diff --git a/C/absmi.c b/C/absmi.c
index 1947dcf50..156a41fea 100644
--- a/C/absmi.c
+++ b/C/absmi.c
@@ -331,7 +331,7 @@ _YAP_absmi(int inp)
       /* YREG =was pointing to where we were going to build the
        * next choice-point. The stack shifter will need to know this
        * to move the local stack */
-      if (YREG => (CELL *) B) {
+      if (YREG > (CELL *) B) {
 	ASP = (CELL *) B;
       }
       else {
diff --git a/C/computils.c b/C/computils.c
index 1455371f6..cc77db61a 100644
--- a/C/computils.c
+++ b/C/computils.c
@@ -41,13 +41,13 @@ STATIC_PROTO (void ShowOp, (char *));
  * afterwards 
  */
 
+#ifdef DEBUG
 static Int arg, rn;
 
 static compiler_vm_op ic;
 
 static CELL *cptr;
 
-#ifdef DEBUG
 char            _YAP_Option[20];
 
 YP_FILE *_YAP_logfile;
diff --git a/C/iopreds.c b/C/iopreds.c
index 1d1a083fe..211e6be60 100644
--- a/C/iopreds.c
+++ b/C/iopreds.c
@@ -4422,17 +4422,17 @@ format(Term tail, Term args, int sno)
 		if (size_args)
 		  radix = arg_size;
 		if (IsVarTerm (args)) {
-		FreeAtomSpace(format_base);
-		  Error(INSTANTIATION_ERROR,args,"~T in format/2");
+		  _YAP_FreeAtomSpace(format_base);
+		  _YAP_Error(INSTANTIATION_ERROR,args,"~T in format/2");
 		  return(FALSE);		
 		} else if (!IsPairTerm (args)) {
-		FreeAtomSpace(format_base);
-		  Error(TYPE_ERROR_LIST,args,"~T in format/2");
+		  _YAP_FreeAtomSpace(format_base);
+		  _YAP_Error(TYPE_ERROR_LIST,args,"~T in format/2");
 		  return(FALSE);
 		}
 		if (radix > 36 || radix < 2) {
-		FreeAtomSpace(format_base);
-		  Error(DOMAIN_ERROR_RADIX,MkIntTerm(radix),"~T in format/2");
+		  _YAP_FreeAtomSpace(format_base);
+		  _YAP_Error(DOMAIN_ERROR_RADIX,MkIntTerm(radix),"~T in format/2");
 		  return(FALSE);
 		}
 		arghd = HeadOfTerm (args);
diff --git a/H/absmi.h b/H/absmi.h
index 91877ad66..e3b9b68b0 100644
--- a/H/absmi.h
+++ b/H/absmi.h
@@ -681,7 +681,7 @@ Macros to check the limits of stacks
 
 #else
 
-#define check_trail() if (Unsigned(TrailTop) - Unsigned(TR) < MinTrailGap) \
+#define check_trail() if (Unsigned(_YAP_TrailTop) - Unsigned(TR) < MinTrailGap) \
 			goto notrailleft
 
 #endif
diff --git a/console/yap.c b/console/yap.c
index abd1b4b42..6a0a793ca 100644
--- a/console/yap.c
+++ b/console/yap.c
@@ -491,6 +491,7 @@ main (int argc, char **argv)
   int BootMode;
   YAP_init_args init_args;
 
+  fprintf(stderr,"Entering YAP\n");
 #ifdef SIMICS
   fprintf(stdout,"Entering YAP\n");
 #endif /* SIMICS */
diff --git a/docs/yap.tex b/docs/yap.tex
index 0eda3f7e4..b42a1ea7c 100644
--- a/docs/yap.tex
+++ b/docs/yap.tex
@@ -671,20 +671,32 @@ CC="gcc -mabi=64" ./configure --...
 Be careful. At least for some versions of @code{GCC}, compiling with
 @code{-g} seems to result in broken code.
 
