gcc/config/rs6000/eabi.asm

   1 /*
   2  * Special support for eabi and SVR4
   3  *
   4  *   Copyright (C) 1995, 1996, 1998, 2000, 2001 Free Software Foundation, Inc.
   5  *   Written By Michael Meissner
   6  *
   7  * This file is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License as published by the
   9  * Free Software Foundation; either version 2, or (at your option) any
  10  * later version.
  11  *
  12  * In addition to the permissions in the GNU General Public License, the
  13  * Free Software Foundation gives you unlimited permission to link the
  14  * compiled version of this file with other programs, and to distribute
  15  * those programs without any restriction coming from the use of this
  16  * file.  (The General Public License restrictions do apply in other
  17  * respects; for example, they cover modification of the file, and
  18  * distribution when not linked into another program.)
  19  *
  20  * This file is distributed in the hope that it will be useful, but
  21  * WITHOUT ANY WARRANTY; without even the implied warranty of
  22  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  23  * General Public License for more details.
  24  *
  25  * You should have received a copy of the GNU General Public License
  26  * along with this program; see the file COPYING.  If not, write to
  27  * the Free Software Foundation, 59 Temple Place - Suite 330,
  28  * Boston, MA 02111-1307, USA.
  29  *
  30  *    As a special exception, if you link this library with files
  31  *    compiled with GCC to produce an executable, this does not cause
  32  *    the resulting executable to be covered by the GNU General Public License.
  33  *    This exception does not however invalidate any other reasons why
  34  *    the executable file might be covered by the GNU General Public License.
  35  */
  36
  37 /* Do any initializations needed for the eabi environment */
  38
  39         .file   "eabi.asm"
  40         .section ".text"
  41         #include "ppc-asm.h"
  42
  43 #ifndef __powerpc64__
  44
  45          .section ".got2","aw"
  46         .align  2
  47 .LCTOC1 = . /* +32768 */
  48
  49 /* Table of addresses */
  50 .Ltable = .-.LCTOC1
  51         .long   .LCTOC1                         /* address we are really at */
  52
  53 .Lsda = .-.LCTOC1
  54         .long   _SDA_BASE_                      /* address of the first small data area */
  55
  56 .Lsdas = .-.LCTOC1
  57         .long   __SDATA_START__                 /* start of .sdata/.sbss section */
  58
  59 .Lsdae = .-.LCTOC1
  60         .long   __SBSS_END__                    /* end of .sdata/.sbss section */
  61
  62 .Lsda2 = .-.LCTOC1
  63         .long   _SDA2_BASE_                     /* address of the second small data area */
  64
  65 .Lsda2s = .-.LCTOC1
  66         .long   __SDATA2_START__                /* start of .sdata2/.sbss2 section */
  67
  68 .Lsda2e = .-.LCTOC1
  69         .long   __SBSS2_END__                   /* end of .sdata2/.sbss2 section */
  70
  71 #ifdef _RELOCATABLE
  72 .Lgots = .-.LCTOC1
  73         .long   __GOT_START__                   /* Global offset table start */
  74
  75 .Lgotm1 = .-.LCTOC1
  76         .long   _GLOBAL_OFFSET_TABLE_-4         /* end of GOT ptrs before BLCL + 3 reserved words */
  77
  78 .Lgotm2 = .-.LCTOC1
  79         .long   _GLOBAL_OFFSET_TABLE_+12        /* start of GOT ptrs after BLCL + 3 reserved words */
  80
  81 .Lgote = .-.LCTOC1
  82         .long   __GOT_END__                     /* Global offset table end */
  83
  84 .Lgot2s = .-.LCTOC1
  85         .long   __GOT2_START__                  /* -mrelocatable GOT pointers start */
  86
  87 .Lgot2e = .-.LCTOC1
  88         .long   __GOT2_END__                    /* -mrelocatable GOT pointers end */
  89
  90 .Lfixups = .-.LCTOC1
  91         .long   __FIXUP_START__                 /* start of .fixup section */
  92
  93 .Lfixupe = .-.LCTOC1
  94         .long   __FIXUP_END__                   /* end of .fixup section */
  95
  96 .Lctors = .-.LCTOC1
  97         .long   __CTOR_LIST__                   /* start of .ctor section */
  98
  99 .Lctore = .-.LCTOC1
 100         .long   __CTOR_END__                    /* end of .ctor section */
 101
 102 .Ldtors = .-.LCTOC1
 103         .long   __DTOR_LIST__                   /* start of .dtor section */
 104
 105 .Ldtore = .-.LCTOC1
 106         .long   __DTOR_END__                    /* end of .dtor section */
 107
 108 .Lexcepts = .-.LCTOC1
 109         .long   __EXCEPT_START__                /* start of .gcc_except_table section */
 110
