initial commit

run

@@ -0,0 +1,13 @@
+#!/bin/sh
+make -s || exit
+cd build
+
+if [ "$1" = "d" ]; then
+    qemu-riscv64 -g 1234 main &
+    riscv64-linux-gnu-gdb -q \
+        -ex "target remote :1234" \
+        main
+else
+    qemu-riscv64 main
+fi
+