glibc/sysdeps/i386/fpu/e_pow.S
Paul Eggert 5a82c74822 Prefer https to http for gnu.org and fsf.org URLs
Also, change sources.redhat.com to sourceware.org.
This patch was automatically generated by running the following shell
script, which uses GNU sed, and which avoids modifying files imported
from upstream:

sed -ri '
  s,(http|ftp)(://(.*\.)?(gnu|fsf|sourceware)\.org($|[^.]|\.[^a-z])),https\2,g
  s,(http|ftp)(://(.*\.)?)sources\.redhat\.com($|[^.]|\.[^a-z]),https\2sourceware.org\4,g
' \
  $(find $(git ls-files) -prune -type f \
      ! -name '*.po' \
      ! -name 'ChangeLog*' \
      ! -path COPYING ! -path COPYING.LIB \
      ! -path manual/fdl-1.3.texi ! -path manual/lgpl-2.1.texi \
      ! -path manual/texinfo.tex ! -path scripts/config.guess \
      ! -path scripts/config.sub ! -path scripts/install-sh \
      ! -path scripts/mkinstalldirs ! -path scripts/move-if-change \
      ! -path INSTALL ! -path  locale/programs/charmap-kw.h \
      ! -path po/libc.pot ! -path sysdeps/gnu/errlist.c \
      ! '(' -name configure \
            -execdir test -f configure.ac -o -f configure.in ';' ')' \
      ! '(' -name preconfigure \
            -execdir test -f preconfigure.ac ';' ')' \
      -print)

and then by running 'make dist-prepare' to regenerate files built
from the altered files, and then executing the following to cleanup:

  chmod a+x sysdeps/unix/sysv/linux/riscv/configure
  # Omit irrelevant whitespace and comment-only changes,
  # perhaps from a slightly-different Autoconf version.
  git checkout -f \
    sysdeps/csky/configure \
    sysdeps/hppa/configure \
    sysdeps/riscv/configure \
    sysdeps/unix/sysv/linux/csky/configure
  # Omit changes that caused a pre-commit check to fail like this:
  # remote: *** error: sysdeps/powerpc/powerpc64/ppc-mcount.S: trailing lines
  git checkout -f \
    sysdeps/powerpc/powerpc64/ppc-mcount.S \
    sysdeps/unix/sysv/linux/s390/s390-64/syscall.S
  # Omit change that caused a pre-commit check to fail like this:
  # remote: *** error: sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S: last line does not end in newline
  git checkout -f sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S
2019-09-07 02:43:31 -07:00

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/* ix87 specific implementation of pow function.
Copyright (C) 1996-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <machine/asm.h>
#include <i386-math-asm.h>
.section .rodata.cst8,"aM",@progbits,8
.p2align 3
.type one,@object
one: .double 1.0
ASM_SIZE_DIRECTIVE(one)
.type limit,@object
limit: .double 0.29
ASM_SIZE_DIRECTIVE(limit)
.type p63,@object
p63: .byte 0, 0, 0, 0, 0, 0, 0xe0, 0x43
ASM_SIZE_DIRECTIVE(p63)
.type p10,@object
p10: .byte 0, 0, 0, 0, 0, 0, 0x90, 0x40
ASM_SIZE_DIRECTIVE(p10)
.section .rodata.cst16,"aM",@progbits,16
.p2align 3
.type infinity,@object
inf_zero:
infinity:
.byte 0, 0, 0, 0, 0, 0, 0xf0, 0x7f
ASM_SIZE_DIRECTIVE(infinity)
.type zero,@object
zero: .double 0.0
ASM_SIZE_DIRECTIVE(zero)
.type 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)
DEFINE_DBL_MIN
#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_pow)
fldl 12(%esp) // y
fxam
#ifdef PIC
LOAD_PIC_REG (cx)
#endif
fnstsw
movb %ah, %dl
andb $0x45, %ah
cmpb $0x40, %ah // is y == 0 ?
je 11f
cmpb $0x05, %ah // is y == <EFBFBD>inf ?
je 12f
cmpb $0x01, %ah // is y == NaN ?
