refactor dir structure, add fib.c

23 files changed, 173 insertions, 1188 deletions

diff --git a/.gitignore b/.gitignore
index bb8c473..757e427 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,28 +1,13 @@
-# GHDL build artifacts
-*.o
-e~*.o
-work-obj*.cf
-tb_pic
-tb_stack
+# All build artifacts land in build/
+build/
 
-# Simulation output
-*.vcd
-
-# Synthesis / P&R outputs
-*.json
-!PIC/hdl-prj.json
-*.fs
-*_pnr.json
-*_timing.json
-
-# SDCC compiler outputs
+# SDCC compiler outputs that may land alongside source
 *.asm
 *.cod
 *.lst
 *.ihx
-program.hex
-# Keep test_uart.hex — it's the assembled firmware
-# (remove this comment and add test_uart.hex here if you regenerate it from source)
+*.hex
+hdl/prog_rom.vhd
 
 # Python cache
 __pycache__/
diff --git a/Makefile b/Makefile
index dbc5712..ca56c27 100644
--- a/Makefile
+++ b/Makefile
@@ -1,54 +1,55 @@
 IMAGE  = fpga-tools
 PODMAN = podman run --rm -v $(CURDIR):/workspace $(IMAGE)
 
+BUILD  = build
+
 # Which C program to build.  Override: make PROG=test_uart
 PROG ?= blink
 
-# ── Host-side C compilation (sdcc on host) ──────────────────────────────────
+$(BUILD):
+	mkdir -p $@
 
-blink.hex: PIC/blink.c
-	sdcc --use-non-free -mpic14 -p16f84a $<
+# -- Host-side C compilation (sdcc on host) --------------------------------------------
 
-test_uart.hex: PIC/test_uart.c
-	sdcc --use-non-free -mpic14 -p16f84a $<
+$(BUILD)/%.hex: fw/%.c | $(BUILD)
+	cd $(BUILD) && sdcc --use-non-free -mpic14 -p16f84a $(CURDIR)/fw/$*.c
 
 # program.hex is what the testbench loads at runtime
-program.hex: $(PROG).hex
+$(BUILD)/program.hex: $(BUILD)/$(PROG).hex
 	cp $< $@
 
 # prog_rom.vhd embeds the program for synthesis
-PIC/prog_rom.vhd: program.hex
+hdl/prog_rom.vhd: $(BUILD)/program.hex
 	python3 hex2rom.py $< > $@
 
 # Regenerate ROM from an arbitrary hex file: make rom HEX=foo.hex
 rom:
-	python3 hex2rom.py $(HEX) > PIC/prog_rom.vhd
+	python3 hex2rom.py $(HEX) > hdl/prog_rom.vhd
 
-# ── Container targets ────────────────────────────────────────────────────────
+# -- Container targets ----------------------------------------------------------------------------
 
-all: PIC/prog_rom.vhd
+all: hdl/prog_rom.vhd
 	$(PODMAN) make -f Makefile.inner
 
-sim: program.hex
+sim: $(BUILD)/program.hex
 	$(PODMAN) make -f Makefile.inner sim
 
-flash: pic_top.fs
+flash: $(BUILD)/pic_top.fs
 	openFPGALoader -b tangprimer25k $<
 
 show-top:
-	$(PODMAN) make -f Makefile.inner pic_top.dot
-	xdot pic_top.dot
+	$(PODMAN) make -f Makefile.inner $(BUILD)/pic_top.dot
+	xdot $(BUILD)/pic_top.dot
 
 show-uart:
-	$(PODMAN) make -f Makefile.inner uart.dot
-	xdot uart.dot
+	$(PODMAN) make -f Makefile.inner $(BUILD)/uart.dot
+	xdot $(BUILD)/uart.dot
 
-# ── Clean ────────────────────────────────────────────────────────────────────
+# -- Clean ----------------------------------------------------------------------------
 
 clean:
 	$(PODMAN) make -f Makefile.inner clean
-	rm -f program.hex PIC/prog_rom.vhd
-	rm -f blink.hex blink.asm blink.cod blink.lst
-	rm -f test_uart.hex test_uart.asm test_uart.cod test_uart.lst
+	rm -rf $(BUILD)
+	rm -f hdl/prog_rom.vhd
 
 .PHONY: all sim clean flash show-top show-uart rom
diff --git a/Makefile.inner b/Makefile.inner
index 3184cc3..957843c 100644
--- a/Makefile.inner
+++ b/Makefile.inner
@@ -1,4 +1,5 @@
-PIC_DIR = PIC
+HDL_DIR = hdl
+BUILD   = build
 
 DEVICE  = GW5A-LV25MG121NES
 FAMILY  = GW5A-25A
@@ -10,72 +11,71 @@ STD     = --std=08
 
 # Synthesizable sources (no testbenches, no VHDL file-I/O packages)
 SYN_FILES = \
-	$(PIC_DIR)/common.vhd \
-	$(PIC_DIR)/decoder.vhd \
-	$(PIC_DIR)/fifo.vhd \
-	$(PIC_DIR)/uart.vhd \
-	$(PIC_DIR)/ALU.vhd \
-	$(PIC_DIR)/stack.vhd \
-	$(PIC_DIR)/dpram.vhd \
-	$(PIC_DIR)/state_machine.vhd \
-	$(PIC_DIR)/PIC.vhd \
-	$(PIC_DIR)/prog_rom.vhd \
-	$(PIC_DIR)/pic_top.vhd
+	$(HDL_DIR)/common.vhd \
+	$(HDL_DIR)/decoder.vhd \
+	$(HDL_DIR)/fifo.vhd \
+	$(HDL_DIR)/uart.vhd \
+	$(HDL_DIR)/ALU.vhd \
+	$(HDL_DIR)/stack.vhd \
+	$(HDL_DIR)/dpram.vhd \
+	$(HDL_DIR)/state_machine.vhd \
+	$(HDL_DIR)/PIC.vhd \
+	$(HDL_DIR)/prog_rom.vhd \
+	$(HDL_DIR)/pic_top.vhd
 
 # Simulation adds the hex-reader package and testbenches
 SIM_FILES = \
-	$(PIC_DIR)/common.vhd \
-	$(PIC_DIR)/decoder.vhd \
-	$(PIC_DIR)/hexfile_reader.vhd \
-	$(PIC_DIR)/fifo.vhd \
-	$(PIC_DIR)/uart.vhd \
-	$(PIC_DIR)/ALU.vhd \
-	$(PIC_DIR)/stack.vhd \
-	$(PIC_DIR)/dpram.vhd \
-	$(PIC_DIR)/state_machine.vhd \
-	$(PIC_DIR)/PIC.vhd
+	$(HDL_DIR)/common.vhd \
+	$(HDL_DIR)/decoder.vhd \
+	$(HDL_DIR)/hexfile_reader.vhd \
+	$(HDL_DIR)/fifo.vhd \
+	$(HDL_DIR)/uart.vhd \
+	$(HDL_DIR)/ALU.vhd \
+	$(HDL_DIR)/stack.vhd \
+	$(HDL_DIR)/dpram.vhd \
+	$(HDL_DIR)/state_machine.vhd \
+	$(HDL_DIR)/PIC.vhd
 
