From 3cb5684d95cb245463cf5e72b3ccc5731eb44246 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Wed, 25 Dec 2019 19:49:20 -0500
Subject: [PATCH] Fixes RTR: the whole top half of the SR should be preserved.

Specifically, the 68000 Reference Manual says: "The supervisor portion of the status register is unaffected." Clearly when I first read that I misread it as the supervisor _flag_ (rather than _portion_) should be preserved.
---
 Processors/68000/Implementation/68000Implementation.hpp | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/Processors/68000/Implementation/68000Implementation.hpp b/Processors/68000/Implementation/68000Implementation.hpp
index d8a23b6d4..c05bb97fa 100644
--- a/Processors/68000/Implementation/68000Implementation.hpp
+++ b/Processors/68000/Implementation/68000Implementation.hpp
@@ -1854,11 +1854,11 @@ template <class T, bool dtack_is_implicit, bool signal_will_perform> void Proces
 									RTE and RTR share an implementation.
 								*/
 								case Operation::RTE_RTR:
-									// If this is RTR, patch out the is_supervisor bit.
+									// If this is RTR, patch out the supervisor half of the status register.
 									if(decoded_instruction_.full == 0x4e77) {
-										source_bus_data_[0].full =
-											(source_bus_data_[0].full & uint32_t(~(1 << 13))) |
-											uint32_t(is_supervisor_ << 13);
+										const auto current_status = get_status();
+										source_bus_data_[0].halves.low.halves.high =
+											uint8_t(current_status >> 8);
 									}
 									set_status(source_bus_data_[0].full);
 								break;