diff --git a/Makefile b/Makefile
index 4402ae9..aa9063d 100644
--- a/Makefile
+++ b/Makefile
@@ -1,13 +1,13 @@
 
-RISCV_GNU_TOOLCHAIN_REV = 7e48594
-NEWLIB_URL = ftp://sourceware.org/pub/newlib/newlib-2.2.0.tar.gz
+RISCV_GNU_TOOLCHAIN_GIT_REVISION = 914224e
+RISCV_GNU_TOOLCHAIN_INSTALL_PREFIX = /opt/riscv32
 
 SHELL = bash
 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 = /opt/riscv32i/bin/riscv32-unknown-elf-
+TOOLCHAIN_PREFIX = $(RISCV_GNU_TOOLCHAIN_INSTALL_PREFIX)i/bin/riscv32-unknown-elf-
 COMPRESSED_ISA = C
 
 test: testbench.vvp firmware/firmware.hex
@@ -63,26 +63,24 @@ firmware/firmware.bin: firmware/firmware.elf
 	chmod -x $@
 
 firmware/firmware.elf: $(FIRMWARE_OBJS) $(TEST_OBJS) firmware/sections.lds
-	$(TOOLCHAIN_PREFIX)gcc -Os -m32 -ffreestanding -nostdlib -o $@ \
+	$(TOOLCHAIN_PREFIX)gcc -Os -ffreestanding -nostdlib -o $@ \
 		-Wl,-Bstatic,-T,firmware/sections.lds,-Map,firmware/firmware.map,--strip-debug \
 		$(FIRMWARE_OBJS) $(TEST_OBJS) -lgcc
 	chmod -x $@
 
 firmware/start.o: firmware/start.S
-	$(TOOLCHAIN_PREFIX)gcc -c -m32 -march=RV32IM$(COMPRESSED_ISA)Xcustom -o $@ $<
+	$(TOOLCHAIN_PREFIX)gcc -c -march=rv32im$(subst C,c,$(COMPRESSED_ISA)) -o $@ $<
 
 firmware/%.o: firmware/%.c
-	$(TOOLCHAIN_PREFIX)gcc -c -m32 -march=RV32I$(COMPRESSED_ISA) -Os --std=c99 $(GCC_WARNS) -ffreestanding -nostdlib -o $@ $<
+	$(TOOLCHAIN_PREFIX)gcc -c -march=rv32i$(subst C,c,$(COMPRESSED_ISA)) -Os --std=c99 $(GCC_WARNS) -ffreestanding -nostdlib -o $@ $<
 
 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 $<)) \
+	$(TOOLCHAIN_PREFIX)gcc -c -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; $(foreach URL,$(NEWLIB_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;) \
-	$(foreach REPO,riscv-gnu-toolchain riscv-binutils-gdb riscv-dejagnu riscv-gcc riscv-glibc, \
+	sudo bash -c 'set -ex; mkdir -p /var/cache/distfiles; \
+	$(foreach REPO,riscv-gnu-toolchain riscv-binutils-gdb riscv-dejagnu riscv-gcc riscv-glibc riscv-newlib, \
 		if ! test -d /var/cache/distfiles/$(REPO).git; then rm -rf /var/cache/distfiles/$(REPO).git.part; \
 			git clone --bare https://github.com/riscv/$(REPO) /var/cache/distfiles/$(REPO).git.part; \
 			mv /var/cache/distfiles/$(REPO).git.part /var/cache/distfiles/$(REPO).git; else \
@@ -90,9 +88,9 @@ download-tools:
 
 define build_tools_template
 build-$(1)-tools:
-	@read -p "This will remove all existing data from /opt/$(1). Type YES to continue: " reply && [[ "$$$$reply" == [Yy][Ee][Ss] || "$$$$reply" == [Yy] ]]
-	sudo bash -c "set -ex; rm -rf /opt/$(1); mkdir -p /opt/$(1); chown $$$${USER}. /opt/$(1)"
-	$(MAKE) build-$(1)-tools-bh
+	@read -p "This will remove all existing data from $(RISCV_GNU_TOOLCHAIN_INSTALL_PREFIX)$(subst riscv32,,$(1)). Type YES to continue: " reply && [[ "$$$$reply" == [Yy][Ee][Ss] || "$$$$reply" == [Yy] ]]
+	sudo bash -c "set -ex; rm -rf $(RISCV_GNU_TOOLCHAIN_INSTALL_PREFIX)$(subst riscv32,,$(1)); mkdir -p $(RISCV_GNU_TOOLCHAIN_INSTALL_PREFIX)$(subst riscv32,,$(1)); chown $$$${USER}. $(RISCV_GNU_TOOLCHAIN_INSTALL_PREFIX)$(subst riscv32,,$(1))"
+	+$(MAKE) build-$(1)-tools-bh
 
