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30891f35fa
We stopped adding "Contributed by" or similar lines in sources in 2012 in favour of git logs and keeping the Contributors section of the glibc manual up to date. Removing these lines makes the license header a bit more consistent across files and also removes the possibility of error in attribution when license blocks or files are copied across since the contributed-by lines don't actually reflect reality in those cases. Move all "Contributed by" and similar lines (Written by, Test by, etc.) into a new file CONTRIBUTED-BY to retain record of these contributions. These contributors are also mentioned in manual/contrib.texi, so we just maintain this additional record as a courtesy to the earlier developers. The following scripts were used to filter a list of files to edit in place and to clean up the CONTRIBUTED-BY file respectively. These were not added to the glibc sources because they're not expected to be of any use in future given that this is a one time task: https://gist.github.com/siddhesh/b5ecac94eabfd72ed2916d6d8157e7dc https://gist.github.com/siddhesh/15ea1f5e435ace9774f485030695ee02 Reviewed-by: Carlos O'Donell <carlos@redhat.com>
460 lines
9.2 KiB
ArmAsm
460 lines
9.2 KiB
ArmAsm
/* ix87 specific implementation of pow function.
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Copyright (C) 1996-2021 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <machine/asm.h>
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#include <i386-math-asm.h>
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#include <libm-alias-finite.h>
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.section .rodata.cst8,"aM",@progbits,8
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.p2align 3
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.type one,@object
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one: .double 1.0
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ASM_SIZE_DIRECTIVE(one)
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.type p2,@object
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p2: .byte 0, 0, 0, 0, 0, 0, 0x10, 0x40
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ASM_SIZE_DIRECTIVE(p2)
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.type p63,@object
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p63: .byte 0, 0, 0, 0, 0, 0, 0xe0, 0x43
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ASM_SIZE_DIRECTIVE(p63)
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.type p64,@object
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p64: .byte 0, 0, 0, 0, 0, 0, 0xf0, 0x43
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ASM_SIZE_DIRECTIVE(p64)
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.type p78,@object
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p78: .byte 0, 0, 0, 0, 0, 0, 0xd0, 0x44
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ASM_SIZE_DIRECTIVE(p78)
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.type pm79,@object
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pm79: .byte 0, 0, 0, 0, 0, 0, 0, 0x3b
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ASM_SIZE_DIRECTIVE(pm79)
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.section .rodata.cst16,"aM",@progbits,16
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.p2align 3
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.type infinity,@object
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inf_zero:
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infinity:
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.byte 0, 0, 0, 0, 0, 0, 0xf0, 0x7f
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ASM_SIZE_DIRECTIVE(infinity)
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.type zero,@object
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zero: .double 0.0
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ASM_SIZE_DIRECTIVE(zero)
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.type minf_mzero,@object
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minf_mzero:
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minfinity:
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.byte 0, 0, 0, 0, 0, 0, 0xf0, 0xff
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mzero:
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.byte 0, 0, 0, 0, 0, 0, 0, 0x80
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ASM_SIZE_DIRECTIVE(minf_mzero)
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DEFINE_LDBL_MIN
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#ifdef PIC
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# define MO(op) op##@GOTOFF(%ecx)
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# define MOX(op,x,f) op##@GOTOFF(%ecx,x,f)
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#else
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# define MO(op) op
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# define MOX(op,x,f) op(,x,f)
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#endif
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.text
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ENTRY(__ieee754_powl)
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fldt 16(%esp) // y
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fxam
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#ifdef PIC
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LOAD_PIC_REG (cx)
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#endif
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fnstsw
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movb %ah, %dl
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andb $0x45, %ah
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cmpb $0x40, %ah // is y == 0 ?
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je 11f
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cmpb $0x05, %ah // is y == <EFBFBD>inf ?
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je 12f
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cmpb $0x01, %ah // is y == NaN ?
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je 30f
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fldt 4(%esp) // x : y
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subl $8,%esp
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cfi_adjust_cfa_offset (8)
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fxam
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fnstsw
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movb %ah, %dh
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andb $0x45, %ah
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cmpb $0x40, %ah
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je 20f // x is <EFBFBD>0
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cmpb $0x05, %ah
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je 15f // x is <EFBFBD>inf
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cmpb $0x01, %ah
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je 32f // x is NaN
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fxch // y : x
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/* fistpll raises invalid exception for |y| >= 1L<<63. */
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fld %st // y : y : x
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fabs // |y| : y : x
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fcompl MO(p63) // y : x
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fnstsw
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sahf
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jnc 2f
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/* First see whether `y' is a natural number. In this case we
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can use a more precise algorithm. */
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fld %st // y : y : x
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fistpll (%esp) // y : x
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fildll (%esp) // int(y) : y : x
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fucomp %st(1) // y : x
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fnstsw
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sahf
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je 9f
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// If y has absolute value at most 0x1p-79, then any finite
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// nonzero x will result in 1. Saturate y to those bounds to
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// avoid underflow in the calculation of y*log2(x).