 TB_FILES = \
-	$(PIC_DIR)/tb_stack.vhd \
-	$(PIC_DIR)/tb_pic.vhd
+	$(HDL_DIR)/tb_stack.vhd \
+	$(HDL_DIR)/tb_pic.vhd
 
-all: $(TOP).fs
+all: $(BUILD)/$(TOP).fs
+
+$(BUILD):
+	mkdir -p $@
 
 # Synthesize
-$(TOP).json: $(SYN_FILES)
-	ghdl -a $(STD) $(SYN_FILES)
-	yosys $(MODULE) -p "ghdl $(STD) $(TOP); memory_map; synth_gowin -json $@ -family gw5a"
+$(BUILD)/$(TOP).json: $(SYN_FILES) | $(BUILD)
+	ghdl -a $(STD) --workdir=$(BUILD) $(SYN_FILES)
+	yosys $(MODULE) -p "ghdl $(STD) --workdir=$(BUILD) $(TOP); memory_map; synth_gowin -json $@ -family gw5a"
 
 # Place and route
-$(TOP)_pnr.json: $(TOP).json $(CST)
+$(BUILD)/$(TOP)_pnr.json: $(BUILD)/$(TOP).json $(CST)
 	nextpnr-himbaechel --json $< --write $@ \
 		--device $(DEVICE) --vopt family=GW5A-25A --vopt cst=$(CST) \
-		--vopt sspi_as_gpio --freq 50 --report $(TOP)_timing.json
+		--vopt sspi_as_gpio --freq 50 --report $(BUILD)/$(TOP)_timing.json
 
 # Pack bitstream
-$(TOP).fs: $(TOP)_pnr.json
+$(BUILD)/$(TOP).fs: $(BUILD)/$(TOP)_pnr.json
 	gowin_pack --sspi_as_gpio --cpu_as_gpio -d $(FAMILY) -o $@ $<
 
-sim: $(SIM_FILES) $(TB_FILES)
-	ghdl -a $(STD) $(SIM_FILES) $(TB_FILES)
-	ghdl -e $(STD) tb_stack
-	ghdl -r $(STD) tb_stack
-	ghdl -e $(STD) tb_pic
-	ghdl -r $(STD) tb_pic --vcd=tb_pic.vcd
+sim: $(SIM_FILES) $(TB_FILES) | $(BUILD)
+	ghdl -a $(STD) --workdir=$(BUILD) $(SIM_FILES) $(TB_FILES)
+	ghdl -e $(STD) --workdir=$(BUILD) -o $(BUILD)/tb_stack tb_stack
+	ghdl -r $(STD) --workdir=$(BUILD) tb_stack
+	ghdl -e $(STD) --workdir=$(BUILD) -o $(BUILD)/tb_pic tb_pic
+	ghdl -r $(STD) --workdir=$(BUILD) tb_pic --vcd=$(BUILD)/tb_pic.vcd
 
-pic_top.dot: $(SYN_FILES)
-	ghdl -a $(STD) $(SYN_FILES)
-	yosys $(MODULE) -p "ghdl $(STD) $(TOP); show -format dot -prefix pic_top"
+$(BUILD)/pic_top.dot: $(SYN_FILES) | $(BUILD)
+	ghdl -a $(STD) --workdir=$(BUILD) $(SYN_FILES)
+	yosys $(MODULE) -p "ghdl $(STD) --workdir=$(BUILD) $(TOP); show -format dot -prefix $(BUILD)/pic_top"
 
-uart.dot: $(PIC_DIR)/fifo.vhd $(PIC_DIR)/uart.vhd
-	ghdl -a $(STD) $(PIC_DIR)/fifo.vhd $(PIC_DIR)/uart.vhd
-	yosys $(MODULE) -p "ghdl $(STD) uart; show -format dot -prefix uart"
+$(BUILD)/uart.dot: $(HDL_DIR)/fifo.vhd $(HDL_DIR)/uart.vhd | $(BUILD)
+	ghdl -a $(STD) --workdir=$(BUILD) $(HDL_DIR)/fifo.vhd $(HDL_DIR)/uart.vhd
+	yosys $(MODULE) -p "ghdl $(STD) --workdir=$(BUILD) uart; show -format dot -prefix $(BUILD)/uart"
 
 clean:
-	rm -f $(TOP).json $(TOP)_pnr.json $(TOP).fs $(TOP)_timing.json
-	rm -f pic_top.dot uart.dot
-	rm -f *.o work-obj08.cf e~*.lst
-	rm -f *.vcd
-	rm -f tb_pic tb_stack
+	rm -rf $(BUILD)
 
