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Diffstat (limited to 'sysdeps/x86_64/fpu/e_powl.S')
| -rw-r--r-- | sysdeps/x86_64/fpu/e_powl.S | 316 |
1 files changed, 316 insertions, 0 deletions
diff --git a/sysdeps/x86_64/fpu/e_powl.S b/sysdeps/x86_64/fpu/e_powl.S new file mode 100644 index 0000000000..8c690e16cc --- /dev/null +++ b/sysdeps/x86_64/fpu/e_powl.S @@ -0,0 +1,316 @@ +/* ix87 specific implementation of pow function. + Copyright (C) 1996, 1997, 1998, 1999, 2001 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include <machine/asm.h> + +#ifdef __ELF__ + .section .rodata +#else + .text +#endif + + .align ALIGNARG(4) + ASM_TYPE_DIRECTIVE(infinity,@object) +inf_zero: +infinity: + .byte 0, 0, 0, 0, 0, 0, 0xf0, 0x7f + ASM_SIZE_DIRECTIVE(infinity) + ASM_TYPE_DIRECTIVE(zero,@object) +zero: .double 0.0 + ASM_SIZE_DIRECTIVE(zero) + ASM_TYPE_DIRECTIVE(minf_mzero,@object) +minf_mzero: +minfinity: + .byte 0, 0, 0, 0, 0, 0, 0xf0, 0xff +mzero: + .byte 0, 0, 0, 0, 0, 0, 0, 0x80 + ASM_SIZE_DIRECTIVE(minf_mzero) + ASM_TYPE_DIRECTIVE(one,@object) +one: .double 1.0 + ASM_SIZE_DIRECTIVE(one) + ASM_TYPE_DIRECTIVE(limit,@object) +limit: .double 0.29 + ASM_SIZE_DIRECTIVE(limit) + +#ifdef PIC +#define MO(op) op##(%rip) +#else +#define MO(op) op +#endif + + .text +ENTRY(__ieee754_powl) + fldt 24(%rsp) // y + fxam + + + fnstsw + movb %ah, %dl + andb $0x45, %ah + cmpb $0x40, %ah // is y == 0 ? + je 11f + + cmpb $0x05, %ah // is y == ±inf ? + je 12f + + cmpb $0x01, %ah // is y == NaN ? + je 30f + + fldt 8(%rsp) // x : y + + fxam + fnstsw + movb %ah, %dh + andb $0x45, %ah + cmpb $0x40, %ah + je 20f // x is ±0 + + cmpb $0x05, %ah + je 15f // x is ±inf + + fxch // y : x + + /* First see whether `y' is a natural number. In this case we + can use a more precise algorithm. */ + fld %st // y : y : x + fistpll -8(%rsp) // y : x + fildll -8(%rsp) // int(y) : y : x + fucomip %st(1),%st // y : x + jne 2f + + /* OK, we have an integer value for y. */ + mov -8(%rsp),%eax + mov -4(%rsp),%edx + orl $0, %edx + fstp %st(0) // x + jns 4f // y >= 0, jump + fdivrl MO(one) // 1/x (now referred to as x) + negl %eax + adcl $0, %edx + negl %edx +4: fldl MO(one) // 1 : x + fxch + +6: shrdl $1, %edx, %eax + jnc 5f + fxch + fmul %st(1) // x : ST*x + fxch +5: fmul %st(0), %st // x*x : ST*x + shrl $1, %edx + movl %eax, %ecx + orl %edx, %ecx + jnz 6b + fstp %st(0) // ST*x + ret + + /* y is ±NAN */ +30: fldt 8(%rsp) // x : y + fldl MO(one) // 1.0 : x : y + fucomip %st(1),%st // x : y + je 31f + fxch // y : x +31: fstp %st(1) + ret + + .align ALIGNARG(4) +2: /* 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 + test $4500,%eax + jz 7f + fsub %st(1) // x-1 : 1.0 : y + fyl2xp1 // log2(x) : y + jmp 8f + +7: fyl2x // log2(x) : y +8: fmul %st(1) // y*log2(x) : y + fst %st(1) // y*log2(x) : y*log2(x) + frndint // int(y*log2(x)) : y*log2(x) + fsubr %st, %st(1) // int(y*log2(x)) : fract(y*log2(x)) + fxch // fract(y*log2(x)) : int(y*log2(x)) + f2xm1 // 2^fract(y*log2(x))-1 : int(y*log2(x)) + faddl