diff --git a/sdk/.gitignore b/sdk/.gitignore
index 8838f76..e526285 100644
--- a/sdk/.gitignore
+++ b/sdk/.gitignore
@@ -2,6 +2,7 @@
 #
 # SPDX-License-Identifier: CC0-1.0
 
-bin/*
-lib/*
+bin
+lib
+opt
 conf.mk
diff --git a/sdk/README.md b/sdk/README.md
index 3ff7277..7183d83 100644
--- a/sdk/README.md
+++ b/sdk/README.md
@@ -1,16 +1,18 @@
 # Authors
 
-2021 Ivan Tatarinov <ivan-tat@ya.ru>
+This document:
+* 2021 Ivan Tatarinov <ivan-tat@ya.ru>
 
 # Contributors
 
-No one yet.
+This document: No one yet.
 
 # Licenses
 
 This document is under [GNU FDL-1.3 or later](https://spdx.org/licenses/GFDL-1.3-or-later.html) license.  
 SJAsmPlus Z80 Assembler is distributed under [zlib](https://spdx.org/licenses/Zlib.html) license.  
 SJAsmPlus Z80 Assembler by aprisobal (*z00m128*) is distributed under [BSD 3-Clause "New" or "Revised"](https://spdx.org/licenses/BSD-3-Clause.html) license.  
+Small Device C Compiler (SDCC) is distributed under [GPL](https://sourceforge.net/projects/sdcc/) licenses.  
 z88dk is distributed under [Clarified Artistic](https://spdx.org/licenses/ClArtistic.html) license.  
 LodePNG C/C++ library is distributed under [zlib](https://spdx.org/licenses/Zlib.html) license.
 
@@ -23,6 +25,7 @@ Directory | Description
 `bin` | Compiled binaries of tools.
 `include` | Header files (`.def`, `.h` etc.) to be included in other sources (assembler, C, etc.).
 `lib` | Libraries, needed for executables (mostly in `bin` directory) to function properly.
+`opt` | Optionally installed bundles (like SDK).
 `src` | The source code of local and downloadable tools. See Makefiles for details.
 `windows-x86` | Compiled binaries of tools and libraries for Windows x86 (32 bit) platform.
 
@@ -53,6 +56,7 @@ Additional packages for targets:
 Target | Packages
 ----|----
 `sjasmplus` | cmake libboost-all-dev libxml2-dev
+`sdcc` | -
 `z88dk` | dos2unix libboost-all-dev texinfo texi2html libxml2-dev subversion bison flex zlib1g-dev m4
 
 To use cross-compilation for Windows platform install *mingw-w64* package.
@@ -91,6 +95,7 @@ Value of `<CFG_VAR>` | Possible values | Description
 Value of `TARGET` | Origin | Description
 ----|----|----
 `sjasmplus` | downloaded | SJAsmPlus Z80 Assembler
+`sdcc` | downloaded | Small Device C Compiler
 `z88dk` | downloaded | z88dk
 `lodepng` | `src/lodepng` | LodePNG library
 `zx7b` | `src/zx7b` | zx7b
@@ -103,6 +108,7 @@ Value of `BUILD` | Target directory | Target system
 
 Compiled binaries are installed into `bin` sub-directory of target directory.
 Compiled libraries are installed into `lib` sub-directory of target directory.
+Complex bundles are installed into `opt` sub-directory of target directory.
 
 Example:
 
