

13 Mar 2007, 08:26

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