Xref:	news2.mv.net comp.os.msdos.djgpp:5674
From:	vecna AT Walden DOT mo DOT net ([vecna])
Newsgroups:	comp.os.msdos.djgpp
Subject:	Setpixel in AT&T inline asm....
Date:	4 Jul 1996 17:54:13 GMT
Organization:	-=MO.NET=- MVP-Net, Inc's Missouri Operations
Lines:	44
Message-ID:	<4rh0g5$m9r@twain.mo.net>
NNTP-Posting-Host:	walden.mo.net
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Alright, I need help with inline ASM in DJGPP. (well, I need help with
any sort of ASM in DJGPP) I was a big time intel asm programmer - in fact
I programmed in 100% assembly at the time so I'm can't live with out ASM.
And I'm really just learning C as I go along here, but right now my problem
isn't with C, it's with AT&T ASM. I'm trying to write a simple putpixel to
a 320x200 virtual screen, which is already allocated and defined as:

char *virscr;

This is my (yes, unoptimized) setpixel routine:

setpixel(int x, int y, char c)
{
  asm("pushl %eax \n\t"
      "pushl %ebx \n\t"
      "pushl %edi \n\t"

      "movzx $_y, %eax \n\t"
      "imul $320, %eax \n\t"
      "movzx $_x, %ebx \n\t"
      "add %ebx, %eax \n\t"
      "mov $_virscr, %ebx \n\t"
      "add %ebx, %eax \n\t"
      "mov %eax, %edi \n\t"
      "movb $_c, %al \n\t"
      "stosb \n\t"

      "popl %edi \n\t"
      "popl %ebx \n\t"
      "popl %eax \n\t");
}

The immediate problem being, it can't recognize movzx. I can't think of any
other alias this was be listed as... not to mention I'm really guessing here.
There's probably tons of other flaws in this routine. (I really don't want to
get into extended ASM just yet). Also, could someone confirm or correct me
that a char is a byte, an int is 16 bits? (or is it 32?) geez, what I wouldn't
give for db, dw, and dd right now.... oh well, thanks in advance.. :)

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[vecna]                crs: code/music/design/www       boingo/crs/eos/#lunar
vecna AT mo DOT net           www page: http://mo.net/~vecna     nineinchnails/quake
moo AT tss DOT survivor DOT org   home of the nin music archive       Eomar on #lunarRPG
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