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Diffstat (limited to 'REORG.TODO/sysdeps/i386/fpu/e_pow.S')
| -rw-r--r-- | REORG.TODO/sysdeps/i386/fpu/e_pow.S | 456 |
1 files changed, 456 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/i386/fpu/e_pow.S b/REORG.TODO/sysdeps/i386/fpu/e_pow.S new file mode 100644 index 0000000000..2edb9a9fbc --- /dev/null +++ b/REORG.TODO/sysdeps/i386/fpu/e_pow.S @@ -0,0 +1,456 @@ +/* ix87 specific implementation of pow function. + Copyright (C) 1996-2017 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, see + <http://www.gnu.org/licenses/>. */ + +#include <machine/asm.h> +#include <i386-math-asm.h> + + .section .rodata.cst8,"aM",@progbits,8 + + .p2align 3 + .type one,@object +one: .double 1.0 + ASM_SIZE_DIRECTIVE(one) + .type limit,@object +limit: .double 0.29 + ASM_SIZE_DIRECTIVE(limit) + .type p63,@object +p63: .byte 0, 0, 0, 0, 0, 0, 0xe0, 0x43 + ASM_SIZE_DIRECTIVE(p63) + .type p10,@object +p10: .byte 0, 0, 0, 0, 0, 0, 0x90, 0x40 + ASM_SIZE_DIRECTIVE(p10) + + .section .rodata.cst16,"aM",@progbits,16 + + .p2align 3 + .type infinity,@object +inf_zero: +infinity: + .byte 0, 0, 0, 0, 0, 0, 0xf0, 0x7f + ASM_SIZE_DIRECTIVE(infinity) + .type zero,@object +zero: .double 0.0 + ASM_SIZE_DIRECTIVE(zero) + .type 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) +DEFINE_DBL_MIN + +#ifdef PIC +# define MO(op) op##@GOTOFF(%ecx) +# define MOX(op,x,f) op##@GOTOFF(%ecx,x,f) +#else +# define MO(op) op +# define MOX(op,x,f) op(,x,f) +#endif + + .text +ENTRY(__ieee754_pow) + fldl 12(%esp) // y + fxam + +#ifdef PIC + LOAD_PIC_REG (cx) +#endif + + 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 + + fldl 4(%esp) // x : y + + subl $8,%esp + cfi_adjust_cfa_offset (8) + + fxam + fnstsw + movb %ah, %dh + andb $0x45, %ah + cmpb $0x40, %ah + je 20f // x is ±0 + + cmpb $0x05, %ah + je 15f // x is ±inf + + cmpb $0x01, %ah + je 32f // x is NaN + + fxch // y : x + + /* fistpll raises invalid exception for |y| >= 1L<<63. */ + fld %st // y : y : x + fabs // |y| : y : x + fcompl MO(p63) // y : x + fnstsw + sahf + jnc 2f + + /* 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 3f + + /* OK, we have an integer value for y. If large enough that + errors may propagate out of the 11 bits excess precision, use + the algorithm for real exponent instead. */ + fld %st // y : y : x + fabs // |y| : y : x + fcompl MO(p10) // y : x + fnstsw + sahf + jnc 2f + popl %eax + cfi_adjust_cfa_offset (-4) + popl %edx + cfi_adjust_cfa_offset (-4) + 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 + + /* If y is even, take the absolute value of x. Otherwise, + ensure all intermediate values that might overflow have the + sign of x. */ + testb $1, %al + jnz 6f + fabs + +6: shrdl $1, %edx, %eax + jnc 5f + fxch + fabs + fmul %st(1) // x : ST*x + fxch +5: fld %st // x : x : ST*x + fabs // |x| : x : ST*x + fmulp // |x|*x : ST*x + shrl $1, %edx + movl %eax, %ecx + orl %edx, %ecx + jnz 6b + fstp %st(0) // ST*x +#ifdef PIC + LOAD_PIC_REG (cx) +#endif + DBL_NARROW_EVAL_UFLOW_NONNAN + ret + + /* y is ±NAN */ +30: fldl 4(%esp) // x : y + fldl MO(one) // 1.0 : x : y + fucomp %st(1) // x : y + fnstsw + sahf + je 31f + fxch // y : x +31: fstp %st(1) + ret + + cfi_adjust_cfa_offset (8) +32: addl $8, %esp + cfi_adjust_cfa_offset (-8) + fstp %st(1) + ret + + cfi_adjust_cfa_offset (8) + .align ALIGNARG(4) +2: // y is a large integer (absolute value at least 1L<<10), but + // may be odd unless at least 1L<<64. So it may be necessary + // to adjust the sign of a negative result afterwards. + fxch // x : y + fabs // |x| : y + fxch // y : x + .align ALIGNARG(4) +3: /* y is a real number. */ + fxch // x : y + fldl MO(one) // 1.0 : x : y + fldl MO(limit) // 0.29 : 1.0 : x : y + fld %st(2) // x : 0.29 : 1.0 : x : y + fsub %st(2) // x-1 : 0.29 : 1.0 : x : y + fabs // |x-1| : 0.29 : 1.0 : x : y + fucompp // 1.0 : x : y + fnstsw + fxch // x : 1.0 : y + sahf + ja 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)) + + // Before