-@item WIN32: The cygwin environment is our suggested approach. The
+@item WIN32: GCC is distributed in the MINGW32 and CYGWIN packages.
+
+The Mingw32 environment is available from the URL:
+
+@code{http://www.mingw.org}
+
+You will need to install the @code{msys} and @code{mingw}
+packages. You should be able to do configure, make and make install.
+
+If you use mingw32 you may want to search the contributed packages for
+the @code{gmp} multi-precision arithmetic library. If you do setup Yap
+with @code{gmp} note that @code{libgmp.dll} must be in the path,
+otherwise Yap will not be able to execute.
+
 CygWin environment is available from the URL:
 
-@code{http://sourceware.cygnus.com}
+@code{http://www.cygwin.com}
 
 @noindent
-and mirrors. Yap should compile under cygwin 20.1 but we suggest using
-the newer 1.1.1 or recent, which has a more complete implementation of
-the WIN32 API and uses GCC2.95.2 instead of egcs. The compilation
-steps under the cygwin shell are as follows:
+and mirrors. We suggest using recent versions of the cygwin shell. The
+compilation steps under the cygwin shell are as follows:
 
 @example
 mkdir cyg
 $YAPSRC/configure --enable-coroutining \\
+                  --enable-depth-limit \\
                   --enable-max-performance
 make
 make install
@@ -702,7 +714,7 @@ You should check the default installation path which is set to
 @code{/PROGRA~1/Yap} in the standard Makefile. This string will usually
 be expanded into @code{c:\Program Files\Yap} by Windows.
 
-The cygwin environment does not provide @t{gm}. You can fetch a dll for
+The cygwin environment does not provide @t{gmp}. You can fetch a dll for
 the @t{gmp} library from @url{http://www.sf.net/projects/mingwrep}.
 
 It is also possible to configure Yap to be a part of the cygwin
@@ -715,8 +727,9 @@ $YAPSRC/configure --enable-coroutining \\
 make
 make install
 @end example
-Yap will then compile using the cygwin library. You can use Yap from a
-cygwin console, or as a standalone application as long as it can fin
+Yap will then compile using the cygwin library and will be installed
+in cygwin's @code{/usr/local}. You can use Yap from a cygwin console,
+or as a standalone application as long as it can find
 @code{cygwin1.dll} in its path.
 
 @end table
diff --git a/library/random/Makefile.in b/library/random/Makefile.in
index dadc2aecf..7f98c7725 100644
--- a/library/random/Makefile.in
+++ b/library/random/Makefile.in
@@ -39,11 +39,7 @@ SOBJS=random@SHLIB_SUFFIX@
 #in some systems we just create a single object, in others we need to
 # create a libray
 
-all: @NEWSHOBJ@
-
-sobjs: $(SOBJS) 
-
-dll: random@SHLIB_SUFFIX@
+all: $(SOBJS) 
 
 random.o: $(srcdir)/random.c
 	$(CC) -c $(CFLAGS) $(SHLIB_CFLAGS) $(srcdir)/random.c -o random.o
@@ -54,38 +50,9 @@ random.o: $(srcdir)/random.c
 @DO_SECOND_LD@random@SHLIB_SUFFIX@: random.o
 @DO_SECOND_LD@	@SHLIB_LD@ -o random@SHLIB_SUFFIX@ random.o
 
-#
-# create a new DLL library on cygwin environments
-#
-# DLLNAME: name of the new dll
-# OBJS: list of object files I want to put in
-# LIBS: list of libraries to link with
-# DEFFILE is the name of the definitions file.
-# BASEFILE temporary 
-# EXPFILE  temporary
-# ENTRY is the entry point  int WINAPI startup (HINSTANCE, DWORD, LPVOID)
-# 
-DLLTOOL=dlltool
-DLLNAME=random.dll
-DLL_LIBS=@DLL_LIBS@ -L../.. -lWYap
-BASE_FILE=random.base
-EXP_FILE=random.exp
-DEF_FILE=$(srcdir)/random.def
-ENTRY_FUNCTION=_win_random@12
-#
-random.dll: $(OBJS)
-	$(LD) -s --base-file $(BASE_FILE) --dll -o $(DLLNAME) $(OBJS) $(DLL_LIBS) -e $(ENTRY_FUNCTION)
-	$(DLLTOOL) --as=$(AS) --dllname $(DLLNAME) --def $(DEF_FILE) --base-file $(BASE_FILE) --output-exp $(EXP_FILE)
-	$(LD) -s --base-file $(BASE_FILE) $(EXP_FILE) -dll -o $(DLLNAME) $(OBJS) $(DLL_LIBS) -e $(ENTRY_FUNCTION)
-	$(DLLTOOL) --as=$(AS) --dllname $(DLLNAME) --def $(DEF_FILE) --base-file $(BASE_FILE) --output-exp $(EXP_FILE)
-	$(LD) $(EXP_FILE) --dll -o $(DLLNAME) $(OBJS) $(DLL_LIBS) -e $(ENTRY_FUNCTION)
-
 install: all
 	$(INSTALL_PROGRAM) $(SOBJS) $(DESTDIR)$(LIBDIR)
 
