diff --git a/makefile b/makefile
index 8db73a45e..d6d6fdf62 100644
--- a/makefile
+++ b/makefile
@@ -49,6 +49,15 @@ MKOCTFILE = mkoctfile
 OFLAGS =
 # For experts only, location of MWrap executable (see docs/install.rst):
 MWRAP = mwrap
+
+# depenency root
+DEPS_ROOT := deps
+
+# xsimd repo url
+XSIMD_URL := https://github.com/xtensor-stack/xsimd.git
+XSIMD_VERSION := 13.0.0
+XSIMD_DIR := $(DEPS_ROOT)/xsimd
+
 # absolute path of this makefile, ie FINUFFT's top-level directory...
 FINUFFT = $(dir $(realpath $(firstword $(MAKEFILE_LIST))))
 
@@ -60,7 +69,7 @@ FINUFFT = $(dir $(realpath $(firstword $(MAKEFILE_LIST))))
 # -fPIC (position-indep code) needed to build dyn lib (.so)
 # Also, we force return (via :=) to the land of simply-expanded variables...
 INCL = -Iinclude
-CXXFLAGS := $(CXXFLAGS) $(INCL) -fPIC -std=c++14
+CXXFLAGS := $(CXXFLAGS) $(INCL) -fPIC -std=c++17
 CFLAGS := $(CFLAGS) $(INCL) -fPIC
 # here /usr/include needed for fftw3.f "fortran header"... (JiriK: no longer)
 FFLAGS := $(FFLAGS) $(INCL) -I/usr/include -fPIC
@@ -116,7 +125,7 @@ OBJSD = $(OBJS) $(OBJSF) $(OBJS_PI)
 
 default: usage
 
-all: test perftest lib examples fortran matlab octave python
+all: test perftest lib examples fortran matlab octave python setup
 
 usage:
 	@echo "Makefile for FINUFFT library. Please specify your task:"
@@ -165,14 +174,14 @@ src/spreadinterp.o: src/ker_horner_allw_loop.c src/ker_lowupsampfac_horner_allw_
 # lib -----------------------------------------------------------------------
 # build library with double/single prec both bundled in...
 lib: $(STATICLIB) $(DYNLIB)
-$(STATICLIB): $(OBJSD)
+$(STATICLIB): setup $(OBJSD)
 	ar rcs $(STATICLIB) $(OBJSD)
 ifeq ($(OMP),OFF)
 	@echo "$(STATICLIB) built, single-thread version"
 else
 	@echo "$(STATICLIB) built, multithreaded version"
 endif
-$(DYNLIB): $(OBJSD)
+$(DYNLIB): setup $(OBJSD)
 # using *absolute* path in the -o here is needed to make portable executables
 # when compiled against it, in mac OSX, strangely...
 	$(CXX) -shared ${LDFLAGS} $(OMPFLAGS) $(OBJSD) -o $(ABSDYNLIB) $(LIBSFFT)
@@ -190,7 +199,7 @@ endif
 # examples (C++/C) -----------------------------------------------------------
 # build all examples (single-prec codes separate, and not all have one)...
 EXAMPLES = $(basename $(wildcard examples/*.c examples/*.cpp))
-examples: $(EXAMPLES)
+examples: setup $(EXAMPLES)
 ifneq ($(MINGW),ON)
   # Windows-MSYS does not find the dynamic libraries, so we make a temporary copy
   # Windows-MSYS has same commands as Linux/OSX
@@ -406,7 +415,35 @@ wheel: $(STATICLIB) $(DYNLIB)
 docker-wheel:
 	docker run --rm -e package_name=finufft -v `pwd`:/io libinlu/manylinux2010_x86_64_fftw /io/python/ci/build-wheels.sh
 
-
+# =============================== SETUP ====================================
+
+define clone_repo
+    @echo "Cloning repository $(1) at tag $(2) into directory $(3)"
+    @if [ ! -d "$(3)" ]; then \
+        git clone --branch $(2) $(1) $(3); \
+    else \
+        cd $(3) && \
+        CURRENT_VERSION=$$(git describe --tags --abbrev=0) && \
+        if [ "$$CURRENT_VERSION" = "$(2)" ]; then \
+            echo "Directory $(3) already exists and is at the correct version $(2)."; \
+        else \
+            echo "Directory $(3) exists but is at version $$CURRENT_VERSION. Checking out the correct version $(2)."; \
+            git fetch --tags && \
+            git checkout $(2) || { echo "Error: Failed to checkout version $(2) in $(3)."; exit 1; }; \
+        fi; \
+    fi
+endef
+
+setup:
+	@echo "Downloading dependencies..."
+	@echo "Downloading xsimd..."
+	mkdir -p $(DEPS_ROOT)
+	$(call clone_repo,$(XSIMD_URL),$(XSIMD_VERSION),$(XSIMD_DIR))
+	@echo "xsimd downloaded in deps/xsimd"
+    CXXFLAGS += -I$(XSIMD_DIR)/include
+
+setupclean:
+	rm -rf $(DEPS_ROOT)
 
 # =============================== DOCUMENTATION =============================
 
@@ -420,7 +457,7 @@ docs/matlabhelp.doc: docs/genmatlabhelp.sh matlab/*.sh matlab/*.docsrc matlab/*.
 
 # =============================== CLEAN UP ==================================
 
-clean: objclean pyclean
+clean: objclean pyclean setupclean
 ifneq ($(MINGW),ON)
   # non-Windows-WSL clean up...
 	rm -f $(STATICLIB) $(DYNLIB)
@@ -440,6 +477,7 @@ else
 	del examples\core, test\core, perftest\core, $(subst /,\, $(FE_DIR))\core
 endif
 
+
 # indiscriminate .o killer; needed before changing threading...
 objclean:
 ifneq ($(MINGW),ON)
@@ -473,3 +511,4 @@ else
   # Windows-WSL...
 	del matlab\finufft_plan.m matlab\finufft.cpp matlab\finufft.mex*
 endif
+