From: Anton Blanchard <anton@ozlabs.org>
To: benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au
Cc: linuxppc-dev@lists.ozlabs.org
Subject: [PATCH] powerpc/sstep: mullw should calculate a 64 bit signed result
Date: Wed, 20 Sep 2017 09:32:19 +1000 [thread overview]
Message-ID: <20170919233219.26184-1-anton@ozlabs.org> (raw)
From: Anton Blanchard <anton@samba.org>
mullw should do a 32 bit signed multiply and create a 64 bit signed
result. It currently truncates the result to 32 bits.
Signed-off-by: Anton Blanchard <anton@samba.org>
---
arch/powerpc/lib/sstep.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index c4cda1afb49d..5e8418c28bd8 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -1651,8 +1651,9 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
goto arith_done;
case 235: /* mullw */
- op->val = (unsigned int) regs->gpr[ra] *
- (unsigned int) regs->gpr[rb];
+ op->val = (long)(int) regs->gpr[ra] *
+ (int) regs->gpr[rb];
+
goto arith_done;
case 266: /* add */
--
2.11.0
next reply other threads:[~2017-09-19 23:32 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-19 23:32 Anton Blanchard [this message]
2017-09-21 1:46 ` powerpc/sstep: mullw should calculate a 64 bit signed result Michael Ellerman
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