DOS ain't dead

File Reading AH=$3F, INT $21 under DPMI | True DPMI (Developers)

posted by DOS386, 27.03.2013, 09:01

> Sorry if this is an old age problem

it is

> I thought HDPMI32 would somehow intercept int 21h/AH=3F in protected mode

Every DPMI host does "intercept".

> and accept 32bit addressing unlike its 16bit counterpart ?

You can have ECX >= 64 KiB and EDX > 1 MiB but only with True DPMI (HDPMI: YES | WATCOM extenders: YES | CWSDPMI : NO), but the buffer must be valid ( see above and http://board.flatassembler.net/topic.php?t=6384 ).

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This is a LOGITECH mouse driver, but some software expect here
the following string:*** This is Copyright 1983 Microsoft ***

Complete thread:

• File Reading AH=3Fh, int 21h under DPMI not working - x86Novice, 17.03.2013, 01:14 (Developers)
  • File Reading AH=3Fh, int 21h under DPMI not working - Japheth, 17.03.2013, 02:45
  • File Reading AH=$3F, INT $21 under DPMI | True DPMI - DOS386, 27.03.2013, 09:01