From 5046dbb4a7eba5eccfd258f92f4735c9ffc8d069 Mon Sep 17 00:00:00 2001 From: Zack Weinberg Date: Thu, 8 Jun 2017 15:39:03 -0400 Subject: Prepare for radical source tree reorganization. All top-level files and directories are moved into a temporary storage directory, REORG.TODO, except for files that will certainly still exist in their current form at top level when we're done (COPYING, COPYING.LIB, LICENSES, NEWS, README), all old ChangeLog files (which are moved to the new directory OldChangeLogs, instead), and the generated file INSTALL (which is just deleted; in the new order, there will be no generated files checked into version control). --- REORG.TODO/sysdeps/x86_64/fpu/e_log2l.S | 91 +++++++++++++++++++++++++++++++++ 1 file changed, 91 insertions(+) create mode 100644 REORG.TODO/sysdeps/x86_64/fpu/e_log2l.S (limited to 'REORG.TODO/sysdeps/x86_64/fpu/e_log2l.S') diff --git a/REORG.TODO/sysdeps/x86_64/fpu/e_log2l.S b/REORG.TODO/sysdeps/x86_64/fpu/e_log2l.S new file mode 100644 index 0000000000..023ec29164 --- /dev/null +++ b/REORG.TODO/sysdeps/x86_64/fpu/e_log2l.S @@ -0,0 +1,91 @@ +/* + * Written by J.T. Conklin . + * Adapted for use as log2 by Ulrich Drepper . + * Public domain. + * + * Changed to use fyl2xp1 for values near 1, . + * Adapted for x86-64 by Andreas Jaeger . + */ + +#include + + .section .rodata.cst8,"aM",@progbits,8 + + .p2align 3 + .type one,@object +one: .double 1.0 + ASM_SIZE_DIRECTIVE(one) + /* It is not important that this constant is precise. It is only + a value which is known to be on the safe side for using the + fyl2xp1 instruction. */ + .type 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_log2l) + fldl MO(one) + fldt 8(%rsp) // x : 1 + fxam + fnstsw + fld %st // x : x : 1 + testb $1, %ah + jnz 3f // in case x is NaN or ħInf +4: fsub %st(2), %st // x-1 : x : 1 + fld %st // x-1 : x-1 : x : 1 + fabs // |x-1| : x-1 : x : 1 + fcompl MO(limit) // x-1 : x : 1 + fnstsw // x-1 : x : 1 + andb $0x45, %ah + jz 2f + fxam + fnstsw + andb $0x45, %ah + cmpb $0x40, %ah + jne 5f + fabs // log2(1) is +0 in all rounding modes. +5: fstp %st(1) // x-1 : 1 + fyl2xp1 // log(x) + ret + +2: fstp %st(0) // x : 1 + fyl2x // log(x) + ret + +3: testb $4, %ah + jnz 4b // in case x is ħInf + fstp %st(1) + fstp %st(1) + fadd %st(0) + ret +END (__ieee754_log2l) + + +ENTRY(__log2l_finite) + fldl MO(one) + fldt 8(%rsp) // x : 1 + fld %st // x : x : 1 + fsub %st(2), %st // x-1 : x : 1 + fld %st // x-1 : x-1 : x : 1 + fabs // |x-1| : x-1 : x : 1 + fcompl MO(limit) // x-1 : x : 1 + fnstsw // x-1 : x : 1 + andb $0x45, %ah + jz 2b + fxam + fnstsw + andb $0x45, %ah + cmpb $0x40, %ah + jne 6f + fabs // log2(1) is +0 in all rounding modes. +6: fstp %st(1) // x-1 : 1 + fyl2xp1 // log(x) + ret +END (__log2l_finite) -- cgit 1.4.1