Exetools - Frame troubles

I'm having trouble understanding what is happening in this code snippet. Quite a few of the Delphi procs start in a similar way with same two FS: statements

Code:

CODE:004BDE62 33 C0                      xor     eax, eax

CODE:004BDE64 55                          push    ebp

CODE:004BDE65 68 FF DE 4B 00             push    offset @@4

CODE:004BDE6A 64 FF 30                    push    dword ptr fs:[eax]

CODE:004BDE6D 64 89 20                    mov     fs:[eax], esp

...

CODE:004BDEFF E9 00 64 F4 FF       @4:    jmp     @HandleFinally

...



  v8 = &v15;

  v7 = v4BDEFF;

  v6 = __readfsdword(0);

  __writefsdword(0, (unsigned int)&v6);

...

In particular, what are the two statements involving FS doing and is there a way to make hexrays do a proper job of handling them?. Sorry for the dumb question, but this is the first time that I've had to look at FS.

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