scaling, we must negate if x is negative and y is an + // odd integer. + testb $2, %dh + jz 291f + // x is negative. If y is an odd integer, negate the result. + fldl 20(%esp) // y : 2^fract(y*log2(x)) : int(y*log2(x)) + fld %st // y : y : 2^fract(y*log2(x)) : int(y*log2(x)) + fabs // |y| : y : 2^fract(y*log2(x)) : int(y*log2(x)) + fcompl MO(p63) // y : 2^fract(y*log2(x)) : int(y*log2(x)) + fnstsw + sahf + jnc 290f + + // We must find out whether y is an odd integer. + fld %st // y : y : 2^fract(y*log2(x)) : int(y*log2(x)) + fistpll (%esp) // y : 2^fract(y*log2(x)) : int(y*log2(x)) + fildll (%esp) // int(y) : y : 2^fract(y*log2(x)) : int(y*log2(x)) + fucompp // 2^fract(y*log2(x)) : int(y*log2(x)) + fnstsw + sahf + jne 291f + + // 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 292f // jump if not odd + // It's an odd integer. + fchs + jmp 292f + + cfi_adjust_cfa_offset (8) +290: fstp %st(0) // 2^fract(y*log2(x)) : int(y*log2(x)) +291: addl $8, %esp + cfi_adjust_cfa_offset (-8) +292: 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)) + DBL_NARROW_EVAL_UFLOW_NONNAN + 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 + fldl MO(one) // 1 + fldl 4(%esp) // x : 1 + fabs // abs(x) : 1 + fucompp // < 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 + fldl MOX(inf_zero, %edx, 4) + ret + + .align ALIGNARG(4) +14: fldl MO(one) + ret + + .align ALIGNARG(4) +13: fldl 4(%esp) // load x == NaN + ret + + cfi_adjust_cfa_offset (8) + .align ALIGNARG(4) + // x is ±inf +15: fstp %st(0) // y + testb $2, %dh + jz 16f // jump if x == +inf + + // fistpll raises invalid exception for |y| >= 1L<<63, so test + // that (in which case y is certainly even) before testing + // whether y is odd. + fld %st // y : y + fabs // |y| : y + fcompl MO(p63) // y + fnstsw + sahf + jnc 16f + + // We must find out whether y is an odd integer. + fld %st // y : y + fistpll (%esp) // y + fildll (%esp) // int(y) : y + fucompp // <empty> + fnstsw + sahf + jne 17f + + // OK, the value is an integer. + popl %eax + cfi_adjust_cfa_offset (-4) + popl %edx + cfi_adjust_cfa_offset (-4) + andb $1, %al + jz 18f // 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) +16: 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) +17: shll $30, %edx // sign bit for y in right position + addl $8, %esp + cfi_adjust_cfa_offset (-8) +18: shrl $31, %edx + fldl MOX(inf_zero, %edx, 8) + ret + + cfi_adjust_cfa_offset (8) + .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 + + // fistpll raises invalid exception for |y| >= 1L<<63, so test + // that (in which case y is certainly even) before testing + // whether y is odd. + fld %st // y : y + fabs // |y| : y + fcompl MO(p63) // y + fnstsw + sahf + jnc 25f + + fld %st // y : y + fistpll (%esp) // y + fildll (%esp) // int(y) : y + fucompp // <empty> + fnstsw + sahf + jne 26f + + // OK, the value is an integer. + popl %eax + cfi_adjust_cfa_offset (-4) + popl %edx + cfi_adjust_cfa_offset (-4) + 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 + + cfi_adjust_cfa_offset (8) +25: fstp %st(0) +26: addl $8, %esp + cfi_adjust_cfa_offset (-8) +27: // 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. +21: testb $2, %dh + jz 22f + + // fistpll raises invalid exception for |y| >= 1L<<63, so test + // that (in which case y is certainly even) before testing + // whether y is odd. + fcoml MO(p63) // y + fnstsw + sahf + jnc 22f + + fld %st // y : y + fistpll (%esp) // y + fildll (%esp) // int(y) : y + fucompp // <empty> + fnstsw + sahf + jne 23f + + // OK, the value is an integer. + popl %eax + cfi_adjust_cfa_offset (-4) + popl %edx + cfi_adjust_cfa_offset (-4) + andb $1, %al + jz 24f // jump if not odd + // It's an odd integer. + fldl MO(mzero) + ret + + cfi_adjust_cfa_offset (8) +22: fstp %st(0) +23: addl $8, %esp // Don't use 2 x pop + cfi_adjust_cfa_offset (-8) +24: fldl MO(zero) + ret + +END(__ieee754_pow) +strong_alias (__ieee754_pow, __pow_finite) |