@@ -186,6 +192,7 @@ Target | Dependencies
 ----|----
 all targets | bash git make wget unzip p7zip
 `sjasmplus` | gcc-g++ cmake libboost-devel
+`sdcc` | -
 `z88dk` | mingw64-i686-gcc-core mingw64-i686-libxml2 patch
 `lodepng` | gcc-core
 `zx7b` | gcc-core
@@ -219,6 +226,7 @@ where:
 Value of `TARGET` | Sources origin | Binaries origin (**Quick setup**) | Build from sources
 ----|----|----|----
 `sjasmplus` | downloaded | downloaded (**yes**) | available
+`sdcc` | downloaded | downloaded (**yes**) | available
 `z88dk` | downloaded | downloaded (**yes**) | available
 `lodepng` | local | precompiled locally (**no**) | available
 `zx7b` | local | precompiled locally (**no**) | available
@@ -296,6 +304,7 @@ These changes are actual for current invocation of command shell and all child p
 * [Windows commands](https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/windows-commands)
 * [SJAsmPlus](https://github.com/sjasmplus/sjasmplus) - Z80 Assembler
 * [SJAsmPlus by aprisobal](https://github.com/z00m128/sjasmplus) - Z80 Assembler
+* [SDCC](https://sourceforge.net/projects/sdcc/) - Small Device C Compiler
 * [Z88DK](https://github.com/z88dk/z88dk) - The Development Kit for Z80 Computers
 * [LodePNG](https://github.com/lvandeve/lodepng) - PNG encoder and decoder in C and C++
 * [Open Source FPGA Foundation Formed to Accelerate Widespread Adoption of Programmable Logic](https://osfpga.org/osfpga-foundation-launched/) - news article (April 8, 2021)
diff --git a/sdk/common.mk b/sdk/common.mk
index 71b32ad..91ec216 100644
--- a/sdk/common.mk
+++ b/sdk/common.mk
@@ -10,66 +10,124 @@
 
 ifndef ZXSDK
 
-ZXSDK		:= $(patsubst %/,%,$(abspath $(dir $(lastword $(MAKEFILE_LIST)))))
+# ZXSDK
 
+# Root (if set acts as a flag of the properly configured environment variables)
+export ZXSDK = $(patsubst %/,%,$(abspath $(dir $(lastword $(MAKEFILE_LIST)))))
+_path = $(ZXSDK)
+
+# Root of platform specific files
 ifeq ($(OS),Windows_NT)
  ifeq ($(PROCESSOR_ARCHITECTURE),X86)
-  ZXSDK_PLATFORM= $(ZXSDK)/windows-x86
+  ZXSDK_PLATFORM = $(ZXSDK)/windows-x86
  else ifeq ($(PROCESSOR_ARCHITECTURE),AMD64)
-  ZXSDK_PLATFORM= $(ZXSDK)/windows-x86
+  ZXSDK_PLATFORM = $(ZXSDK)/windows-x86
  else ifeq ($(PROCESSOR_ARCHITECTURE),EM64T)
-  ZXSDK_PLATFORM= $(ZXSDK)/windows-x86
+  ZXSDK_PLATFORM = $(ZXSDK)/windows-x86
  else
   $(warning Unsupported platform: "$(PROCESSOR_ARCHITECTURE)")
-  ZXSDK_PLATFORM= $(ZXSDK)/windows-x86
+  ZXSDK_PLATFORM = $(ZXSDK)/windows-x86
  endif
 else
  ZXSDK_PLATFORM	= $(ZXSDK)
 endif
-
-Z88DK		:= $(ZXSDK)/src/z88dk
-ZCCCFG		:= $(Z88DK)/lib/config
-PATH		:= $(ZXSDK_PLATFORM)/bin:$(Z88DK)/bin:$(ZXSDK):$(PATH)
-
-ifeq ($(OS),Windows_NT)
-PATH		:= $(ZXSDK_PLATFORM)/lib:$(PATH)
-# Fix paths under Cygwin for z88dk on Windows
-ifeq ($(shell echo $$OSTYPE),cygwin)
-ZCCCFG		:= $(shell cygpath -m $(ZCCCFG))
-endif
-else	# $(OS)!=Windows_NT
-export LD_LIBRARY_PATH:=$(ZXSDK_PLATFORM)/lib
-endif	# $(OS)!=Windows_NT
-
-export ZXSDK
 export ZXSDK_PLATFORM
+
+# "bin" directory (platform specific)
+_path := $(_path):$(ZXSDK_PLATFORM)/bin
+
+# "lib" directory (platform specific)
+ifeq ($(OS),Windows_NT)
+ _path := $(_path):$(ZXSDK_PLATFORM)/lib
+else
+ export LD_LIBRARY_PATH = $(ZXSDK_PLATFORM)/lib
+endif
+
+# SDCC
+
+# Root (platform specific)
+export SDCCHOME	= $(ZXSDK_PLATFORM)/opt/sdcc
+
+# "bin" directory (platform specific)
+_path := $(_path):$(SDCCHOME)/bin
+
+# "include" directory (platform specific)
+ifeq ($(OS),Windows_NT)
+ SDCCINCLUDE = $(SDCCHOME)/include
+else
+ SDCCINCLUDE = $(SDCCHOME)/share/sdcc/include
+endif
+export SDCCINCLUDE
+
+# "lib" directory (platform specific)
+ifeq ($(OS),Windows_NT)
+ SDCCLIB = $(SDCCHOME)/lib
+else
+ SDCCLIB = $(SDCCHOME)/share/sdcc/lib
+endif
+export SDCCLIB
+
+# Z88DK
+
+# Root
+Z88DK = $(ZXSDK)/src/z88dk
+
+# "bin" directory
+_path := $(_path):$(Z88DK)/bin
+
+# Configuration file
+ZCCCFG = $(Z88DK)/lib/config
+ifeq ($(OS),Windows_NT)
+ # Fix paths under Cygwin for Z88DK on Windows
+ ifeq ($(shell echo $$OSTYPE),cygwin)
+  ZCCCFG = $(shell cygpath -m $(ZCCCFG))
+ endif
+endif
 export ZCCCFG
-export PATH
+
+# PATH
+
+export PATH := $(_path):$(PATH)
+undefine _path
 