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fld %st // y : y : x
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fabs // |y| : y : x
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fcompl MO(pm79) // y : x
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fnstsw
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sahf
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jnc 3f
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fstp %st(0) // pop y
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fldl MO(pm79) // 0x1p-79 : x
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testb $2, %dl
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jnz 3f // y > 0
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fchs // -0x1p-79 : x
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jmp 3f
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9: /* OK, we have an integer value for y. Unless very small
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(we use < 4), use the algorithm for real exponent to avoid
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accumulation of errors. */
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fld %st // y : y : x
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fabs // |y| : y : x
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fcompl MO(p2) // y : x
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fnstsw
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sahf
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jnc 3f
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popl %eax
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cfi_adjust_cfa_offset (-4)
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popl %edx
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cfi_adjust_cfa_offset (-4)
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orl $0, %edx
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fstp %st(0) // x
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jns 4f // y >= 0, jump
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fdivrl MO(one) // 1/x (now referred to as x)
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negl %eax
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adcl $0, %edx
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negl %edx
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4: fldl MO(one) // 1 : x
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fxch
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/* If y is even, take the absolute value of x. Otherwise,
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ensure all intermediate values that might overflow have the
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sign of x. */
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testb $1, %al
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jnz 6f
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fabs
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6: shrdl $1, %edx, %eax
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jnc 5f
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fxch
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fabs
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fmul %st(1) // x : ST*x
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fxch
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5: fld %st // x : x : ST*x
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fabs // |x| : x : ST*x
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fmulp // |x|*x : ST*x
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shrl $1, %edx
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movl %eax, %ecx
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orl %edx, %ecx
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jnz 6b
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fstp %st(0) // ST*x
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#ifdef PIC
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LOAD_PIC_REG (cx)
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#endif
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LDBL_CHECK_FORCE_UFLOW_NONNAN
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ret
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/* y is <20>NAN */
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30: fldt 4(%esp) // x : y
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fldl MO(one) // 1.0 : x : y
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fucomp %st(1) // x : y
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fnstsw
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sahf
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je 33f
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31: /* At least one argument NaN, and result should be NaN. */
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faddp
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ret
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33: jp 31b
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/* pow (1, NaN); check if the NaN signaling. */
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testb $0x40, 23(%esp)
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jz 31b
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fstp %st(1)
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ret
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cfi_adjust_cfa_offset (8)
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32: addl $8, %esp
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cfi_adjust_cfa_offset (-8)
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faddp
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ret
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cfi_adjust_cfa_offset (8)
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.align ALIGNARG(4)
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2: // y is a large integer (absolute value at least 1L<<63).
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// If y has absolute value at least 1L<<78, then any finite
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// nonzero x will result in 0 (underflow), 1 or infinity (overflow).
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// Saturate y to those bounds to avoid overflow in the calculation
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// of y*log2(x).
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fld %st // y : y : x
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fabs // |y| : y : x
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fcompl MO(p78) // y : x
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fnstsw
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sahf
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jc 3f
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fstp %st(0) // pop y
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fldl MO(p78) // 1L<<78 : x
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testb $2, %dl
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jz 3f // y > 0
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fchs // -(1L<<78) : x
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.align ALIGNARG(4)
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3: /* y is a real number. */
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subl $28, %esp
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cfi_adjust_cfa_offset (28)
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fstpt 12(%esp) // x
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fstpt (%esp) // <empty>
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call HIDDEN_JUMPTARGET (__powl_helper) // <result>
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addl $36, %esp
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cfi_adjust_cfa_offset (-36)
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ret
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// pow(x,<EFBFBD>0) = 1, unless x is sNaN
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.align ALIGNARG(4)
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11: fstp %st(0) // pop y
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fldt 4(%esp) // x
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fxam
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fnstsw
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andb $0x45, %ah
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cmpb $0x01, %ah
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je 112f // x is NaN
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111: fstp %st(0)
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fldl MO(one)
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ret
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112: testb $0x40, 11(%esp)
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jnz 111b
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fadd %st(0)
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ret
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// y == <EFBFBD>inf
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.align ALIGNARG(4)
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12: fstp %st(0) // pop y
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fldl MO(one) // 1
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fldt 4(%esp) // x : 1
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fabs // abs(x) : 1
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fucompp // < 1, == 1, or > 1
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fnstsw
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andb $0x45, %ah
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cmpb $0x45, %ah
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je 13f // jump if x is NaN
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cmpb $0x40, %ah
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je 14f // jump if |x| == 1
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shlb $1, %ah
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xorb %ah, %dl
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andl $2, %edx
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fldl MOX(inf_zero, %edx, 4)
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ret
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.align ALIGNARG(4)
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14: fldl MO(one)
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ret
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.align ALIGNARG(4)
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13: fldt 4(%esp) // load x == NaN
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fadd %st(0)
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ret
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cfi_adjust_cfa_offset (8)
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.align ALIGNARG(4)
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// x is <EFBFBD>inf
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15: fstp %st(0) // y
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testb $2, %dh
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jz 16f // jump if x == +inf
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// fistpll raises invalid exception for |y| >= 1L<<63, but y
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// may be odd unless we know |y| >= 1L<<64.
