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authorUlrich Drepper <drepper@redhat.com>1997-03-16 20:28:07 +0000
committerUlrich Drepper <drepper@redhat.com>1997-03-16 20:28:07 +0000
commit0d8733c4fc3695c7987548d10c344445f3eb552d (patch)
tree4a2fe41c465963794a6f9d4d1717494972336e14 /sysdeps/libm-i387/e_powf.S
parent1ed4222e5724ce863a95c15eb530dfab7ef0451c (diff)
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1997-03-16 18:43  Ulrich Drepper  <drepper@cygnus.com>

	* manual/filesys.texi: Add documentation for scandir and alphasort.

	* math/math.c (fpclassify): Correct stupid typos.

	* math/libm-test.c: New file.  libm test suite by Andreas Jaeger.

	* nss/nss_files/files-hosts.c: Add gethostbyname2 imlementation.

	* posix/Makefile (routines): Add bsd-getpgrp.
	* posix/bsd-getpgrp.c: New file.
	* posix/unistd.h [__FAVOR_BSD]: Define macro getpgrp which maps
	calls to __bsd_getpgrp.

	* sysdeps/generic/getpgrp.c: De-ANSI-declfy.

	* sysdeps/i386/huge_val.h: New file.  ix87 specific infinity values.
	* sysdeps/m68k/huge_val.h: New file.  m68k specific infinity values.
	* sysdeps/generic/huge_val.h: Remove definition of long double
	definition.  Make it the same as the double definition.

	* sysdeps/libm-i387/e_acos.S: Fix bug in FPU stack handling.
	* sysdeps/libm-i387/e_acosf.S: Likewise.
	* sysdeps/libm-i387/e_acosl.S: Likewise.
	* sysdeps/libm-i387/e_asin.S: Likewise.
	* sysdeps/libm-i387/e_asinf.S: Likewise.
	* sysdeps/libm-i387/e_asinl.S: Likewise.
	* sysdeps/libm-i387/e_exp.S: Likewise.
	* sysdeps/libm-i387/e_expf.S: Likewise.
	* sysdeps/libm-i387/e_expl.S: Likewise.
	* sysdeps/libm-i387/e_scalbn.S: Likewise.
	* sysdeps/libm-i387/e_scalbnf.S: Likewise.
	* sysdeps/libm-i387/e_scalbnl.S: Likewise.

	* sysdeps/libm-i387/e_log.S: Optimize branch code.
	* sysdeps/libm-i387/e_logf.S: Likewise.
	* sysdeps/libm-i387/e_logl.S: Likewise.
	* sysdeps/libm-i387/e_log10.S: Likewise.
	* sysdeps/libm-i387/e_log10f.S: Likewise.
	* sysdeps/libm-i387/e_log10l.S: Likewise.

	* sysdeps/libm-i387/e_pow.S: Major rewrite to handle special cases.
	* sysdeps/libm-i387/e_powf.S: Likewise.
	* sysdeps/libm-i387/e_powl.S: Likewise.

	* sysdeps/libm-i387/e_expm1.S: Change return value for -inf
	argument to -1.0.
	* sysdeps/libm-i387/e_expm1f.S: Likewise.
	* sysdeps/libm-i387/e_expm1l.S: Likewise.

	* sysdeps/libm-i387/e_isinfl.c: Return -1 for -inf.

	* sysdeps/libm-i387/e_logbl.S: Correct return value.  Discard first
	stack element after fxtract.

	* sysdeps/libm-ieee754/e_atan2l.c: New file.  `long double'
	implementation for atan2 function.

	* sysdeps/libm-ieee754/k_standard.c: Return NAN for libm not in
	_SVID_ mode when acos, asin, atan2, log, log10 is called with
	argument out of range.
	Add new error case for pow(+0,neg).

	* sysdeps/libm-ieee754/s_fpclassifyf.c: Correct recognition of
	NaN and +-inf.
	* sysdeps/libm-ieee754/s_fpclassifyl.c: Mask out explicit leading
	digit in stupid 80 bit formats.

	* sysdeps/libm-ieee754/s_isinf.c: Rewrite to return -1 for -inf.
	* sysdeps/libm-ieee754/s_isinff.c: Likewise.
	* sysdeps/libm-ieee754/s_isinfl.c: Likewise.

	* sysdeps/libm-ieee754/s_scalbnl.c (huge, tiny): Adapt values for
	long double type.