 endif	# !ZXSDK
 
+# Default values
+
 -include $(ZXSDK)/conf.mk
 
-ifeq ($(OS),Windows_NT)
-EXESUFFIX	:= .exe
-DLLSUFFIX	:= .dll
-else
-EXESUFFIX	:=
-DLLSUFFIX	:= .so
-endif
-
+# C compiler
 ifeq ($(BUILD),mingw32)
-CC		:= i686-w64-mingw32-gcc
-EXESUFFIX	:= .exe
-DLLSUFFIX	:= .dll
-USE_PREFIX	?= $(ZXSDK)/windows-x86
+ CC = i686-w64-mingw32-gcc
 else ifeq ($(BUILD),mingw64)
-CC		:= x86_64-w64-mingw32-gcc
-EXESUFFIX	:= .exe
-DLLSUFFIX	:= .dll
-USE_PREFIX	?= $(ZXSDK)/windows-x86_64
+ CC = x86_64-w64-mingw32-gcc
 endif
 
-# Default values
-USE_PREFIX		?= $(ZXSDK_PLATFORM)
-USE_SJASMPLUS_VERSION	?= z00m128
+# Filename suffixes (platform specific)
+ifeq ($(BUILD),mingw32)
+ EXESUFFIX = .exe
+ DLLSUFFIX = .dll
+else ifeq ($(BUILD),mingw64)
+ EXESUFFIX = .exe
+ DLLSUFFIX = .dll
+else
+ ifeq ($(OS),Windows_NT)
+  EXESUFFIX = .exe
+  DLLSUFFIX = .dll
+ else
+  EXESUFFIX =
+  DLLSUFFIX = .so
+ endif
+endif
+
+# Default path where to install files (platform specific)
+ifeq ($(BUILD),mingw32)
+ USE_PREFIX ?= $(ZXSDK)/windows-x86
+else ifeq ($(BUILD),mingw64)
+ USE_PREFIX ?= $(ZXSDK)/windows-x86_64
+else
+USE_PREFIX ?= $(ZXSDK_PLATFORM)
+endif
+
+# Version of SJAsmPlus compiler to use
+USE_SJASMPLUS_VERSION ?= z00m128
diff --git a/sdk/extract.sh b/sdk/extract.sh
index 47509e3..3cc39cc 100755
--- a/sdk/extract.sh
+++ b/sdk/extract.sh
@@ -283,7 +283,7 @@ if [[ $o_use_tmp -eq 0 ]]; then
 		;;
 	.7z)
 		if [[ "$o_subdir" = '.' ]]; then
-			7z x -bd -o "$o_output" "$o_input"
+			7z x -bd -o"$o_output" "$o_input"
 		else
 			7z x -bd "$o_input"
 		fi
diff --git a/sdk/setenv.bat b/sdk/setenv.bat
index 66bcda0..68b09d8 100644
--- a/sdk/setenv.bat
+++ b/sdk/setenv.bat
@@ -6,7 +6,16 @@ rem SPDX-License-Identifier: GPL-3.0-or-later
 if not x%ZXSDK% == x exit /b
 set ZXSDK=%~dp0
 set ZXSDK=%ZXSDK:~0,-1%
+set _path=%ZXSDK%
 set ZXSDK_PLATFORM=%ZXSDK%\windows-x86
+set _path=%_path%;%ZXSDK_PLATFORM%\bin
+set _path=%_path%;%ZXSDK_PLATFORM%\lib
+set SDCCHOME=%ZXSDK_PLATFORM%\opt\sdcc
+set _path=%_path%:%SDCCHOME%\bin
+set SDCCINCLUDE=%SDCCHOME%\include
+set SDCCLIB=%SDCCHOME%\lib
 set Z88DK=%ZXSDK%\src\z88dk
+set _path=%_path%;%Z88DK%\bin
 set ZCCCFG=%Z88DK%\lib\config
-set PATH=%ZXSDK_PLATFORM%\bin;%Z88DK%\bin;%ZXSDK_PLATFORM%\lib;%PATH%
+set PATH=%_path%;%PATH%
+set _path=
\ No newline at end of file
diff --git a/sdk/setenv.sh b/sdk/setenv.sh
index 8a2cc9e..9e3b14d 100644
--- a/sdk/setenv.sh
+++ b/sdk/setenv.sh
@@ -2,27 +2,57 @@
 # SPDX-FileCopyrightText: 2021 Ivan Tatarinov <ivan-tat@ya.ru>
 #
 # SPDX-License-Identifier: GPL-3.0-or-later
+#
+# Supported environments:
+#   * GNU on Linux, FreeBSD etc.
+#   * GNU on Windows NT (using MinGW/MSYS/Cygwin/WSL)
 