 .PHONY: all sim clean
diff --git a/PIC/prog_rom.vhd b/PIC/prog_rom.vhd
deleted file mode 100644
index f3dcf64..0000000
--- a/PIC/prog_rom.vhd
+++ /dev/null
@@ -1,1045 +0,0 @@
-library ieee;
-use ieee.std_logic_1164.all;
-use ieee.numeric_std.all;
-
-entity prog_rom is
-  generic (
-    DEPTH : positive := 1024
-  );
-  port (
-    addr : in  std_logic_vector(12 downto 0);
-    data : out std_logic_vector(13 downto 0)
-  );
-end entity prog_rom;
-
-architecture rtl of prog_rom is
-  type rom_t is array (0 to 1024 - 1) of std_logic_vector(13 downto 0);
-  constant rom : rom_t := (
-       0 => "00000000000000",
-       1 => "10100000000010",
-       2 => "11000001101111",
-       3 => "00000010011010",
-       4 => "11000000000001",
-       5 => "00000010011011",
-       6 => "11000010000000",
-       7 => "00000000000000",
-       8 => "00000000000000",
-       9 => "10000100010010",
-      10 => "00000000000000",
-      11 => "00000000000000",
-      12 => "01001010000011",
-      13 => "00000000000000",
-      14 => "00000010011101",
-      15 => "00100000011011",
-      16 => "00000010011100",
-      17 => "11000001110001",
-      18 => "00000010011110",
-      19 => "11000000000001",
-      20 => "00000010011111",
-      21 => "01001010000011",
-      22 => "00000000000000",
-      23 => "00100000011100",
-      24 => "00000010100000",
-      25 => "00100000011101",
-      26 => "00000010100001",
-      27 => "11000011111111",
-      28 => "00011110011100",
-      29 => "01110000000011",
-      30 => "00001110011101",
-      31 => "00100000100001",
-      32 => "00010000100000",
-      33 => "01100100000011",
-      34 => "10100010011010",
-      35 => "11000000000100",
-      36 => "00011100011110",
-      37 => "00000010100000",
-      38 => "00000110100001",
-      39 => "00110110100001",
-      40 => "00100000011111",
-      41 => "00011110100001",
-      42 => "00100000100000",
-      43 => "00000010011010",
-      44 => "00100000100001",
-      45 => "00000010011011",
-      46 => "11000010000000",
-      47 => "00000000000000",
-      48 => "00000000000000",
-      49 => "10000100010010",
-      50 => "00000000000000",
-      51 => "00000000000000",
-      52 => "01001010000011",
-      53 => "00000000000000",
-      54 => "00000010100011",
-      55 => "00100000011011",
-      56 => "00000010100010",
-      57 => "00100000011110",
-      58 => "00000010011010",
-      59 => "00100000011111",
-      60 => "00000010011011",
-      61 => "11000010000000",
-      62 => "00000000000000",
-      63 => "00000000000000",
-      64 => "10000100010010",
-      65 => "00000000000000",
-      66 => "00000000000000",
-      67 => "01001010000011",
-      68 => "00000000000000",
-      69 => "00000010100101",
-      70 => "00000010100001",
-      71 => "00100000011011",
-      72 => "00000010100000",
-      73 => "00000010100100",
-      74 => "11000000000010",
-      75 => "00011100011110",
-      76 => "00000010100000",
-      77 => "00000110100001",
-      78 => "00110110100001",
-      79 => "00100000011111",
-      80 => "00011110100001",
-      81 => "00100000100000",
-      82 => "00000010011010",
-      83 => "00100000100001",
-      84 => "00000010011011",
-      85 => "11000010000000",
-      86 => "00000000000000",
-      87 => "00000000000000",
-      88 => "10000100010010",
-      89 => "00000000000000",
-      90 => "00000000000000",
-      91 => "01001010000011",
-      92 => "00000000000000",
-      93 => "00000010100001",
-      94 => "00000010100111",
-      95 => "00100000011011",
-      96 => "00000010100110",
-      97 => "00000010100000",
-      98 => "01001010000011",
-      99 => "00000000000000",
-     100 => "00100000100010",
-     101 => "00000010100110",
-     102 => "00100000100011",
-     103 => "00000010100111",
-     104 => "11000011111111",
-     105 => "00011110100010",
-     106 => "01110000000011",
-     107 => "00001110100011",
-     108 => "00100000100111",
-     109 => "00010000100110",
-     110 => "01100100000011",
-     111 => "10100010010011",
-     112 => "00100000100100",
-     113 => "00000010011010",
-     114 => "00100000100101",
-     115 => "00000010011011",
-     116 => "11000010000000",
-     117 => "00000000000000",
-     118 => "00000000000000",
-     119 => "10000100110011",
-     120 => "00000000000000",
-     121 => "00000000000000",
-     122 => "01001010000011",
-     123 => "00000000000000",
-     124 => "00000010100110",
-     125 => "00100000100000",
-     126 => "01001010000011",
-     127 => "01001100000011",
-     128 => "00000010000100",
-     129 => "01001110000011",
-     130 => "01001010000011",
-     131 => "00000000000000",
-     132 => "01100000100001",
-     133 => "01011110000011",
-     134 => "00100000100110",
-     135 => "01001010000011",
-     136 => "01001100000011",
-     137 => "00000010000000",
-     138 => "01001010000011",
-     139 => "00000000000000",
-     140 => "00101010100100",
-     141 => "01100100000011",
-     142 => "00101010100101",
-     143 => "00101010100000",
-     144 => "01100100000011",
-     145 => "00101010100001",
-     146 => "10100001100010",
-     147 => "11000000000110",
-     148 => "01001010000011",
-     149 => "00000000000000",
-     150 => "00011110011110",
-     151 => "01100000000011",
-     152 => "00101010011111",
-     153 => "10100000010101",
-     154 => "00000000000000",
-     155 => "00000000000000",
-     156 => "10100010011110",
-     157 => "00000000001000",
-     158 => "00000110110101",
-     159 => "11000000000001",
-     160 => "00000010101111",
-     161 => "11000001100111",
-     162 => "00000010101110",
-     163 => "11000010000000",
-     164 => "00000010110000",
-     165 => "00100000101110",
-     166 => "00000010011010",
-     167 => "00100000101111",
-     168 => "00000010011011",
-     169 => "00100000110000",
-     170 => "10000101000110",
-     171 => "11000001000011",
-     172 => "10000101011110",
-     173 => "11000000111010",
-     174 => "10000101011110",
-     175 => "00100000110101",
-     176 => "00000010101110",
-     177 => "00000110101111",
-     178 => "11000011001000",
-     179 => "00001000101110",
-     180 => "01110000000011",
-     181 => "10100011000000",
-     182 => "11000000110010",
-     183 => "10000101011110",
-     184 => "00100000101110",
-     185 => "00000010110000",
-     186 => "11000000111000",
-     187 => "00011100110000",
-     188 => "00000010101110",
-     189 => "11000000000001",
-     190 => "00000010101111",
-     191 => "10100011001101",
-     192 => "11000001100100",
-     193 => "00001000101110",
-     194 => "01110000000011",
-     195 => "10100011001101",
-     196 => "11000000110001",
-     197 => "10000101011110",
-     198 => "00100000101110",
-     199 => "00000010110000",
-     200 => "11000010011100",
-     201 => "00011100110000",
-     202 => "00000010101110",
-     203 => "11000000000001",
-     204 => "00000010101111",
-     205 => "11000000110000",
