Get DPMI Capabilities

Returns information about the capabilities of the DPMI host,
including its support or lack of support for optional
features in the DPMI Specification.  Clients can use this
information to optimize their use of system resources in the
current environment.

Call With:

   AX     = 0401H
   ES:(E)DI= selector:offset of 128-byte buffer

Returns:

   if function successful
   Carry flag= clear (this function always succeeds in DPMI
           1.0)
   AX     = capabilities flags

           Bits   Significance
           0      0 = PAGED ACCESSED/DIRTY capability not
           supported
                  1 = PAGED ACCESSED/DIRTY capability
           supported
           1      0 = EXCEPTIONS RESTARTABILITY capability
           not supported
                  1 = EXCEPTIONS RESTARTABILITY capability
           supported
           2      0 = DEVICE MAPPING capability not
           supported
                  1 = DEVICE MAPPING capability supported
           3      0 = CONVENTIONAL MEMORY MAPPING
                     capability not supported
                  1 = CONVENTIONAL MEMORY MAPPING
           capability supported
           4      0 = DEMAND ZERO-FILL capability not
           supported
                  1 = DEMAND ZERO-FILL capability supported
           5      0 = WRITE-PROTECT CLIENT capability not
           supported
                  1 = WRITE-PROTECT CLIENT capability
           supported
           6      0 = WRITE-PROTECT HOST capability not
           supported
                  1 = WRITE-PROTECT HOST capability
           supported
           7-15   reserved
   CX     = reserved, must be 0
   DX     = reserved, must be 0
   ES:(E)DI = selector:offset of 128-byte buffer filled in
           by host with information as follows:

           Offset   Length   Contents
           0        1        Host major version number as a
           decimal number
           1        1        Host minor version number as a
           decimal number
           2        1-126    ASCIIZ (null-terminated) string
                             identifying the DPMI host
                             vendor

   if function unsuccessful
   Carry flag= set (this function always fails in DPMI 0.9)

Notes:

o  PAGE ACCESSED/DIRTY capability means the DPMI host
   maintains page dirty and accessed bits that can be read
   and written with the Get and Set Page Attributes
   functions (Int 31H Functions 0506H and 0507H).  This
   capability must be supported, and must read and write the
   hardware-level dirty and accessed bits, if the DPMI host
   does not provide demand-paged virtual memory.  If the
   DPMI host does support virtual memory, this capability is
   optional, and if present gives the client the ability to
   read and write virtual page dirty and accessed bits
   maintained by the host.
o  EXCEPTION RESTARTABILITY capability means that a faulting
   instruction inside the host kernel can always be
   restarted if the client's exception handler corrects the
   reason for the exception and returns.  Exception
   restartability allows a client to provide virtual memory
   under a DPMI host without virtual memory, or to support
   memory-mapped files under any DPMI host.
o  DEVICE MAPPING capability means that the DPMI host
   supports the optional Map Device function (Int 31H
   Function 0508H).
o  CONVENTIONAL MEMORY MAPPING capability means that the
   DPMI host supports the optional Map Conventional Memory
   function (Int 31H Fn 0509H).
o  DEMAND ZERO-FILL capability means the DPMI host
   guarantees that all committed pages are initialized to
   zero when they are created.  If this capability is not
   supported, the contents of newly committed pages are
   undefined.

o    WRITE-PROTECT CLIENT capability means the DPMI host
   guarantees that the client is running at a privilege
   level such that write protection of pages is effective
   for the client's accesses and will geneate page faults.

o  WRITE-PROTECT HOST capability means the DPMI host
   guarantees that the host has configured the system such
   that write protection of pages is effective for the
   host's accesses and will generate page faults.

o  The host major and minor version numbers are OEM-specific
   and are not the DPMI version numbers.