G'Day John,
 
-=> Quoting John Gardeniers to Frank Adam <=-
 FA> Just curious why is REGS a union and not a struct ? It feels like
 FA> one..

 JG> Because the registers come in a variety of sizes REGS has to be
 JG> a union.  Al & AH are byte wide (CHAR) while AX is the same two but
 JG> joined at the hips, therefore it's a word (INT).  For those with
 JG> something a little more than advanced than my XT there is also a 32
 JG> bit version (EAX?).  When I was trying to get the hang of this
 JG> structure/union thing I found that it all made sense once I saw it
No-no, i've been using regs and unions for some time, but i could never 
find any in debt info on *how* they work. 
Eg, i access regs.h.ah, and then regs.x.ax. Now according to the manuals 
and articles i've seen, i would've thought that the first struct fills up 
the union, and the second can't be accessed, but it can. 
 
 FA> adress of DTA(Disk Transfer Adress) ?
 FA> ptr = (char far*) MK_FP((unsigned)sregs.es,(usigned)regs.x.dx);
 JG> The error is in using ES:DX, it should be ES:BX.  I just have to
Thanks, will try that.

 JG> ask, why do you (or anyone else) use such long winded code?
 JG> Whenever I need to do anything at the register level I simply use
 JG> in-line assembler code.  This is even more important if you are
Because although i can read some assembly , i'm not at all comfortable 
writing them. 
So my motto is, if in doubt(that's mostly), let the compiler do it. :)       
There is also something about it not being ISO, and i believe i've heard 
that certain compilers don't support inline asm. (??) 
I personally rather look at one of my old code and be able to read it
without thinking much about it. Using the regpacks will do that for me, 
Borland's use of _AX,_CX etc. would make it even easier. 
With compilers and PCs getting better and faster, the only time i'd 
consider asm is if a program truely needs more speed.

  L8r Frank (fadam{at}ozemail.com.au).
                    
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