diff --git a/.gitignore b/.gitignore
index 66f233f..a9d7413 100644
--- a/.gitignore
+++ b/.gitignore
@@ -14,6 +14,10 @@
 /dhrystone/timing.txt
 /dhrystone/*.d
 /dhrystone/*.o
+/riscv-gnu-toolchain-riscv32i
+/riscv-gnu-toolchain-riscv32ic
+/riscv-gnu-toolchain-riscv32im
+/riscv-gnu-toolchain-riscv32imc
 /testbench.exe
 /testbench_sp.exe
 /testbench_axi.exe
diff --git a/Makefile b/Makefile
index 5b2520f..5948bd5 100644
--- a/Makefile
+++ b/Makefile
@@ -1,9 +1,14 @@
 
+RISCV_GNU_TOOLCHAIN_REV = 3134bf4
+GCC_URL = http://mirrors.kernel.org/gnu/gcc/gcc-5.3.0/gcc-5.3.0.tar.gz
+NEWLIB_URL = ftp://sourceware.org/pub/newlib/newlib-2.2.0.tar.gz
+BINUTILS_URL = http://mirrors.kernel.org/gnu/binutils/binutils-2.26.tar.gz
+
 TEST_OBJS = $(addsuffix .o,$(basename $(wildcard tests/*.S)))
 FIRMWARE_OBJS = firmware/start.o firmware/irq.o firmware/print.o firmware/sieve.o firmware/multest.o firmware/stats.o
 GCC_WARNS  = -Werror -Wall -Wextra -Wshadow -Wundef -Wpointer-arith -Wcast-qual -Wcast-align -Wwrite-strings
 GCC_WARNS += -Wredundant-decls -Wstrict-prototypes -Wmissing-prototypes -pedantic # -Wconversion
-TOOLCHAIN_PREFIX = riscv32-unknown-elf-
+TOOLCHAIN_PREFIX = /opt/riscv32i/bin/riscv32-unknown-elf-
 # COMPRESSED_ISA = C
 
 test: testbench.exe firmware/firmware.hex
@@ -71,13 +76,38 @@ tests/%.o: tests/%.S tests/riscv_test.h tests/test_macros.h
 	$(TOOLCHAIN_PREFIX)gcc -c -m32 -march=RV32IM -o $@ -DTEST_FUNC_NAME=$(notdir $(basename $<)) \
 		-DTEST_FUNC_TXT='"$(notdir $(basename $<))"' -DTEST_FUNC_RET=$(notdir $(basename $<))_ret $<
 
+download-tools:
+	sudo bash -c 'set -ex; mkdir -p /var/cache/distfiles; $(foreach URL,$(GCC_URL) $(NEWLIB_URL) $(BINUTILS_URL), \
+		if ! test -f /var/cache/distfiles/$(notdir $(URL)); then wget -O /var/cache/distfiles/$(notdir $(URL)).part $(URL); \
+			mv /var/cache/distfiles/$(notdir $(URL)).part /var/cache/distfiles/$(notdir $(URL)); fi;)'
+
+define build_tools_template
+build-$(1)-tools:
+	@read -p "This will remove all existing data from /opt/$(1). Type YES to continue: " reply && [[ "$$$$reply" == [Yy][Ee][Ss] || "$$$$reply" == [Yy] ]]
+	sudo bash -c "set -ex; rm -rf /opt/$(1); mkdir -p /opt/$(1); chown $$$${USER}. /opt/$(1)"
+	set -ex; if ! test -d riscv-gnu-toolchain-$(1); then git clone https://github.com/riscv/riscv-gnu-toolchain riscv-gnu-toolchain-$(1); \
+		else cd riscv-gnu-toolchain-$(1); git checkout master; git pull; fi
+	set -ex; cd riscv-gnu-toolchain-$(1); rm -rf build; git checkout $(RISCV_GNU_TOOLCHAIN_REV); mkdir -p build
+	set -ex; cd riscv-gnu-toolchain-$(1)/build; ../configure --with-xlen=32 --with-arch=$(2) --prefix=/opt/$(1) --disable-float --disable-atomic
+	+set -ex; cd riscv-gnu-toolchain-$(1)/build; make
+
+.PHONY: build-$(1)-tools
+endef
+
+$(eval $(call build_tools_template,riscv32i,I))
+$(eval $(call build_tools_template,riscv32ic,IC))
+$(eval $(call build_tools_template,riscv32im,IM))
+$(eval $(call build_tools_template,riscv32imc,IMC))
+
 toc:
 	gawk '/^-+$$/ { y=tolower(x); gsub("[^a-z0-9]+", "-", y); gsub("-$$", "", y); printf("- [%s](#%s)\n", x, y); } { x=$$0; }' README.md
 