je 30f
fldl 4(%esp) // x : y
subl $8,%esp
cfi_adjust_cfa_offset (8)
fxam
fnstsw
movb %ah, %dh
andb $0x45, %ah
cmpb $0x40, %ah
je 20f // x is <EFBFBD>0
cmpb $0x05, %ah
je 15f // x is <EFBFBD>inf
cmpb $0x01, %ah
je 32f // x is NaN
fxch // y : x
/* fistpll raises invalid exception for |y| >= 1L<<63. */
fld %st // y : y : x
fabs // |y| : y : x
fcompl MO(p63) // y : x
fnstsw
sahf
jnc 2f
/* 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
fucomp %st(1) // y : x
fnstsw
sahf
jne 3f
/* OK, we have an integer value for y. If large enough that
errors may propagate out of the 11 bits excess precision, use
the algorithm for real exponent instead. */
fld %st // y : y : x
fabs // |y| : y : x
fcompl MO(p10) // y : x
fnstsw
sahf
jnc 2f
popl %eax
cfi_adjust_cfa_offset (-4)
popl %edx
cfi_adjust_cfa_offset (-4)
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
/* If y is even, take the absolute value of x. Otherwise,
ensure all intermediate values that might overflow have the
sign of x. */
testb $1, %al
jnz 6f
fabs
6: shrdl $1, %edx, %eax
jnc 5f
fxch
fabs
fmul %st(1) // x : ST*x
fxch
5: fld %st // x : x : ST*x
fabs // |x| : x : ST*x
fmulp // |x|*x : ST*x
shrl $1, %edx
movl %eax, %ecx
orl %edx, %ecx
jnz 6b
fstp %st(0) // ST*x
#ifdef PIC
LOAD_PIC_REG (cx)
#endif
DBL_NARROW_EVAL_UFLOW_NONNAN
ret
/* y is <20>NAN */
30: fldl 4(%esp) // x : y
fldl MO(one) // 1.0 : x : y
fucomp %st(1) // x : y
fnstsw
sahf
je 31f
fxch // y : x
31: fstp %st(1)
ret
cfi_adjust_cfa_offset (8)
32: addl $8, %esp
cfi_adjust_cfa_offset (-8)
fstp %st(1)
ret
cfi_adjust_cfa_offset (8)
.align ALIGNARG(4)
2: // y is a large integer (absolute value at least 1L<<10), but
// may be odd unless at least 1L<<64. So it may be necessary
// to adjust the sign of a negative result afterwards.
fxch // x : y
fabs // |x| : y
fxch // y : x
.align ALIGNARG(4)
3: /* y is a real number. */
fxch // x : y
fldl MO(one) // 1.0 : x : y
fldl MO(limit) // 0.29 : 1.0 : x : y
fld %st(2) // x : 0.29 : 1.0 : x : y
fsub %st(2) // x-1 : 0.29 : 1.0 : x : y
fabs // |x-1| : 0.29 : 1.0 : x : y
fucompp // 1.0 : x : y
fnstsw
fxch // x : 1.0 : y
sahf
ja 7f
fsub %st(1) // x-1 : 1.0 : y
fyl2xp1 // log2(x) : y
jmp 8f
7: fyl2x // log2(x) : y
8: fmul %st(1) // y*log2(x) : y
fst %st(1) // y*log2(x) : y*log2(x)
frndint // int(y*log2(x)) : y*log2(x)
fsubr %st, %st(1) // int(y*log2(x)) : fract(y*log2(x))
fxch // fract(y*log2(x)) : int(y*log2(x))
f2xm1 // 2^fract(y*log2(x))-1 : int(y*log2(x))
faddl MO(one) // 2^fract(y*log2(x)) : int(y*log2(x))
// Before scaling, we must negate if x is negative and y is an
// odd integer.
testb $2, %dh
jz 291f
// x is negative. If y is an odd integer, negate the result.
fldl 20(%esp) // y : 2^fract(y*log2(x)) : int(y*log2(x))
fld %st // y : y : 2^fract(y*log2(x)) : int(y*log2(x))
fabs // |y| : y : 2^fract(y*log2(x)) : int(y*log2(x))
fcompl MO(p63) // y : 2^fract(y*log2(x)) : int(y*log2(x))
fnstsw
sahf
jnc 290f
// We must find out whether y is an odd integer.
fld %st // y : y : 2^fract(y*log2(x)) : int(y*log2(x))
fistpll (%esp) // y : 2^fract(y*log2(x)) : int(y*log2(x))
fildll (%esp) // int(y) : y : 2^fract(y*log2(x)) : int(y*log2(x))
fucompp // 2^fract(y*log2(x)) : int(y*log2(x))
fnstsw
sahf
jne 291f
// OK, the value is an integer, but is it odd?
popl %eax
cfi_adjust_cfa_offset (-4)
popl %edx
cfi_adjust_cfa_offset (-4)
andb $1, %al
jz 292f // jump if not odd
// It's an odd integer.