MO(one) // 2^fract(y*log2(x)) : int(y*log2(x)) + fscale // 2^fract(y*log2(x))*2^int(y*log2(x)) : int(y*log2(x)) + fstp %st(1) // 2^fract(y*log2(x))*2^int(y*log2(x)) + ret + + + // pow(x,±0) = 1 + .align ALIGNARG(4) +11: fstp %st(0) // pop y + fldl MO(one) + ret + + // y == ±inf + .align ALIGNARG(4) +12: fstp %st(0) // pop y + fldt 8(%rsp) // x + fabs + fcompl MO(one) // < 1, == 1, or > 1 + fnstsw + andb $0x45, %ah + cmpb $0x45, %ah + je 13f // jump if x is NaN + + cmpb $0x40, %ah + je 14f // jump if |x| == 1 + + shlb $1, %ah + xorb %ah, %dl + andl $2, %edx +#ifdef PIC + lea inf_zero(%rip),%rcx + fldl (%rcx, %rdx, 4) +#else + fldl inf_zero(,%rdx, 4) +#endif + ret + + .align ALIGNARG(4) +14: fldl MO(one) + ret + + .align ALIGNARG(4) +13: fldt 8(%rsp) // load x == NaN + ret + + .align ALIGNARG(4) + // x is ±inf +15: fstp %st(0) // y + testb $2, %dh + jz 16f // jump if x == +inf + + // We must find out whether y is an odd integer. + fld %st // y : y + fistpll -8(%rsp) // y + fildll -8(%rsp) // int(y) : y + fucomip %st(1),%st + ffreep %st // <empty> + jne 17f + + // OK, the value is an integer, but is it odd? + mov -8(%rsp), %eax + mov -4(%rsp), %edx + andb $1, %al + jz 18f // jump if not odd + // It's an odd integer. + shrl $31, %edx +#ifdef PIC + lea minf_mzero(%rip),%rcx + fldl (%rcx, %rdx, 8) +#else + fldl minf_mzero(,%rdx, 8) +#endif + ret + + .align ALIGNARG(4) +16: fcompl MO(zero) + fnstsw + shrl $5, %eax + andl $8, %eax +#ifdef PIC + lea inf_zero(%rip),%rcx + fldl (%rcx, %rax, 1) +#else + fldl inf_zero(,%rax, 1) +#endif + ret + + .align ALIGNARG(4) +17: shll $30, %edx // sign bit for y in right position +18: shrl $31, %edx +#ifdef PIC + lea inf_zero(%rip),%rcx + fldl (%rcx, %rdx, 8) +#else + fldl inf_zero(,%rdx, 8) +#endif + ret + + .align ALIGNARG(4) + // x is ±0 +20: fstp %st(0) // y + testb $2, %dl + jz 21f // y > 0 + + // x is ±0 and y is < 0. We must find out whether y is an odd integer. + testb $2, %dh + jz 25f + + fld %st // y : y + fistpll -8(%rsp) // y + fildll -8(%rsp) // int(y) : y + fucomip %st(1),%st + ffreep %st // <empty> + jne 26f + + // OK, the value is an integer, but is it odd? + mov -8(%rsp),%eax + mov -4(%rsp),%edx + andb $1, %al + jz 27f // jump if not odd + // It's an odd integer. + // Raise divide-by-zero exception and get minus infinity value. + fldl MO(one) + fdivl MO(zero) + fchs + ret + +25: fstp %st(0) +26: +27: // Raise divide-by-zero exception and get infinity value. + fldl MO(one) + fdivl MO(zero) + ret + + .align ALIGNARG(4) + // x is ±0 and y is > 0. We must find out whether y is an odd integer. +21: testb $2, %dh + jz 22f + + fld %st // y : y + fistpll -8(%rsp) // y + fildll -8(%rsp) // int(y) : y + fucomip %st(1),%st + ffreep %st // <empty> + jne 23f + + // OK, the value is an integer, but is it odd? + mov -8(%rsp),%eax + mov -4(%rsp),%edx + andb $1, %al + jz 24f // jump if not odd + // It's an odd integer. + fldl MO(mzero) + ret + +22: fstp %st(0) +23: +24: fldl MO(zero) + ret + +END(__ieee754_powl) |