 build-$(1)-tools-bh:
 	+set -ex; \
@@ -101,30 +99,32 @@ build-$(1)-tools-bh:
 	if [ -d /var/cache/distfiles/riscv-dejagnu.git ]; then reference_riscv_dejagnu="--reference /var/cache/distfiles/riscv-dejagnu.git"; else reference_riscv_dejagnu=""; fi; \
 	if [ -d /var/cache/distfiles/riscv-gcc.git ]; then reference_riscv_gcc="--reference /var/cache/distfiles/riscv-gcc.git"; else reference_riscv_gcc=""; fi; \
 	if [ -d /var/cache/distfiles/riscv-glibc.git ]; then reference_riscv_glibc="--reference /var/cache/distfiles/riscv-glibc.git"; else reference_riscv_glibc=""; fi; \
+	if [ -d /var/cache/distfiles/riscv-newlib.git ]; then reference_riscv_newlib="--reference /var/cache/distfiles/riscv-newlib.git"; else reference_riscv_newlib=""; fi; \
 	rm -rf riscv-gnu-toolchain-$(1); git clone $$$$reference_riscv_gnu_toolchain https://github.com/riscv/riscv-gnu-toolchain riscv-gnu-toolchain-$(1); \
-	cd riscv-gnu-toolchain-$(1); git checkout $(RISCV_GNU_TOOLCHAIN_REV); \
+	cd riscv-gnu-toolchain-$(1); git checkout $(RISCV_GNU_TOOLCHAIN_GIT_REVISION); \
 	git submodule update --init $$$$reference_riscv_binutils_gdb riscv-binutils-gdb; \
 	git submodule update --init $$$$reference_riscv_dejagnu riscv-dejagnu; \
 	git submodule update --init $$$$reference_riscv_gcc riscv-gcc; \
 	git submodule update --init $$$$reference_riscv_glibc riscv-glibc; \
-	mkdir build; cd build; ../configure --with-arch=$(2) --prefix=/opt/$(1); make
+	git submodule update --init $$$$reference_riscv_newlib riscv-newlib; \
+	mkdir build; cd build; ../configure --with-arch=$(2) --prefix=$(RISCV_GNU_TOOLCHAIN_INSTALL_PREFIX)$(subst riscv32,,$(1)); make
 
 .PHONY: build-$(1)-tools
 endef
 
-$(eval $(call build_tools_template,riscv32i,RV32I))
-$(eval $(call build_tools_template,riscv32ic,RV32IC))
-$(eval $(call build_tools_template,riscv32im,RV32IM))
-$(eval $(call build_tools_template,riscv32imc,RV32IMC))
+$(eval $(call build_tools_template,riscv32i,rv32i))
+$(eval $(call build_tools_template,riscv32ic,rv32ic))
+$(eval $(call build_tools_template,riscv32im,rv32im))
+$(eval $(call build_tools_template,riscv32imc,rv32imc))
 
 build-tools:
-	@echo "This will remove all existing data from /opt/riscv32i, /opt/riscv32ic, /opt/riscv32im, and /opt/riscv32imc."
+	@echo "This will remove all existing data from $(RISCV_GNU_TOOLCHAIN_INSTALL_PREFIX)i, $(RISCV_GNU_TOOLCHAIN_INSTALL_PREFIX)ic, $(RISCV_GNU_TOOLCHAIN_INSTALL_PREFIX)im, and $(RISCV_GNU_TOOLCHAIN_INSTALL_PREFIX)imc."
 	@read -p "Type YES to continue: " reply && [[ "$$reply" == [Yy][Ee][Ss] || "$$reply" == [Yy] ]]
-	sudo bash -c "set -ex; rm -rf /opt/riscv32{i,ic,im,imc}; mkdir -p /opt/riscv32{i,ic,im,imc}; chown $${USER}. /opt/riscv32{i,ic,im,imc}"
-	$(MAKE) build-riscv32i-tools-bh
-	$(MAKE) build-riscv32ic-tools-bh
-	$(MAKE) build-riscv32im-tools-bh
-	$(MAKE) build-riscv32imc-tools-bh
+	sudo bash -c "set -ex; rm -rf $(RISCV_GNU_TOOLCHAIN_INSTALL_PREFIX){i,ic,im,imc}; mkdir -p $(RISCV_GNU_TOOLCHAIN_INSTALL_PREFIX){i,ic,im,imc}; chown $${USER}. $(RISCV_GNU_TOOLCHAIN_INSTALL_PREFIX){i,ic,im,imc}"
+	+$(MAKE) build-riscv32i-tools-bh
+	+$(MAKE) build-riscv32ic-tools-bh
+	+$(MAKE) build-riscv32im-tools-bh
+	+$(MAKE) build-riscv32imc-tools-bh
 
 toc:
 	gawk '/^-+$$/ { y=tolower(x); gsub("[^a-z0-9]+", "-", y); gsub("-$$", "", y); printf("- [%s](#%s)\n", x, y); } { x=$$0; }' README.md
diff --git a/README.md b/README.md
index df557e6..adb66d9 100644
--- a/README.md
+++ b/README.md
@@ -23,6 +23,7 @@ PicoRV32 is free and open hardware licensed under the [ISC license](http://en.wi
 - [Pico Co-Processor Interface (PCPI)](#pico-co-processor-interface-pcpi)
 - [Custom Instructions for IRQ Handling](#custom-instructions-for-irq-handling)
 - [Building a pure RV32I Toolchain](#building-a-pure-rv32i-toolchain)
+- [Linking binaries with newlib for PicoRV32](#linking-binaries-with-newlib-for-picorv32)
 - [Evaluation: Timing and Utilization on Xilinx 7-Series FPGAs](#evaluation-timing-and-utilization-on-xilinx-7-series-fpgas)
 
 
@@ -596,13 +597,18 @@ Example:
 Building a pure RV32I Toolchain
 -------------------------------
 
+TL;DR: Run the following commands to build the complete toolchain:
+
+    make download-tools
+    make -j$(nproc) build-tools
+
 The default settings in the [riscv-tools](https://github.com/riscv/riscv-tools) build
 scripts will build a compiler, assembler and linker that can target any RISC-V ISA,
 but the libraries are built for RV32G and RV64G targets. Follow the instructions
 below to build a complete toolchain (including libraries) that target a pure RV32I
 CPU.
 
