diff --git a/Makefile b/Makefile
index 66aea8e..474cfb4 100644
--- a/Makefile
+++ b/Makefile
@@ -24,7 +24,7 @@
 
 # artifact paths
 SRC:=src
-BUILD:=build
+BUILD:=build/c
 BIN:=bin
 
 # if set, network filesystem is enabled. libcurl and libcrypto
diff --git a/Makefile.js b/Makefile.js
index dfcf927..4228f38 100644
--- a/Makefile.js
+++ b/Makefile.js
@@ -22,44 +22,61 @@
 # THE SOFTWARE.
 #
 
+# artifact paths
+JS:=js
+SRC:=src
+BUILD:=build/js
+
 # Build the Javascript version of TinyEMU
 EMCC=emcc
 EMCFLAGS=-O2 --llvm-opts 2 -Wall -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -MMD -fno-strict-aliasing -DCONFIG_FS_NET
 #EMCFLAGS+=-Werror
-EMLDFLAGS=-O3 --closure 0 -s NO_EXIT_RUNTIME=1 -s NO_FILESYSTEM=1 -s "EXPORTED_FUNCTIONS=['_console_queue_char','_vm_start','_fs_import_file','_display_key_event','_display_mouse_event','_display_wheel_event','_net_write_packet','_net_set_carrier']" -s 'EXPORTED_RUNTIME_METHODS=["ccall", "cwrap"]' --js-library js/lib.js
+EMLDFLAGS=-O3 --closure 0 -s NO_EXIT_RUNTIME=1 -s NO_FILESYSTEM=1 -s "EXPORTED_FUNCTIONS=['_console_queue_char','_vm_start','_fs_import_file','_display_key_event','_display_mouse_event','_display_wheel_event','_net_write_packet','_net_set_carrier']" -s 'EXPORTED_RUNTIME_METHODS=["ccall", "cwrap"]' --js-library $(JS)/lib.js
 EMLDFLAGS_ASMJS:=$(EMLDFLAGS) -s WASM=0
 EMLDFLAGS_WASM:=$(EMLDFLAGS) -s WASM=1 -s TOTAL_MEMORY=67108864 -s ALLOW_MEMORY_GROWTH=1
 
-PROGS=js/riscvemu32.js js/riscvemu32-wasm.js js/riscvemu64.js js/riscvemu64-wasm.js
+PROGS=$(addprefix $(JS)/,riscvemu32.js riscvemu32-wasm.js riscvemu64.js riscvemu64-wasm.js)
 
-all: $(PROGS)
+all: $(BUILD) $(PROGS)
 
 JS_OBJS=jsemu.js.o softfp.js.o virtio.js.o fs.js.o fs_net.js.o fs_wget.js.o fs_utils.js.o simplefb.js.o pci.js.o json.js.o block_net.js.o
 JS_OBJS+=iomem.js.o cutils.js.o aes.js.o sha256.js.o
 
-RISCVEMU64_OBJS=$(JS_OBJS) riscv_cpu64.js.o riscv_machine.js.o machine.js.o
-RISCVEMU32_OBJS=$(JS_OBJS) riscv_cpu32.js.o riscv_machine.js.o machine.js.o
+RISCVEMU64_OBJS=$(addprefix $(BUILD)/,$(JS_OBJS) riscv_cpu64.js.o riscv_machine.js.o machine.js.o)
+RISCVEMU32_OBJS=$(addprefix $(BUILD)/,$(JS_OBJS) riscv_cpu32.js.o riscv_machine.js.o machine.js.o)
 
-js/riscvemu64.js: $(RISCVEMU64_OBJS) js/lib.js
+# build path macro
+define mkbuild
+$(addprefix $(BUILD)/,$1)
+endef
+
+$(JS)/riscvemu64.js: $(RISCVEMU64_OBJS) $(JS)/lib.js
 	$(EMCC) $(EMLDFLAGS_ASMJS) -o $@ $(RISCVEMU64_OBJS)
 
-js/riscvemu32.js: $(RISCVEMU32_OBJS) js/lib.js
+$(JS)/riscvemu32.js: $(RISCVEMU32_OBJS) $(JS)/lib.js
 	$(EMCC) $(EMLDFLAGS_ASMJS) -o $@ $(RISCVEMU32_OBJS)
 
-js/riscvemu64-wasm.js: $(RISCVEMU64_OBJS) js/lib.js
+$(JS)/riscvemu64-wasm.js: $(RISCVEMU64_OBJS) $(JS)/lib.js
 	$(EMCC) $(EMLDFLAGS_WASM) -o $@ $(RISCVEMU64_OBJS)
 
-js/riscvemu32-wasm.js: $(RISCVEMU32_OBJS) js/lib.js
+$(JS)/riscvemu32-wasm.js: $(RISCVEMU32_OBJS) $(JS)/lib.js
 	$(EMCC) $(EMLDFLAGS_WASM) -o $@ $(RISCVEMU32_OBJS)
 
-riscv_cpu32.js.o: riscv_cpu.c
+$(BUILD)/riscv_cpu32.js.o: $(SRC)/riscv_cpu.c
 	$(EMCC) $(EMCFLAGS) -DMAX_XLEN=32 -DCONFIG_RISCV_MAX_XLEN=32 -c -o $@ $<
 
-riscv_cpu64.js.o: riscv_cpu.c
+$(BUILD)/riscv_cpu64.js.o: $(SRC)/riscv_cpu.c
 	$(EMCC) $(EMCFLAGS) -DMAX_XLEN=64 -DCONFIG_RISCV_MAX_XLEN=64 -c -o $@ $<
 
-
-%.js.o: %.c
+$(BUILD)/%.js.o: $(SRC)/%.c
 	$(EMCC) $(EMCFLAGS) -c -o $@ $<
 
--include $(wildcard *.d)
+.PHONY: $(BUILD)
+$(BUILD):
+	@mkdir -p $(BUILD)/js
+
+.PHONY: clean
+clean:
+	rm -rf $(BUILD)
+
+-include $(wildcard $(BUILD)/*.d)