	* sysdeps/libm-ieee754/w_atan2.c: Do not raise exception expect when
	in SVID mode.
	* sysdeps/libm-ieee754/w_atan2f.c: Likewise.
	* sysdeps/libm-ieee754/w_atan2l.c: Likewise.

	* sysdeps/libm-ieee754/w_pow.c: Distinguish error cases for x is +0
	or -0.

	* sysdeps/posix/isfdtype.c: Add cast to prevent warning.

	* sysdeps/stub/fcntlbits.h: Update copyright.
	* sysdeps/unix/bsd/fcntlbits.h: Likewise.
	* sysdeps/unix/bsd/bsd4.4/fcntlbits.h: Likewise.
	* sysdeps/unix/bsd/sun/sunos4/fcntlbits.h: Likewise.
	* sysdeps/unix/bsd/ultrix4/fcntlbits.h: Likewise.
	* sysdeps/unix/common/fcntlbits.h: Likewise.
	* sysdeps/unix/sysv/fcntlbits.h: Likewise.  Define O_FSYNC as alias
	of O_SYNC.  Add BSD compatibility macros FAPPEND, FFSYNC, FNONBLOCK,
	and FNDELAY.
	* sysdeps/unix/sysv/irix4/fcntlbits.h: Likewise.

	* sysdeps/unix/readdir_r.c: Don't copy whole `struct dirent' record,
	only reclen bytes.

	* sysdeps/unix/sysv/linux/fcntlbits.h [__USE_GNU]: Add O_READ, O_WRITE
	and O_NORW.
	* sysdeps/unix/sysv/linux/alpha/fcntlbits.h: Likewise.

	* sysdeps/unix/sysv/linux/init-first.h: Add copyright.

	* sysdeps/unix/sysv/linux/fxstat.c: New file.  Rewrite kernel-level
	struct stat to user-level form.
	* sysdeps/unix/sysv/linux/lxstat: New file.
	* sysdeps/unix/sysv/linux/xstat: New file.
	* sysdeps/unix/sysv/linux/kernel_stat.h: Define struct stat used in
	kernel.
	* sysdeps/unix/sysv/linux/statbuf.h (struct stat): Change definition
	to use prescribed types for elements.
	(_STAT_VER): Change to value 3.
	* sysdeps/unix/sysv/linux/alph/statbuf.h: Likewise.
	* sysdeps/unix/sysv/linux/Dist: Add kernel_stat.h.
	* sysdeps/unix/sysv/linux/alpha/Dist: Likewise.

	* time/Makefile: Correct dependencies for test-tz.

1997-03-16 14:59  Philip Blundell  <phil@london.uk.eu.org>

	* resolv/netdb.h: Add prototypes for gai_strerror and getnameinfo
	(needed for IPv6 basic sockets API).

1997-03-16 15:02  a sun  <asun@zoology.washington.edu>

	* sysdeps/unix/sysv/linux/net/if_ppp.h: Don't use incompatible
	kernel header.
	* sysdeps/unix/sysv/linux/net/ppp_defs.h: Likewise.

1997-03-14 17:15  Ulrich Drepper  <drepper@cygnus.com>

	* db/hash/hash_bigkey.c (__big_delete): Don't call __free_ovflpage
	without testing for last_bfp to be NULL.
	Reported by fabsoft@fabserver1.zarm.uni-bremen.de.

1997-03-13 11:42  Jim Meyering  <meyering@asic.sc.ti.com>

	* time/mktime.c (TIME_T_MIN): Work around a bug in Cray C 5.0.3.0.

1997-03-14 04:00  Kurt Garloff  <garloff@kg1.ping.de>

	* sysdeps/unix/sysv/linux/fcntlbits.h (O_FSYNC): Make alias for O_SYNC.
	(FASYNC): Move to __USE_BSD section.  Create new macro O_ASYNC.

1997-03-14 02:50  Ulrich Drepper  <drepper@cygnus.com>

	* nis/nss_nis/nis-hosts.c (_nss_nis_gethostbyname2_r): New
	functions.  Compare result for correct address type.
	(_nss_nis_gethostbyname_r): Use _nss_nis_gethostbyname2_r.
	Reported by Mirko Streckenbach <mirko@marian.hil.de>.