-The following commands will build the RISC-V gnu toolchain and libraries for a
+The following commands will build the RISC-V GNU toolchain and libraries for a
 pure RV32I target, and install it in `/opt/riscv32i`:
 
     # Ubuntu packages needed:
@@ -614,7 +620,7 @@ 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 7e48594
+    git checkout 914224e
     git submodule update --init --recursive
 
     mkdir build; cd build
@@ -643,7 +649,25 @@ 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 7e48594 (2016-08-16) of riscv-gnu-toolchain.*
+*Note: This instructions are for git rev 914224e (2017-01-06) of riscv-gnu-toolchain.*
+
+
+Linking binaries with newlib for PicoRV32
+-----------------------------------------
+
+The tool chains (see last section for install instructions) come with a version of
+the newlib C standard library.
+
+Use the linker script [firmware/riscv.ld](firmware/riscv.ld) for linking binaries
+against the newlib library. Using this linker script will create a binary that
+has its entry point at 0x10000. (The default linker script does not have a static
+entry point, thus a proper ELF loader would be needed that can determine the
+entry point at runtime while loading the program.)
+
+Newlib comes with a few syscall stubs. You need to provide your own implementation
+of those syscalls and link your program with this implementation, overwriting the
+default stubs from newlib. See `syscalls.c` in [scripts/cxxdemo/](scripts/cxxdemo/)
+for an example of how to do that.
 
 
 Evaluation: Timing and Utilization on Xilinx 7-Series FPGAs
diff --git a/dhrystone/Makefile b/dhrystone/Makefile
index 3b282f0..e66f313 100644
--- a/dhrystone/Makefile
+++ b/dhrystone/Makefile
@@ -1,6 +1,6 @@
 USE_MYSTDLIB = 0
 OBJS = dhry_1.o dhry_2.o stdlib.o
-CFLAGS = -MD -O3 -m32 -march=RV32IM -DTIME -DRISCV
+CFLAGS = -MD -O3 -march=rv32im -DTIME -DRISCV
 TOOLCHAIN_PREFIX = /opt/riscv32im/bin/riscv32-unknown-elf-
 
 ifeq ($(USE_MYSTDLIB),1)
@@ -44,7 +44,7 @@ dhry.elf: $(OBJS) sections.lds
 	chmod -x $@
 else
 dhry.elf: $(OBJS)
-	$(TOOLCHAIN_PREFIX)gcc $(CFLAGS) -Wl,-Bstatic,-Map,dhry.map,--strip-debug -o $@ $(OBJS) -lgcc -lc
+	$(TOOLCHAIN_PREFIX)gcc $(CFLAGS) -Wl,-Bstatic,-T,../firmware/riscv.ld,-Map,dhry.map,--strip-debug -o $@ $(OBJS) -lgcc -lc
 	chmod -x $@
 endif
 
diff --git a/firmware/custom_ops.S b/firmware/custom_ops.S
index d8512f6..71889b9 100644
--- a/firmware/custom_ops.S
+++ b/firmware/custom_ops.S
@@ -5,32 +5,98 @@
 // binary, for any purpose, commercial or non-commercial, and by any
 // means.
 
-#define q0 0
-#define q1 1
-#define q2 2
-#define q3 3
+#define regnum_q0   0
+#define regnum_q1   1
+#define regnum_q2   2
+#define regnum_q3   3
 
-.macro getq rd qs
-custom0 \rd,\qs,0,0
-.endm
+#define regnum_x0   0
+#define regnum_x1   1
+#define regnum_x2   2
+#define regnum_x3   3
+#define regnum_x4   4
+#define regnum_x5   5
+#define regnum_x6   6
+#define regnum_x7   7
+#define regnum_x8   8
+#define regnum_x9   9
+#define regnum_x10 10
+#define regnum_x11 11
+#define regnum_x12 12
+#define regnum_x13 13
+#define regnum_x14 14
+#define regnum_x15 15
+#define regnum_x16 16
+#define regnum_x17 17
+#define regnum_x18 18
+#define regnum_x19 19
+#define regnum_x20 20
+#define regnum_x21 21
+#define regnum_x22 22
+#define regnum_x23 23
+#define regnum_x24 24
+#define regnum_x25 25
+#define regnum_x26 26
+#define regnum_x27 27
+#define regnum_x28 28
+#define regnum_x29 29
+#define regnum_x30 30
+#define regnum_x31 31
 