fchs
jmp 292f
cfi_adjust_cfa_offset (8)
290: fstp %st(0) // 2^fract(y*log2(x)) : int(y*log2(x))
291: addl $8, %esp
cfi_adjust_cfa_offset (-8)
292: fscale // +/- 2^fract(y*log2(x))*2^int(y*log2(x)) : int(y*log2(x))
fstp %st(1) // +/- 2^fract(y*log2(x))*2^int(y*log2(x))
DBL_NARROW_EVAL_UFLOW_NONNAN
ret
// pow(x,<EFBFBD>0) = 1
.align ALIGNARG(4)
11: fstp %st(0) // pop y
fldl MO(one)
ret
// y == <EFBFBD>inf
.align ALIGNARG(4)
12: fstp %st(0) // pop y
fldl MO(one) // 1
fldl 4(%esp) // x : 1
fabs // abs(x) : 1
fucompp // < 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(one)
ret
.align ALIGNARG(4)
13: fldl 4(%esp) // load x == NaN
ret
cfi_adjust_cfa_offset (8)
.align ALIGNARG(4)
// x is <EFBFBD>inf
15: fstp %st(0) // y
testb $2, %dh
jz 16f // jump if x == +inf
// fistpll raises invalid exception for |y| >= 1L<<63, so test
// that (in which case y is certainly even) before testing
// whether y is odd.
fld %st // y : y
fabs // |y| : y
fcompl MO(p63) // y
fnstsw
sahf
jnc 16f
// We must find out whether y is an odd integer.
fld %st // y : y
fistpll (%esp) // y
fildll (%esp) // int(y) : y
fucompp // <empty>
fnstsw
sahf
jne 17f
// OK, the value is an integer.
popl %eax
cfi_adjust_cfa_offset (-4)
popl %edx
cfi_adjust_cfa_offset (-4)
andb $1, %al
jz 18f // jump if not odd
// It's an odd integer.
shrl $31, %edx
fldl MOX(minf_mzero, %edx, 8)
ret
cfi_adjust_cfa_offset (8)
.align ALIGNARG(4)
16: fcompl MO(zero)
addl $8, %esp
cfi_adjust_cfa_offset (-8)
fnstsw
shrl $5, %eax
andl $8, %eax
fldl MOX(inf_zero, %eax, 1)
ret
cfi_adjust_cfa_offset (8)
.align ALIGNARG(4)
17: shll $30, %edx // sign bit for y in right position
addl $8, %esp
cfi_adjust_cfa_offset (-8)
18: shrl $31, %edx
fldl MOX(inf_zero, %edx, 8)
ret
cfi_adjust_cfa_offset (8)
.align ALIGNARG(4)
// x is <EFBFBD>0
20: fstp %st(0) // y
testb $2, %dl
jz 21f // y > 0
// x is <EFBFBD>0 and y is < 0. We must find out whether y is an odd integer.
testb $2, %dh
jz 25f
// fistpll raises invalid exception for |y| >= 1L<<63, so test
// that (in which case y is certainly even) before testing
// whether y is odd.
fld %st // y : y
fabs // |y| : y
fcompl MO(p63) // y
fnstsw
sahf
jnc 25f
fld %st // y : y
fistpll (%esp) // y
fildll (%esp) // int(y) : y
fucompp // <empty>
fnstsw
sahf
jne 26f
// OK, the value is an integer.
popl %eax
cfi_adjust_cfa_offset (-4)
popl %edx
cfi_adjust_cfa_offset (-4)
andb $1, %al
jz 27f // jump if not odd
// It's an odd integer.
// Raise divide-by-zero exception and get minus infinity value.
fldl MO(one)
fdivl MO(zero)
fchs
ret
cfi_adjust_cfa_offset (8)
25: fstp %st(0)
26: addl $8, %esp
cfi_adjust_cfa_offset (-8)
27: // Raise divide-by-zero exception and get infinity value.
fldl MO(one)
fdivl MO(zero)
ret
cfi_adjust_cfa_offset (8)
.align ALIGNARG(4)
// x is <EFBFBD>0 and y is > 0. We must find out whether y is an odd integer.
21: testb $2, %dh
jz 22f
// fistpll raises invalid exception for |y| >= 1L<<63, so test
// that (in which case y is certainly even) before testing
// whether y is odd.
fcoml MO(p63) // y
fnstsw
sahf
jnc 22f
fld %st // y : y
fistpll (%esp) // y
fildll (%esp) // int(y) : y
fucompp // <empty>
fnstsw
sahf
jne 23f
// OK, the value is an integer.
popl %eax
cfi_adjust_cfa_offset (-4)
popl %edx
cfi_adjust_cfa_offset (-4)
andb $1, %al
jz 24f // jump if not odd
// It's an odd integer.
fldl MO(mzero)
ret
cfi_adjust_cfa_offset (8)
22: fstp %st(0)
23: addl $8, %esp // Don't use 2 x pop
cfi_adjust_cfa_offset (-8)
24: fldl MO(zero)
ret
END(__ieee754_pow)
strong_alias (__ieee754_pow, __pow_finite)