License added.

drv/LICENSE.md

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2026 Scott Duensing
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

drv/README.md

@@ -11,9 +11,12 @@ Windows 3.1 Device Driver Adaptation Guide (DDAG).  Where the DDAG is silent,
 behavior follows the Windows 3.1 SDK, Wine's Win16 comm code, or the stock
 driver as far as it is known; those cases are called out below.
 
-> Status: the driver was rewritten to the DDAG on 2026-10-12.  The rewrite
+> Status: the driver was rewritten to the DDAG on 2026-10-12.  Built with
-> compiles and links under Open Watcom with the Win16 headers but has not yet
+> Open Watcom (`watcom.mk`), it runs: JoeyLib's Win16 port installs it as
-> been built with MSVC 1.52 or run on hardware.  See
+> `comm.drv` on Windows for Workgroups 3.11 under DOSBox Staging, where COM1
+> opens and echoes, and 16 KB go out and come back in order at the full line
+> rate at 57600 and at 115200 (`KPCBR_115200`).  It has not yet been built
+> with MSVC 1.52 or run on hardware.  See
 > [Verification checklist](#verification-checklist).
 
 
@@ -36,6 +39,7 @@ driver as far as it is known; those cases are called out below.
 - [Verification checklist](#verification-checklist)
 - [Future work](#future-work)
 - [References](#references)
+- [License](#license)
 
 
 ## Files
@@ -48,7 +52,10 @@ driver as far as it is known; those cases are called out below.
 | `lpt.c` | LPT1-LPT3 support (polled output through BIOS INT 17h) |
 | `commdrv.def` | Module definition: module name `COMM`, export ordinals, FIXED segments |
 | `makefile` | NMAKE build for MSVC 1.52 |
+| `watcom.mk` | GNU make build with Open Watcom v2 (on Linux) |
+| `kpcomm.lnk` | wlink directives for the Open Watcom build: what `commdrv.def` gives MSVC's linker |
 | `ring0.md` | Notes for moving interrupt handling to ring 0, if it is ever needed |
+| `LICENSE.md` | The MIT License |
 
 
 ## Building
@@ -79,15 +86,30 @@ Two rules matter for anyone changing the code:
   DS-relative, so any out-parameter that can point at a stack variable is
   declared `FAR`.
 
-A compile check without MSVC is possible with Open Watcom 2.0 (Win16 target,
+### With Open Watcom
-small model, SS != DS):
+
+`watcom.mk` builds the same driver with Open Watcom v2's 16-bit Windows
+target, with GNU make on Linux.  It uses the Open Watcom JoeyLib's installer
+sets up (`../../joeylib/toolchains/opt/openWatcom`) unless `WATCOM` names
+another; it needs the 16-bit Windows libraries (`lib286/win`).
 
 ```
-wcc -q -bt=windows -ms -zu -zw -bd -zp2 -2 -w4 commdrv.c
+cd drv
+make -f watcom.mk                   builds bin/kpcomm.drv
+make -f watcom.mk clean             removes obj/ and bin/
+make -f watcom.mk OBJ=DIR BIN=DIR   builds somewhere else
 ```
 
-Expect W200 "referenced but never assigned" warnings for variables set
+The flags match the MSVC build's (see `watcom.mk`), with no stack probes
-inside `_asm` blocks; Watcom does not see those assignments.
+(`-s`: Watcom adds them by default).  `kpcomm.lnk` carries `commdrv.def`'s
+module name, description, fixed segments and export ordinals; the sources'
+`_export` exports the entry points too, which wlink's warning W1121 reports
+and the link file turns off.  The W200 "referenced but never assigned"
+warnings for variables set inside `_asm` blocks are turned off as well
+(`-wcd=200`): Watcom does not see those assignments, and the code it
+generates for them is right (they are memory operands).  JoeyLib's installer
+builds the driver this way (its `kpcomm` component), into its own build
+tree.
 
 
 ## Installing
@@ -576,6 +598,13 @@ disabled.
 
 ## Verification checklist
 
+Confirmed in emulation (2026-10-12): an Open Watcom build on Windows for
+Workgroups 3.11 under DOSBox Staging, through JoeyLib's Win16 port and its
+gates.  COM1 opens and closes (item 4, COM1 only), and 16 KB go out and come
+back in order at the full line rate at 57600 and at 115200 through
+`KPCBR_115200` (items 3 and 6, without flow control and without other load);
+Windows' own COMM.DRV refuses `KPCBR_115200`, as it should.
+
 Not yet confirmed on hardware with an MSVC 1.52 build:
 
 1. **Build.**  It compiles and links cleanly under MSVC 1.52, including
@@ -629,3 +658,26 @@ Not yet confirmed on hardware with an MSVC 1.52 build:
   `COMMDRV30`): https://jeffpar.github.io/kbarchive/kb/080/Q80901/
 - KB Q83449, Windows 3.1 serial communications Q&A
 - KB Q101417, the MSR shadow at offset 35 of the ComDEB
+
+
+## License
+
+KPCOMM is distributed under the MIT License (`LICENSE.md`): it may be used,
+changed and shipped, alone or with a program, as source or as the built
+driver, as long as the copyright and permission notice go with it.  The
+license covers this folder; the rest of the repository is not under it.
+
+Built with Open Watcom (`watcom.mk`), the driver also carries Open Watcom
+code (its DLL start-up and C library helpers), and Open Watcom's license
+(the Sybase Open Watcom Public License, section 2.2(d)) asks for a notice,
+in the driver and in its documentation, that the source of that code is
+available and where.  The built `kpcomm.drv` carries the notice (never
+shown); a program that ships it puts this line in its documentation:
+
+```
+This software contains code from Open Watcom. Its source code is available
+under the terms of the Sybase Open Watcom Public License version 1.0 from
+https://github.com/open-watcom/open-watcom-v2
+```
+
+The MSVC build carries none of Open Watcom's code.