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fld %st // y : y
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fabs // |y| : y
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fcompl MO(p64) // y
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fnstsw
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sahf
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jnc 16f
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fldl MO(p63) // p63 : y
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fxch // y : p63
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fprem // y%p63 : p63
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fstp %st(1) // y%p63
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// We must find out whether y is an odd integer.
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fld %st // y : y
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fistpll (%esp) // y
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fildll (%esp) // int(y) : y
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fucompp // <empty>
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fnstsw
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sahf
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jne 17f
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// OK, the value is an integer, but is it odd?
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popl %eax
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cfi_adjust_cfa_offset (-4)
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popl %edx
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cfi_adjust_cfa_offset (-4)
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andb $1, %al
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jz 18f // jump if not odd
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// It's an odd integer.
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shrl $31, %edx
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fldl MOX(minf_mzero, %edx, 8)
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ret
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cfi_adjust_cfa_offset (8)
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.align ALIGNARG(4)
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16: fcompl MO(zero)
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addl $8, %esp
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cfi_adjust_cfa_offset (-8)
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fnstsw
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shrl $5, %eax
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andl $8, %eax
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fldl MOX(inf_zero, %eax, 1)
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ret
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cfi_adjust_cfa_offset (8)
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.align ALIGNARG(4)
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17: shll $30, %edx // sign bit for y in right position
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addl $8, %esp
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cfi_adjust_cfa_offset (-8)
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18: shrl $31, %edx
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fldl MOX(inf_zero, %edx, 8)
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ret
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cfi_adjust_cfa_offset (8)
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.align ALIGNARG(4)
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// x is <EFBFBD>0
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20: fstp %st(0) // y
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testb $2, %dl
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jz 21f // y > 0
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// x is <EFBFBD>0 and y is < 0. We must find out whether y is an odd integer.
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testb $2, %dh
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jz 25f
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// fistpll raises invalid exception for |y| >= 1L<<63, but y
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// may be odd unless we know |y| >= 1L<<64.
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fld %st // y : y
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fabs // |y| : y
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fcompl MO(p64) // y
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fnstsw
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sahf
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jnc 25f
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fldl MO(p63) // p63 : y
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fxch // y : p63
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fprem // y%p63 : p63
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fstp %st(1) // y%p63
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fld %st // y : y
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fistpll (%esp) // y
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fildll (%esp) // int(y) : y
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fucompp // <empty>
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fnstsw
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sahf
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jne 26f
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// OK, the value is an integer, but is it odd?
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popl %eax
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cfi_adjust_cfa_offset (-4)
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popl %edx
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cfi_adjust_cfa_offset (-4)
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andb $1, %al
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jz 27f // jump if not odd
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// It's an odd integer.
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// Raise divide-by-zero exception and get minus infinity value.
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fldl MO(one)
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fdivl MO(zero)
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fchs
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ret
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cfi_adjust_cfa_offset (8)
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25: fstp %st(0)
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26: addl $8, %esp
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cfi_adjust_cfa_offset (-8)
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27: // Raise divide-by-zero exception and get infinity value.
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fldl MO(one)
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fdivl MO(zero)
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ret
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cfi_adjust_cfa_offset (8)
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.align ALIGNARG(4)
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// x is <EFBFBD>0 and y is > 0. We must find out whether y is an odd integer.
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21: testb $2, %dh
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jz 22f
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// fistpll raises invalid exception for |y| >= 1L<<63, but y
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// may be odd unless we know |y| >= 1L<<64.
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fld %st // y : y
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fcompl MO(p64) // y
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fnstsw
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sahf
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jnc 22f
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fldl MO(p63) // p63 : y
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fxch // y : p63
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fprem // y%p63 : p63
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fstp %st(1) // y%p63
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fld %st // y : y
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fistpll (%esp) // y
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fildll (%esp) // int(y) : y
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fucompp // <empty>
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fnstsw
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sahf
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jne 23f
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// OK, the value is an integer, but is it odd?
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popl %eax
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cfi_adjust_cfa_offset (-4)
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popl %edx
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cfi_adjust_cfa_offset (-4)
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andb $1, %al
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jz 24f // jump if not odd
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// It's an odd integer.
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fldl MO(mzero)
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ret
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cfi_adjust_cfa_offset (8)
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22: fstp %st(0)
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23: addl $8, %esp // Don't use 2 x pop
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cfi_adjust_cfa_offset (-8)
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24: fldl MO(zero)
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ret
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END(__ieee754_powl)
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libm_alias_finite (__ieee754_powl, __powl)
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