 111 .Lexcepte = .-.LCTOC1
 112         .long   __EXCEPT_END__                  /* end of .gcc_except_table section */
 113
 114 .Linit = .-.LCTOC1
 115         .long   .Linit_p                        /* address of variable to say we've been called */
 116
 117         .text
 118         .align  2
 119 .Lptr:
 120         .long   .LCTOC1-.Laddr                  /* PC relative pointer to .got2 */
 121 #endif
 122
 123         .data
 124         .align  2
 125 .Linit_p:
 126         .long   0
 127
 128         .text
 129
 130 FUNC_START(__eabi)
 131
 132 /* Eliminate -mrelocatable code if not -mrelocatable, so that this file can
 133    be assembled with other assemblers than GAS.  */
 134
 135 #ifndef _RELOCATABLE
 136         addis   10,0,.Linit_p@ha                /* init flag */
 137         addis   11,0,.LCTOC1@ha                 /* load address of .LCTOC1 */
 138         lwz     9,.Linit_p@l(10)                /* init flag */
 139         addi    11,11,.LCTOC1@l
 140         cmplwi  2,9,0                           /* init flag != 0? */
 141         bnelr   2                               /* return now, if we've been called already */
 142         stw     1,.Linit_p@l(10)                /* store a nonzero value in the done flag */
 143
 144 #else /* -mrelocatable */
 145         mflr    0
 146         bl      .Laddr                          /* get current address */
 147 .Laddr:
 148         mflr    12                              /* real address of .Laddr */
 149         lwz     11,(.Lptr-.Laddr)(12)           /* linker generated address of .LCTOC1 */
 150         add     11,11,12                        /* correct to real pointer */
 151         lwz     12,.Ltable(11)                  /* get linker's idea of where .Laddr is */
 152         lwz     10,.Linit(11)                   /* address of init flag */
 153         subf.   12,12,11                        /* calculate difference */
 154         lwzx    9,10,12                         /* done flag */
 155         cmplwi  2,9,0                           /* init flag != 0? */
 156         mtlr    0                               /* restore in case branch was taken */
 157         bnelr   2                               /* return now, if we've been called already */
 158         stwx    1,10,12                         /* store a nonzero value in the done flag */
 159         beq+    0,.Lsdata                       /* skip if we don't need to relocate */
 160
 161 /* We need to relocate the .got2 pointers.  */
 162
 163         lwz     3,.Lgot2s(11)                   /* GOT2 pointers start */
 164         lwz     4,.Lgot2e(11)                   /* GOT2 pointers end */
 165         add     3,12,3                          /* adjust pointers */
 166         add     4,12,4
 167         bl      FUNC_NAME(__eabi_convert)       /* convert pointers in .got2 section */
 168
 169 /* Fixup the .ctor section for static constructors */
 170
 171         lwz     3,.Lctors(11)                   /* constructors pointers start */
 172         lwz     4,.Lctore(11)                   /* constructors pointers end */
 173         bl      FUNC_NAME(__eabi_convert)       /* convert constructors */
 174
 175 /* Fixup the .dtor section for static destructors */
 176
 177         lwz     3,.Ldtors(11)                   /* destructors pointers start */
 178         lwz     4,.Ldtore(11)                   /* destructors pointers end */
 179         bl      FUNC_NAME(__eabi_convert)       /* convert destructors */
 180
 181 /* Fixup the .gcc_except_table section for G++ exceptions */
 182
 183         lwz     3,.Lexcepts(11)                 /* exception table pointers start */
 184         lwz     4,.Lexcepte(11)                 /* exception table pointers end */
 185         bl      FUNC_NAME(__eabi_convert)       /* convert exceptions */
 186
 187 /* Fixup the addresses in the GOT below _GLOBAL_OFFSET_TABLE_-4 */
 188
 189         lwz     3,.Lgots(11)                    /* GOT table pointers start */
 190         lwz     4,.Lgotm1(11)                   /* GOT table pointers below _GLOBAL_OFFSET_TABLE-4 */
 191         bl      FUNC_NAME(__eabi_convert)       /* convert lower GOT */
 192
 193 /* Fixup the addresses in the GOT above _GLOBAL_OFFSET_TABLE_+12 */
 194
 195         lwz     3,.Lgotm2(11)                   /* GOT table pointers above _GLOBAL_OFFSET_TABLE+12 */
 196         lwz     4,.Lgote(11)                    /* GOT table pointers end */
 197         bl      FUNC_NAME(__eabi_convert)       /* convert lower GOT */
 198
 199 /* Fixup any user initialized pointers now (the compiler drops pointers to */