 clean:
+	rm -rf riscv-gnu-toolchain-riscv32i riscv-gnu-toolchain-riscv32ic \
+		riscv-gnu-toolchain-riscv32im riscv-gnu-toolchain-riscv32imc
 	rm -vrf $(FIRMWARE_OBJS) $(TEST_OBJS) check.smt2 check.vcd synth.v synth.log \
 		firmware/firmware.elf firmware/firmware.bin firmware/firmware.hex firmware/firmware.map \
 		testbench.exe testbench_sp.exe testbench_synth.exe testbench.vcd
 
-.PHONY: test view test_sp test_axi test_synth toc clean
+.PHONY: test view test_sp test_axi test_synth download-tools toc clean
 
diff --git a/README.md b/README.md
index 6a7495e..08deca1 100644
--- a/README.md
+++ b/README.md
@@ -537,17 +537,31 @@ pure RV32I target, and install it in `/opt/riscv32i`:
 
     git clone https://github.com/riscv/riscv-gnu-toolchain riscv-gnu-toolchain-rv32i
     cd riscv-gnu-toolchain-rv32i
-    git checkout acfa480
+    git checkout 3134bf4
 
     mkdir build; cd build
-    ../configure --with-xlen=32 --with-arch=I --prefix=/opt/riscv32i
+    ../configure --with-xlen=32 --with-arch=I --prefix=/opt/riscv32i --disable-float --disable-atomic
     make -j$(nproc)
 
 The commands will all be named using the prefix `riscv32-unknown-elf-`, which
-makes it easy to install them side-by-side with the regular riscv-tools, which
-are using the name prefix `riscv64-unknown-elf-` by default.
+makes it easy to install them side-by-side with the regular riscv-tools (those
+are using the name prefix `riscv64-unknown-elf-` by default).
 
-*Note: This instructions are for git rev acfa480 (2016-04-06) of riscv-gnu-toolchain.*
+The following make targets build toolchains for `RV32I[M][C]` using this sequence
+of commands (not including installing prerequisites):
+
+| Command                                  | Install Directory  | ISA       |
+|:---------------------------------------- |:------------------ |:--------  |
+| `make -j$(nproc) build-riscv32i-tools`   | `/opt/riscv32i/`   | `RV32I`   |
+| `make -j$(nproc) build-riscv32ic-tools`  | `/opt/riscv32ic/`  | `RV32IC`  |
+| `make -j$(nproc) build-riscv32im-tools`  | `/opt/riscv32im/`  | `RV32IM`  |
+| `make -j$(nproc) build-riscv32imc-tools` | `/opt/riscv32imc/` | `RV32IMC` |
+
+By default calling any of those make targets will (re-)download the toolchain
+sources. Run `make download-tools` to download the sources to `/var/cache/distfiles/`
+once in advance.
+
+*Note: This instructions are for git rev 3134bf4 (2016-04-08) of riscv-gnu-toolchain.*
 
 
 Evaluation: Timing and Utilization on Xilinx 7-Series FPGAs