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List:       qemu-ppc
Subject:    [Qemu-ppc] [PULL 11/19] target/ppc: Set float_tininess_before_rounding at cpu reset
From:       David Gibson <david () gibson ! dropbear ! id ! au>
Date:       2019-08-29 6:08:19
Message-ID: 20190829060827.25731-12-david () gibson ! dropbear ! id ! au
[Download RAW message or body]

From: Richard Henderson <richard.henderson@linaro.org>

As defined in Power 3.0 section 4.4.4 "Underflow Exception",
a tiny result is detected before rounding.

Fixes: https://bugs.launchpad.net/qemu/+bug/1841491
Reported-by: Paul Clarke <pc@us.ibm.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20190827020013.27154-1-richard.henderson@linaro.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 target/ppc/translate_init.inc.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/target/ppc/translate_init.inc.c b/target/ppc/translate_init.inc.c
index 4a21ed7289..023138c2f9 100644
--- a/target/ppc/translate_init.inc.c
+++ b/target/ppc/translate_init.inc.c
@@ -10461,6 +10461,10 @@ static void ppc_cpu_reset(CPUState *s)
     s->exception_index = POWERPC_EXCP_NONE;
     env->error_code = 0;
 
+    /* tininess for underflow is detected before rounding */
+    set_float_detect_tininess(float_tininess_before_rounding,
+                              &env->fp_status);
+
     for (i = 0; i < ARRAY_SIZE(env->spr_cb); i++) {
         ppc_spr_t *spr = &env->spr_cb[i];
 
-- 
2.21.0



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