 if [[ "x$ZXSDK" == x ]]; then
-	ZXSDK=$(dirname $(realpath "$BASH_SOURCE"))
+	export ZXSDK=$(dirname $(realpath "$BASH_SOURCE"))
+	_path=$ZXSDK
 	if [[ x$OS == xWindows_NT ]]; then
+		case $PROCESSOR_ARCHITECTURE in
+		X86|AMD64|EM64T)
+			;;
+		*)
+			echo "WARNING: Unsupported platform: \"$PROCESSOR_ARCHITECTURE\"" >&2
+			;;
+		esac
 		ZXSDK_PLATFORM=$ZXSDK/windows-x86
 	else
 		ZXSDK_PLATFORM=$ZXSDK
 	fi
-	Z88DK=$ZXSDK/src/z88dk
-	ZCCCFG=$Z88DK/lib/config
-	PATH=$ZXSDK_PLATFORM/bin:$Z88DK/bin:$ZXSDK:$PATH
+	export ZXSDK_PLATFORM
+	_path=$_path:$ZXSDK_PLATFORM/bin
 	if [[ x$OS == xWindows_NT ]]; then
-		PATH=$ZXSDK_PLATFORM/lib:$PATH
-		# Fix paths under Cygwin for z88dk on Windows
-		if [[ x$OSTYPE == xcygwin ]]; then
-			ZCCCFG=`cygpath -m $ZCCCFG`
-		fi
+		_path=$_path:$ZXSDK_PLATFORM/lib
 	else
 		export LD_LIBRARY_PATH=$ZXSDK_PLATFORM/lib
 	fi
-	export ZXSDK
-	export ZXSDK_PLATFORM
+	export SDCCHOME=$ZXSDK_PLATFORM/opt/sdcc
+	_path=$_path:$SDCCHOME/bin
+	if [[ x$OS == xWindows_NT ]]; then
+		SDCCINCLUDE=$SDCCHOME/include
+	else
+		SDCCINCLUDE=$SDCCHOME/share/sdcc/include
+	fi
+	export SDCCINCLUDE
+	if [[ x$OS == xWindows_NT ]]; then
+		SDCCLIB=$SDCCHOME/lib
+	else
+		SDCCLIB=$SDCCHOME/share/sdcc/lib
+	fi
+	export SDCCLIB
+	Z88DK=$ZXSDK/src/z88dk
+	_path=$_path:$Z88DK/bin
+	ZCCCFG=$Z88DK/lib/config
+	if [[ x$OS == xWindows_NT ]]; then
+		# Fix paths under Cygwin for Z88DK on Windows
+		if [[ x$OSTYPE == xcygwin ]]; then
+			ZCCCFG=`cygpath -m $ZCCCFG`
+		fi
+	fi
 	export ZCCCFG
+	PATH=$_path:$PATH
+	unset _path
 fi
diff --git a/sdk/src/.gitignore b/sdk/src/.gitignore
index a0a8ee8..1b0fd50 100644
--- a/sdk/src/.gitignore
+++ b/sdk/src/.gitignore
@@ -3,6 +3,7 @@
 # SPDX-License-Identifier: CC0-1.0
 