-     206 => "00000010110000",
-     207 => "11000000001010",
-     208 => "00001000101110",
-     209 => "01110000000011",
-     210 => "10100011011010",
-     211 => "00100000101110",
-     212 => "00000010110001",
-     213 => "11000011110110",
-     214 => "00011100110001",
-     215 => "00000010101110",
-     216 => "00101010110000",
-     217 => "10100011001111",
-     218 => "00100000110000",
-     219 => "00000010110001",
-     220 => "00100000101111",
-     221 => "01110100000011",
-     222 => "10100011100011",
-     223 => "00100000110000",
-     224 => "11101000110000",
-     225 => "01100100000011",
-     226 => "10100011100101",
-     227 => "00100000110001",
-     228 => "10000101011110",
-     229 => "00100000101110",
-     230 => "00000010101111",
-     231 => "11000000110000",
-     232 => "00011100101111",
-     233 => "00000010101110",
-     234 => "10000101011110",
-     235 => "11000000000001",
-     236 => "00000010101111",
-     237 => "11000001110111",
-     238 => "00000010101110",
-     239 => "11000010000000",
-     240 => "00000010110000",
-     241 => "00100000101110",
-     242 => "00000010011010",
-     243 => "00100000101111",
-     244 => "00000010011011",
-     245 => "00100000110000",
-     246 => "10000101000110",
-     247 => "00101010110101",
-     248 => "00000110110010",
-     249 => "00000110110011",
-     250 => "00000110110100",
-     251 => "00100000110100",
-     252 => "00000010101000",
-     253 => "00101000101000",
-     254 => "00000010110100",
-     255 => "00100000110100",
-     256 => "01110100000011",
-     257 => "10100011111011",
-     258 => "00101000110011",
-     259 => "00000010101000",
-     260 => "00000010110011",
-     261 => "00100000101000",
-     262 => "11101000011110",
-     263 => "01110100000011",
-     264 => "10100011111010",
-     265 => "00100000110010",
-     266 => "00000010101000",
-     267 => "00101000101000",
-     268 => "00000010110010",
-     269 => "11101001110100",
-     270 => "01110100000011",
-     271 => "10100011111001",
-     272 => "10100010101011",
-     273 => "00000000001000",
-     274 => "11101000000000",
-     275 => "01100100000011",
-     276 => "10100100011010",
-     277 => "11101010000000",
-     278 => "01100100000011",
-     279 => "10100100100100",
-     280 => "00000110011011",
-     281 => "11010000000000",
-     282 => "00100000011010",
-     283 => "00000010000100",
-     284 => "01001110000011",
-     285 => "01100000011011",
-     286 => "01011110000011",
-     287 => "00100000000000",
-     288 => "00000010011011",
-     289 => "00101010000100",
-     290 => "00100000000000",
-     291 => "00000000001000",
-     292 => "00000000000000",
-     293 => "00000000000000",
-     294 => "10000101000001",
-     295 => "00000010011001",
-     296 => "00111110011010",
-     297 => "00001110011011",
-     298 => "00101010011011",
-     299 => "00000000000000",
-     300 => "00000000000000",
-     301 => "10000101000001",
-     302 => "00000010011000",
-     303 => "00100000011001",
-     304 => "00000010011011",
-     305 => "00100000011000",
-     306 => "00000000001000",
-     307 => "11101000000000",
-     308 => "01100100000011",
-     309 => "10100100111010",
-     310 => "11101010000000",
-     311 => "01100100000011",
-     312 => "10100101000001",
-     313 => "11010000000000",
-     314 => "00100000011010",
-     315 => "00000010000100",
-     316 => "01001110000011",
-     317 => "01100000011011",
-     318 => "01011110000011",
-     319 => "00100000000000",
-     320 => "00000000001000",
-     321 => "00100000011011",
-     322 => "00000010001010",
-     323 => "00100000011010",
-     324 => "00000010000010",
-     325 => "00000000001000",
-     326 => "00000010101100",
-     327 => "00100000011011",
-     328 => "00000010101011",
-     329 => "00100000011010",
-     330 => "00000010101010",
-     331 => "00100000101010",
-     332 => "00000010011010",
-     333 => "00100000101011",
-     334 => "00000010011011",
-     335 => "00100000101100",
-     336 => "10000100110011",
-     337 => "00000010101101",
-     338 => "00100000101101",
-     339 => "01100100000011",
-     340 => "10100101011101",
-     341 => "00100000101101",
-     342 => "10000101011110",
-     343 => "00101010101010",
-     344 => "01100100000011",
-     345 => "00101010101011",
-     346 => "01100100000011",
-     347 => "00101010101100",
-     348 => "10100101001011",
-     349 => "00000000001000",
-     350 => "00000010101000",
-     351 => "01001010000011",
-     352 => "00100001110010",
-     353 => "00000010101001",
-     354 => "01100000101001",
-     355 => "10100101011111",
-     356 => "00100000101000",
-     357 => "00000011110000",
-     358 => "00000000001000",
-     359 => "11010001001000",
-     360 => "11010001100101",
-     361 => "11010001101100",
-     362 => "11010001101100",
-     363 => "11010001101111",
-     364 => "11010000001101",
-     365 => "11010000001010",
-     366 => "11010000000000",
-     367 => "11010000000001",
-     368 => "11010000000000",
-     369 => "11010001111010",
-     370 => "11010000000001",
-     371 => "11010000110110",
-     372 => "11010000000000",
-     373 => "11010000000001",
-     374 => "11010000000000",
-     375 => "11010000001101",
-     376 => "11010000001010",
-     377 => "11010000000000",
-     378 => "11010000000000",
-     379 => "00000000000000",
-     380 => "00000000000000",
-     381 => "00000000000000",
-     382 => "00000000000000",
-     383 => "00000000000000",
-     384 => "00000000000000",
-     385 => "00000000000000",
-     386 => "00000000000000",
-     387 => "00000000000000",
-     388 => "00000000000000",
-     389 => "00000000000000",
-     390 => "00000000000000",
-     391 => "00000000000000",
-     392 => "00000000000000",
-     393 => "00000000000000",
-     394 => "00000000000000",
-     395 => "00000000000000",
-     396 => "00000000000000",
-     397 => "00000000000000",
-     398 => "00000000000000",
-     399 => "00000000000000",
-     400 => "00000000000000",
-     401 => "00000000000000",
-     402 => "00000000000000",
-     403 => "00000000000000",
-     404 => "00000000000000",
-     405 => "00000000000000",
-     406 => "00000000000000",
-     407 => "00000000000000",
-     408 => "00000000000000",
-     409 => "00000000000000",
-     410 => "00000000000000",
-     411 => "00000000000000",
-     412 => "00000000000000",
-     413 => "00000000000000",
-     414 => "00000000000000",
-     415 => "00000000000000",
-     416 => "00000000000000",
-     417 => "00000000000000",
-     418 => "00000000000000",
-     419 => "00000000000000",
-     420 => "00000000000000",
-     421 => "00000000000000",
-     422 => "00000000000000",
-     423 => "00000000000000",
-     424 => "00000000000000",
-     425 => "00000000000000",
-     426 => "00000000000000",
-     427 => "00000000000000",
-     428 => "00000000000000",
-     429 => "00000000000000",
-     430 => "00000000000000",
