Add docs and tests for copy_special instruction. Fixes encoding issue that tests revealed.

2017-12-01 18:01:00 -08:00
parent 4eb9a54096
commit 3b1b33e0ac
6 changed files with 41 additions and 4 deletions
--- a/lib/cretonne/meta/base/instructions.py
+++ b/lib/cretonne/meta/base/instructions.py
@@ -539,7 +539,12 @@ regmove = Instruction(

 copy_special = Instruction(
        'copy_special', r"""
-        Copies a value from one special register to another. e.g. rbp -> rsp.
+        Copies the contents of ''src'' register to ''dst'' register.
+
+        This instructions copies the contents of one register to another
+        register without involving any SSA values. This is used for copying
+        special registers, e.g. copying the stack register to the frame
+        register in a function prologue.
        """,
        ins=(src, dst),
        other_side_effects=True)