 .downloads
+sdcc
 sjasmplus
 sjasmplus-z00m128
 z88dk
diff --git a/sdk/src/Makefile b/sdk/src/Makefile
index 3740a79..0c62142 100644
--- a/sdk/src/Makefile
+++ b/sdk/src/Makefile
@@ -38,6 +38,7 @@ INSTALL_PROGRAM	?= $(INSTALL)
 
 TARGETS=\
  sjasmplus\
+ sdcc\
  z88dk\
  lodepng\
  zx7b\
@@ -77,6 +78,7 @@ else
  $(error Unknown SJAsmPlus version selected: `$(USE_SJASMPLUS_VERSION)')
 endif
 
+include sdcc.inc.mk
 include z88dk.inc.mk
 include lodepng.inc.mk
 include tools.inc.mk
diff --git a/sdk/src/sdcc.inc.mk b/sdk/src/sdcc.inc.mk
new file mode 100644
index 0000000..1733973
--- /dev/null
+++ b/sdk/src/sdcc.inc.mk
@@ -0,0 +1,127 @@
+# sdcc.inc.mk - script to download and build SDCC.
+#
+# This file is a part of main Makefile.
+#
+# SPDX-FileCopyrightText: 2021 Ivan Tatarinov <ivan-tat@ya.ru>
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+.downloads/sdcc:
+	mkdir -p $@
+
+.PHONY: $(foreach t,build install uninstall clean distclean,$(t)-sdcc)
+
+ifeq ($(_DoBuild),1)
+
+SDCC_ARCHIVE		= .downloads/sdcc/sdcc-src-4.1.0.tar.bz2
+SDCC_ARCHIVE_SHA256	= 81edf776d5a2dc61a4b5c3408929db7b25874d69c46e4a71b116be1322fd533f
+SDCC_ARCHIVE_TYPE	= .tar.bz2
+SDCC_ARCHIVE_SUBDIR	= sdcc
+
+.downloads/sdcc/sdcc-src-4.1.0.tar.bz2: | .downloads/sdcc
+	wget -c https://sourceforge.net/projects/sdcc/files/sdcc/4.1.0/$(@F)/download -O $@
+
+sdcc/.extracted: $(SDCC_ARCHIVE)
+	rm -rf $(@D)
+	extract.sh $<\
+	 --sha256 $(SDCC_ARCHIVE_SHA256)\
+	 --type $(SDCC_ARCHIVE_TYPE)\
+	 --subdir $(SDCC_ARCHIVE_SUBDIR)\
+	 --output $(@D)
+	touch $@
+
+build-sdcc: | sdcc/.extracted sdcc.mk
+	$(MAKE) -w -C sdcc -f ../sdcc.mk
+
+install-sdcc: | sdcc/.extracted sdcc.mk
+	$(MAKE) -w -C sdcc -f ../sdcc.mk prefix=$(SDCCHOME) install
+
+ ifeq ($(_DoClean),1)
+
+uninstall-sdcc: | sdcc/.extracted sdcc.mk
+	$(MAKE) -w -C sdcc -f ../sdcc.mk prefix=$(SDCCHOME) uninstall
+
+clean-sdcc: | sdcc/.extracted sdcc.mk
+	$(MAKE) -w -C sdcc -f ../sdcc.mk clean
+
+distclean-sdcc:
+	rm -rf sdcc
+
+ else	#  !_DoClean
+
+uninstall-sdcc\
+clean-sdcc\
+distclean-sdcc:;
+
+ endif	#  !_DoClean
+
+endif	# _DoBuild
+
+ifeq ($(_UsePrecompiledOnWindows),1)
+
+SDCC_ARCHIVE		= .downloads/sdcc/sdcc-4.1.0-setup.exe
+SDCC_ARCHIVE_SHA256	= cbf064c9f1a3f9a73db6d2c8ba3a43563fa3a2d2966f52cf5a571a3064222ed8
+SDCC_ARCHIVE_TYPE	= .7z
+SDCC_ARCHIVE_SUBDIR	= .
+
+SDCC_SUBDIRS=\
+ bin\
+ doc\
+ include\
+ lib\
+ non-free
+
+.downloads/sdcc/sdcc-4.1.0-setup.exe: | .downloads/sdcc
+	wget -c https://sourceforge.net/projects/sdcc/files/sdcc-win32/4.1.0/$(@F)/download -O $@
+
+sdcc/.extracted: $(SDCC_ARCHIVE)
+	rm -rf $(@D)
+	extract.sh $<\
+	 --sha256 $(SDCC_ARCHIVE_SHA256)\
+	 --type $(SDCC_ARCHIVE_TYPE)\
+	 --subdir $(SDCC_ARCHIVE_SUBDIR)\
+	 --output $(@D)
+	touch $@
+
+build-sdcc: sdcc/.extracted
+
+install-sdcc: | sdcc/.extracted
+	cd sdcc;\