-.macro setq qd rs
-custom0 \qd,\rs,0,1
-.endm
+#define regnum_zero 0
+#define regnum_ra   1
+#define regnum_sp   2
+#define regnum_gp   3
+#define regnum_tp   4
+#define regnum_t0   5
+#define regnum_t1   6
+#define regnum_t2   7
+#define regnum_s0   8
+#define regnum_s1   9
+#define regnum_a0  10
+#define regnum_a1  11
+#define regnum_a2  12
+#define regnum_a3  13
+#define regnum_a4  14
+#define regnum_a5  15
+#define regnum_a6  16
+#define regnum_a7  17
+#define regnum_s2  18
+#define regnum_s3  19
+#define regnum_s4  20
+#define regnum_s5  21
+#define regnum_s6  22
+#define regnum_s7  23
+#define regnum_s8  24
+#define regnum_s9  25
+#define regnum_s10 26
+#define regnum_s11 27
+#define regnum_t3  28
+#define regnum_t4  29
+#define regnum_t5  30
+#define regnum_t6  31
 
-.macro retirq
-custom0 0,0,0,2
-.endm
+// x8 is s0 and also fp
+#define regnum_fp   8
 
-.macro maskirq rd rs
-custom0 \rd,\rs,0,3
-.endm
+#define r_type_insn(_f7, _rs2, _rs1, _f3, _rd, _opc) \
+.word (((_f7) << 25) | ((_rs2) << 20) | ((_rs1) << 15) | ((_f3) << 12) | ((_rd) << 7) | ((_opc) << 0))
 
-.macro waitirq rd
-custom0 \rd,0,0,4
-.endm
+#define picorv32_getq_insn(_rd, _qs) \
+r_type_insn(0b0000000, 0, regnum_ ## _qs, 0b100, regnum_ ## _rd, 0b0001011)
 
-.macro timer rd rs
-custom0 \rd,\rs,0,5
-.endm
+#define picorv32_setq_insn(_qd, _rs) \
+r_type_insn(0b0000001, 0, regnum_ ## _rs, 0b010, regnum_ ## _qd, 0b0001011)
+
+#define picorv32_retirq_insn() \
+r_type_insn(0b0000010, 0, 0, 0b000, 0, 0b0001011)
+
+#define picorv32_maskirq_insn(_rd, _rs) \
+r_type_insn(0b0000011, 0, regnum_ ## _rs, 0b110, regnum_ ## _rd, 0b0001011)
+
+#define picorv32_waitirq_insn(_rd) \
+r_type_insn(0b0000100, 0, 0, 0b100, regnum_ ## _rd, 0b0001011)
+
+#define picorv32_timer_insn(_rd, _rs) \
+r_type_insn(0b0000101, 0, regnum_ ## _rs, 0b110, regnum_ ## _rd, 0b0001011)
 