-     431 => "00000000000000",
-     432 => "00000000000000",
-     433 => "00000000000000",
-     434 => "00000000000000",
-     435 => "00000000000000",
-     436 => "00000000000000",
-     437 => "00000000000000",
-     438 => "00000000000000",
-     439 => "00000000000000",
-     440 => "00000000000000",
-     441 => "00000000000000",
-     442 => "00000000000000",
-     443 => "00000000000000",
-     444 => "00000000000000",
-     445 => "00000000000000",
-     446 => "00000000000000",
-     447 => "00000000000000",
-     448 => "00000000000000",
-     449 => "00000000000000",
-     450 => "00000000000000",
-     451 => "00000000000000",
-     452 => "00000000000000",
-     453 => "00000000000000",
-     454 => "00000000000000",
-     455 => "00000000000000",
-     456 => "00000000000000",
-     457 => "00000000000000",
-     458 => "00000000000000",
-     459 => "00000000000000",
-     460 => "00000000000000",
-     461 => "00000000000000",
-     462 => "00000000000000",
-     463 => "00000000000000",
-     464 => "00000000000000",
-     465 => "00000000000000",
-     466 => "00000000000000",
-     467 => "00000000000000",
-     468 => "00000000000000",
-     469 => "00000000000000",
-     470 => "00000000000000",
-     471 => "00000000000000",
-     472 => "00000000000000",
-     473 => "00000000000000",
-     474 => "00000000000000",
-     475 => "00000000000000",
-     476 => "00000000000000",
-     477 => "00000000000000",
-     478 => "00000000000000",
-     479 => "00000000000000",
-     480 => "00000000000000",
-     481 => "00000000000000",
-     482 => "00000000000000",
-     483 => "00000000000000",
-     484 => "00000000000000",
-     485 => "00000000000000",
-     486 => "00000000000000",
-     487 => "00000000000000",
-     488 => "00000000000000",
-     489 => "00000000000000",
-     490 => "00000000000000",
-     491 => "00000000000000",
-     492 => "00000000000000",
-     493 => "00000000000000",
-     494 => "00000000000000",
-     495 => "00000000000000",
-     496 => "00000000000000",
-     497 => "00000000000000",
-     498 => "00000000000000",
-     499 => "00000000000000",
-     500 => "00000000000000",
-     501 => "00000000000000",
-     502 => "00000000000000",
-     503 => "00000000000000",
-     504 => "00000000000000",
-     505 => "00000000000000",
-     506 => "00000000000000",
-     507 => "00000000000000",
-     508 => "00000000000000",
-     509 => "00000000000000",
-     510 => "00000000000000",
-     511 => "00000000000000",
-     512 => "00000000000000",
-     513 => "00000000000000",
-     514 => "00000000000000",
-     515 => "00000000000000",
-     516 => "00000000000000",
-     517 => "00000000000000",
-     518 => "00000000000000",
-     519 => "00000000000000",
-     520 => "00000000000000",
-     521 => "00000000000000",
-     522 => "00000000000000",
-     523 => "00000000000000",
-     524 => "00000000000000",
-     525 => "00000000000000",
-     526 => "00000000000000",
-     527 => "00000000000000",
-     528 => "00000000000000",
-     529 => "00000000000000",
-     530 => "00000000000000",
-     531 => "00000000000000",
-     532 => "00000000000000",
-     533 => "00000000000000",
-     534 => "00000000000000",
-     535 => "00000000000000",
-     536 => "00000000000000",
-     537 => "00000000000000",
-     538 => "00000000000000",
-     539 => "00000000000000",
-     540 => "00000000000000",
-     541 => "00000000000000",
-     542 => "00000000000000",
-     543 => "00000000000000",
-     544 => "00000000000000",
-     545 => "00000000000000",
-     546 => "00000000000000",
-     547 => "00000000000000",
-     548 => "00000000000000",
-     549 => "00000000000000",
-     550 => "00000000000000",
-     551 => "00000000000000",
-     552 => "00000000000000",
-     553 => "00000000000000",
-     554 => "00000000000000",
-     555 => "00000000000000",
-     556 => "00000000000000",
-     557 => "00000000000000",
-     558 => "00000000000000",
-     559 => "00000000000000",
-     560 => "00000000000000",
-     561 => "00000000000000",
-     562 => "00000000000000",
-     563 => "00000000000000",
-     564 => "00000000000000",
-     565 => "00000000000000",
-     566 => "00000000000000",
-     567 => "00000000000000",
-     568 => "00000000000000",
-     569 => "00000000000000",
-     570 => "00000000000000",
-     571 => "00000000000000",
-     572 => "00000000000000",
-     573 => "00000000000000",
-     574 => "00000000000000",
-     575 => "00000000000000",
-     576 => "00000000000000",
-     577 => "00000000000000",
-     578 => "00000000000000",
-     579 => "00000000000000",
-     580 => "00000000000000",
-     581 => "00000000000000",
-     582 => "00000000000000",
-     583 => "00000000000000",
-     584 => "00000000000000",
-     585 => "00000000000000",
-     586 => "00000000000000",
-     587 => "00000000000000",
-     588 => "00000000000000",
-     589 => "00000000000000",
-     590 => "00000000000000",
-     591 => "00000000000000",
-     592 => "00000000000000",
-     593 => "00000000000000",
-     594 => "00000000000000",
-     595 => "00000000000000",
-     596 => "00000000000000",
-     597 => "00000000000000",
-     598 => "00000000000000",
-     599 => "00000000000000",
-     600 => "00000000000000",
-     601 => "00000000000000",
-     602 => "00000000000000",
-     603 => "00000000000000",
-     604 => "00000000000000",
-     605 => "00000000000000",
-     606 => "00000000000000",
-     607 => "00000000000000",
-     608 => "00000000000000",
-     609 => "00000000000000",
-     610 => "00000000000000",
-     611 => "00000000000000",
-     612 => "00000000000000",
-     613 => "00000000000000",
-     614 => "00000000000000",
-     615 => "00000000000000",
-     616 => "00000000000000",
-     617 => "00000000000000",
-     618 => "00000000000000",
-     619 => "00000000000000",
-     620 => "00000000000000",
-     621 => "00000000000000",
-     622 => "00000000000000",
-     623 => "00000000000000",
-     624 => "00000000000000",
-     625 => "00000000000000",
-     626 => "00000000000000",
-     627 => "00000000000000",
-     628 => "00000000000000",
-     629 => "00000000000000",
-     630 => "00000000000000",
-     631 => "00000000000000",
-     632 => "00000000000000",
-     633 => "00000000000000",
-     634 => "00000000000000",
-     635 => "00000000000000",
-     636 => "00000000000000",
-     637 => "00000000000000",
-     638 => "00000000000000",
-     639 => "00000000000000",
-     640 => "00000000000000",
-     641 => "00000000000000",
-     642 => "00000000000000",
-     643 => "00000000000000",
-     644 => "00000000000000",
-     645 => "00000000000000",
-     646 => "00000000000000",
-     647 => "00000000000000",
-     648 => "00000000000000",
-     649 => "00000000000000",
-     650 => "00000000000000",
-     651 => "00000000000000",
-     652 => "00000000000000",
-     653 => "00000000000000",
-     654 => "00000000000000",
-     655 => "00000000000000",