+	{ echo '# This file was automatically generated by Make.';\
+	echo '.PHONY: install';\
+	echo 'install:\';\
+	find $(SDCC_SUBDIRS) -type f\
+	| sed -Ee 's,(.+), $$(DEST)$$(prefix)/\1\\,';\
+	echo '';\
+	find $(SDCC_SUBDIRS) -type d\
+	| sed -Ee 's,(.+),$$(prefix)/\1\\,';\
+	echo -e ':\n\tmkdir -p $$@';\
+	for d in $(SDCC_SUBDIRS); do\
+		if [ $$d = bin ]; then\
+			find $$d -type f\
+			| awk '{print gensub(/^(.+)\/([^/]+)/, "$$(DEST)$$(prefix)/\\1/\\2: \\1/\\2 | $$(DEST)$$(prefix)/\\1\n\t$$(INSTALL_PROGRAM) -m 755 $$< $$@", "g")}';\
+		else\
+			find $$d -type f\
+			| awk '{print gensub(/^(.+)\/([^/]+)/, "$$(DEST)$$(prefix)/\\1/\\2: \\1/\\2 | $$(DEST)$$(prefix)/\\1\n\t$$(INSTALL) -m 644 $$< $$@", "g")}';\
+		fi;\
+	done; } >install.mk;\
+	$(MAKE) -w -f install.mk DEST=$(DEST) prefix=$(prefix) INSTALL=$(INSTALL) INSTALL_PROGRAM=$(INSTALL_PROGRAM) install
+
+ ifeq ($(_DoClean),1)
+
+uninstall-sdcc:
+	test '$(SDCCHOME)' = . || rm -rf $(SDCCHOME)
+
+clean-sdcc\
+distclean-sdcc:
+	rm -rf sdcc
+
+ else	#  !_DoClean
+
+uninstall-sdcc\
+clean-sdcc\
+distclean-sdcc:;
+
+ endif	#  !_DoClean
+
+endif	# _UsePrecompiledOnWindows
diff --git a/sdk/src/sdcc.mk b/sdk/src/sdcc.mk
new file mode 100644
index 0000000..72151b3
--- /dev/null
+++ b/sdk/src/sdcc.mk
@@ -0,0 +1,51 @@
+# sdcc.mk - build and install SDCC from sources.
+#
+# SPDX-FileCopyrightText: 2021 Ivan Tatarinov <ivan-tat@ya.ru>
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+#
+# Supported environments:
+#   * GNU on Linux, FreeBSD etc.
+#   * GNU on Windows NT (using MinGW/MSYS/Cygwin/WSL)
+#
+# Build:
+#   make [BUILD=<BUILD>] -w -C sdcc -f ../sdcc.mk [all | build]
+# Install / Uninstall:
+#   make [BUILD=<BUILD>] [prefix=<PREFIX>] -w -C sdcc -f ../sdcc.mk install | uninstall
+# Clean:
+#   make [BUILD=<BUILD>] -w -C sdcc -f ../sdcc.mk clean | distclean
+#
+# where:
+#   <BUILD> is one of: mingw32, mingw64.
+#   <PREFIX> is a prefix directory to install files into.
+
+include ../../common.mk
+
+# Use absolute path for install/uninstall (a feature of SDCC build process)
+
+prefix	?= $(USE_PREFIX)/opt/sdcc
+
+.PHONY: all
+all: build
+
+$(DESTDIR)$(prefix):
+	mkdir -p $@
+
+Makefile: configure
+	./configure
+
+.PHONY: build
+build: | Makefile
+	$(MAKE)
+
+.PHONY: install
+install: | Makefile $(DESTDIR)$(prefix)
+	$(MAKE) prefix=$(shell realpath $(DESTDIR)$(prefix)) $@
+
+.PHONY: uninstall
+uninstall: | Makefile
+	$(MAKE) prefix=$(shell realpath $(DESTDIR)$(prefix)) $@
+
+.PHONY: clean distclean
+clean distclean: | Makefile
+	$(MAKE) $@
diff --git a/sdk/src/sjasmplus-z00m128.inc.mk b/sdk/src/sjasmplus-z00m128.inc.mk
index 6ad1375..b468b35 100644
--- a/sdk/src/sjasmplus-z00m128.inc.mk
+++ b/sdk/src/sjasmplus-z00m128.inc.mk
@@ -88,7 +88,7 @@ sjasmplus-z00m128/.extracted: $(SJASMPLUS_ARCHIVE)
 install-sjasmplus: $(DESTDIR)$(bindir)/sjasmplus$(EXESUFFIX)
 
