Borland x86 inlined assembler; get a label's address?

Question

I am using Borland Turbo C++ with some inlined assembler code, so presumably Turbo Assembler (TASM) style assembly code. I wish to do the following:

void foo         


        

Answer 1

I think the problem you're running into is that a label inside the __asm block and the label in the C++ code are two completely different things. I wouldn't expect that you could reference a C++ label in that way from inline assembly, but I must say it's been a very long time since I've used Turbo C++.

Have you tried the lea instruction instead of mov?

Answer 2

This is a variant of Ivan's suggestion but give this a try:

void foo::bar( void )
{
    __asm
    {
      mov eax, offset SomeLabel
      // ...
    }
    // ...
    __asm SomeLabel:
    // ...
}

Answer 3

I don't know about your compiler / assembler specifically, but a trick I've used quite a bit is to call the next location and then pop the stack into your register. Be certain the call you make only pushes the return address.

Answer 4

Just guessing since I haven't used inline assembler with any C/++ compiler...

void foo::bar( void )
{
    __asm
    {
      mov eax, SomeLabel
      // ...
    }
    // ...
    __asm
    {
      SomeLabel:
      // ...
    }
    // ...
}

I don't know the exact syntax of TASM.

Answer 5

one of the options would be to use separate "naked" (prolog-less) procedure SomeLabel instead of label

Answer 6

Does the Turbo C++ environment have a way to set options for TASM (I know that some of the Borland IDEs did)?

If so, see if changing the option for "Maximum passes (/m)" to 2 or more helps (it might default to 1 pass).

Also, if you're using a long label name that might pose a problem - at least one IDE had the default set to 12. Change the "Maximum symbol length (/mv) option".

This information is based on Borland's RAD Studio IDE:

• http://docs.codegear.com/docs/radstudio/radstudio2007/RS2007_helpupdates/HUpdate4/EN/html/devcommon/tasm32_options_xml.html