diff --git a/firmware/riscv.ld b/firmware/riscv.ld
new file mode 100644
index 0000000..20fd2fb
--- /dev/null
+++ b/firmware/riscv.ld
@@ -0,0 +1,200 @@
+/* Default linker script, for normal executables */
+/* Copyright (C) 2014-2016 Free Software Foundation, Inc.
+   Copying and distribution of this script, with or without modification,
+   are permitted in any medium without royalty provided the copyright
+   notice and this notice are preserved.  */
+OUTPUT_FORMAT("elf32-littleriscv", "elf32-littleriscv",
+	      "elf32-littleriscv")
+OUTPUT_ARCH(riscv)
+ENTRY(_start)
+SECTIONS
+{
+  . = 0x00010000;
+  .text           :
+  {
+    *(.text)
+    *(.text.unlikely .text.*_unlikely .text.unlikely.*)
+    *(.text.exit .text.exit.*)
+    *(.text.startup .text.startup.*)
+    *(.text.hot .text.hot.*)
+    *(.stub .text.* .gnu.linkonce.t.*)
+    /* .gnu.warning sections are handled specially by elf32.em.  */
+    *(.gnu.warning)
+  }
+  .init           :
+  {
+    KEEP (*(SORT_NONE(.init)))
+  }
+  .plt            : { *(.plt) }
+  .iplt           : { *(.iplt) }
+  .fini           :
+  {
+    KEEP (*(SORT_NONE(.fini)))
+  }
+  PROVIDE (__etext = .);
+  PROVIDE (_etext = .);
+  PROVIDE (etext = .);
+  .rodata         : { *(.rodata .rodata.* .gnu.linkonce.r.*) }
+  .rodata1        : { *(.rodata1) }
+  .sdata2         :
+  {
+    *(.sdata2 .sdata2.* .gnu.linkonce.s2.*)
+  }
+  .sbss2          : { *(.sbss2 .sbss2.* .gnu.linkonce.sb2.*) }
+  .eh_frame_hdr : { *(.eh_frame_hdr) *(.eh_frame_entry .eh_frame_entry.*) }
+  .eh_frame       : ONLY_IF_RO { KEEP (*(.eh_frame)) *(.eh_frame.*) }
+  .gcc_except_table   : ONLY_IF_RO { *(.gcc_except_table
+  .gcc_except_table.*) }
+  .gnu_extab   : ONLY_IF_RO { *(.gnu_extab*) }
+  /* These sections are generated by the Sun/Oracle C++ compiler.  */
+  .exception_ranges   : ONLY_IF_RO { *(.exception_ranges
+  .exception_ranges*) }
+  /* Adjust the address for the data segment.  We want to adjust up to
+     the same address within the page on the next page up.  */
+  . = DATA_SEGMENT_ALIGN (CONSTANT (MAXPAGESIZE), CONSTANT (COMMONPAGESIZE));
+  /* Exception handling  */
+  .eh_frame       : ONLY_IF_RW { KEEP (*(.eh_frame)) *(.eh_frame.*) }
+  .gnu_extab      : ONLY_IF_RW { *(.gnu_extab) }
+  .gcc_except_table   : ONLY_IF_RW { *(.gcc_except_table .gcc_except_table.*) }
+  .exception_ranges   : ONLY_IF_RW { *(.exception_ranges .exception_ranges*) }
+  /* Thread Local Storage sections  */
+  .tdata	  : { *(.tdata .tdata.* .gnu.linkonce.td.*) }
+  .tbss		  : { *(.tbss .tbss.* .gnu.linkonce.tb.*) *(.tcommon) }
+  .preinit_array     :
+  {
+    PROVIDE_HIDDEN (__preinit_array_start = .);
+    KEEP (*(.preinit_array))
+    PROVIDE_HIDDEN (__preinit_array_end = .);
+  }
+  .init_array     :
+  {
+    PROVIDE_HIDDEN (__init_array_start = .);
+    KEEP (*(SORT_BY_INIT_PRIORITY(.init_array.*) SORT_BY_INIT_PRIORITY(.ctors.*)))
+    KEEP (*(.init_array EXCLUDE_FILE (*crtbegin.o *crtbegin?.o *crtend.o *crtend?.o ) .ctors))
+    PROVIDE_HIDDEN (__init_array_end = .);
+  }
+  .fini_array     :
+  {
+    PROVIDE_HIDDEN (__fini_array_start = .);
+    KEEP (*(SORT_BY_INIT_PRIORITY(.fini_array.*) SORT_BY_INIT_PRIORITY(.dtors.*)))
+    KEEP (*(.fini_array EXCLUDE_FILE (*crtbegin.o *crtbegin?.o *crtend.o *crtend?.o ) .dtors))
+    PROVIDE_HIDDEN (__fini_array_end = .);
+  }
+  .ctors          :
+  {
+    /* gcc uses crtbegin.o to find the start of
+       the constructors, so we make sure it is
+       first.  Because this is a wildcard, it
+       doesn't matter if the user does not
+       actually link against crtbegin.o; the
+       linker won't look for a file to match a
+       wildcard.  The wildcard also means that it
+       doesn't matter which directory crtbegin.o
+       is in.  */
+    KEEP (*crtbegin.o(.ctors))
+    KEEP (*crtbegin?.o(.ctors))
+    /* We don't want to include the .ctor section from
+       the crtend.o file until after the sorted ctors.
+       The .ctor section from the crtend file contains the
+       end of ctors marker and it must be last */
+    KEEP (*(EXCLUDE_FILE (*crtend.o *crtend?.o ) .ctors))
+    KEEP (*(SORT(.ctors.*)))
+    KEEP (*(.ctors))
+  }
+  .dtors          :
+  {
+    KEEP (*crtbegin.o(.dtors))
+    KEEP (*crtbegin?.o(.dtors))
+    KEEP (*(EXCLUDE_FILE (*crtend.o *crtend?.o ) .dtors))
+    KEEP (*(SORT(.dtors.*)))
+    KEEP (*(.dtors))
+  }
+  .jcr            : { KEEP (*(.jcr)) }
+  .data.rel.ro : { *(.data.rel.ro.local* .gnu.linkonce.d.rel.ro.local.*) *(.data.rel.ro .data.rel.ro.* .gnu.linkonce.d.rel.ro.*) }
+  .dynamic        : { *(.dynamic) }
+  . = DATA_SEGMENT_RELRO_END (0, .);
+  .data           :
+  {
+    *(.data .data.* .gnu.linkonce.d.*)
+    SORT(CONSTRUCTORS)
+  }
+  .data1          : { *(.data1) }
+  .got            : { *(.got.plt) *(.igot.plt) *(.got) *(.igot) }
+  /* We want the small data sections together, so single-instruction offsets
+     can access them all, and initialized data all before uninitialized, so
+     we can shorten the on-disk segment size.  */
+  .sdata          :
+  {
+    _gp = . + 0x800;
+    *(.srodata.cst16) *(.srodata.cst8) *(.srodata.cst4) *(.srodata.cst2) *(.srodata .srodata.*)
+    *(.sdata .sdata.* .gnu.linkonce.s.*)
+  }
+  _edata = .; PROVIDE (edata = .);
+  . = .;
+  __bss_start = .;
+  .sbss           :
+  {
+    *(.dynsbss)
+    *(.sbss .sbss.* .gnu.linkonce.sb.*)
+    *(.scommon)
+  }
+  .bss            :
+  {
+   *(.dynbss)
+   *(.bss .bss.* .gnu.linkonce.b.*)
+   *(COMMON)
+   /* Align here to ensure that the .bss section occupies space up to
+      _end.  Align after .bss to ensure correct alignment even if the
+      .bss section disappears because there are no input sections.
+      FIXME: Why do we need it? When there is no .bss section, we don't