 200 /* each of the relocs that it does in the .fixup section).  */
 201
 202 .Lfix:
 203         lwz     3,.Lfixups(11)                  /* fixup pointers start */
 204         lwz     4,.Lfixupe(11)                  /* fixup pointers end */
 205         bl      FUNC_NAME(__eabi_uconvert)      /* convert user initialized pointers */
 206
 207 .Lsdata:
 208         mtlr    0                               /* restore link register */
 209 #endif /* _RELOCATABLE */
 210
 211 /* Only load up register 13 if there is a .sdata and/or .sbss section */
 212         lwz     3,.Lsdas(11)                    /* start of .sdata/.sbss section */
 213         lwz     4,.Lsdae(11)                    /* end of .sdata/.sbss section */
 214         cmpw    1,3,4                           /* .sdata/.sbss section non-empty? */
 215         beq-    1,.Lsda2l                       /* skip loading r13 */
 216
 217         lwz     13,.Lsda(11)                    /* load r13 with _SDA_BASE_ address */
 218
 219 /* Only load up register 2 if there is a .sdata2 and/or .sbss2 section */
 220
 221 .Lsda2l:
 222         lwz     3,.Lsda2s(11)                   /* start of .sdata/.sbss section */
 223         lwz     4,.Lsda2e(11)                   /* end of .sdata/.sbss section */
 224         cmpw    1,3,4                           /* .sdata/.sbss section non-empty? */
 225         beq+    1,.Ldone                        /* skip loading r2 */
 226
 227         lwz     2,.Lsda2(11)                    /* load r2 with _SDA2_BASE_ address */
 228
 229 /* Done adjusting pointers, return by way of doing the C++ global constructors.  */
 230
 231 .Ldone:
 232         b       FUNC_NAME(__init)       /* do any C++ global constructors (which returns to caller) */
 233 FUNC_END(__eabi)
 234
 235 /* Special subroutine to convert a bunch of pointers directly.
 236    r0           has original link register
 237    r3           has low pointer to convert
 238    r4           has high pointer to convert
 239    r5 .. r10    are scratch registers
 240    r11          has the address of .LCTOC1 in it.
 241    r12          has the value to add to each pointer
 242    r13 .. r31   are unchanged */
 243
 244 FUNC_START(__eabi_convert)
 245         cmplw   1,3,4                           /* any pointers to convert? */
 246         subf    5,3,4                           /* calculate number of words to convert */
 247         bclr    4,4                             /* return if no pointers */
 248
 249         srawi   5,5,2
 250         addi    3,3,-4                          /* start-4 for use with lwzu */
 251         mtctr   5
 252
 253 .Lcvt:
 254         lwzu    6,4(3)                          /* pointer to convert */
 255         cmpi    0,6,0
 256         beq-    .Lcvt2                          /* if pointer is null, don't convert */
 257
 258         add     6,6,12                          /* convert pointer */
 259         stw     6,0(3)
 260 .Lcvt2:
 261         bdnz+   .Lcvt
 262         blr
 263
 264 FUNC_END(__eabi_convert)
 265
 266 /* Special subroutine to convert the pointers the user has initialized.  The
 267    compiler has placed the address of the initialized pointer into the .fixup
 268    section.
 269
 270    r0           has original link register
 271    r3           has low pointer to convert
 272    r4           has high pointer to convert
 273    r5 .. r10    are scratch registers
 274    r11          has the address of .LCTOC1 in it.
 275    r12          has the value to add to each pointer
 276    r13 .. r31   are unchanged */
 277
 278 FUNC_START(__eabi_uconvert)
 279         cmplw   1,3,4                           /* any pointers to convert? */
 280         subf    5,3,4                           /* calculate number of words to convert */
 281         bclr    4,4                             /* return if no pointers */
 282
 283         srawi   5,5,2
 284         addi    3,3,-4                          /* start-4 for use with lwzu */
 285         mtctr   5
 286
 287 .Lucvt:
 288         lwzu    6,4(3)                          /* next pointer to pointer to convert */
 289         add     6,6,12                          /* adjust pointer */
 290         lwz     7,0(6)                          /* get the pointer it points to */
 291         stw     6,0(3)                          /* store adjusted pointer */
 292         add     7,7,12                          /* adjust */
 293         stw     7,0(6)
 294         bdnz+   .Lucvt
 295         blr
 296
 297 FUNC_END(__eabi_uconvert)
 298
 299 #endif