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Re: [PATCH] Avoid extra float->double conversion
- From: Richard Allen <rsaxvc at rsaxvc dot net>
- To: newlib at sourceware dot org
- Date: Wed, 19 Apr 2017 19:03:18 -0500
- Subject: Re: [PATCH] Avoid extra float->double conversion
- Authentication-results: sourceware.org; auth=none
- References: <CAMY0PLVpmE2_5WL2jZLq8M=Zv-EE6f7u8VE0hy1gX4T7vCYvSw@mail.gmail.com>
There were a few more spots triggering double-precision math.
Attached patch updated to include comparisons and multiplies.
On Wed, Apr 19, 2017 at 6:53 PM, Richard Allen <rsaxvc@rsaxvc.net> wrote:
> Patch avoids an unnecessary float->double
> conversion to save a small amount of codespace.
>
> -Richard
From 361abc1541b9a0f76a018a92b7e9d1e561cc35e8 Mon Sep 17 00:00:00 2001
From: Richard <rsaxvc@rsaxvc.net>
Date: Wed, 19 Apr 2017 18:37:17 -0500
Subject: [PATCH 2/2] Remove extra double-precision rounding and comparisons
Replace rint() with rintf() to avoid unnecessary
increase in precision, use float constants
to avoid doing compare, conversion, and multiplication
using doubles.
---
newlib/libm/math/wf_pow.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/newlib/libm/math/wf_pow.c b/newlib/libm/math/wf_pow.c
index bd9de0ad0..b92e47d8e 100644
--- a/newlib/libm/math/wf_pow.c
+++ b/newlib/libm/math/wf_pow.c
@@ -125,12 +125,12 @@
exc.arg2 = (double)y;
if (_LIB_VERSION == _SVID_) {
exc.retval = HUGE;
- y *= 0.5;
- if(x<0.0&&rint(y)!=y) exc.retval = -HUGE;
+ y *= 0.5f;
+ if(x<0.0f&&rintf(y)!=y) exc.retval = -HUGE;
} else {
exc.retval = HUGE_VAL;
- y *= 0.5;
- if(x<0.0&&rint(y)!=y) exc.retval = -HUGE_VAL;
+ y *= 0.5f;
+ if(x<0.0f&&rintf(y)!=y) exc.retval = -HUGE_VAL;
}
if (_LIB_VERSION == _POSIX_)
errno = ERANGE;
--
2.11.0