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381 lines
7.9 KiB
ArmAsm
381 lines
7.9 KiB
ArmAsm
/* ix87 specific implementation of pow function.
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Copyright (C) 1996, 1997, 1998, 1999, 2001, 2004, 2005, 2007
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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, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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/* Reactos modifications */
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#include <asm.inc>
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#define ALIGNARG(log2) log2
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#define ASM_TYPE_DIRECTIVE(name,typearg)
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#define ASM_SIZE_DIRECTIVE(name)
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#define cfi_adjust_cfa_offset(x)
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PUBLIC _pow
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.data
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ASSUME nothing
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.align ALIGNARG(4)
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ASM_TYPE_DIRECTIVE(infinity,@object)
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inf_zero:
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infinity:
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.byte 0, 0, 0, 0, 0, 0, HEX(f0), HEX(7f)
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ASM_SIZE_DIRECTIVE(infinity)
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ASM_TYPE_DIRECTIVE(zero,@object)
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zero:
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.double 0.0
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ASM_SIZE_DIRECTIVE(zero)
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ASM_TYPE_DIRECTIVE(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, HEX(f0), HEX(ff)
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mzero:
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.byte 0, 0, 0, 0, 0, 0, 0, HEX(80)
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ASM_SIZE_DIRECTIVE(minf_mzero)
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ASM_TYPE_DIRECTIVE(one,@object)
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one:
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.double 1.0
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ASM_SIZE_DIRECTIVE(one)
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ASM_TYPE_DIRECTIVE(limit,@object)
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limit:
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.double 0.29
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ASM_SIZE_DIRECTIVE(limit)
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ASM_TYPE_DIRECTIVE(p63,@object)
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p63:
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.byte 0, 0, 0, 0, 0, 0, HEX(e0), HEX(43)
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ASM_SIZE_DIRECTIVE(p63)
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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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.code
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_pow:
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fld qword ptr [esp + 12] // 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 ax
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mov dl, ah
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and ah, HEX(045)
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cmp ah, HEX(040) // is y == 0 ?
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je L11
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cmp ah, 5 // is y == <EFBFBD>inf ?
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je L12
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cmp ah, 1 // is y == NaN ?
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je L30
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fld qword ptr [esp + 4] // x : y
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sub esp, 8
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cfi_adjust_cfa_offset (8)
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fxam
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fnstsw ax
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mov dh, ah
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and ah, HEX(45)
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cmp ah, HEX(040)
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je L20 // x is <EFBFBD>0
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cmp ah, 5
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je L15 // x is <EFBFBD>inf
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fxch st(1) // 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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fcomp qword ptr ds:MO(p63) // y : x
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fnstsw ax
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sahf
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jnc L2
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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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fistp qword ptr [esp] // y : x
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fild qword ptr [esp] // int(y) : y : x
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fucomp st(1) // y : x
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fnstsw ax
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sahf
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jne L2
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/* OK, we have an integer value for y. */
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pop eax
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cfi_adjust_cfa_offset (-4)
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pop edx
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cfi_adjust_cfa_offset (-4)
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or edx, 0
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fstp st // x
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jns L4 // y >= 0, jump
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fdivr qword ptr MO(one) // 1/x (now referred to as x)
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neg eax
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adc edx, 0
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neg edx
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L4: fld qword ptr MO(one) // 1 : x
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fxch st(1)
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L6: shrd eax, edx, 1
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jnc L5
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fxch st(1)
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fmul st, st(1) // x : ST*x
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fxch st(1)
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L5: fmul st, st // x*x : ST*x
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shr edx, 1
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mov ecx, eax
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or ecx, edx
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jnz L6
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fstp st // ST*x
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ret
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/* y is <20>NAN */
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L30:
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fld qword ptr [esp + 4] // x : y
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fld qword ptr MO(one) // 1.0 : x : y
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fucomp st(1) // x : y
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fnstsw ax
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sahf
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je L31
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fxch st(1) // y : x
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L31:fstp st(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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L2: /* y is a real number. */
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fxch st(1) // x : y
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fld qword ptr MO(one) // 1.0 : x : y
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fld qword ptr MO(limit) // 0.29 : 1.0 : x : y
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fld st(2) // x : 0.29 : 1.0 : x : y
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fsub st, st(2) // x-1 : 0.29 : 1.0 : x : y
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fabs // |x-1| : 0.29 : 1.0 : x : y
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fucompp // 1.0 : x : y
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fnstsw ax
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fxch st(1) // x : 1.0 : y
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sahf
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ja L7
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fsub st, st(1) // x-1 : 1.0 : y
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fyl2xp1 // log2(x) : y
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jmp L8
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L7: fyl2x // log2(x) : y
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L8: fmul st, st(1) // y*log2(x) : y
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fst st(1) // y*log2(x) : y*log2(x)
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frndint // int(y*log2(x)) : y*log2(x)
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fsub st(1), st // int(y*log2(x)) : fract(y*log2(x))
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fxch // fract(y*log2(x)) : int(y*log2(x))
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f2xm1 // 2^fract(y*log2(x))-1 : int(y*log2(x))
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fadd qword ptr MO(one) // 2^fract(y*log2(x)) : int(y*log2(x))
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fscale // 2^fract(y*log2(x))*2^int(y*log2(x)) : int(y*log2(x))