1997-02-17 01:40  Zlatko Calusic  <zcalusic@srce.hr>

	* time/strptime.c (recursive): Return rp to caller.
	(strptime_internal): First check for long names, then abbreviated
	(month & weekday).

1997-03-10 19:44  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* Makeconfig: Remove useless definitions of ASFLAGS-%.
	* config.make.in (ASFLAGS-.so): Remove.
	* configure.in: Don't substitute ASFLAGS_SO.
	* sysdeps/sparc/configure.in: Remove file.
	* sysdeps/sparc/Makefile (ASFLAGS-.so): Define.

1997-03-11 17:00  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* time/strptime.c (strptime_internal) [case 'Y']: Always subtract
	1900 from year, regardless of century.

1997-03-12 05:43  Ulrich Drepper  <drepper@cygnus.com>

	* stdlib/strtod.c (_tens_in_limb) [BITS_PER_MP_LIMB > 32]: Make
	all numbers unsigned to make buggy gccs happy.
	Patch by Bryan W. Headley <bheadley@interaccess.com>.

	* sysdeps/unix/sysv/linux/netinet/ip.h: Add backward-compatibility
	definitions.  Patch by a sun <asun@zoology.washington.edu>.
	Pretty print header.

	* Makerules (build-shlib): Also create symlink if library is versioned.
	based on a patch by H.J. Lu <hjl@gnu.ai.mit.edu>.
	Remove special rule to libc.so symlink.

1997-03-11 20:16  Andreas Jaeger  <aj@arthur.pfalz.de>

	* manual/math.texi (Domain and Range Errors): Change descriptions
	according to recent changes for ISO C 9X.

1997-03-11 22:39  Ulrich Drepper  <drepper@cygnus.com>

	* sysdeps/libm-ieee754/k_standard.c (__kernel_standard): Correct
	return values for acos, asin, and atan2.
	Reported by Andreas Jaeger <aj@arthur.pfalz.de>.

1997-03-10 18:16 Thorsten Kukuk  <kukuk@vt.uni-paderborn.de>

	* ypclnt.c (__yp_bind): Fix possible buffer overflow.

1997-03-10 18:06  Bernd Schmidt  <crux@Pool.Informatik.RWTH-Aachen.DE>

	* dirent/alphasort.c (alphasort): Interpret arguments as pointers
	to pointers to directory entries so that alphasort really can be
	used as argument for scandir.

1997-03-09 23:33  Andreas Jaeger  <aj@arthur.pfalz.de>

	* string/strdup.c: Declare memcpy if !(_LIBC || STDC_HEADERS)
	instead of strcpy.

1997-03-10 03:34  Ulrich Drepper  <drepper@cygnus.com>

	* catgets/catgets.c (catopen): Always add NLSPATH to search path for
	catalogs, not only if the envvar NLSPATH is not available.
	Reported by Andries.Brouwer@cwi.nl.

1997-03-10 02:46  Ulrich Drepper  <drepper@cygnus.com>

	* Makeconfig (localtime-file): Don't define using installation
	directory.
	(inst_localtime-file): New variable.
	* time/Makefile (installed-localtime-file): Use inst_localtime-file.
	Reported by Edward Seidl <seidl@janed.com>.

1997-03-10 02:31  H.J. Lu  <hjl@gnu.ai.mit.edu>

	* time/Makefile: Add source files to dependencies for test data.

1997-03-09 22:53  Thorsten Kukuk  <kukuk@weber.uni-paderborn.de>

	* nis/nss_nis/nis-ethers.c: Don't ignore return value of yp_all.
	* nis/nss_nis/nis-proto.c: Likewise.
	* nis/nss_nis/nis-rpc.c: Likewise.
	* nis/nss_nis/nis-service.c: Likewise.

1997-03-08 14:37  Miguel de Icaza  <miguel@nuclecu.unam.mx>

	* sysdeps/sparc/dl-machine.h (elf_machine_rela): Upgrade to
	versioning;  Added missing R_SPARC_WDISP30 handling.
	(RTLD_START): Implement it.

	* sysdeps/unix/sysv/linux/sparc/brk.c: Fix.

	* sysdeps/unix/sysv/linux/sparc/start.c: Startup code for
	Linux/SPARC.

