1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  23  */
  24 /*
  25  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  26  * Use is subject to license terms.
  27  */
  28 
  29         .file "log.s"
  30 
  31 #include "libm.h"
  32 LIBM_ANSI_PRAGMA_WEAK(log,function)
  33 #include "libm_synonyms.h"
  34 #include "libm_protos.h"
  35 
  36         ENTRY(log)
  37         fldln2                          / loge(2)
  38         movl    8(%esp),%eax            / eax <-- hi_32(x)
  39         testl   $0x80000000,%eax
  40         jnz     .maybe_0_or_less
  41         testl   $0x7fffffff,%eax
  42         jz      .maybe_0
  43         fldl    4(%esp)                 / arg, loge(2)
  44         fyl2x                           / loge(2)*log2(arg); ln(arg)
  45         ret
  46 
  47 .maybe_0:
  48         movl    4(%esp),%ecx            / ecx <-- lo_32(x)
  49         cmpl    $0,%ecx
  50         je      .zero                   / no branch if x is +denormal
  51 .neg_nan_reentry:
  52         fldl    4(%esp)                 / arg, loge(2)
  53         fyl2x                           / loge(2)*log2(arg); ln(arg)
  54         ret
  55 
  56 .zero_or_less:
  57         / x =< 0
  58         testl   $0x7fffffff,%eax
  59         jnz     .less_than_0
  60         movl    4(%esp),%ecx            / ecx <-- lo_32(x)
  61         cmpl    $0,%ecx
  62         jne     .less_than_0            / branch if x is -denormal
  63 .zero:
  64         / x = +/-0
  65         pushl   %ebp
  66         movl    %esp,%ebp
  67         PIC_SETUP(1)
  68         pushl   $16
  69         jmp     .merge
  70         
  71 .maybe_0_or_less:
  72         cmpl    $0xfff00000,%eax        / -INF below hi_32(x)?
  73         ja      .neg_nan_reentry
  74         jb      .zero_or_less
  75         movl    4(%esp),%ecx            / ecx <-- lo_32(x)
  76         cmpl    $0,%ecx                 / is x NaN or -INF?
  77         jne     .neg_nan_reentry        / branch if x is NaN with signbit = 1
  78         / x = -INF
  79 .less_than_0:
  80         pushl   %ebp
  81         movl    %esp,%ebp
  82         PIC_SETUP(2)
  83         pushl   $17
  84 .merge:
  85         fstp    %st(0)                  / stack empty
  86         pushl   12(%ebp)
  87         pushl   8(%ebp)
  88         pushl   12(%ebp)
  89         pushl   8(%ebp)
  90         call    PIC_F(_SVID_libm_err)
  91         addl    $20,%esp
  92         PIC_WRAPUP
  93         leave
  94         ret
  95         .align  4
  96         SET_SIZE(log)