 $(DESTDIR)$(bindir)/sjasmplus$(EXESUFFIX): sjasmplus-z00m128/sjasmplus$(EXESUFFIX) | $(DESTDIR)$(bindir)
-	$(INSTALL_PROGRAM) $< $@
+	$(INSTALL_PROGRAM) -m 755 $< $@
 
 ifeq ($(_DoClean),1)
 
diff --git a/sdk/src/sjasmplus-z00m128.mk b/sdk/src/sjasmplus-z00m128.mk
index 4cdf0c7..dfc0b6a 100644
--- a/sdk/src/sjasmplus-z00m128.mk
+++ b/sdk/src/sjasmplus-z00m128.mk
@@ -45,7 +45,7 @@ $(srcdir)/sjasmplus$(EXESUFFIX): | Makefile
 install: $(foreach t,$(BINS),$(DESTDIR)$(bindir)/$(t))
 
 $(DESTDIR)$(bindir)/sjasmplus$(EXESUFFIX): sjasmplus$(EXESUFFIX) | $(DESTDIR)$(bindir)
-	$(INSTALL_PROGRAM) $< $@
+	$(INSTALL_PROGRAM) -m 755 $< $@
 
 .PHONY: uninstall
 uninstall:
diff --git a/sdk/src/sjasmplus.inc.mk b/sdk/src/sjasmplus.inc.mk
index 2a0efb5..e12279d 100644
--- a/sdk/src/sjasmplus.inc.mk
+++ b/sdk/src/sjasmplus.inc.mk
@@ -102,7 +102,7 @@ sjasmplus/.extracted: $(SJASMPLUS_ARCHIVE)
 install-sjasmplus: $(DESTDIR)$(bindir)/sjasmplus$(EXESUFFIX)
 
 $(DESTDIR)$(bindir)/sjasmplus$(EXESUFFIX): sjasmplus/sjasmplus$(EXESUFFIX) | $(DESTDIR)$(bindir)
-	$(INSTALL_PROGRAM) $< $@
+	$(INSTALL_PROGRAM) -m 755 $< $@
 
 ifeq ($(_DoClean),1)
 
diff --git a/sdk/src/sjasmplus.mk b/sdk/src/sjasmplus.mk
index 70fcc0d..7feb102 100644
--- a/sdk/src/sjasmplus.mk
+++ b/sdk/src/sjasmplus.mk
@@ -54,7 +54,7 @@ build/Makefile: | build
 install: $(foreach t,$(BINS),$(DESTDIR)$(bindir)/$(t))
 
 $(DESTDIR)$(bindir)/sjasmplus$(EXESUFFIX): build/sjasmplus$(EXESUFFIX) | $(DESTDIR)$(bindir)
-	$(INSTALL_PROGRAM) $< $@
+	$(INSTALL_PROGRAM) -m 755 $< $@
 