-     656 => "00000000000000",
-     657 => "00000000000000",
-     658 => "00000000000000",
-     659 => "00000000000000",
-     660 => "00000000000000",
-     661 => "00000000000000",
-     662 => "00000000000000",
-     663 => "00000000000000",
-     664 => "00000000000000",
-     665 => "00000000000000",
-     666 => "00000000000000",
-     667 => "00000000000000",
-     668 => "00000000000000",
-     669 => "00000000000000",
-     670 => "00000000000000",
-     671 => "00000000000000",
-     672 => "00000000000000",
-     673 => "00000000000000",
-     674 => "00000000000000",
-     675 => "00000000000000",
-     676 => "00000000000000",
-     677 => "00000000000000",
-     678 => "00000000000000",
-     679 => "00000000000000",
-     680 => "00000000000000",
-     681 => "00000000000000",
-     682 => "00000000000000",
-     683 => "00000000000000",
-     684 => "00000000000000",
-     685 => "00000000000000",
-     686 => "00000000000000",
-     687 => "00000000000000",
-     688 => "00000000000000",
-     689 => "00000000000000",
-     690 => "00000000000000",
-     691 => "00000000000000",
-     692 => "00000000000000",
-     693 => "00000000000000",
-     694 => "00000000000000",
-     695 => "00000000000000",
-     696 => "00000000000000",
-     697 => "00000000000000",
-     698 => "00000000000000",
-     699 => "00000000000000",
-     700 => "00000000000000",
-     701 => "00000000000000",
-     702 => "00000000000000",
-     703 => "00000000000000",
-     704 => "00000000000000",
-     705 => "00000000000000",
-     706 => "00000000000000",
-     707 => "00000000000000",
-     708 => "00000000000000",
-     709 => "00000000000000",
-     710 => "00000000000000",
-     711 => "00000000000000",
-     712 => "00000000000000",
-     713 => "00000000000000",
-     714 => "00000000000000",
-     715 => "00000000000000",
-     716 => "00000000000000",
-     717 => "00000000000000",
-     718 => "00000000000000",
-     719 => "00000000000000",
-     720 => "00000000000000",
-     721 => "00000000000000",
-     722 => "00000000000000",
-     723 => "00000000000000",
-     724 => "00000000000000",
-     725 => "00000000000000",
-     726 => "00000000000000",
-     727 => "00000000000000",
-     728 => "00000000000000",
-     729 => "00000000000000",
-     730 => "00000000000000",
-     731 => "00000000000000",
-     732 => "00000000000000",
-     733 => "00000000000000",
-     734 => "00000000000000",
-     735 => "00000000000000",
-     736 => "00000000000000",
-     737 => "00000000000000",
-     738 => "00000000000000",
-     739 => "00000000000000",
-     740 => "00000000000000",
-     741 => "00000000000000",
-     742 => "00000000000000",
-     743 => "00000000000000",
-     744 => "00000000000000",
-     745 => "00000000000000",
-     746 => "00000000000000",
-     747 => "00000000000000",
-     748 => "00000000000000",
-     749 => "00000000000000",
-     750 => "00000000000000",
-     751 => "00000000000000",
-     752 => "00000000000000",
-     753 => "00000000000000",
-     754 => "00000000000000",
-     755 => "00000000000000",
-     756 => "00000000000000",
-     757 => "00000000000000",
-     758 => "00000000000000",
-     759 => "00000000000000",
-     760 => "00000000000000",
-     761 => "00000000000000",
-     762 => "00000000000000",
-     763 => "00000000000000",
-     764 => "00000000000000",
-     765 => "00000000000000",
-     766 => "00000000000000",
-     767 => "00000000000000",
-     768 => "00000000000000",
-     769 => "00000000000000",
-     770 => "00000000000000",
-     771 => "00000000000000",
-     772 => "00000000000000",
-     773 => "00000000000000",
-     774 => "00000000000000",
-     775 => "00000000000000",
-     776 => "00000000000000",
-     777 => "00000000000000",
-     778 => "00000000000000",
-     779 => "00000000000000",
-     780 => "00000000000000",
-     781 => "00000000000000",
-     782 => "00000000000000",
-     783 => "00000000000000",
-     784 => "00000000000000",
-     785 => "00000000000000",
-     786 => "00000000000000",
-     787 => "00000000000000",
-     788 => "00000000000000",
-     789 => "00000000000000",
-     790 => "00000000000000",
-     791 => "00000000000000",
-     792 => "00000000000000",
-     793 => "00000000000000",
-     794 => "00000000000000",
-     795 => "00000000000000",
-     796 => "00000000000000",
-     797 => "00000000000000",
-     798 => "00000000000000",
-     799 => "00000000000000",
-     800 => "00000000000000",
-     801 => "00000000000000",
-     802 => "00000000000000",
-     803 => "00000000000000",
-     804 => "00000000000000",
-     805 => "00000000000000",
-     806 => "00000000000000",
-     807 => "00000000000000",
-     808 => "00000000000000",
-     809 => "00000000000000",
-     810 => "00000000000000",
-     811 => "00000000000000",
-     812 => "00000000000000",
-     813 => "00000000000000",
-     814 => "00000000000000",
-     815 => "00000000000000",
-     816 => "00000000000000",
-     817 => "00000000000000",
-     818 => "00000000000000",
-     819 => "00000000000000",
-     820 => "00000000000000",
-     821 => "00000000000000",
-     822 => "00000000000000",
-     823 => "00000000000000",
-     824 => "00000000000000",
-     825 => "00000000000000",
-     826 => "00000000000000",
-     827 => "00000000000000",
-     828 => "00000000000000",
-     829 => "00000000000000",
-     830 => "00000000000000",
-     831 => "00000000000000",
-     832 => "00000000000000",
-     833 => "00000000000000",
-     834 => "00000000000000",
-     835 => "00000000000000",
-     836 => "00000000000000",
-     837 => "00000000000000",
-     838 => "00000000000000",
-     839 => "00000000000000",
-     840 => "00000000000000",
-     841 => "00000000000000",
-     842 => "00000000000000",
-     843 => "00000000000000",
-     844 => "00000000000000",
-     845 => "00000000000000",
-     846 => "00000000000000",
-     847 => "00000000000000",
-     848 => "00000000000000",
-     849 => "00000000000000",
-     850 => "00000000000000",
-     851 => "00000000000000",
-     852 => "00000000000000",
-     853 => "00000000000000",
-     854 => "00000000000000",
-     855 => "00000000000000",
-     856 => "00000000000000",
-     857 => "00000000000000",
-     858 => "00000000000000",
-     859 => "00000000000000",
-     860 => "00000000000000",
-     861 => "00000000000000",
-     862 => "00000000000000",
-     863 => "00000000000000",
-     864 => "00000000000000",
-     865 => "00000000000000",
-     866 => "00000000000000",
-     867 => "00000000000000",
-     868 => "00000000000000",
-     869 => "00000000000000",
-     870 => "00000000000000",
-     871 => "00000000000000",
-     872 => "00000000000000",
-     873 => "00000000000000",
-     874 => "00000000000000",
-     875 => "00000000000000",
-     876 => "00000000000000",
-     877 => "00000000000000",
-     878 => "00000000000000",
-     879 => "00000000000000",
-     880 => "00000000000000",
