Merge pull request #257 from riscv/comment

Comment riscv_set_register, register_write_direct

src/target/riscv/riscv-013.c

@@ -1056,6 +1056,10 @@ static unsigned register_size(struct target *target, unsigned number)
 		return riscv_xlen(target);
 }
 
+/**
+ * Immediately write the new value to the requested register. This mechanism
+ * bypasses any caches.
+ */
 static int register_write_direct(struct target *target, unsigned number,
 		uint64_t value)
 {

src/target/riscv/riscv.c

@@ -1770,6 +1770,10 @@ bool riscv_has_register(struct target *target, int hartid, int regid)
 	return 1;
 }
 
+/**
+ * This function is called when the debug user wants to change the value of a
+ * register. The new value may be cached, and may not be written until the hart
+ * is resumed. */
 int riscv_set_register(struct target *target, enum gdb_regno r, riscv_reg_t v)
 {
 	return riscv_set_register_on_hart(target, riscv_current_hartid(target), r, v);