+      pad the .data section.  */
+   . = ALIGN(. != 0 ? 32 / 8 : 1);
+  }
+  . = ALIGN(32 / 8);
+  . = SEGMENT_START("ldata-segment", .);
+  . = ALIGN(32 / 8);
+  _end = .; PROVIDE (end = .);
+  . = DATA_SEGMENT_END (.);
+  /* Stabs debugging sections.  */
+  .stab          0 : { *(.stab) }
+  .stabstr       0 : { *(.stabstr) }
+  .stab.excl     0 : { *(.stab.excl) }
+  .stab.exclstr  0 : { *(.stab.exclstr) }
+  .stab.index    0 : { *(.stab.index) }
+  .stab.indexstr 0 : { *(.stab.indexstr) }
+  .comment       0 : { *(.comment) }
+  /* DWARF debug sections.
+     Symbols in the DWARF debugging sections are relative to the beginning
+     of the section so we begin them at 0.  */
+  /* DWARF 1 */
+  .debug          0 : { *(.debug) }
+  .line           0 : { *(.line) }
+  /* GNU DWARF 1 extensions */
+  .debug_srcinfo  0 : { *(.debug_srcinfo) }
+  .debug_sfnames  0 : { *(.debug_sfnames) }
+  /* DWARF 1.1 and DWARF 2 */
+  .debug_aranges  0 : { *(.debug_aranges) }
+  .debug_pubnames 0 : { *(.debug_pubnames) }
+  /* DWARF 2 */
+  .debug_info     0 : { *(.debug_info .gnu.linkonce.wi.*) }
+  .debug_abbrev   0 : { *(.debug_abbrev) }
+  .debug_line     0 : { *(.debug_line .debug_line.* .debug_line_end ) }
+  .debug_frame    0 : { *(.debug_frame) }
+  .debug_str      0 : { *(.debug_str) }
+  .debug_loc      0 : { *(.debug_loc) }
+  .debug_macinfo  0 : { *(.debug_macinfo) }
+  /* SGI/MIPS DWARF 2 extensions */
+  .debug_weaknames 0 : { *(.debug_weaknames) }
+  .debug_funcnames 0 : { *(.debug_funcnames) }
+  .debug_typenames 0 : { *(.debug_typenames) }
+  .debug_varnames  0 : { *(.debug_varnames) }
+  /* DWARF 3 */
+  .debug_pubtypes 0 : { *(.debug_pubtypes) }
+  .debug_ranges   0 : { *(.debug_ranges) }
+  /* DWARF Extension.  */
+  .debug_macro    0 : { *(.debug_macro) }
+  .debug_addr     0 : { *(.debug_addr) }
+  .gnu.attributes 0 : { KEEP (*(.gnu.attributes)) }
+  /DISCARD/ : { *(.note.GNU-stack) *(.gnu_debuglink) *(.gnu.lto_*) }
+}
+
diff --git a/firmware/riscv_ld.diff b/firmware/riscv_ld.diff
new file mode 100644
index 0000000..104a245
--- /dev/null
+++ b/firmware/riscv_ld.diff
@@ -0,0 +1,90 @@
+--- <(riscv32-unknown-elf-ld -z nocombreloc -verbose)	2017-01-13 16:55:07.569030165 +0100
++++ riscv.ld	2017-01-13 16:56:47.796761642 +0100
+@@ -1,9 +1,3 @@
+-GNU ld (GNU Binutils) 2.28.51.20170101
+-  Supported emulations:
+-   elf32lriscv
+-   elf64lriscv
+-using internal linker script:
+-==================================================
+ /* Default linker script, for normal executables */
+ /* Copyright (C) 2014-2016 Free Software Foundation, Inc.
+    Copying and distribution of this script, with or without modification,
+@@ -13,62 +7,26 @@
+ 	      "elf32-littleriscv")
+ OUTPUT_ARCH(riscv)
+ ENTRY(_start)
+-SEARCH_DIR("/opt/new_riscv32i/riscv32-unknown-elf/lib");
+ SECTIONS
+ {
+-  /* Read-only sections, merged into text segment: */
+-  PROVIDE (__executable_start = SEGMENT_START("text-segment", 0x10000)); . = SEGMENT_START("text-segment", 0x10000) + SIZEOF_HEADERS;
+-  .interp         : { *(.interp) }
+-  .note.gnu.build-id : { *(.note.gnu.build-id) }
+-  .hash           : { *(.hash) }
+-  .gnu.hash       : { *(.gnu.hash) }
+-  .dynsym         : { *(.dynsym) }
+-  .dynstr         : { *(.dynstr) }
+-  .gnu.version    : { *(.gnu.version) }
+-  .gnu.version_d  : { *(.gnu.version_d) }
+-  .gnu.version_r  : { *(.gnu.version_r) }
+-  .rela.init      : { *(.rela.init) }
+-  .rela.text      : { *(.rela.text .rela.text.* .rela.gnu.linkonce.t.*) }
+-  .rela.fini      : { *(.rela.fini) }
+-  .rela.rodata    : { *(.rela.rodata .rela.rodata.* .rela.gnu.linkonce.r.*) }
+-  .rela.data.rel.ro   : { *(.rela.data.rel.ro .rela.data.rel.ro.* .rela.gnu.linkonce.d.rel.ro.*) }
+-  .rela.data      : { *(.rela.data .rela.data.* .rela.gnu.linkonce.d.*) }
+-  .rela.tdata	  : { *(.rela.tdata .rela.tdata.* .rela.gnu.linkonce.td.*) }
+-  .rela.tbss	  : { *(.rela.tbss .rela.tbss.* .rela.gnu.linkonce.tb.*) }
+-  .rela.ctors     : { *(.rela.ctors) }
+-  .rela.dtors     : { *(.rela.dtors) }
+-  .rela.got       : { *(.rela.got) }
+-  .rela.sdata     : { *(.rela.sdata .rela.sdata.* .rela.gnu.linkonce.s.*) }
+-  .rela.sbss      : { *(.rela.sbss .rela.sbss.* .rela.gnu.linkonce.sb.*) }
+-  .rela.sdata2    : { *(.rela.sdata2 .rela.sdata2.* .rela.gnu.linkonce.s2.*) }
+-  .rela.sbss2     : { *(.rela.sbss2 .rela.sbss2.* .rela.gnu.linkonce.sb2.*) }
+-  .rela.bss       : { *(.rela.bss .rela.bss.* .rela.gnu.linkonce.b.*) }
+-  .rela.iplt      :
+-    {
+-      PROVIDE_HIDDEN (__rela_iplt_start = .);
+-      *(.rela.iplt)
+-      PROVIDE_HIDDEN (__rela_iplt_end = .);
+-    }
+-  .rela.plt       :
+-    {
+-      *(.rela.plt)
+-    }
+-  .init           :
+-  {
+-    KEEP (*(SORT_NONE(.init)))
+-  }
+-  .plt            : { *(.plt) }
+-  .iplt           : { *(.iplt) }
++  . = 0x00010000;
+   .text           :
+   {
++    *(.text)
+     *(.text.unlikely .text.*_unlikely .text.unlikely.*)
+     *(.text.exit .text.exit.*)
+     *(.text.startup .text.startup.*)
+     *(.text.hot .text.hot.*)
+-    *(.text .stub .text.* .gnu.linkonce.t.*)
++    *(.stub .text.* .gnu.linkonce.t.*)
+     /* .gnu.warning sections are handled specially by elf32.em.  */
+     *(.gnu.warning)
+   }
++  .init           :
++  {
++    KEEP (*(SORT_NONE(.init)))
++  }
++  .plt            : { *(.plt) }
++  .iplt           : { *(.iplt) }
+   .fini           :
+   {
+     KEEP (*(SORT_NONE(.fini)))
+@@ -240,5 +198,3 @@
+   /DISCARD/ : { *(.note.GNU-stack) *(.gnu_debuglink) *(.gnu.lto_*) }
+ }
+ 
+-
+-==================================================
diff --git a/firmware/start.S b/firmware/start.S
index dda08ed..06d4744 100644
--- a/firmware/start.S
+++ b/firmware/start.S
@@ -34,8 +34,8 @@
 
