/* ix87 specific implementation of pow function. Copyright (C) 1996, 1997, 1998, 1999, 2001, 2004, 2005 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Ulrich Drepper , 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, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. */ /*#include */ #include #ifdef __MINGW32__ # define ASM_TYPE_DIRECTIVE(name,typearg) # define ASM_SIZE_DIRECTIVE(name) # define cfi_adjust_cfa_offset(a) # define C_LABEL(name) _ ## name: # define C_SYMBOL_NAME(name) _ ## name # define ASM_GLOBAL_DIRECTIVE .global # define ALIGNARG(log2) 1<= 1L<<63. */ fld %st // y : y : x fabs // |y| : y : x fcompl MO(p63) // y : x fnstsw sahf jnc .L2 /* 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 .L2 /* OK, we have an integer value for y. */ popl %eax cfi_adjust_cfa_offset (-4) popl %edx cfi_adjust_cfa_offset (-4) orl $0, %edx fstp %st(0) // x jns .L4 // y >= 0, jump fdivrl MO(one) // 1/x (now referred to as x) negl %eax adcl $0, %edx negl %edx .L4: fldl MO(one) // 1 : x fxch .L6: shrdl $1, %edx, %eax jnc .L5 fxch fmul %st(1) // x : ST*x fxch .L5: fmul %st(0), %st // x*x : ST*x shrl $1, %edx movl %eax, %ecx orl %edx, %ecx jnz .L6 fstp %st(0) // ST*x ret /* y is ±NAN */ .L30: fldt 4(%esp) // x : y fldl MO(one) // 1.0 : x : y fucomp %st(1) // x : y fnstsw sahf je .L31 fxch // y : x .L31: fstp %st(1) ret cfi_adjust_cfa_offset (8) .align ALIGNARG(4) .L2: /* y is a real number. */ fxch // x : y fldl MO(one) // 1.0 : x : y fld %st(1) // x : 1.0 : x : y fsub %st(1) // x-1 : 1.0 : x : y fabs // |x-1| : 1.0 : x : y fcompl MO(limit) // 1.0 : x : y fnstsw fxch // x : 1.0 : y sahf ja .L7 fsub %st(1) // x-1 : 1.0 : y fyl2xp1 // log2(x) : y jmp .L8 .L7: fyl2x // log2(x) : y .L8: fmul %st(1) // y*log2(x) : y fxam fnstsw andb $0x45, %ah cmpb $0x05, %ah // is y*log2(x) == ±inf ? je .L28 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)) fscale // 2^fract(y*log2(x))*2^int(y*log2(x)) : int(y*log2(x)) addl $8, %esp cfi_adjust_cfa_offset (-8) fstp %st(1) // 2^fract(y*log2(x))*2^int(y*log2(x)) ret cfi_adjust_cfa_offset (8) .L28: fstp %st(1) // y*log2(x) fldl MO(one) // 1 : y*log2(x) fscale // 2^(y*log2(x)) : y*log2(x) addl $8, %esp cfi_adjust_cfa_offset (-8) fstp %st(1) // 2^(y*log2(x)) ret // pow(x,±0) = 1 .align ALIGNARG(4) .L11: fstp %st(0) // pop y fldl MO(one) ret // y == ±inf .align ALIGNARG(4) .L12: fstp %st(0) // pop y fldt 4(%esp) // x fabs fcompl MO(one) // < 1, == 1, or > 1 fnstsw andb $0x45, %ah cmpb $0x45, %ah je .L13 // jump if x is NaN cmpb $0x40, %ah je .L14 // jump if |x| == 1 shlb $1, %ah xorb %ah, %dl andl $2, %edx fldl MOX(inf_zero, %edx, 4) ret .align ALIGNARG(4) .L14: fldl MO(one) ret .align ALIGNARG(4) .L13: fldt 4(%esp) // load x == NaN ret cfi_adjust_cfa_offset (8) .align ALIGNARG(4) // x is ±inf .L15: fstp %st(0) // y testb $2, %dh jz .L16 // jump if x == +inf // We must find out whether y is an odd integer. fld %st // y : y fistpll (%esp) // y fildll (%esp) // int(y) : y fucompp // fnstsw sahf jne .L17 // 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 .L18 // 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) .L16: 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) .L17: shll $30, %edx // sign bit for y in right position addl $8, %esp cfi_adjust_cfa_offset (-8) .L18: shrl $31, %edx fldl MOX(inf_zero, %edx, 8) ret cfi_adjust_cfa_offset (8) .align ALIGNARG(4) // x is ±0 .L20: fstp %st(0) // y testb $2, %dl jz .L21 // y > 0 // x is ±0 and y is < 0. We must find out whether y is an odd integer. testb $2, %dh jz .L25 fld %st // y : y fistpll (%esp) // y fildll (%esp) // int(y) : y fucompp // fnstsw sahf jne .L26 // 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 .L27 // 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) .L25: fstp %st(0) .L26: addl $8, %esp cfi_adjust_cfa_offset (-8) .L27: // 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 ±0 and y is > 0. We must find out whether y is an odd integer. .L21: testb $2, %dh jz .L22 fld %st // y : y fistpll (%esp) // y fildll (%esp) // int(y) : y fucompp // fnstsw sahf jne .L23 // 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 .L24 // jump if not odd // It's an odd integer. fldl MO(mzero) ret cfi_adjust_cfa_offset (8) .L22: fstp %st(0) .L23: addl $8, %esp // Don't use 2 x pop cfi_adjust_cfa_offset (-8) .L24: fldl MO(zero) ret END(RT_NOCRT(powl)) //END(__ieee754_powl)