Add a Makefile to easily compile examples/codegen.rs to assembly.

Author: bombela

Makefile

@@ -0,0 +1,20 @@
+# Makefile useful during development.
+# `make asm` compiles examples/codegen.rs to assembly.
+# The output can then be reviewed for correctness.
+
+NV?=nightly
+override FLAGS += -Z build-std=core -Z build-std-features=panic_immediate_abort --release
+MCU?=avr-atmega328p
+AVR_CPU_FREQUENCY_HZ?=16000000
+export AVR_CPU_FREQUENCY_HZ
+
+build:
+	cargo +$(NV) build $(FLAGS) --target=$(MCU).json -v
+	cargo +$(NV) build --example codegen $(FLAGS) --target=$(MCU).json -v
+
+asm:
+	cargo +$(NV) rustc --example codegen $(FLAGS) --target=$(MCU).json -- --emit asm
+	@echo target/$(MCU)/release/examples/*.s
+
+asmclean:
+	-rm target/*/release/deps/*.s