drv/commdrv.c

@@ -139,6 +139,21 @@ PortStateT      ports[MAX_PORTS];         // One per COM port, indexed by cid; s
 volatile bool   portsSuspended = false;   // Set while a DOS application owns the hardware
 static uint16_t biosSelector   = 0;       // DPMI selector for segment 0040h (0 = not created yet)
 
+#ifdef __WATCOMC__
+// -----------------------------------------------------------------------
+// Open Watcom's notice
+//
+// Open Watcom's license (the Sybase Open Watcom Public License, section
+// 2.2(d)) asks for a notice, in the driver and in its documentation, that
+// the source of the Open Watcom code it carries (its DLL start-up and C
+// library helpers) is available, and where.  This is the driver's copy,
+// never shown; it is not static, so the compiler keeps it although nothing
+// reads it.  README.md gives the same text for the documentation.  The
+// MSVC build carries none of Open Watcom's code.
+// -----------------------------------------------------------------------
+const char owplNotice[] = "This software contains code from Open Watcom. Its source code is available under the terms of the Sybase Open Watcom Public License version 1.0 from https://github.com/open-watcom/open-watcom-v2";
+#endif
+
 
 // -----------------------------------------------------------------------
 // addErrors - Record CE_* bits from application context

drv/kpcomm.lnk

@@ -0,0 +1,18 @@
+# kpcomm.lnk -- wlink directives for KPCOMM.DRV built with Open Watcom
+# (watcom.mk): what commdrv.def gives MSVC's linker. The module name stays
+# COMM, as USER.EXE imports the driver by that name, and the entry points
+# keep the stock driver's ordinals. Code and data are fixed and preloaded.
+# The sources' _export exports the entry points too (W1121, off): the
+# ordinals come from here.
+system windows_dll
+disable 1121
+option modname=COMM
+option description 'KPCOMM -- High-Speed Serial Communications Driver'
+option heapsize=1024
+segment type code preload fixed
+segment type data preload fixed
+export INICOM.1, SETCOM.2, SETQUE.3, RECCOM.4, SNDCOM.5, CTX.6, TRMCOM.7, STACOM.8
+export CEXTFCN.9, CFLUSH.10, CEVT.11, CEVTGET.12, CSETBRK.13, CCLRBRK.14, GETDCB.15
+export WEP.16 resident
+export SUSPENDOPENCOMMPORTS.17, REACTIVATEOPENCOMMPORTS.18, COMMWRITESTRING.19, READCOMMSTRING.20
+export ENABLENOTIFICATION.100, COMMNOTIFYWNDPROC.101

drv/watcom.mk

@@ -0,0 +1,44 @@
+# watcom.mk -- KPCOMM.DRV built on Linux with Open Watcom v2's 16-bit
+# Windows target, for hosts without MSVC 1.52 (the makefile, for NMAKE, is
+# the MSVC build). Uses the Open Watcom JoeyLib's installer sets up, unless
+# WATCOM names another.
+#
+#   make -f watcom.mk                bin/kpcomm.drv
+#   make -f watcom.mk clean          remove obj/ and bin/
+#   make -f watcom.mk OBJ=DIR BIN=DIR   build somewhere else
+#
+# Compiler flags, as the MSVC build's: Windows target (-bt=windows) DLL
+# (-bd), small model with SS != DS (-ms -zu), Windows prolog for exported
+# functions (-zw), no stack probes (-s), 286 code (-2), structures packed
+# on 2 bytes (-zp2), all warnings (-w4). The _asm blocks set variables
+# Watcom cannot see set (W200), so those warnings are off (-wcd=200);
+# kpcomm.lnk is commdrv.def for wlink.
+
+WATCOM ?= $(abspath $(CURDIR)/../../joeylib/toolchains/opt/openWatcom)
+export WATCOM
+export PATH := $(WATCOM)/binl64:$(PATH)
+
+CC      := wcc
+LINK    := wlink
+CFLAGS  := -q -bt=windows -bd -ms -zu -zw -s -2 -zp2 -os -w4 -wcd=200 -we -i=$(WATCOM)/h -i=$(WATCOM)/h/win
+
+OBJ     ?= obj
+BIN     ?= bin
+TARGET  := $(BIN)/kpcomm.drv
+OBJS    := $(OBJ)/commdrv.obj $(OBJ)/isr.obj $(OBJ)/lpt.obj
+
+all: $(TARGET)
+
+$(OBJ)/%.obj: %.c commdrv.h watcom.mk | $(OBJ)
+	$(CC) $(CFLAGS) -fo=$@ $<
+
+$(TARGET): $(OBJS) kpcomm.lnk | $(BIN)
+	$(LINK) option quiet @kpcomm.lnk name $@ $(foreach o,$(OBJS),file $(o)) option map=$(OBJ)/kpcomm.map
+
+$(OBJ) $(BIN):
+	mkdir -p $@
+
+clean:
+	rm -rf $(OBJ) $(BIN)
+
+.PHONY: all clean