hi,
     I can not get the following code to compile on my Borland C++ compiler
the error I keep getting is Label not defined, I have tried lots of wierd
things trying to get this to work but nothing works.  Is there something
special that I have to do when using labels, or do I have to set something
in my options.  Any help would be great!!!

void WaitRetrace (){    asm{
       mov   dx, 3dah
  l1:
       in    al, dx
       and   al, 08h
       jnz   l1
  l2:
       in    al, dx
       and   al, 08h
       jz    l2
   }

                                                Thanks in advance.
                    ,,,

---------------oOO--<_>--OOo------------------------------------------

           "then redefine success."

Yes, in Borland C++, labels cannot be in the asm block.  So, you need
to rewrite it like this:

void WaitRetrace () {    
  asm{
       mov   dx, 3dah
  }

  l1:
  asm {
       in    al, dx
       and   al, 08h
       jnz   l1
  }

  l2:
  asm {
       in    al, dx
       and   al, 08h
       jz    l2
  }

Hope this helps.

Gerry Miller

: > hi,
: >      I can not get the following code to compile on my Borland C++ compiler
: > the error I keep getting is Label not defined, I have tried lots of wierd
: > things trying to get this to work but nothing works.  Is there something
: > special that I have to do when using labels, or do I have to set something
: > in my options.  Any help would be great!!!
: >
: > void WaitRetrace (){    asm{
: >        mov   dx, 3dah
: >   l1:
: >        in    al, dx
: >        and   al, 08h
: >        jnz   l1
: >   l2:
: >        in    al, dx
: >        and   al, 08h
: >        jz    l2
: >    }
: > }

: Yes, in Borland C++, labels cannot be in the asm block.  So, you need
: to rewrite it like this:

: void WaitRetrace () {    
:   asm{
:        mov   dx, 3dah
:   }

:   l1:
:   asm {
:        in    al, dx
:        and   al, 08h
:        jnz   l1
:   }

:   l2:
:   asm {
:        in    al, dx
:        and   al, 08h
:        jz    l2
:   }
: }

: Hope this helps.

: Gerry Miller

Actually, labels can be in the asm block, with some restrictions: the labels
can only be used locally ( you can't jump to them from anywhere outside the

K.Akala

    You can't have labels in inline assembly blocks in BC 3.1
    (I won't comment on the fact, I might use words some people
    might find offensive). Write it like this:

 void WaitRetrace()
 {
 asm{
        mov   dx, 3dah
 }
 l1:
 asm{
        in    al, dx
        and   al, 08h
        jnz   l1
 }
 l2:
 asm{
        in    al, dx
        and   al, 08h
        jz    l2
 }
    }
 }

    Nice, isn't it?

    But - a friend told me yesterday you _can_ have labels in
    inline assembly blocks if the first character of the label is

Slama

: hi,
:      I can not get the following code to compile on my Borland C++ compiler
:      the error I keep getting is Label not defined.

This will work (or it is what I do anyway).  I don't know if there is a
better way.

: void WaitRetrace (){    asm{
:        mov   dx, 3dah}
:   l1:
asm {
:        in    al, dx
:        and   al, 08h
:        jnz   l1}
:   l2:
asm {
:        in    al, dx
:        and   al, 08h
:        jz    l2
:    }
: }

hmmm, messy.

For something this small you could just slap in a heap of asm's.

void waitretrace()
{
      asm    mov   dx, 3dah
  l1:
      asm    in    al, dx
      asm    and   al, 08h
      asm    jnz   l1
  l2:
      asm    in    al, dx
      asm    and   al, 08h
      asm    jz    l2

looks better, but it is up to you.

anyone know of a way to get around this, cause it is a bit of a pain.

andy.

As I recall Borland is a little lacking when it comes to inline
assembly.  I believe if you do the following:

asm {
     /* asm code here */
    }
   l1:
asm {

etc...it should work.

...Boone

        void waitrace(){
                while(inportb(0x3da) & 8);
                while(!(inportb(0x3da) & 8));
        }

--

        Maxtal Pty Ltd,            
        81A Glebe Point Rd, GLEBE   Mem: SA IT/9/22,SC22/WG21
        NSW 2037, AUSTRALIA         Phone: 61-2-566-2189

You can not put labels within a asm { }. Try this
void WaitRetrace(void)
{
    asm mov dx,3dah
l1: asm {
        in al,dx
        and al,8
        jnz l1
    }
l2: asm {
        in al,dx
        and al,8
        jz l2
    }

+----------------------+-----------------------------------------------+

| VeriFone Inc.        |                                               |
| 12830 Earhart Avenue |                                               |
| Auburn, CA  95602    |                                               |
+----------------------+-----------------------------------------------+

Or better yet, write the function externally as a .asm file and link
it in.  No limits then :)  and you'd be using TASM so you could do stuff like:

model small, c
ideal
proc WaitRetrace C USES ax dx
        mov dx, 3dah
l1:
        in al, dx
        and al, 08h
        jnz l1
l2:
        in al, dx
        and al, 08h
        jz l2
endp WaitRetrace

Somehow, I doubt this...
--\Richard Cooley Extraordinaire                "Yeah.  Arrgh."


"LILO - it's not just a boot loader, it's a way of life" -- me

Unfortunately this was one of the first things I learnt when switching to
(IMHO the far better) Borland from Mickeysoft.  The labels must be defined
outside of the enclosing asm {}.  i.e.

void WaitRetrace ()
{    
        asm {
        mov   dx, 3dah
        }
l1:
        asm {
        in    al, dx
        and   al, 08h
        jnz   l1
        }
l2:
        asm {
        in    al, dx
        and   al, 08h
        jz    l2
        }

L8r
--
Julian Nicholls

My opinions bear no relation to my employer's!

No need to save ax,dx if called from C.
C requires to restore: cs,ip,ss,sp,ds,bp - always,
si,di - if register variables are used (compiler option)
Some 32-bit compilers require restore all except aex,ecx,edx.

A few comments.

1)  I usually save the registers I use in a proc, for safety's sake.
    You can elide them if you don't need them :)
2)  Actually, you should probably say "<compiler xxx> requires to restore
    yyy registers" for completeness sake, but I'm hardly one to lecture
    on *that* topic :)
3)  I wouldn't save cs or ip--I assume you mean the caller's cs:ip.  That's
    on the stack already.
4)  I wouldn't change ss:sp unless I was switching stacks; in this case, I'd
    be using the same stack.  No need to save those regs.
5)  The extended call syntax saves bp if you use USES or ARGS or LOCAL; look
    at a listing file some time--you'll see what I mean.

Basically, An external asm program, properly written, shouldn't have to
worry about the registers you mentioned, especially if it's written to link
into the C program's code segment!
--
Richard Cooley Extraordinaire           "Yeah.  Arrgh."


"LILO - it's not just a boot loader, it's a way of life" -- me