 .PHONY: uninstall
 uninstall:
diff --git a/sdk/src/tools/Makefile b/sdk/src/tools/Makefile
index c149f1f..58eefd5 100644
--- a/sdk/src/tools/Makefile
+++ b/sdk/src/tools/Makefile
@@ -68,7 +68,7 @@ install: $(foreach t,$(BINS),$(DESTDIR)$(bindir)/$(t))
 # $1 = target
 define install_bin_rule =
 $$(DESTDIR)$$(bindir)/$1: build/$1 | $$(DESTDIR)$$(bindir)
-	$$(INSTALL_PROGRAM) $$< $$@
+	$$(INSTALL_PROGRAM) -m 755 $$< $$@
 endef
 
 $(foreach t,$(BINS),$(eval $(call install_bin_rule,$(t))))
diff --git a/sdk/src/zx7b/Makefile b/sdk/src/zx7b/Makefile
index 823104c..9546493 100644
--- a/sdk/src/zx7b/Makefile
+++ b/sdk/src/zx7b/Makefile
@@ -51,10 +51,10 @@ build/dzx7b$(EXESUFFIX): $(srcdir)/dzx7b.c Makefile | build
 install: $(foreach t,$(BINS),$(DESTDIR)$(bindir)/$(t))
 
 $(DESTDIR)$(bindir)/zx7b$(EXESUFFIX): build/zx7b$(EXESUFFIX) | $(DESTDIR)$(bindir)
-	$(INSTALL_PROGRAM) $< $@
+	$(INSTALL_PROGRAM) -m 755 $< $@
 
 $(DESTDIR)$(bindir)/dzx7b$(EXESUFFIX): build/dzx7b$(EXESUFFIX) | $(DESTDIR)$(bindir)
-	$(INSTALL_PROGRAM) $< $@
+	$(INSTALL_PROGRAM) -m 755 $< $@
 
 .PHONY: uninstall
 uninstall:
diff --git a/sdk/windows-x86/.gitignore b/sdk/windows-x86/.gitignore
new file mode 100644
index 0000000..7d03c7c
--- /dev/null
+++ b/sdk/windows-x86/.gitignore
@@ -0,0 +1,5 @@
+# SPDX-FileCopyrightText: 2021 Ivan Tatarinov <ivan-tat@ya.ru>
+#
+# SPDX-License-Identifier: CC0-1.0
+
+opt
diff --git a/software/esxdos/Makefile b/software/esxdos/Makefile
index e98202b..410f7cf 100644
--- a/software/esxdos/Makefile
+++ b/software/esxdos/Makefile
@@ -126,21 +126,12 @@ ESXDOS_ARCHIVE_TYPE	= .zip
 ESXDOS_ARCHIVE_SUBDIR	= .
 
 build/.extracted: $(ESXDOS_ARCHIVE) | build
-	echo '$(ESXDOS_ARCHIVE_SHA256)  $<' >$<.sha256
-	sha256sum -c $<.sha256
-	rm -f $<.sha256
 	rm -rf $(@D)
-	test '$(@D)' = '$(ESXDOS_ARCHIVE_SUBDIR)' -o '$(ESXDOS_ARCHIVE_SUBDIR)' = . || rm -rf $(ESXDOS_ARCHIVE_SUBDIR)
-ifeq ($(ESXDOS_ARCHIVE_TYPE),.zip)
- ifeq ($(ESXDOS_ARCHIVE_SUBDIR),.)
-	unzip -nq $< -d $(@D)
- else
-	unzip -nq $<
- endif
-else
- $(error Not implemented)
-endif
-	test '$(@D)' = '$(ESXDOS_ARCHIVE_SUBDIR)' -o '$(ESXDOS_ARCHIVE_SUBDIR)' = . || mv $(ESXDOS_ARCHIVE_SUBDIR) $(@D)
+	extract.sh $<\
+	 --sha256 $(ESXDOS_ARCHIVE_SHA256)\
+	 --type $(ESXDOS_ARCHIVE_TYPE)\
+	 --subdir $(ESXDOS_ARCHIVE_SUBDIR)\
+	 --output $(@D)
 	touch $@
 
 .downloads/esxdos/esxdos089.zip: | .downloads/esxdos
@@ -202,9 +193,6 @@ uninstall:
 
 .PHONY: clean
 clean:
-	rm -f\
- .downloads/esxdos/esxdos089.zip.sha256\
- .downloads/esxdos
 	rm -rf build/*
 
 .PHONY: distclean