-     881 => "00000000000000",
-     882 => "00000000000000",
-     883 => "00000000000000",
-     884 => "00000000000000",
-     885 => "00000000000000",
-     886 => "00000000000000",
-     887 => "00000000000000",
-     888 => "00000000000000",
-     889 => "00000000000000",
-     890 => "00000000000000",
-     891 => "00000000000000",
-     892 => "00000000000000",
-     893 => "00000000000000",
-     894 => "00000000000000",
-     895 => "00000000000000",
-     896 => "00000000000000",
-     897 => "00000000000000",
-     898 => "00000000000000",
-     899 => "00000000000000",
-     900 => "00000000000000",
-     901 => "00000000000000",
-     902 => "00000000000000",
-     903 => "00000000000000",
-     904 => "00000000000000",
-     905 => "00000000000000",
-     906 => "00000000000000",
-     907 => "00000000000000",
-     908 => "00000000000000",
-     909 => "00000000000000",
-     910 => "00000000000000",
-     911 => "00000000000000",
-     912 => "00000000000000",
-     913 => "00000000000000",
-     914 => "00000000000000",
-     915 => "00000000000000",
-     916 => "00000000000000",
-     917 => "00000000000000",
-     918 => "00000000000000",
-     919 => "00000000000000",
-     920 => "00000000000000",
-     921 => "00000000000000",
-     922 => "00000000000000",
-     923 => "00000000000000",
-     924 => "00000000000000",
-     925 => "00000000000000",
-     926 => "00000000000000",
-     927 => "00000000000000",
-     928 => "00000000000000",
-     929 => "00000000000000",
-     930 => "00000000000000",
-     931 => "00000000000000",
-     932 => "00000000000000",
-     933 => "00000000000000",
-     934 => "00000000000000",
-     935 => "00000000000000",
-     936 => "00000000000000",
-     937 => "00000000000000",
-     938 => "00000000000000",
-     939 => "00000000000000",
-     940 => "00000000000000",
-     941 => "00000000000000",
-     942 => "00000000000000",
-     943 => "00000000000000",
-     944 => "00000000000000",
-     945 => "00000000000000",
-     946 => "00000000000000",
-     947 => "00000000000000",
-     948 => "00000000000000",
-     949 => "00000000000000",
-     950 => "00000000000000",
-     951 => "00000000000000",
-     952 => "00000000000000",
-     953 => "00000000000000",
-     954 => "00000000000000",
-     955 => "00000000000000",
-     956 => "00000000000000",
-     957 => "00000000000000",
-     958 => "00000000000000",
-     959 => "00000000000000",
-     960 => "00000000000000",
-     961 => "00000000000000",
-     962 => "00000000000000",
-     963 => "00000000000000",
-     964 => "00000000000000",
-     965 => "00000000000000",
-     966 => "00000000000000",
-     967 => "00000000000000",
-     968 => "00000000000000",
-     969 => "00000000000000",
-     970 => "00000000000000",
-     971 => "00000000000000",
-     972 => "00000000000000",
-     973 => "00000000000000",
-     974 => "00000000000000",
-     975 => "00000000000000",
-     976 => "00000000000000",
-     977 => "00000000000000",
-     978 => "00000000000000",
-     979 => "00000000000000",
-     980 => "00000000000000",
-     981 => "00000000000000",
-     982 => "00000000000000",
-     983 => "00000000000000",
-     984 => "00000000000000",
-     985 => "00000000000000",
-     986 => "00000000000000",
-     987 => "00000000000000",
-     988 => "00000000000000",
-     989 => "00000000000000",
-     990 => "00000000000000",
-     991 => "00000000000000",
-     992 => "00000000000000",
-     993 => "00000000000000",
-     994 => "00000000000000",
-     995 => "00000000000000",
-     996 => "00000000000000",
-     997 => "00000000000000",
-     998 => "00000000000000",
-     999 => "00000000000000",
-    1000 => "00000000000000",
-    1001 => "00000000000000",
-    1002 => "00000000000000",
-    1003 => "00000000000000",
-    1004 => "00000000000000",
-    1005 => "00000000000000",
-    1006 => "00000000000000",
-    1007 => "00000000000000",
-    1008 => "00000000000000",
-    1009 => "00000000000000",
-    1010 => "00000000000000",
-    1011 => "00000000000000",
-    1012 => "00000000000000",
-    1013 => "00000000000000",
-    1014 => "00000000000000",
-    1015 => "00000000000000",
-    1016 => "00000000000000",
-    1017 => "00000000000000",
-    1018 => "00000000000000",
-    1019 => "00000000000000",
-    1020 => "00000000000000",
-    1021 => "00000000000000",
-    1022 => "00000000000000",
-    1023 => "00000000000000" 
-  );
-begin
-  data <= rom(to_integer(unsigned(addr(9 downto 0))));
-end architecture rtl;
diff --git a/PIC/blink.c b/fw/blink.c
index 6789b0a..6789b0a 100644
--- a/PIC/blink.c
+++ b/fw/blink.c
diff --git a/fw/fib.c b/fw/fib.c
new file mode 100644
index 0000000..2ba9535
--- /dev/null
+++ b/fw/fib.c
@@ -0,0 +1,84 @@
+#include <pic16f84a.h>
+
+typedef unsigned char uint8_t;
+
+__sfr __at(0x70) UART_TX;
+__sfr __at(0x71) UART_RX;
+__sfr __at(0x72) UART_STATUS;
+
+static volatile uint8_t _d0, _d1, _d2;
+
+// Custom delay to make the output readable at 50MHz
+static void delay(void) {
+    _d0 = 0;
+    do {
+        _d1 = 0;
+        do {
+            _d2 = 0;
+            do { _d2++; } while (_d2 != 0);
+        } while (++_d1 != 50); // Increased for 50MHz visibility
+        _d0++;
+    } while (_d0 != 20);
+}
+
+static void uart_send(uint8_t byte) {
+    while (UART_STATUS & 0x01); 
+    UART_TX = byte;
+}
+
+static void uart_puts_rom(const char *s) {
+    while (*s) {
+        uart_send((uint8_t)*s);
+        s++;
+    }
+}
+
+// Simple BCD printer for 8-bit numbers
+void print_uint8(uint8_t v) {
+    uint8_t started = 0;
+    
+    // Hundreds
+    if (v >= 200) { uart_send('2'); v -= 200; started = 1; }
+    else if (v >= 100) { uart_send('1'); v -= 100; started = 1; }
+
+    // Tens
+    uint8_t tens = '0';
+    while (v >= 10) { v -= 10; tens++; }
+    if (started || tens != '0') { uart_send(tens); }
+
+    // Units
+    uart_send(v + '0');
+}
+
+void main(void) {
+    uint8_t a, b, next;
+    
+    uart_puts_rom("\x1B[2J\x1B[H"); // Clear screen, Home cursor
+    uart_puts_rom("PIC16F84A @ 50MHz Fibonacci\r\n");
+    uart_puts_rom("---------------------------\r\n");
+
+    while (1) {
+        a = 0;
+        b = 1;
+
+        while (a <= 233) { // Max 8-bit Fib is 233
+            print_uint8(a);
+            uart_puts_rom(", ");
+
+            next = a + b;
+            a = b;
+            b = next;
+
+            delay();
+            
+            // Break before overflow
+            if (a == 233) {
+                print_uint8(a);
+                break;
+            }
+        }
+        
+        uart_puts_rom("\r\nRestarting...\r\n");
+        delay();
+    }
+}
diff --git a/PIC/test_uart.c b/fw/test_uart.c
index 2656371..4e18dc5 100644
--- a/PIC/test_uart.c
+++ b/fw/test_uart.c
@@ -18,7 +18,7 @@ static void delay(void) {
             do { _d2++; } while (_d2 != 0);
         } while (++_d1 != 30);
         _d0++;
-    } while (_d0 != 116);
+    } while (_d0 != 10);
 }
 