 reset_vec:
 	// no more than 16 bytes here !
-	waitirq zero
-	maskirq zero, zero
+	picorv32_waitirq_insn(zero)
+	picorv32_maskirq_insn(zero, zero)
 	j start
 
 
@@ -48,19 +48,19 @@ irq_vec:
 
 #ifdef ENABLE_QREGS
 
-	setq q2, x1
-	setq q3, x2
+	picorv32_setq_insn(q2, x1)
+	picorv32_setq_insn(q3, x2)
 
 	lui x1, %hi(irq_regs)
 	addi x1, x1, %lo(irq_regs)
 
-	getq x2, q0
+	picorv32_getq_insn(x2, q0)
 	sw x2,   0*4(x1)
 
-	getq x2, q2
+	picorv32_getq_insn(x2, q2)
 	sw x2,   1*4(x1)
 
-	getq x2, q3
+	picorv32_getq_insn(x2, q3)
 	sw x2,   2*4(x1)
 
 #ifdef ENABLE_FASTIRQ
@@ -180,7 +180,7 @@ irq_vec:
 
 	// arg1 = interrupt type
 #ifdef ENABLE_QREGS
-	getq a1, q1
+	picorv32_getq_insn(a1, q1)
 #else
 	addi a1, tp, 0
 #endif
@@ -196,13 +196,13 @@ irq_vec:
 	addi x1, a0, 0
 
 	lw x2,   0*4(x1)
-	setq q0, x2
+	picorv32_setq_insn(q0, x2)
 
 	lw x2,   1*4(x1)
-	setq q1, x2
+	picorv32_setq_insn(q1, x2)
 
 	lw x2,   2*4(x1)
-	setq q2, x2
+	picorv32_setq_insn(q2, x2)
 
 #ifdef ENABLE_FASTIRQ
 	lw x5,   5*4(x1)
@@ -252,8 +252,8 @@ irq_vec:
 	lw x31, 31*4(x1)
 #endif
 
-	getq x1, q1
-	getq x2, q2
+	picorv32_getq_insn(x1, q1)
+	picorv32_getq_insn(x2, q2)
 
 #else // ENABLE_QREGS
 
@@ -319,7 +319,7 @@ irq_vec:
 
 #endif // ENABLE_QREGS
 
-	retirq
+	picorv32_retirq_insn()
 