1997-03-02 18:06  Miguel de Icaza  <miguel@nuclecu.unam.mx>

	* sysdeps/sparc/dl-machine.h (RTLD_START): Make arg as expected by
	the dynamic linker instead of having a new conditional define.
	Thanks to Richard Henderson for pointing this out.
	* elf/rtld.c: Remove usage of ELF_ADJUST_ARG.

1997-03-20 20:44  Thomas Bushnell, n/BSG  <thomas@gnu.ai.mit.edu>

	* sysdeps/mach/hurd/euidaccess.c: Define as __euidaccess and make
	euidaccess weak alias.

1997-03-07 10:30  Thomas Bushnell, n/BSG  <thomas@gnu.ai.mit.edu>

	* stdio-common/printf_fphex.c (MIN): New macro.

	* sysdeps/generic/netinet/in.h: Include <sys/types.h>.

	* sysdeps/generic/sys/mman.h (msync): Mention third arg.

	* sysdeps/generic/netinet/in.h: Add definitions for IPv6 basic
	API.  (See change by Philip Blundell on Feb 16, 1997.)

1997-03-05 10:40  Thomas Bushnell, n/BSG  <thomas@gnu.ai.mit.edu>

	* hurd/hurd.h (vpprintf): Include <stdarg.h>.  New declaration.

	* hurd/set-host.c (_hurd_set_host_config): Cast second arg to
	__file_name_split.

	* mach/mach_error.c (mach_error_string_int): Give full prototype.
	* mach/errstring.c (mach_error_string_int): Likewise.
	* mach/error_compat.c (__mach_error_map_compat): Likewise.
	* hurd/vpprintf.c (pwrite, vpprintf): Likewise.
	* stdio/vasprintf.c (vasprintf): Likewise.

	* mach/mach/mach_traps.h: Include <mach/kern_return.h>.

	* mach/spin-solid.c: Include <mach/mach_traps.h>.
	* mach/spin-solid.c (__spin_lock_solid): Provide arg to
	swtch_pri.

	* mach/mach_init.c: Include <mach/mig_support.h>.

	* mach/mach_error.h (mach_error_string, mach_error,
	mach_error_type): Always provide prototypes.

	* mach/mach/error.h (mach_error_fn_t): Comment out declaration; it
	appears to be entirely unused dead code.

	* stdio/stdio.h (freopen): Fix spelling error.

1997-03-02 13:38  Miles Bader  <miles@gnu.ai.mit.edu>

	* string/argz.h (__need_error_t): New macro, before including <errno.h>
	[!__const] (__const): New macro.
	[!__error_t_defined] (error_t): New typedef.

	* sysdeps/generic/socketbits.h: Add PF_FILE as synonym for PF_LOCAL
	* sysdeps/unix/sysv/linux/socketbits.h: Likewise.
Diffstat (limited to 'sysdeps/libm-i387/e_powf.S')
-rw-r--r--sysdeps/libm-i387/e_powf.S230
1 files changed, 211 insertions, 19 deletions
diff --git a/sysdeps/libm-i387/e_powf.S b/sysdeps/libm-i387/e_powf.S
index 9d6bc510b6..54af93c961 100644
--- a/sysdeps/libm-i387/e_powf.S
+++ b/sysdeps/libm-i387/e_powf.S
@@ -1,5 +1,5 @@
 /* ix87 specific implementation of pow function.
-   Copyright (C) 1996 Free Software Foundation, Inc.
+   Copyright (C) 1996, 1997 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
 
@@ -27,67 +27,107 @@
 #endif
 
 	.align ALIGNARG(4)
+	ASM_TYPE_DIRECTIVE(infinity,@object)
+inf_zero:
+infinity:
+	.byte 0, 0, 0, 0, 0, 0, 0xf0, 0x7f
+	ASM_SIZE_DIRECTIVE(infinity)
+	ASM_TYPE_DIRECTIVE(zero,@object)
+zero:	.double 0.0
+	ASM_SIZE_DIRECTIVE(zero)
+	ASM_TYPE_DIRECTIVE(minf_mzero,@object)
+minf_mzero:
+minfinity:
+	.byte 0, 0, 0, 0, 0, 0, 0xf0, 0xff
+mzero:
+	.byte 0, 0, 0, 0, 0, 0, 0, 0x80
+	ASM_SIZE_DIRECTIVE(minf_mzero)
 	ASM_TYPE_DIRECTIVE(one,@object)
 one:	.double 1.0
 	ASM_SIZE_DIRECTIVE(one)
 	ASM_TYPE_DIRECTIVE(limit,@object)
 limit:	.double 0.29
 	ASM_SIZE_DIRECTIVE(limit)
+	ASM_TYPE_DIRECTIVE(nan,@object)
+nan:	.byte 0, 0, 0, 0, 0, 0, 0xff, 0x7f
+	ASM_SIZE_DIRECTIVE(nan)
 
