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a91fd168a0
The x86_64/x86 powl implementations mishandle sNaN arguments, both by returning sNaN in some cases (instead of doing arithmetic on the arguments to produce the result when NaN arguments result in NaN results) and by treating sNaN the same as qNaN for arguments (1, sNaN) and (sNaN, 0), contrary to TS 18661-1 which requires those cases to return qNaN instead of 1. This patch makes the x86_64/x86 powl implementations follow TS 18661-1 semantics for sNaN arguments; sNaN tests are also added for pow. Given the problems with testing float and double sNaN arguments on 32-bit x86 (sNaN tests disabled because the compiler may convert unnecessarily to a qNaN when passing arguments), no changes are made to the powf and pow implementations there. Tested for x86_64 and x86. [BZ #20916] * sysdeps/i386/fpu/e_powl.S (__ieee754_powl): Do not return 1 for arguments (sNaN, 0) or (1, sNaN). Do arithmetic on NaN arguments to compute result. * sysdeps/x86_64/fpu/e_powl.S (__ieee754_powl): Likewise. * math/libm-test.inc (pow_test_data): Add tests of sNaN arguments.
460 lines
9.2 KiB
ArmAsm
460 lines
9.2 KiB
ArmAsm
/* ix87 specific implementation of pow function.
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Copyright (C) 1996-2016 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
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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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<http://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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.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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strong_alias (__ieee754_powl, __powl_finite)
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