| /* |
| * Written by J.T. Conklin <jtc@netbsd.org>. |
| * Public domain. |
| * |
| * Adapted for `long double' by Ulrich Drepper <drepper@cygnus.com>. |
| * Adapted for x86-64 by Andreas Jaeger <aj@suse.de>. |
| */ |
| |
| #include <machine/asm.h> |
| |
| RCSID("$NetBSD: s_log1p.S,v 1.7 1995/05/09 00:10:58 jtc Exp $") |
| |
| .section .rodata |
| |
| .align ALIGNARG(4) |
| /* The fyl2xp1 can only be used for values in |
| -1 + sqrt(2) / 2 <= x <= 1 - sqrt(2) / 2 |
| 0.29 is a safe value. |
| */ |
| #if defined(__clang__) |
| /* Necessary in the absence of a .tfloat directive in the assembler. */ |
| limit: |
| .byte 0xe1, 0x7a, 0x14, 0xae, 0x47, 0xe1, 0x7a, 0x94, 0xfd, 0x3f |
| #else |
| limit: .tfloat 0.29 |
| #endif |
| /* Please note: we use a double value here. Since 1.0 has |
| an exact representation this does not effect the accuracy |
| but it helps to optimize the code. */ |
| one: .double 1.0 |
| |
| /* |
| * Use the fyl2xp1 function when the argument is in the range -0.29 to 0.29, |
| * otherwise fyl2x with the needed extra computation. |
| */ |
| #ifdef PIC |
| #define MO(op) op##(%rip) |
| #else |
| #define MO(op) op |
| #endif |
| |
| .text |
| ENTRY(__log1pl) |
| fldln2 |
| |
| fldt 8(%rsp) |
| |
| fxam |
| fnstsw |
| fld %st |
| testb $1, %ah |
| jnz 3f // in case x is NaN or ±Inf |
| 4: |
| fabs |
| fldt MO(limit) |
| fcompp |
| fnstsw |
| andb $1,%ah |
| jz 2f |
| |
| movzwl 8+8(%rsp), %eax |
| xorb $0x80, %ah |
| cmpl $0xc040, %eax |
| jae 5f |
| |
| faddl MO(one) |
| 5: fyl2x |
| ret |
| |
| 2: fyl2xp1 |
| ret |
| |
| 3: testb $4, %ah |
| jnz 4b // in case x is ±Inf |
| fstp %st(1) |
| fstp %st(1) |
| fadd %st(0) |
| ret |
| |
| END (__log1pl) |