 #ifdef PIC
 #define MO(op) op##@GOTOFF(%ecx)
+#define MOX(op,x,f) op##@GOTOFF(%ecx,x,f)
 #else
 #define MO(op) op
+#define MOX(op,x,f) op(,x,f)
 #endif
 
 	.text
 ENTRY(__ieee754_powf)
-	flds	4(%esp)		// x
-	flds	8(%esp)		// y : x
+	flds	8(%esp)	// y
+	fxam
+	fnstsw
+	movb	%ah, %dl
+	andb	$0x45, %ah
+	cmpb	$0x40, %ah	// is y == 0 ?
+	je	11f
+
+	cmpb	$0x05, %ah	// is y == ±inf ?
+	je	12f
+
+	cmpb	$0x01, %ah	// is y == NaN ?
+	je	30f
 
 #ifdef	PIC
 	call	1f
 1:	popl	%ecx
 	addl	$_GLOBAL_OFFSET_TABLE_+[.-1b], %ecx
 #endif
-	subl	$8,%esp
+
+	flds	4(%esp)		// x : y
+
+	subl	$4, %esp
+
+	fxam
+	fnstsw
+	movb	%ah, %dh
+	andb	$0x45, %ah
+	cmpb	$0x40, %ah
+	je	20f		// x is ±0
+
+	cmpb	$0x05, %ah
+	je	15f		// x is ±inf
+
+	fxch			// y : x
 
 	/* First see whether `y' is a natural number.  In this case we
 	   can use a more precise algorithm.  */
 	fld	%st		// y : y : x
-	fistpll	(%esp)		// y : x
-	fildll	(%esp)		// int(y) : y : x
+	fistpl	(%esp)		// y : x
+	fildl	(%esp)		// int(y) : y : x
 	fucomp	%st(1)		// y : x
 	fnstsw
 	sahf
 	jne	2f
 
 	/* OK, we have an integer value for y.  */
-	ftst			// y : x
-	fstp	%st(0)		// x
-	fnstsw
-	sahf
-	popl	%eax
 	popl	%edx
-	jnc	4f		// y >= 0, jump
+	orl	$0, %edx
+	fstp	%st(0)		// x
+	jns	4f		// y >= 0, jump
 	fdivrl	MO(one)		// 1/x		(now referred to as x)
-	negl	%eax
-	adcl	$0, %edx
 	negl	%edx
 4:	fldl	MO(one)		// 1 : x
 	fxch
 
-6:	shrdl	$1, %edx, %eax
+6:	shrl	$1, %edx
 	jnc	5f
 	fxch
 	fmul	%st(1)		// x : ST*x
 	fxch
 5:	fmul	%st(0), %st	// x*x : ST*x
-	movl	%eax, %ecx
-	orl	%edx, %ecx
+	testl	%edx, %edx
 	jnz	6b
 	fstp	%st(0)		// ST*x
-	ret
+30:	ret
 
