/*
 ** Revision History in reverse order:
 **
 **  The following changes were incorporated in the 08.22.87 release:
 **
 **  08.10.87 - Added wns_dmode() to set the display mode.
 **             wns_dmode(PAINT) sets the window display mode to paint
 **             style, wn_dmode(FLASH) sets the display mode to
 **             flash style.  This function eliminates the need to set
 **             wn_sbit and wns_mtflg to produce the desired effects.
 **
 **  07.17.87 - wn_puts() & wn_putsa() perform simple range checking to
 **             insure that the string being displayed is/stays within
 **             the target window.
 **
 **  06.22.87 - Let's "C" specific code removed. Support will continue
 **             for previous versions but Mark William's products will
 **             not be supported in this or future releases.  This
 **             action is being as the result of compiler limitations.
 **
 **  06.17.87 - wn_activate now does INSTANT screen updates. Ditto
 **             for wn_move.  wn_mtype() returns 1 for EGA.
 **             BLAZING screen updates on EGAs.
 **
 **  06.07.87 - wns_wtext() was incorrectely computing the offset for
 **             windows with wn_wrap enabled!
 **
 **  The following changes were incorporated in the 06.04.87 release:
 **
 **  06.03.87  - Support for BORLAND Turbo C!!
 **
 **  The following changes were incorporated in the 05.12.87 release:
 **
 **  05.12.87  - wns_text was incorrectly compensating for single line
 **              borderless windows (Attachmate follow up).
 **
 **  05.04.87  - EXPLODING windows are now supported!! Simply add 800 to
 **              the video page when calling wn_open()!
 **
 **            - Calls of the form wn_insrow(wn,0) and wn_delrow(wn,0)
 **              caused the border to be klobbered.  wn_insrow() and
 **              wn_delrow() were taught about borders.
 **
 **  03.31.87  - wn_printf [wns_wtext()] was incorrectly displaying graphics
 **              characters. Thanks to Mark MacGee for reporting the problem.
 **
 **  03.23.87  - Attachmate reported that wn_gets was doing funny things
 **              on single line bordered windows on PCs and PC clones but
 **              was fine on ATs and AT clones!  It would appear that the
 **              PC/PC_CLONE BIOS can not deal with scrolling single line
 **              windows.  wn_delrow() was taught to erase single line
 **              windows and avoid using the BIOS for this special case.
 **
 **  03.19.87  - Argh!! Datalight elected to use M_I86 as a predefined
 **              equate.  References to M_I86 were changed to
 **              MSCV3 | MSCV4. (Datalight 3.XX)
 **
 **  The following changes were incorporated in the 03.15.87 release:
 **
 **  03.01.87  - wn_activate was incorrectly computing the coordinates of
 **              unbordered windows.  Thanks to Peter Fletcher for reporting
 **              the problem and supplying a solution.
 **
 **  01.22.87  - wn_dborder() was using the wrong attribute (wn-style,
 **              instead of wn->bstyle). Thanks to Peter Partch for
 **              reporting the problem and supplying a solution.
 **
 **  01.06.87  - wn_activate was not walking through the current linked
 **              list of windows. In rare cases this would cause two
 **              windows to be considered non-overlapping when in fact
 **              they were.  Thanks to Robert Klotz for reporting the
 **              problem.
 **
 **  The following changes were incorporated in the 01.01.87 release:
 **
 **  12.19.86  - Removed a needless call to wn_err(wn,"wn_printf") in
 **              wn_title().
 **
 **  12.16.86  - Improved centering logic for window titles.
 **              Thanks to Steve Liberty for suggesting the change.
 **
 **  12.14.86  - Incorporated compiler specific equates in windows.h.
 **
 **  12.13.86  - wns_mtype() returns 0 for mode 3, 2 for mode 0 or 2,
 **              and 7 for mode 7. (Internal Use - This change allowed
 **              for the prevention of blue on black characters when
 **              the video mode is 2 and a color monitor is in use.
 **              (wns_fixc & wns_mtype).
 **
 **            - BASIC support for Mark Williams "Lets C".
 **
 **            - Tightend free() checks in wn_activate, wn_close, and
 **              wn_restore.
 **
 **  12.12.86  - wn_puts() was not adding the original physical cursor
 **              location to the logical cursor location.
 **              Thanks to Marek Glowacki for reporting the problem.
 **
 **  12.10.86  - Allow v_locate() to position the cursor slightly off
 **              the screen.  Previous limit was (24,79) current limit
 **              is (25,80) which is just beyond the edge of the screen.
 **              This was done to insure that hidden cursors remain out
 **              of view.
 **
 **            - Improved cursor handling when wn_dmaflg = FALSE.
 **
 **  12.09.86  - Taught wn_activate to honor cursor position of window
 **              being activated. This will insure the cursor is always
 **              in the right logical and physical position.
 **              More cosmetic enhancement than logic error correction.
 **
 **  The following changes were incorporated in the 12.01.86 release:
 **
 **  11.28.86  - Reverse video attribute was not being set correctly
 **              on MGAs - corrected.
 **
 **  11.19.86  - wn_dborder was incorrectly computing the row offset.
 **              Thanks to Steve Thatcher for reporting the problem.
 **
 **  11.16.86  - Added ".smeth" member to window control block. This
 **              member defines the scrolling method to be used in
 **              the window. It can be set to BIOS or DMAS, the default
 **              is DMAS.
 **
 **            - All routines that reference wn_activate will return
 **              NULL if the window could not be activated.  This is
 **              usually due to a lack of free memory.
 **
 **  The following changes were incorporated in the 11.14.86 release:
 **
 **  11.13.86  - Closing windows in random order when exiting "sometimes"
 **              produced null pointer assignment error messages or
 **              incorrect screen images - corrected.
 **
 **            - wn_natrib() was not storing the newly defined window
 **              attribute in the window control block - corrected.
 **
 **  11.09.86  - Support for Datalight C added.
 **
 **  11.02.86  - v_border() added.  Allows color of border area to be
 **              set on CGAs with color monitors.
 **
 **  11.01.86  - wn_fixcsr was not adding the original physical cursor
 **              location to the logical cursor location.
 **              Thanks to Bill Harts for reporting the problem.
 **
 **            - wn_puts was computing the virtual cursor location
 **              incorrectly. Thanks to Eric Lundstrom!
 **
 **            - Logic to dectect null strings was incorporated into
 **              _vidblt.  This will prevent 64k worth of trash from
 **              being blitted to the video ram.
 **
 **  10.30.86  - All references to MSC in "windows.h" were changed
 **              to M_I86.  This forces "windows.fns" to be included
 **              under Microsoft C.  This change was also applied to
 **              "windows.c".
 **
 **  10.26.86  - Full float, long, etc. support for wn_printf in
 **              all Lattice versions.  Microsoft 3.XX is the only
 **              one in the dark ages.
 **
 **  10.23.86  - Tip of the hat to Russ Thackson for the improved
 **              overlaping window detection technique incorporated
 **              in wn_activate().
 **
 **  The following changes were incorporated in the 10.22.86 release:
 **
 **  10.22.86  - wn_activate() was causing unnecessary window
 **              thrashing on non-overlapping windows. Corrected.
 **
 **  The following changes were incorporated in the 10.10.86 release:
 **
 **  09.27.86  - Tiled windows are now supported! wn_activate() added.
 **
 **            - wn_gets() was not calling wns_err - corrected.  This
 **              was not a bug, just continued support for wild pointer
 **              checks.
 **
 **  09.25.86  - New logic for vidblt(). Fast mode now works on color
 **              without causing snow or flicker!!  Video updates now
 **              occur at the fastest possible speed!  The effect of
 **              wn_sbit now conforms exactly to the description in the
 **              manual.
 **
 **            - wn_printf (CI86) now has full float support. Thanks
 **              to Rob Sullivan for reporting the CI86 problem. Lattice
 **              and MSC Version 3.0 are the only hold outs for full
 **              wn_print support.  MSC Version 3.0 support will never
 **              be incorporated. If you are using MSC Version 3.00
 **              you will have to upgrade to Version 4.XX.  The price
 **              of the update is well worth it. Version 4.00 is a
 **              work of art! Lattice support will be delayed until
 **              Lattice gets around to supporting vsprintf() as
 **              defined by the evolving ANSI standard.
 **
 **  09.17.86  - seperate modules to decrease memory overhead.
 **
 **            - link list support (wn_open,wn_close,WINDOWPTR struct)
 **              This is the ground work for tiled window support.
 **
 **  09.02.86  - use registers in wns_savres() for speed (MSC).
 **
 **  The following changes were incorporated in the 08.30.86 release:
 **
 **  08.28.86  - wn_gets was delclared as (char *) but returning
 **              (void).  Corrected to return (char *).
 **
 **  08.27.86  - wns_wtext() was not correctly handling borderless
 **              windows. Corrected.
 **
 **            - wn_printf() was not correctly handing cases such as:
 **              wn_printf(wn,"%s %d %f %d\n", "text", 2, 2.2, 5);
 **              The window boss now supports a complete implementation
 **              of printf formatting under Microsoft C Version 4.00.
 **              All other compilers and versions support an INTEGER only
 **              wn_printf.  This will be corrected in a future release.
 **
 **  08.16.86  - Added wn_gets(). Get string in window with validation.
 **
 **  The following chages were incorporated in the 06.02.86 release.
 **
 **  06.02.86  - v_smode was using bh instead of ah. Corrected.
 **              Thanks to Rob Rainwater!!
 **
 **  05.26.86  - Added wn_natrib. Set new window attribute NOW!
 **
 **  05.25.86  - Corrected a potential problem with a couple of the routies
 **              in MSVLIB.ASM. Registers SI & DI were being used but not
 **              being saved. This "may" cause spurious probles with "C"
 **              programs that use register variables.  Microsoft C 3.0 only.
 **
 **            - wn_titla was not calling wns_fixc. Corrected.
 **
 **  05.24.86  - Added wn_titla. write window title with attributes.
 **
 **  05.10.86  - wn_putsa was not calling wns_fixc.  This caused problems
 **              when CGA was in mode bw80 but putsa was called with a
 **              valid color atrib.
 **
 **  The following changes were incororated in the 05.08.86 release.
 **
 **  05.07.86  - Additions for Microsoft "C" version 3.0
 **
 **  05.05.86  - wn_printf fix for lattice version 3.0.
 **
 **  04.25.86  - Added support for handling backspace, delete, & BELL
 **              characters correctly (wns_wtext).
 **
 **              Incorporated v_wtty in vlib.asm.
 **
 **  Initial Release..
 **
 **  01.24.86  - Initial release with a bit of a false start thanks to
 **              Microsoft's Lib.
 **
 */
  
 /* End */