-install_win32: dll
-	$(INSTALL_PROGRAM) -m 755 random.dll $(LIBDIR)/random.dll
-
 clean:
 	rm -f *.o *~ $(OBJS) $(SOBJS) *.BAK
 
diff --git a/library/regex/Makefile.in b/library/regex/Makefile.in
index 51c684d08..0b2365c3c 100644
--- a/library/regex/Makefile.in
+++ b/library/regex/Makefile.in
@@ -39,11 +39,7 @@ SOBJS=regexp@SHLIB_SUFFIX@ @NO_BUILTIN_REGEXP@ regcomp@SHLIB_SUFFIX@ regexec@SHL
 #in some systems we just create a single object, in others we need to
 # create a libray
 
-all: @NEWSHOBJ@
-
-sobjs: $(SOBJS) 
-
-dll: regexp@SHLIB_SUFFIX@
+all: $(SOBJS)
 
 regexp.o: $(srcdir)/regexp.c  @NO_BUILTIN_REGEXP@ $(srcdir)/regex2.h  $(srcdir)/engine.c
 	$(CC) -c $(CFLAGS) $(SHLIB_CFLAGS) $(srcdir)/regexp.c -o regexp.o
@@ -63,11 +59,11 @@ regexec.o: $(srcdir)/regexec.c
 @DO_SECOND_LD@%@SHLIB_SUFFIX@: %.o
 @DO_SECOND_LD@	@SHLIB_LD@ -o $@ $<
 
-@DO_SECOND_LD@regexp@SHLIB_SUFFIX@: regexp.o
-@DO_SECOND_LD@	@SHLIB_LD@ -o regexp@SHLIB_SUFFIX@ regexp.o
+@DO_SECOND_LD@regexp@SHLIB_SUFFIX@: regexp.o @MERGE_DLL_OBJS@ regcomp.o regerror.o regfree.o regexec.o
+@DO_SECOND_LD@	@SHLIB_LD@ -o regexp@SHLIB_SUFFIX@ regexp.o @MERGE_DLL_OBJS@ regcomp.o regerror.o regfree.o regexec.o
 
-@DO_SECOND_LD@regcomp@SHLIB_SUFFIX@: regcomp.o
-@DO_SECOND_LD@	@SHLIB_LD@ -o regcomp@SHLIB_SUFFIX@ regcomp.o
+@DO_SECOND_LD@regcomp@SHLIB_SUFFIX@: regcomp.o @MERGE_DLL_OBJS@ regfree.o
+@DO_SECOND_LD@	@SHLIB_LD@ -o regcomp@SHLIB_SUFFIX@ regcomp.o @MERGE_DLL_OBJS@ regfree.o
 
 @DO_SECOND_LD@regerror@SHLIB_SUFFIX@: regerror.o
 @DO_SECOND_LD@	@SHLIB_LD@ -o regerror@SHLIB_SUFFIX@ regerror.o
@@ -78,38 +74,9 @@ regexec.o: $(srcdir)/regexec.c
 @DO_SECOND_LD@regexec@SHLIB_SUFFIX@: regexec.o
 @DO_SECOND_LD@	@SHLIB_LD@ -o regexec@SHLIB_SUFFIX@ regexec.o
 
-#
-# create a new DLL library on cygwin environments
-#
-# DLLNAME: name of the new dll
-# OBJS: list of object files I want to put in
-# LIBS: list of libraries to link with
-# DEFFILE is the name of the definitions file.
-# BASEFILE temporary 
-# EXPFILE  temporary
-# ENTRY is the entry point  int WINAPI startup (HINSTANCE, DWORD, LPVOID)
-# 
-DLLTOOL=dlltool
-DLLNAME=regexp.dll
-DLL_LIBS=@DLL_LIBS@ -L../.. -lWYap
-BASE_FILE=regexp.base
-EXP_FILE=regexp.exp
-DEF_FILE=$(srcdir)/regexp.def
-ENTRY_FUNCTION=_win_regexp@12
-#
-regexp.dll: $(OBJS)
-	$(LD) -s --base-file $(BASE_FILE) --dll -o $(DLLNAME) $(OBJS) $(DLL_LIBS) -e $(ENTRY_FUNCTION)
-	$(DLLTOOL) --as=$(AS) --dllname $(DLLNAME) --def $(DEF_FILE) --base-file $(BASE_FILE) --output-exp $(EXP_FILE)
-	$(LD) -s --base-file $(BASE_FILE) $(EXP_FILE) -dll -o $(DLLNAME) $(OBJS) $(DLL_LIBS) -e $(ENTRY_FUNCTION)
-	$(DLLTOOL) --as=$(AS) --dllname $(DLLNAME) --def $(DEF_FILE) --base-file $(BASE_FILE) --output-exp $(EXP_FILE)
-	$(LD) $(EXP_FILE) --dll -o $(DLLNAME) $(OBJS) $(DLL_LIBS) -e $(ENTRY_FUNCTION)
-
 install: all
 	$(INSTALL_PROGRAM) $(SOBJS) $(DESTDIR)$(LIBDIR)
 
