refactor asm more

src/compiler/arch/riscv/mod.rs

@@ -0,0 +1,13 @@
+mod asm;
+mod compile;
+mod reg;
+mod single;
+mod instr;
+
+use crate::util::BitsI32;
+use single::*;
+
+pub use asm::*;
+pub use compile::*;
+pub use reg::*;
+pub use instr::*;