Extended memory availabil

 BBS: Inland Empire Archive
Date: 06-22-92 (19:55)             Number: 1223
From: MATT HART                    Refer#: NONE
  To: JIM TANNER                    Recvd: NO  
Subj: Extended memory availabil      Conf: (2) Quik_Bas

 JT> faster, better, etc., and why...?

In mine, I use boolean logic to set the function to true or
false, which will be faster than the comparison IF THEN
that you did.  The interrupt routine itself will be fairly
fast.  The whole thing can be done in assembler pretty
easily, and be smaller and faster still.

Here's my boolean logic:
    XMSInstalled = ((OutRegs.AX MOD 256)=&H80)

A reader pointed out that THIS would be even faster:
     XMSInstalled = ((OutRegs.AX AND &HFF) = &H80)

The AND &HFF masks out the upper byte and doesn't have to
do the MOD division - logical operations are always faster
than mathematical operations (an AND versus a MOD).  I
don't remember who it was - but thanks out there!  For my
own use though, I do this stuff in assembly, where you can
act directly upon half registers.
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 * Origin: Midnight Micro!  V.32/REL  (918)451-3306 (1:170/600)