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math: Remove i386 ilogb/ilogbf/llogb/llogbf 

The new float and double implementation does not required an
extra function call and error handling uses math_err function,
which results in better performance on i386 as well.

With gcc-14 on AMD AMD Ryzen 9 5900X, master shows:

$ ./benchtests/bench-ilogb
  "ilogb": {
   "subnormal": {
    "duration": 3.68863e+09,
    "iterations": 1.72228e+08,
    "max": 89.2995,
    "min": 21.016,
    "mean": 21.4171
   },
   "normal": {
    "duration": 3.68878e+09,
    "iterations": 1.72948e+08,
    "max": 78.6065,
    "min": 21.127,
    "mean": 21.3288
   }
  }
$ ./benchtests/bench-ilogbf
  "ilogbf": {
   "subnormal": {
    "duration": 3.68835e+09,
    "iterations": 1.66716e+08,
    "max": 46.953,
    "min": 21.793,
    "mean": 22.1236
   },
   "normal": {
    "duration": 3.68784e+09,
    "iterations": 1.66168e+08,
    "max": 46.9715,
    "min": 21.904,
    "mean": 22.1935
   }
  }

While with this patch:

$ ./benchtests/bench-ilogb
  "ilogb": {
   "subnormal": {
    "duration": 3.68134e+09,
    "iterations": 4.17516e+08,
    "max": 32.5045,
    "min": 8.3245,
    "mean": 8.81723
   },
   "normal": {
    "duration": 3.6677e+09,
    "iterations": 6.79468e+08,
    "max": 50.9305,
    "min": 5.3465,
    "mean": 5.3979
   }
}
$ ./benchtests/bench-ilogbf
  "ilogbf": {
   "subnormal": {
    "duration": 3.67553e+09,
    "iterations": 5.11032e+08,
    "max": 35.927,
    "min": 7.0485,
    "mean": 7.19237
   },
   "normal": {
    "duration": 3.66877e+09,
    "iterations": 6.556e+08,
    "max": 26.3625,
    "min": 5.5315,
    "mean": 5.59605
   }
 }

Checked on i686-linux-gnu.

Reviewed-by: Wilco Dijkstra  <Wilco.Dijkstra@arm.com>
This commit is contained in:
Adhemerval Zanella 2025-04-28 16:54:49 -03:00
parent 39775f00b1
commit 7c00a20397
6 changed files with 0 additions and 90 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

41
sysdeps/i386/fpu/e_ilogb.S
View File

@ -1,41 +0,0 @@
/*
* Public domain.
*/
#include <machine/asm.h>
RCSID("$NetBSD: s_ilogb.S,v 1.5 1995/10/12 15:53:09 jtc Exp $")
ENTRY(__ieee754_ilogb)
fldl 4(%esp)
/* I added the following ugly construct because ilogb(+-Inf) is
required to return INT_MAX in ISO C99.
-- jakub@redhat.com. */
fxam /* Is NaN or +-Inf? */
fstsw %ax
movb $0x45, %dh
andb %ah, %dh
cmpb $0x05, %dh
je 1f /* Is +-Inf, jump. */
cmpb $0x40, %dh
je 2f /* Is +-0, jump. */
fxtract
pushl %eax
cfi_adjust_cfa_offset (4)
fstp %st
fistpl (%esp)
fwait
popl %eax
cfi_adjust_cfa_offset (-4)
ret
1: fstp %st
movl $0x7fffffff, %eax
ret
2: fstp %st
movl $0x80000000, %eax /* FP_ILOGB0 */
ret
END (__ieee754_ilogb)

41
sysdeps/i386/fpu/e_ilogbf.S
View File

@ -1,41 +0,0 @@
/*
* Public domain.
*/
#include <machine/asm.h>
RCSID("$NetBSD: s_ilogbf.S,v 1.4 1995/10/22 20:32:43 pk Exp $")
ENTRY(__ieee754_ilogbf)
flds 4(%esp)
/* I added the following ugly construct because ilogb(+-Inf) is
required to return INT_MAX in ISO C99.
-- jakub@redhat.com. */
fxam /* Is NaN or +-Inf? */
fstsw %ax
movb $0x45, %dh
andb %ah, %dh
cmpb $0x05, %dh
je 1f /* Is +-Inf, jump. */
cmpb $0x40, %dh
je 2f /* Is +-0, jump. */
fxtract
pushl %eax
cfi_adjust_cfa_offset (4)
fstp %st
fistpl (%esp)
fwait
popl %eax
cfi_adjust_cfa_offset (-4)
ret
1: fstp %st
movl $0x7fffffff, %eax
ret
2: fstp %st
movl $0x80000000, %eax /* FP_ILOGB0 */
ret
END (__ieee754_ilogbf)

2
sysdeps/i386/fpu/w_ilogb.c
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@ -1,2 +0,0 @@
#include <math-type-macros-double.h>
#include <w_ilogb_template.c>

2
sysdeps/i386/fpu/w_ilogbf.c
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@ -1,2 +0,0 @@
#include <math-type-macros-float.h>
#include <w_ilogb_template.c>

2
sysdeps/i386/fpu/w_llogb.c
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@ -1,2 +0,0 @@
#include <math-type-macros-double.h>
#include <w_llogb_template.c>

2
sysdeps/i386/fpu/w_llogbf.c
View File

@ -1,2 +0,0 @@
#include <math-type-macros-float.h>
#include <w_llogb_template.c>