From d475b5b93e30562abce91a7a3405356eb3ee6f74 Mon Sep 17 00:00:00 2001
From: Michael Munday <munday@ca.ibm.com>
Date: Wed, 18 Jan 2017 15:43:24 -0500
Subject: [PATCH] Add some TODOs to the saveregs and restoreregs macros.

When unwinding the stack using the internal unwinder we may need to
restore floating point registers clobbered by C calls. Since I'm
not sure yet I'm going to be conservative and save/restore them
for now. Most probably we want to, at the very least, avoid restoring
them when cleanly exiting the interpreter.
---
 src/vm_s390x.dasc | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/vm_s390x.dasc b/src/vm_s390x.dasc
index d1cf9524..637a174b 100644
--- a/src/vm_s390x.dasc
+++ b/src/vm_s390x.dasc
@@ -104,6 +104,7 @@
 |  stmg r6, r15, SAVE_GPRS_P
 |  lay sp, -CFRAME_SPACE(sp)	// Allocate stack frame.
 |  // TODO: save backchain?
+|  // TODO: is it necessary to save all float registers?
 |  std f8, SAVE_FPR8		// f8-f15 are callee-saved.
 |  std f9, SAVE_FPR9
 |  std f10, SAVE_FPR10
@@ -115,6 +116,7 @@
 |.endmacro
 |
 |.macro restoreregs
+|  // TODO: restore float registers only when unwinding?
 |  ld f8, SAVE_FPR8		// f8-f15 are callee-saved.
 |  ld f9, SAVE_FPR9
 |  ld f10, SAVE_FPR10