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add esp, 8
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cfi_adjust_cfa_offset (-8)
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fstp st(1) // 2^fract(y*log2(x))*2^int(y*log2(x))
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ret
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// pow(x,<EFBFBD>0) = 1
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.align ALIGNARG(4)
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L11:fstp st(0) // pop y
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fld qword ptr MO(one)
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ret
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// y == <EFBFBD>inf
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.align ALIGNARG(4)
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L12: fstp st(0) // pop y
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fld qword ptr MO(one) // 1
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fld qword ptr [esp + 4] // x : 1
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fabs // abs(x) : 1
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fucompp // < 1, == 1, or > 1
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fnstsw ax
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and ah, HEX(45)
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cmp ah, HEX(45)
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je L13 // jump if x is NaN
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cmp ah, HEX(40)
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je L14 // jump if |x| == 1
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shl ah, 1
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xor dl, ah
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and edx, 2
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fld qword ptr MOX(inf_zero, edx, 4)
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ret
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.align ALIGNARG(4)
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L14:fld qword ptr MO(one)
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ret
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.align ALIGNARG(4)
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L13:fld qword ptr [esp + 4] // load x == NaN
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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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L15: fstp st(0) // y
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test dh, 2
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jz L16 // jump if x == +inf
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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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fistp qword ptr [esp] // y
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fild qword ptr [esp] // int(y) : y
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fucompp // <empty>
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fnstsw ax
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sahf
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jne L17
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// OK, the value is an integer, but is the number of bits small
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// enough so that all are coming from the mantissa?
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pop eax
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cfi_adjust_cfa_offset (-4)
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pop edx
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cfi_adjust_cfa_offset (-4)
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and al, 1
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jz L18 // jump if not odd
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mov eax, edx
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or edx, edx
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jns L155
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neg eax
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L155:
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cmp eax, HEX(000200000)
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ja L18 // does not fit in mantissa bits
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// It's an odd integer.
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shr edx, 31
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fld qword ptr 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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L16:fcomp qword ptr ds:MO(zero)
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add esp, 8
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cfi_adjust_cfa_offset (-8)
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fnstsw ax
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shr eax, 5
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and eax, 8
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fld qword ptr 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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L17: shl edx, 30 // sign bit for y in right position
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add esp, 8
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cfi_adjust_cfa_offset (-8)
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L18: shr edx, 31
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fld qword ptr 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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L20: fstp st(0) // y
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test dl, 2
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jz L21 // 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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test dh, 2
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jz L25
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fld st // y : y
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fistp qword ptr [esp] // y
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fild qword ptr [esp] // int(y) : y
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fucompp // <empty>
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fnstsw ax
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sahf
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jne L26
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// OK, the value is an integer, but is the number of bits small
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// enough so that all are coming from the mantissa?
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pop eax
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cfi_adjust_cfa_offset (-4)
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pop edx
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cfi_adjust_cfa_offset (-4)
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and al, 1
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jz L27 // jump if not odd
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cmp edx, HEX(0ffe00000)
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jbe L27 // does not fit in mantissa bits
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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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fld qword ptr MO(one)
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fdiv qword ptr 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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L25: fstp st(0)
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L26: add esp, 8
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cfi_adjust_cfa_offset (-8)
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L27: // Raise divide-by-zero exception and get infinity value.
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fld qword ptr MO(one)
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fdiv qword ptr 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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L21:test dh, 2
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jz L22
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fld st // y : y
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fistp qword ptr [esp] // y
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fild qword ptr [esp] // int(y) : y
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fucompp // <empty>
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fnstsw ax
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sahf
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jne L23
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// OK, the value is an integer, but is the number of bits small
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// enough so that all are coming from the mantissa?
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pop eax
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cfi_adjust_cfa_offset (-4)
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pop edx
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cfi_adjust_cfa_offset (-4)
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and al, 1
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jz L24 // jump if not odd
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cmp edx, HEX(0ffe00000)
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jae L24 // does not fit in mantissa bits
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// It's an odd integer.
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fld qword ptr MO(mzero)
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ret
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cfi_adjust_cfa_offset (8)
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L22: fstp st(0)
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L23: add esp, 8 // Don't use 2 x pop
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cfi_adjust_cfa_offset (-8)
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L24: fld qword ptr MO(zero)
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ret
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END
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