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Re: [PATCH] Optimized generic expf and exp2f
- From: "Gabriel F. T. Gomes" <gabriel at inconstante dot eti dot br>
- To: Joseph Myers <joseph at codesourcery dot com>
- Cc: Szabolcs Nagy <szabolcs dot nagy at arm dot com>, GNU C Library <libc-alpha at sourceware dot org>, <nd at arm dot com>
- Date: Thu, 7 Sep 2017 10:03:41 -0300
- Subject: Re: [PATCH] Optimized generic expf and exp2f
- Authentication-results: sourceware.org; auth=none
- References: <59AED6DA.6000509@arm.com> <alpine.DEB.2.20.1709052014180.6352@digraph.polyomino.org.uk>
On Tue, 5 Sep 2017 20:45:44 +0000
Joseph Myers <joseph@codesourcery.com> wrote:
>On Tue, 5 Sep 2017, Szabolcs Nagy wrote:
>
>> +static inline int
>> +ieee_2008_issignaling (float x)
>> +{
>> + uint32_t ix = asuint (x);
>> + ix ^= 0x00400000; /* IEEE 754-2008 snan bit. */
>> + return 2 * ix > 2u * 0x7fc00000;
>> +}
>
>This doesn't seem to be used, but if you need issignaling tests in future
>functions (powf?), you need to respect HIGH_ORDER_BIT_IS_SET_FOR_SNAN from
>nan-high-order-bit.h.
Is that also valid for _Float128 (meaning that test-math-issignaling.cc
needs to check for that, as well)? It was my understanding that it isn't.