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Re: [PATCH] Improves __ieee754_exp() performance by greater than 5x on sparc/x86.
- From: Joseph Myers <joseph at codesourcery dot com>
- To: Patrick McGehearty <patrick dot mcgehearty at oracle dot com>
- Cc: <libc-alpha at sourceware dot org>
- Date: Tue, 5 Dec 2017 23:19:52 +0000
- Subject: Re: [PATCH] Improves __ieee754_exp() performance by greater than 5x on sparc/x86.
- Authentication-results: sourceware.org; auth=none
- References: <email@example.com>
On Mon, 4 Dec 2017, Patrick McGehearty wrote:
> +/* ln2_32hi2 = high 32 bits of log(1./2.)/2. */
> + ln2_32hi2 = 0x1.62e42fee00000p-7,
> +/* ln2_32lo2 = low 32 bits of log(1./2.)/2. */
> + ln2_32lo2 = 0x1.a39ef35793c76p-39,
Those comments aren't accurate descriptions. In this patch version these
have changed to be high and low parts of log(2)/64, so the comments should
reflect that - and the name should be changed to say 64 not 32 and the
users updated accordingly. Furthermore, the low part isn't just a low 32
bits, it has more than that, so again the comment should reflect that.
OK with those fixes.
Joseph S. Myers