[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[Qemu-devel] [PATCH 5/7] target-arm: Correct ABD's handling of negative

From: Peter Maydell
Subject: [Qemu-devel] [PATCH 5/7] target-arm: Correct ABD's handling of negative zeroes
Date: Fri, 11 Mar 2011 18:12:24 +0000

Implement ABD by taking the absolute value of the difference
of the operands (as the ARM ARM specifies) rather than by
flipping the order of the operands to the subtract based
on the results of a comparison. The latter approch gives
the wrong answers for some edge cases like negative zero.

Signed-off-by: Peter Maydell <address@hidden>
 target-arm/neon_helper.c |    4 +---
 1 files changed, 1 insertions(+), 3 deletions(-)

diff --git a/target-arm/neon_helper.c b/target-arm/neon_helper.c
index 8eb4cef..1905545 100644
--- a/target-arm/neon_helper.c
+++ b/target-arm/neon_helper.c
@@ -1788,9 +1788,7 @@ uint32_t HELPER(neon_abd_f32)(CPUState *env, uint32_t a, 
uint32_t b)
     float32 f0 = make_float32(a);
     float32 f1 = make_float32(b);
-    return float32_val((float32_compare_quiet(f0, f1, NFS) == 1)
-                    ? float32_sub(f0, f1, NFS)
-                    : float32_sub(f1, f0, NFS));
+    return float32_val(float32_abs(float32_sub(f0, f1, NFS)));
 uint32_t HELPER(neon_add_f32)(CPUState *env, uint32_t a, uint32_t b)

reply via email to

[Prev in Thread] Current Thread [Next in Thread]