sysdeps/unix/sysv/linux/sparc/sparc64/brk.S

   1 /* Copyright (C) 1997-2015 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Richard Henderson <richard@gnu.ai.mit.edu>, 1997.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 /* __brk is a special syscall under Linux since it never returns an
  20    error.  Instead, the error condition is indicated by returning the old
  21    break value (instead of the new, requested one).  */
  22
  23 #include <sysdep.h>
  24 #define _ERRNO_H
  25 #include <bits/errno.h>
  26
  27 #ifdef PIC
  28 .section .bss
  29         .align 8
  30         .globl __curbrk
  31 __curbrk: .skip 8
  32         .type __curbrk,@object
  33         .size __curbrk,8
  34 #else
  35 .common __curbrk, 8, 8
  36 #endif
  37
  38         .text
  39 ENTRY (__brk)
  40         save    %sp, -192, %sp
  41         cfi_def_cfa_register(%fp)
  42         cfi_window_save
  43         cfi_register(%o7, %i7)
  44 #ifdef PIC
  45         SETUP_PIC_REG(l7)
  46 #endif
  47
  48         LOADSYSCALL(brk)
  49         mov     %i0, %o0
  50
  51         ta      0x6d
  52
  53         /* All the ways we can fail... */
  54         bcs,pn  %xcc, .Lerr1
  55          nop
  56         brz,pt  %i0, .Lok
  57          subcc  %i0, %o0, %g0
  58         bne,pn  %xcc, .Lerr0
  59          nop
  60
  61         /* Update __curbrk and return cleanly.  */
  62 .Lok:
  63 #ifndef PIC
  64         sethi   %hi(__curbrk), %g1
  65         or      %g1, %lo(__curbrk), %g1
  66 #else
  67         sethi   %gdop_hix22(__curbrk), %g1
  68         xor     %g1, %gdop_lox10(__curbrk), %g1
  69         ldx     [%l7 + %g1], %g1, %gdop(__curbrk)
  70 #endif
  71         stx     %o0, [%g1]
  72         mov     %g0, %i0
  73
  74         /* Don't use "ret" cause the preprocessor will eat it.  */
  75         jmpl    %i7+8, %g0
  76          restore
  77
  78         /* What a horrible way to die.  */
  79 .Lerr0: set     ENOMEM, %o0
  80 .Lerr1:
  81 #ifndef _LIBC_REENTRANT
  82 #ifndef PIC
  83         sethi   %hi(errno), %g1
  84         or      %g1, %lo(errno), %g1
  85 #else
  86         sethi   %gdop_hix22(errno), %g1
  87         xor     %g1, %gdop_lox10(errno), %g1
  88         ldx     [%l7 + %g1], %g1, %gdop(errno)
  89 #endif
  90         st      %o0, [%g1]
  91 #else
  92 #if IS_IN (libc)
  93         call    HIDDEN_JUMPTARGET(__errno_location)
  94 #else
  95         call    __errno_location
  96 #endif
  97          mov    %o0,%l1
  98         st      %l1, [%o0]
  99 #endif
 100         sub     %g0, 1, %i0
 101         jmpl    %i7+8, %g0
 102          restore
 103 END (__brk)
 104
 105 weak_alias (__brk, brk)