add cycle[h].rs, instret[h].rs, and mcounteren.rs modules

update mod.rs

Author: dkhayes117

src/register/cycle.rs

@@ -0,0 +1,6 @@
+//! cycle register
+//! Shadow of mcycle register that can be read in user mode
+//! must have mcounteren::cy bit enabled for user mode access
+
+read_csr_as_usize!(0xC00, __read_cycle);
+read_composite_csr!(super::cycleh::read(), read());

src/register/cycleh.rs

@@ -0,0 +1,5 @@
+//! cycleh register
+//! Shadow of mcycleh register that can be read in user mode
+//! must have mcounteren::cy bit enabled for user mode access
+
+read_csr_as_usize_rv32!(0xC80, __read_cycleh);

src/register/instret.rs

@@ -0,0 +1,6 @@
+//! instret register
+//! shadow of minstret register for user mode
+//! mcounteren::ir must be enabled to use in user mode
+
+read_csr_as_usize!(0xC02, __read_instret);
+read_composite_csr!(super::instreth::read(), read());

src/register/instreth.rs

@@ -0,0 +1,5 @@
+//! instreth register
+//! shadow of minstreth register for user mode
+//! mcounteren::ir must be enabled to use in user mode
+
+read_csr_as_usize!(0xC82, __read_instreth);