🚀 go-pugleaf

Zhang Ya Xin writes:

>    We have a TANG IBM/PC 386 which has 4M of memory. Normally the adress
>of memory in the PC consists of a segment plus an offset, say, ****:****.
>1M is the limitation. My question is how can I access the memory beyond 1M?
>In other words, is there an adress of the memory beyond 1M in the PC?

   For my thesis (a prototype for a real-time image processing board), I
needed to access memory above 1M on a 386, for storing images above 1M and
also accessing the board's memory which is at 8M, just above the PC's
memory.  An MS-DOS function call (int 15H, AH = 87H) is all that's
needed for the memory transfer, which can transfer a buffer to extended
memory and vice-versa.  The source and destination addresses are specified
before the fuction call.  More details and example assembly code can be
found in an MS-DOS book, which I don't recall the name of (maybe it's just
"MS-DOS").  A memory transfer of up to 64K can be done, but Turbo C wouldn't
allow me to declare such a large array, so I had to go with 32K.

						Jens

P.S. To any potential employers: I would like to get a DSP job, as my thesis
     has given me experience with the design, simulation, and construction of
     an image processing board.  E-mail for more details if you're looking
     for a design engineer (BS in Electrical and Computer Engineering, almost
     MS in Computer Engineering).  Thanks.