Re: LPTx:

 BBS: Inland Empire Archive
Date: 03-10-92 (23:11)             Number: 170
From: DONN BLY                     Refer#: NONE
  To: MIKE LININGER                 Recvd: NO  
Subj: Re: LPTx:                      Conf: (11) Quik_Bas

 > Is there a way to peek at some memory locations to
 > determine which printer ports LPT1:, LPT2:, LPT3: are
 > available on any given system.  I know you do it with on
 > errors and try to open the device for output, but I
 > would like stay away from on errors statements that
 > balloon the size of the code.


The addresses of LPT ports 1 through three are stored in
memory in the following address ranges:

   0040:0008 - 0040:0009  Address of LPT1:
   0040:000A - 0040:000B  Address of LPT2:
   0040:000C - 0040:000D  Address of LPT3:

In other words, to get the address of LPT1: you can do this:

   DEF SEG=&H40
   BaseAddr% = PEEK(8) + PEEK(9)*256
   DEF SEG

The equipment flag is stored at 0040:0010-0040:0011, and
part of that (bits 14 & 15) will tell you the number of
LPT ports installed.

   DEF SEG=&H40
   NumPorts% = (PEEK(17) AND &HC0) \ &H40
   DEF SEG

This information is also available from int 0x11


--- OPMED 3.00
 * Origin: The Loft *HST/DS/V42bis* [NC, SDS] (1:236/7)