 #ifndef ENABLE_QREGS
 .balign 0x200
@@ -378,7 +378,7 @@ start:
 #  define TEST(n) \
 	.global n; \
 	addi x1, zero, 1000; \
-	timer zero, x1; \
+	picorv32_timer_insn(zero, x1); \
 	jal zero,n; \
 	.global n ## _ret; \
 	n ## _ret:
diff --git a/scripts/cxxdemo/Makefile b/scripts/cxxdemo/Makefile
index e858761..2d95019 100644
--- a/scripts/cxxdemo/Makefile
+++ b/scripts/cxxdemo/Makefile
@@ -22,7 +22,7 @@ firmware32.hex: firmware.elf start.elf hex8tohex32.py
 	rm -f start.tmp firmware.tmp
 
 firmware.elf: firmware.o syscalls.o
-	$(CC) $(LDFLAGS) -o $@ $^ $(LDLIBS)
+	$(CC) $(LDFLAGS) -o $@ $^ -T ../../firmware/riscv.ld $(LDLIBS)
 	chmod -x firmware.elf
 
 start.elf: start.S start.ld
diff --git a/tests/div.S b/tests/div.S
index a4504a7..24dc9ff 100644
--- a/tests/div.S
+++ b/tests/div.S
@@ -22,10 +22,10 @@ RVTEST_CODE_BEGIN
   TEST_RR_OP( 4, div, -3,  20,  -6 );
   TEST_RR_OP( 5, div,  3, -20,  -6 );
 
-  TEST_RR_OP( 6, div, -1<<63, -1<<63,  1 );
-  TEST_RR_OP( 7, div, -1<<63, -1<<63, -1 );
+  TEST_RR_OP( 6, div, -1<<31, -1<<31,  1 );
+  TEST_RR_OP( 7, div, -1<<31, -1<<31, -1 );
 
-  TEST_RR_OP( 8, div, -1, -1<<63, 0 );
+  TEST_RR_OP( 8, div, -1, -1<<31, 0 );
   TEST_RR_OP( 9, div, -1,      1, 0 );
   TEST_RR_OP(10, div, -1,      0, 0 );
 
diff --git a/tests/rem.S b/tests/rem.S
index c318e2c..7955736 100644
--- a/tests/rem.S
+++ b/tests/rem.S
@@ -22,10 +22,10 @@ RVTEST_CODE_BEGIN
   TEST_RR_OP( 4, rem,  2,  20,  -6 );
   TEST_RR_OP( 5, rem, -2, -20,  -6 );
 
-  TEST_RR_OP( 6, rem,  0, -1<<63,  1 );
-  TEST_RR_OP( 7, rem,  0, -1<<63, -1 );
+  TEST_RR_OP( 6, rem,  0, -1<<31,  1 );
+  TEST_RR_OP( 7, rem,  0, -1<<31, -1 );
 
-  TEST_RR_OP( 8, rem, -1<<63, -1<<63, 0 );
+  TEST_RR_OP( 8, rem, -1<<31, -1<<31, 0 );
   TEST_RR_OP( 9, rem,      1,      1, 0 );
   TEST_RR_OP(10, rem,      0,      0, 0 );
 
diff --git a/tests/remu.S b/tests/remu.S
index 38d641d..a96cfc1 100644
--- a/tests/remu.S
+++ b/tests/remu.S
@@ -22,10 +22,10 @@ RVTEST_CODE_BEGIN
   TEST_RR_OP( 4, remu,  20,  20,  -6 );
   TEST_RR_OP( 5, remu, -20, -20,  -6 );
 
-  TEST_RR_OP( 6, remu,      0, -1<<63,  1 );
-  TEST_RR_OP( 7, remu, -1<<63, -1<<63, -1 );
+  TEST_RR_OP( 6, remu,      0, -1<<31,  1 );
+  TEST_RR_OP( 7, remu, -1<<31, -1<<31, -1 );
 
-  TEST_RR_OP( 8, remu, -1<<63, -1<<63, 0 );
+  TEST_RR_OP( 8, remu, -1<<31, -1<<31, 0 );
   TEST_RR_OP( 9, remu,      1,      1, 0 );
   TEST_RR_OP(10, remu,      0,      0, 0 );
 
diff --git a/tests/sb.S b/tests/sb.S
index 1a8598c..05d1894 100644
--- a/tests/sb.S
+++ b/tests/sb.S
@@ -19,13 +19,7 @@ RVTEST_CODE_BEGIN
 
   TEST_ST_OP( 2, lb, sb, 0xffffffaa, 0, tdat );
   TEST_ST_OP( 3, lb, sb, 0x00000000, 1, tdat );
-#ifdef __RISCVEL
   TEST_ST_OP( 4, lh, sb, 0xffffefa0, 2, tdat );
-#elif defined(__RISCVEB)
-#else
-  TEST_ST_OP( 4, lh, sb, 0xffffa0ef, 2, tdat );
-#error unknown endianness!
-#endif
   TEST_ST_OP( 5, lb, sb, 0x0000000a, 3, tdat );
 
   # Test with negative offset
diff --git a/tests/sh.S b/tests/sh.S
index 6c464e5..387e181 100644
--- a/tests/sh.S
+++ b/tests/sh.S
@@ -19,13 +19,7 @@ RVTEST_CODE_BEGIN
 
   TEST_ST_OP( 2, lh, sh, 0x000000aa, 0, tdat );
   TEST_ST_OP( 3, lh, sh, 0xffffaa00, 2, tdat );
-#ifdef __RISCVEL
   TEST_ST_OP( 4, lw, sh, 0xbeef0aa0, 4, tdat );
-#elif defined(__RISCVEB)
-#else
-  TEST_ST_OP( 4, lw, sh, 0x0aa0beef, 4, tdat );
-#error unknown endianness!
-#endif
   TEST_ST_OP( 5, lh, sh, 0xffffa00a, 6, tdat );
 
   # Test with negative offset