[PATCH 0/2] Minor updates to the new math code

[PATCH 0/2] Minor updates to the new math code

[Szabolcs Nagy]

Further issues caught while testing the same code for glibc.
The generated code should not change on any targets.
Tested on aarch64.

Szabolcs Nagy (2):
   Fix the documentation comments for log_inline in pow
   Remove float compare option from sincosf

  newlib/libm/common/pow.c     |  6 +++---
  newlib/libm/common/sincosf.h | 11 +----------
  2 files changed, 4 insertions(+), 13 deletions(-)

-- 
2.14.1

[PATCH 1/2] Fix the documentation comments for log_inline in pow

[Szabolcs Nagy]

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From 3d8215160f71affa1a5a0977cac79e0aba33e868 Mon Sep 17 00:00:00 2001
From: Szabolcs Nagy <szabolcs.nagy@arm.com>
Date: Tue, 10 Jul 2018 17:13:27 +0100
Subject: [PATCH 1/2] Fix the documentation comments for log_inline in pow

There was a typo and the arguments were not explained clearly.
---
 newlib/libm/common/pow.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/newlib/libm/common/pow.c b/newlib/libm/common/pow.c
index a5504e5e9..e02817ec2 100644
--- a/newlib/libm/common/pow.c
+++ b/newlib/libm/common/pow.c
@@ -53,9 +53,9 @@ top12 (double x)
   return asuint64 (x) >> 52;
 }
 
-/* Compute y+tail = log(x) where the rounded result is y and tail has about
-   additional 15 bits precision.  The bit representation of x if in ix, but
-   normalized in the subnormal range using sign bit too for the exponent.  */
+/* Compute y+TAIL = log(x) where the rounded result is y and TAIL has about
+   additional 15 bits precision.  IX is the bit representation of x, but
+   normalized in the subnormal range using the sign bit for the exponent.  */
 static inline double_t
 log_inline (uint64_t ix, double_t *tail)
 {
-- 
2.14.1

[PATCH 2/2] Remove float compare option from sincosf

[Szabolcs Nagy]

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From 82d80802dd01b6cbbf361c027e1af02e626bd5bd Mon Sep 17 00:00:00 2001
From: Szabolcs Nagy <szabolcs.nagy@arm.com>
Date: Tue, 10 Jul 2018 17:14:32 +0100
Subject: [PATCH 2/2] Remove float compare option from sincosf

PREFER_FLOAT_COMPARISON setting was not correct as it could raise
spurious exceptions.  Fixing it is easy: just use ISLESS(x, y) instead
of abstop12(x) < abstop12(y) with appropriate non-signaling definition
for ISLESS.  However it seems this setting is not very useful (there is
only minor performance difference on various architectures), so remove
this option for now.
---
 newlib/libm/common/sincosf.h | 11 +----------
 1 file changed, 1 insertion(+), 10 deletions(-)

diff --git a/newlib/libm/common/sincosf.h b/newlib/libm/common/sincosf.h
index 27f24ffe3..3cac8e88f 100644
--- a/newlib/libm/common/sincosf.h
+++ b/newlib/libm/common/sincosf.h
@@ -43,21 +43,12 @@ extern const sincos_t __sincosf_table[2] HIDDEN;
 
 extern const uint32_t __inv_pio4[] HIDDEN;
 
-/* abstop12 assumes floating point reinterpret is fast by default.
-   If floating point comparisons are faster, define PREFER_FLOAT_COMPARISON.  */
-#if PREFER_FLOAT_COMPARISON
-static inline float
-abstop12 (float x)
-{
-  return fabsf (x);
-}
-#else
+/* Top 12 bits of the float representation with the sign bit cleared.  */
 static inline uint32_t
 abstop12 (float x)
 {
   return (asuint (x) >> 20) & 0x7ff;
 }
-#endif
 
 /* Compute the sine and cosine of inputs X and X2 (X squared), using the
    polynomial P and store the results in SINP and COSP.  N is the quadrant,
-- 
2.14.1

Re: [PATCH 0/2] Minor updates to the new math code

[Corinna Vinschen]

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On Jul 11 11:10, Szabolcs Nagy wrote:
> Further issues caught while testing the same code for glibc.
> The generated code should not change on any targets.
> Tested on aarch64.
> 
> Szabolcs Nagy (2):
>   Fix the documentation comments for log_inline in pow
>   Remove float compare option from sincosf
> 
>  newlib/libm/common/pow.c     |  6 +++---
>  newlib/libm/common/sincosf.h | 11 +----------
>  2 files changed, 4 insertions(+), 13 deletions(-)
> 
> -- 
> 2.14.1

Pushed.


Thanks,
Corinna

-- 
Corinna Vinschen
Cygwin Maintainer
Red Hat

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