Minimal assembly example

README.md

@@ -164,6 +164,7 @@ The uvm32 memory size is set at compile time with `-DUVM32_MEMORY_SIZE=X` (in by
  * [host-parallel](host-parallel) parallel vm host running multiple vm instances concurrently, with baked in bytecode
  * [host-arduino](host-arduino) vm host as Arduino sketch (tested on Arduino Uno ATmega328P, uses 9950 bytes of flash/1254 bytes RAM)
  * [apps/helloworld](apps/helloworld) C hello world program
+ * [apps/hello-asm](apps/hello-asm) Minimal hello world assembly
  * [apps/fib](apps/fib) C fibonacci series program (iterative and recursive)
  * [apps/sketch](apps/sketch) C Arduino/Wiring/Processing type program in `setup()` and `loop()` style
  * [apps/rust-hello](apps/rust-hello) Rust hello world program (note, the version of rust installed by brew on mac has issues, use the official rust installer from https://rust-lang.org/learn/get-started/)

apps/Makefile

@@ -6,10 +6,12 @@ all:
 	(cd helloworld && make)
 	(cd zig-mandel && make)
 	(cd rust-hello && make)
+	(cd hello-asm && make)
 
 clean:
 	(cd sketch && make clean)
 	(cd helloworld && make clean)
 	(cd zig-mandel && make clean)
 	(cd rust-hello && make clean)
+	(cd hello-asm && make clean)
 

apps/hello-asm/Makefile

@@ -0,0 +1,27 @@
+PROJECT:=hello-asm
+
+DOCKER_IMAGE=riscv-dev
+DOCKER_CMD:=docker run --rm -v ${PWD}../../../:/data -w /data/apps/${PROJECT} ${DOCKER_IMAGE}
+PREFIX:=${DOCKER_CMD} riscv64-unknown-elf-
+CFLAGS+=-I../../common
+CFLAGS+=-fno-stack-protector
+CFLAGS+=-static-libgcc -fdata-sections -ffunction-sections
+CFLAGS+=-g -Os -march=rv32ima_zicsr -mabi=ilp32 -static
+LDFLAGS:= -T ../linker.ld -nostdlib -Wl,--gc-sections
+LIBS:= #-lgcc # needed for softfp
+
+SRCS=hello-asm.s
+
+all:
+	${PREFIX}gcc -o ${PROJECT}.elf ${CFLAGS} ${LDFLAGS} ${SRCS} ${LIBS}
+	$(PREFIX)objcopy ${PROJECT}.elf -O binary ${PROJECT}.bin
+
+disasm: all
+	$(PREFIX)objdump -S -d -f ${PROJECT}.elf
+
+test: all
+	../../host/host ${PWD}/${PROJECT}.bin
+
+clean:
+	rm -f ${PROJECT}.o ${PROJECT}.elf ${PROJECT}.bin
+

apps/hello-asm/hello-asm.s

@@ -0,0 +1,9 @@
+.section .initial_jump , "ax", %progbits
+.global _start
+_start:
+la     a5, str
+csrrw zero,0x13b,a5 # println
+csrwi 0x138,0 # halt
+str:
+.ascii "Hi"
+