-install_win32: dll
-	$(INSTALL_PROGRAM) -m 755 regexp.dll $(LIBDIR)/regexp.dll
-
 clean:
 	rm -f *.o *~ $(OBJS) $(SOBJS) *.BAK
 
diff --git a/library/regex/regcomp.c b/library/regex/regcomp.c
index bcdf9d3d3..2f2d17af5 100644
--- a/library/regex/regcomp.c
+++ b/library/regex/regcomp.c
@@ -77,7 +77,7 @@ unsigned char collate_substitute_table[UCHAR_MAX + 1][STR_LEN];
 struct collate_st_char_pri collate_char_pri_table[UCHAR_MAX + 1];
 struct collate_st_chain_pri collate_chain_pri_table[TABLE_SIZE];
 
-#if _MSC_VER || defined(__MINGW32__)
+#if _MSC_VER || defined(__MINGW32__) || defined(__CYGWIN__)
 #define isblank(X) isspace(X)
 #define isascii(X) ((unsigned int)(X) < 0177)
 #endif
diff --git a/library/regex/utils.h b/library/regex/utils.h
index 326652bd9..74d5fc0f9 100644
--- a/library/regex/utils.h
+++ b/library/regex/utils.h
@@ -38,7 +38,7 @@
  */
 
 /* utility definitions */
-#if defined(_WIN32) || defined(__MINGW32__)
+#if defined(_WIN32) || defined(__MINGW32__) || defined(__CYGWIN__)
 #define	DUPMAX		((unsigned int)-2)	/* xxx is this right? */
 #else
 #define	DUPMAX		_POSIX2_RE_DUP_MAX	/* xxx is this right? */
diff --git a/library/system/Makefile.in b/library/system/Makefile.in
index 98f437c00..67c4ec094 100644
--- a/library/system/Makefile.in
+++ b/library/system/Makefile.in
@@ -39,9 +39,7 @@ SOBJS=sys@SHLIB_SUFFIX@
 #in some systems we just create a single object, in others we need to
 # create a libray
 
-all: @NEWSHOBJ@
-
-sobjs: $(SOBJS) 
+all: $(SOBJS) 
 
 sys.o: $(srcdir)/sys.c
 	$(CC) -c $(CFLAGS) $(SHLIB_CFLAGS) $(srcdir)/sys.c -o sys.o
@@ -52,38 +50,9 @@ sys.o: $(srcdir)/sys.c
 @DO_SECOND_LD@sys@SHLIB_SUFFIX@: sys.o
 @DO_SECOND_LD@	@SHLIB_LD@ -o sys@SHLIB_SUFFIX@ sys.o
 
-#
-# create a new DLL library on mingw32 environments
-#
-# DLLNAME: name of the new dll
-# OBJS: list of object files I want to put in
-# LIBS: list of libraries to link with
-# DEFFILE is the name of the definitions file.
-# BASEFILE temporary 
-# EXPFILE  temporary
-# ENTRY is the entry point  int WINAPI startup (HINSTANCE, DWORD, LPVOID)
-# 
-DLLTOOL=dlltool
-DLLNAME=sys.dll
-DLL_LIBS=@DLL_LIBS@ -L../.. -lWYap
-BASE_FILE=sys.base
-EXP_FILE=sys.exp
-DEF_FILE=$(srcdir)/sys.def
-ENTRY_FUNCTION=_win_sys@12
-#
-sys.dll: $(OBJS)
-	$(LD) -s --base-file $(BASE_FILE) --dll -o $(DLLNAME) $(OBJS) $(DLL_LIBS) -e $(ENTRY_FUNCTION)
-	$(DLLTOOL) --as=$(AS) --dllname $(DLLNAME) --def $(DEF_FILE) --base-file $(BASE_FILE) --output-exp $(EXP_FILE)
-	$(LD) -s --base-file $(BASE_FILE) $(EXP_FILE) -dll -o $(DLLNAME) $(OBJS) $(DLL_LIBS) -e $(ENTRY_FUNCTION)
-	$(DLLTOOL) --as=$(AS) --dllname $(DLLNAME) --def $(DEF_FILE) --base-file $(BASE_FILE) --output-exp $(EXP_FILE)
-	$(LD) $(EXP_FILE) --dll -o $(DLLNAME) $(OBJS) $(DLL_LIBS) -e $(ENTRY_FUNCTION)
-
 install: all
 	$(INSTALL_PROGRAM) $(SOBJS) $(DESTDIR)$(LIBDIR)
 