 static void uart_send(uint8_t byte) {
@@ -36,12 +36,16 @@ static void uart_puts_rom(const char *s) {
 
 void main(void) {
     counter = 0;
-    uart_puts_rom("Hello\r\n");
+    uart_puts_rom("counter\r\n");
 
     while (1) {
         uint8_t v = counter;
         uint8_t started = 0;
 
+
+        uart_puts_rom("\r");
+		uart_puts_rom("\x1B[K");        
+
         uart_send('C');
         uart_send(':');
 
@@ -59,8 +63,6 @@ void main(void) {
         // Units (always)
         uart_send(v + '0');
 
-        uart_puts_rom("\r\n");
-
         counter++;
         delay();
     }
diff --git a/PIC/ALU.vhd b/hdl/ALU.vhd
index b7c0344..b7c0344 100644
--- a/PIC/ALU.vhd
+++ b/hdl/ALU.vhd
diff --git a/PIC/PIC.vhd b/hdl/PIC.vhd
index a31bec7..a31bec7 100644
--- a/PIC/PIC.vhd
+++ b/hdl/PIC.vhd
diff --git a/PIC/common.vhd b/hdl/common.vhd
index c986ec5..c986ec5 100644
--- a/PIC/common.vhd
+++ b/hdl/common.vhd
diff --git a/PIC/decoder.vhd b/hdl/decoder.vhd
index 5a1eb2c..5a1eb2c 100644
--- a/PIC/decoder.vhd
+++ b/hdl/decoder.vhd
diff --git a/PIC/dpram.vhd b/hdl/dpram.vhd
index 44d7adf..44d7adf 100644
--- a/PIC/dpram.vhd
+++ b/hdl/dpram.vhd
diff --git a/PIC/fifo.vhd b/hdl/fifo.vhd
index 9dd8523..9dd8523 100644
--- a/PIC/fifo.vhd
+++ b/hdl/fifo.vhd
diff --git a/PIC/hdl-prj.json b/hdl/hdl-prj.json
index b557c2b..b557c2b 100644
--- a/PIC/hdl-prj.json
+++ b/hdl/hdl-prj.json
diff --git a/PIC/hexfile_reader.vhd b/hdl/hexfile_reader.vhd
index 143a264..143a264 100644
--- a/PIC/hexfile_reader.vhd
+++ b/hdl/hexfile_reader.vhd
diff --git a/PIC/pic_top.vhd b/hdl/pic_top.vhd
index f0cb4bd..f0cb4bd 100644
--- a/PIC/pic_top.vhd
+++ b/hdl/pic_top.vhd
diff --git a/PIC/stack.vhd b/hdl/stack.vhd
index fd376c0..fd376c0 100644
--- a/PIC/stack.vhd
+++ b/hdl/stack.vhd
diff --git a/PIC/state_machine.vhd b/hdl/state_machine.vhd
index 24da581..5b1c623 100644
--- a/PIC/state_machine.vhd
+++ b/hdl/state_machine.vhd
@@ -210,6 +210,14 @@ begin
 
             if not is_phantom then
               we_status <= '1';
+              -- branch instructions complete over 2 cycles; pulse instr_ret only
+              -- on the phantom NOP cycle (below), not here
+              if instr.op /= GOTO and instr.op /= CALL and
+                 instr.op /= RETUR and instr.op /= RETLW then
+                instr_ret <= '1';
+              end if;
+            elsif not is_skip_phantom then
+              -- branch phantom NOP: this is the true end of the 2-cycle instruction
               instr_ret <= '1';
             end if;
             state <= IFetch;
diff --git a/PIC/tb_pic.vhd b/hdl/tb_pic.vhd
index 067e154..6e82ae2 100644
--- a/PIC/tb_pic.vhd
+++ b/hdl/tb_pic.vhd
@@ -8,7 +8,7 @@ end entity tb_pic;
 
 architecture behavioural of tb_pic is
   constant T_clk   : time   := 20 ns;  -- 50M
-  constant HEX_FILE : string := "program.hex";
+  constant HEX_FILE : string := "build/program.hex";
   constant SIM_CYCLES : integer := 800_000;
 
   signal clk    : std_logic := '0';
diff --git a/PIC/tb_stack.vhd b/hdl/tb_stack.vhd
index 5b386e9..5b386e9 100644
--- a/PIC/tb_stack.vhd
+++ b/hdl/tb_stack.vhd
diff --git a/PIC/uart.vhd b/hdl/uart.vhd
index a0fad93..a0fad93 100644
--- a/PIC/uart.vhd
+++ b/hdl/uart.vhd
diff --git a/test_uart.c b/test_uart.c
deleted file mode 100644
index e69de29..0000000
--- a/test_uart.c
+++ /dev/null
diff --git a/test_uart.hex b/test_uart.hex
deleted file mode 100644
index 70d8c2f..0000000
--- a/test_uart.hex
+++ /dev/null
@@ -1,50 +0,0 @@
-:020000040000FA
-:10000000000002286F309A0001309B008030000011
-:100010000000122100000000831200009D001B0858
-:100020009C0071309E0001309F00831200001C086C
-:10003000A0001D08A100FF309C07031C9D032108A0
-:10004000200403199A2804301E07A000A101A10D65
-:100050001F08A10720089A0021089B00803000009B
-:10006000000012210000000083120000A3001B0802
-:10007000A2001E089A001F089B00803000000000AC
-:1000800012210000000083120000A500A1001B083F
-:10009000A000A40002301E07A000A101A10D1F08AE
-:1000A000A10720089A0021089B0080300000000072
-:1000B00012210000000083120000A100A7001B080D
-:1000C000A600A000831200002208A6002308A700B3
-:1000D000FF30A207031CA303270826040319932853
-:1000E00024089A0025089B0080300000000033217E
-:1000F0000000000083120000A600200883120313F2
-:1001000084008313831200002118831726088312AA
-:100110000313800083120000A40A0319A50AA00A91
-:100120000319A10A62280630831200009E070318F3
-:100130009F0A1528000000009E280800B501013024
-:10014000AF006730AE008030B0002E089A002F0854
-:100150009B00300846213508AE00AF0143305E21D8
-:100160003A305E21C8302E02031CC02832305E2196
-:100170002E08B00038303007AE000130AF00CD2877
-:1001800064302E02031CCD2831305E212E08B000D1
-:100190009C303007AE000130AF003030B0000A3084
-:1001A0002E02031CDA282E08B100F6303107AE000B
-:1001B000B00ACF283008B1002F08031DE32830080B
-:1001C000303A0319E52831085E212E08AF0030309F
-:1001D0002F07AE005E210130AF007730AE008030D7
-:1001E000B0002E089A002F089B0030084621B50A5F
-:1001F000B201B301B4013408A800280AB4003408DD
-:10020000031DFB28330AA800B30028081E3A031D6B
-:10021000FA283208A800280AB200743A031DF92807
-:10022000AB280800003A03191A29803A0319242937
-:100230009B0100341A08840083131B1883170008DD
-:100240009B00840A0008080000000000412199007A
-:100250009A0F9B039B0A0000000041219800190897
-:100260009B0018080800003A03193A29803A03193C
-:10027000412900341A08840083131B1883170008CF
-:1002800008001B088A001A0882000800AC001B083E
-:10029000AB001A08AA002A089A002B089B002C0819
-:1002A0003321AD002D0803195D292D085E21AA0A0E
-:1002B0000319AB0A0319AC0A4B290800A8008312E2
-:1002C0007208A90029185F292808F000080048349E
-:1002D00065346C346C346F340D340A3400340134BA
-:1002E00000347A34013436340034013400340D34AF
-:0602F0000A340034003462
-:00000001FF