sysdeps/i386/fpu/s_frexpf.S

   1 /* ix87 specific frexp implementation for float.
   2    Copyright (C) 1997, 2000, 2005 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <machine/asm.h>
  22 #include "bp-sym.h"
  23 #include "bp-asm.h"
  24
  25 #ifdef __ELF__
  26         .section .rodata
  27 #else
  28         .text
  29 #endif
  30
  31         .align ALIGNARG(4)
  32         ASM_TYPE_DIRECTIVE(two25,@object)
  33 two25:  .byte 0, 0, 0, 0x4c
  34         ASM_SIZE_DIRECTIVE(two25)
  35
  36 #ifdef PIC
  37 #define MO(op) op##@GOTOFF(%edx)
  38 #else
  39 #define MO(op) op
  40 #endif
  41
  42 #define PARMS   LINKAGE         /* no space for saved regs */
  43 #define VAL     PARMS
  44 #define EXPP    VAL+4
  45
  46         .text
  47 ENTRY (BP_SYM (__frexpf))
  48         ENTER
  49
  50         movl    VAL(%esp), %eax
  51         xorl    %ecx, %ecx
  52         movl    %eax, %edx
  53         andl    $0x7fffffff, %eax
  54         jz      1f
  55         cmpl    $0x7f800000, %eax
  56         jae     1f
  57
  58         cmpl    $0x00800000, %eax
  59         jae     2f
  60
  61         flds    VAL(%esp)
  62 #ifdef  PIC
  63         LOAD_PIC_REG (dx)
  64 #endif
  65         fmuls   MO(two25)
  66         movl    $-25, %ecx
  67         fstps   VAL(%esp)
  68         fwait
  69         movl    VAL(%esp), %eax
  70         movl    %eax, %edx
  71         andl    $0x7fffffff, %eax
  72
  73 2:      shrl    $23, %eax
  74         andl    $0x807fffff, %edx
  75         subl    $126, %eax
  76         orl     $0x3f000000, %edx
  77         addl    %eax, %ecx
  78         movl    %edx, VAL(%esp)
  79
  80         /* Store %ecx in the variable pointed to by the second argument,
  81            get the factor from the stack and return.  */
  82 1:      movl    EXPP(%esp), %eax
  83         CHECK_BOUNDS_BOTH_WIDE (%eax, EXPP(%esp), $4)
  84         flds    VAL(%esp)
  85         movl    %ecx, (%eax)
  86
  87         LEAVE
  88         ret
  89 END (BP_SYM (__frexpf))
  90 weak_alias (BP_SYM (__frexpf), BP_SYM (frexpf))