partial update sampler unit test

hw/unit_tests/tex_unit/tex_sampler/Makefile

@@ -0,0 +1,30 @@
+TOP = VX_tex_sampler
+
+PARAMS ?=
+
+INCLUDE = -I../../../rtl/ -I../../../rtl/libs -I../../../rtl/tex_unit
+
+SRCS = main.cpp
+
+all: build
+
+CF += -std=c++11 -fms-extensions -I../..
+VF += $(PARAMS)
+
+VF += --language 1800-2009 --assert -Wall --trace
+VF += -Wno-DECLFILENAME
+VF += --x-initial unique
+VF += -exe $(SRCS) $(INCLUDE)
+VF += $(PARAMS)
+
+gen:
+	verilator $(VF) -cc $(TOP).v -CFLAGS '$(CF)' --exe $(SRCS) 
+	
+build: gen
+	(cd obj_dir && make -j -f V$(TOP).mk)
+
+run: build
+	(cd obj_dir && ./V$(TOP))
+
+clean:
+	rm -rf obj_dir