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List:       qemu-ppc
Subject:    [Qemu-ppc] [PATCH 01/13] PPC: Allow Rc bit to be set on mtspr
From:       Mark Cave-Ayland <mark.cave-ayland () ilande ! co ! uk>
Date:       2015-10-23 13:56:26
Message-ID: 1445608598-24485-2-git-send-email-mark.cave-ayland () ilande ! co ! uk
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From: Alexander Graf <agraf@suse.de>

According to the ISA setting the Rc bit on mtspr is undefined behavior.
Real 750 hardware simply ignores the bit and doesn't touch cr0 though.

Unfortunately, Mac OS 9 relies on this fact and executes a few mtspr
instructions (to set XER for example) with Rc set.

So let's handle the bit the same way hardware does and ignore it.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
---
 target-ppc/translate.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/target-ppc/translate.c b/target-ppc/translate.c
index c2bc1a7..d1f0f13 100644
--- a/target-ppc/translate.c
+++ b/target-ppc/translate.c
@@ -9884,7 +9884,7 @@ GEN_HANDLER(mtcrf, 0x1F, 0x10, 0x04, 0x00000801, PPC_MISC),
 GEN_HANDLER(mtmsrd, 0x1F, 0x12, 0x05, 0x001EF801, PPC_64B),
 #endif
 GEN_HANDLER(mtmsr, 0x1F, 0x12, 0x04, 0x001FF801, PPC_MISC),
-GEN_HANDLER(mtspr, 0x1F, 0x13, 0x0E, 0x00000001, PPC_MISC),
+GEN_HANDLER(mtspr, 0x1F, 0x13, 0x0E, 0x00000000, PPC_MISC),
 GEN_HANDLER(dcbf, 0x1F, 0x16, 0x02, 0x03C00001, PPC_CACHE),
 GEN_HANDLER(dcbi, 0x1F, 0x16, 0x0E, 0x03E00001, PPC_CACHE),
 GEN_HANDLER(dcbst, 0x1F, 0x16, 0x01, 0x03E00001, PPC_CACHE),
-- 
1.7.10.4



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