 	.align ALIGNARG(4)
 2:	/* y is a real number.  */
@@ -114,7 +154,159 @@ ENTRY(__ieee754_powf)
 	f2xm1			// 2^fract(y*log2(x))-1 : int(y*log2(x))
 	faddl	MO(one)		// 2^fract(y*log2(x)) : int(y*log2(x))
 	fscale			// 2^fract(y*log2(x))*2^int(y*log2(x)) : int(y*log2(x))
-	addl	$8, %esp
+	addl	$4, %esp
 	fstp	%st(1)		// 2^fract(y*log2(x))*2^int(y*log2(x))
 	ret
+
+
+	// pow(x,±0) = 1
+	.align ALIGNARG(4)
+11:	fstp	%st(0)		// pop y
+	fldl	MO(one)
+	ret
+
+	// y == ±inf
+	.align ALIGNARG(4)
+12:	fstp	%st(0)		// pop y
+	flds	4(%esp)		// x
+	fabs
+	fcompl	MO(one)		// < 1, == 1, or > 1
+	fnstsw
+	andb	$0x45, %ah
+	cmpb	$0x45, %ah
+	je	13f		// jump if x is NaN
+
+	cmpb	$0x40, %ah
+	je	14f		// jump if |x| == 1
+
+	shlb	$1, %ah
+	xorb	%ah, %dl
+	andl	$2, %edx
+	fldl	MOX(inf_zero, %edx, 4)
+	ret
+
+	.align ALIGNARG(4)
+14:	fldl	MO(nan)
+	faddl	MO(zero)	// raise invalid exception
+	ret
+
+	.align ALIGNARG(4)
+13:	flds	4(%esp)		// load x == NaN
+	ret
+
+	.align ALIGNARG(4)
+	// x is ±inf
+15:	fstp	%st(0)		// y
+	testb	$2, %dh
+	jz	16f		// jump if x == +inf
+
+	// We must find out whether y is an odd integer.
+	fld	%st		// y : y
+	fistpl	(%esp)		// y
+	fildl	(%esp)		// int(y) : y
+	fucompp			// <empty>
+	fnstsw
+	sahf
+	jne	17f
+
+	// OK, the value is an integer, but is the number of bits small
+	// enough so that all are coming from the mantissa?
+	popl	%edx
+	testb	$1, %dl
+	jz	18f		// jump if not odd
+	movl	%edx, %eax
+	orl	%edx, %edx
+	jns	155f
+	negl	%eax
+155:	cmpl	$0x01000000, %eax
+	ja	18f		// does not fit in mantissa bits
+	// It's an odd integer.
+	shrl	$31, %edx
+	fldl	MOX(minf_mzero, %edx, 8)
+	ret
+
+	.align ALIGNARG(4)
+16:	fcompl	MO(zero)
+	addl	$4, %esp
+	fnstsw
+	shrl	$5, %eax
+	andl	$8, %eax
+	fldl	MOX(inf_zero, %eax, 1)
+	ret
+
+	.align ALIGNARG(4)
+17:	shll	$30, %edx	// sign bit for y in right position
+	addl	$4, %esp
+18:	shrl	$31, %edx
+	fldl	MOX(inf_zero, %edx, 8)
+	ret
+
+	.align ALIGNARG(4)
+	// x is ±0
+20:	fstp	%st(0)		// y
+	testb	$2, %dl
+	jz	21f		// y > 0
+
+	// x is ±0 and y is < 0.  We must find out whether y is an odd integer.
+	testb	$2, %dh
+	jz	25f
+
+	fld	%st		// y : y
+	fistpl	(%esp)		// y
+	fildl	(%esp)		// int(y) : y
+	fucompp			// <empty>
+	fnstsw
+	sahf
+	jne	26f
+
+	// OK, the value is an integer, but is the number of bits small
+	// enough so that all are coming from the mantissa?
+	popl	%edx
+	testb	$1, %dl
+	jz	27f		// jump if not odd
+	cmpl	$0xff000000, %edx
+	jbe	27f		// does not fit in mantissa bits
+	// It's an odd integer.
+	// Raise divide-by-zero exception and get minus infinity value.
+	fldl	MO(one)
+	fdivl	MO(zero)
+	fchs
+	ret
+
+25:	fstp	%st(0)
+26:	popl	%eax
+27:	// Raise divide-by-zero exception and get infinity value.
+	fldl	MO(one)
+	fdivl	MO(zero)
+	ret
+
+	.align ALIGNARG(4)
+	// x is ±0 and y is > 0.  We must find out whether y is an odd integer.
+21:	testb	$2, %dh
+	jz	22f
+
+	fld	%st		// y : y
+	fistpl	(%esp)		// y
+	fildl	(%esp)		// int(y) : y
+	fucompp			// <empty>
+	fnstsw
+	sahf
+	jne	23f
+
+	// OK, the value is an integer, but is the number of bits small
+	// enough so that all are coming from the mantissa?
+	popl	%edx
+	testb	$1, %dl
+	jz	24f		// jump if not odd
+	cmpl	$0xff000000, %edx
+	jbe	24f		// does not fit in mantissa bits
+	// It's an odd integer.
+	fldl	MO(mzero)
+	ret
+
+22:	fstp	%st(0)
+23:	popl	%eax
+24:	fldl	MO(zero)
+	ret
+
 END(__ieee754_powf)