Accessing registers in Microsoft Visual C++???

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4 total messages Started by Rich Edwards Sat, 23 Sep 1995 16:24

#4277

Author: Rich Edwards
Date: Sat, 23 Sep 1995 16:24

22 lines
997 bytes

Hi there!
I was wondering if Microsoft C compilers have an equivalent to
Borland's register pseudovariables.  I'm trying to compile IPX/SPX
functions written for the Borland compiler in Microsoft's compiler, but
I'm receiving compiler errors.

For example, the following code:

  _BX = 0x0010;
  _AL = 0x00;

  if (_AL == 0)
    return 0;

compiles in Borland, but I get an error "undeclared variable" message
w/ Microsoft.
I checked Microsoft's Knowledge base but found nothing.
Any help would be appreciated.
Thanks.

chappie@ix.netcom.com
Rich

Re: Accessing registers in Microsoft Visual C++???

#4278

Author: Joel Rubin
Date: Sat, 23 Sep 1995 21:45

44 lines
1658 bytes

In article <441ccm$mqu@ixnews7.ix.netcom.com>, chappie@ix.netcom.com 
says...
>
>Hi there!
>I was wondering if Microsoft C compilers have an equivalent to
>Borland's register pseudovariables.  I'm trying to compile IPX/SPX
>functions written for the Borland compiler in Microsoft's compiler, but
>I'm receiving compiler errors.
>
>For example, the following code:
>
>  _BX = 0x0010;
>  _AL = 0x00;
>
>  if (_AL == 0)
>    return 0;
>
>compiles in Borland, but I get an error "undeclared variable" message
>w/ Microsoft.
>I checked Microsoft's Knowledge base but found nothing.
>Any help would be appreciated.
>Thanks.
>
>chappie@ix.netcom.com
>Rich

In Microsoft C(++) you have to use in-line assembler instead.

_asm {
 mov bx,10
 mov al,0
 cmp al,0
 jne not_zero
}
return 0;
not_zero: ...


(Yes, I know you can do this more efficiently--I'm trying to copy the 
logic of the "C".)

As with Borland, you can avoid the {} and put _asm in front of every 
line. Unlike Borland, there is no option for using a full assembler with 
the inline stuff.

Re: Accessing registers in Microsoft Visual C++???

#4279

Author: kim sang woo
Date: Tue, 26 Sep 1995 01:44

27 lines
1420 bytes

Rich Edwards (chappie@ix.netcom.com) wrote:
: Hi there!
: I was wondering if Microsoft C compilers have an equivalent to
: Borland's register pseudovariables.  I'm trying to compile IPX/SPX
: functions written for the Borland compiler in Microsoft's compiler, but
: I'm receiving compiler errors.

: For example, the following code:

:   _BX = 0x0010;
:   _AL = 0x00;

   this is not supported by VC++ and other compilers as well.
The best way to rewrite this is use external assembler function.  This is
one of reason why I never use inline assembler in my C code.

:   if (_AL == 0)
:     return 0;

: compiles in Borland, but I get an error "undeclared variable" message
: w/ Microsoft.
: I checked Microsoft's Knowledge base but found nothing.
: Any help would be appreciated.
: Thanks.

: chappie@ix.netcom.com
: Rich

Re: Accessing registers in Microsoft Visual C++???

#4280

Author: Thomas R Goerz
Date: Fri, 29 Sep 1995 13:42

33 lines
1834 bytes

Andreas Jonsson (sa324@utb.shv.hb.se) wrote:
: >> I was wondering if Microsoft C compilers have an equivalent to
: >> Borland's register pseudovariables.  I'm trying to compile IPX/SPX
: >> functions written for the Borland compiler in Microsoft's compiler, but
: >> I'm receiving compiler errors.
: >> 
: >> For example, the following code:
: >> 
: >>   _BX = 0x0010;
: >>   _AL = 0x00;
: > 
: >Microsoft doesn't have this -- only Borland has it.
: 
: How could I do it in Microsoft VC 1.5++?
: 
: 
: ----------------------------------------------------------------
: !     Andreas Jonsson, Berghalla, S-516 92 ASPERED, SWEDEN     !
: !       E-mail: sa324@utb.shv.hb.se    macki@enter.hb.se       !
: !--------------------------------------------------------------!
: !    Computer Science Applied to System Analysis and Design    !
: !                University of Boras, Sweden                   !
: ----------------------------------------------------------------
: 

I forget the exact syntax, but something like this should work:

__asm {
	mov bx,0x0010
	mov al,0x00
}

This is how you do inline assembly in Microsoft C++

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