-install_win32: dll
-	$(INSTALL_PROGRAM) -m 755 sys.dll $(LIBDIR)/sys.dll
-
 clean:
 	rm -f *.o *~ $(OBJS) $(SOBJS) *.BAK
 
diff --git a/library/yap2swi/Makefile.in b/library/yap2swi/Makefile.in
index 86bb8a1f4..fbbe48d64 100644
--- a/library/yap2swi/Makefile.in
+++ b/library/yap2swi/Makefile.in
@@ -39,11 +39,7 @@ SOBJS=yap2swi@SHLIB_SUFFIX@
 #in some systems we just create a single object, in others we need to
 # create a libray
 
-all: @NEWSHOBJ@
-
-sobjs: $(SOBJS) 
-
-dll: yap2swi@SHLIB_SUFFIX@
+all: $(SOBJS) 
 
 yap2swi.o: $(srcdir)/yap2swi.c
 	$(CC) -c $(CFLAGS) $(SHLIB_CFLAGS) $(srcdir)/yap2swi.c -o yap2swi.o
@@ -54,38 +50,9 @@ yap2swi.o: $(srcdir)/yap2swi.c
 @DO_SECOND_LD@yap2swi@SHLIB_SUFFIX@: yap2swi.o
 @DO_SECOND_LD@	@SHLIB_LD@ -o yap2swi@SHLIB_SUFFIX@ yap2swi.o
 
-#
-# create a new DLL library on cygwin environments
-#
-# DLLNAME: name of the new dll
-# OBJS: list of object files I want to put in
-# LIBS: list of libraries to link with
-# DEFFILE is the name of the definitions file.
-# BASEFILE temporary 
-# EXPFILE  temporary
-# ENTRY is the entry point  int WINAPI startup (HINSTANCE, DWORD, LPVOID)
-# 
-DLLTOOL=dlltool
-DLLNAME=yap2swi.dll
-DLL_LIBS=@DLL_LIBS@ -L../.. -lWYap
-BASE_FILE=yap2swi.base
-EXP_FILE=yap2swi.exp
-DEF_FILE=$(srcdir)/yap2swi.def
-ENTRY_FUNCTION=_win_yap2swi@12
-#
-yap2swi.dll: $(OBJS)
-	$(LD) -s --base-file $(BASE_FILE) --dll -o $(DLLNAME) $(OBJS) $(DLL_LIBS) -e $(ENTRY_FUNCTION)
-	$(DLLTOOL) --as=$(AS) --dllname $(DLLNAME) --def $(DEF_FILE) --base-file $(BASE_FILE) --output-exp $(EXP_FILE)
-	$(LD) -s --base-file $(BASE_FILE) $(EXP_FILE) -dll -o $(DLLNAME) $(OBJS) $(DLL_LIBS) -e $(ENTRY_FUNCTION)
-	$(DLLTOOL) --as=$(AS) --dllname $(DLLNAME) --def $(DEF_FILE) --base-file $(BASE_FILE) --output-exp $(EXP_FILE)
-	$(LD) $(EXP_FILE) --dll -o $(DLLNAME) $(OBJS) $(DLL_LIBS) -e $(ENTRY_FUNCTION)
-
 install: all
 	$(INSTALL_PROGRAM) $(SOBJS) $(DESTDIR)$(LIBDIR)
 
-install_win32: dll
-	$(INSTALL_PROGRAM) -m 755 yap2swi.dll $(LIBDIR)/yap2swi.dll
-
 clean:
 	rm -f *.o *~ $(OBJS) $(SOBJS) *.BAK