gcc/config/rs6000/eabi.asm

   1 /*
   2  * Special support for eabi and SVR4
   3  *
   4  *   Copyright (C) 1995, 1996, 1998, 2000, 2001, 2008, 2009
   5  *   Free Software Foundation, Inc.
   6  *   Written By Michael Meissner
   7  *
   8  * This file is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU General Public License as published by the
  10  * Free Software Foundation; either version 3, or (at your option) any
  11  * later version.
  12  *
  13  * This file is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * General Public License for more details.
  17  *
  18  * Under Section 7 of GPL version 3, you are granted additional
  19  * permissions described in the GCC Runtime Library Exception, version
  20  * 3.1, as published by the Free Software Foundation.
  21  *
  22  * You should have received a copy of the GNU General Public License and
  23  * a copy of the GCC Runtime Library Exception along with this program;
  24  * see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  25  * <http://www.gnu.org/licenses/>.
  26  */
  27
  28 /* Do any initializations needed for the eabi environment */
  29
  30         .section ".text"
  31         #include "ppc-asm.h"
  32
  33 #ifndef __powerpc64__
  34
  35          .section ".got2","aw"
  36         .align  2
  37 .LCTOC1 = . /* +32768 */
  38
  39 /* Table of addresses */
  40 .Ltable = .-.LCTOC1
  41         .long   .LCTOC1                         /* address we are really at */
  42
  43 .Lsda = .-.LCTOC1
  44         .long   _SDA_BASE_                      /* address of the first small data area */
  45
  46 .Lsdas = .-.LCTOC1
  47         .long   __SDATA_START__                 /* start of .sdata/.sbss section */
  48
  49 .Lsdae = .-.LCTOC1
  50         .long   __SBSS_END__                    /* end of .sdata/.sbss section */
  51
  52 .Lsda2 = .-.LCTOC1
  53         .long   _SDA2_BASE_                     /* address of the second small data area */
  54
  55 .Lsda2s = .-.LCTOC1
  56         .long   __SDATA2_START__                /* start of .sdata2/.sbss2 section */
  57
  58 .Lsda2e = .-.LCTOC1
  59         .long   __SBSS2_END__                   /* end of .sdata2/.sbss2 section */
  60
  61 #ifdef _RELOCATABLE
  62 .Lgots = .-.LCTOC1
  63         .long   __GOT_START__                   /* Global offset table start */
  64
  65 .Lgotm1 = .-.LCTOC1
  66         .long   _GLOBAL_OFFSET_TABLE_-4         /* end of GOT ptrs before BLCL + 3 reserved words */
  67
  68 .Lgotm2 = .-.LCTOC1
  69         .long   _GLOBAL_OFFSET_TABLE_+12        /* start of GOT ptrs after BLCL + 3 reserved words */
  70
  71 .Lgote = .-.LCTOC1
  72         .long   __GOT_END__                     /* Global offset table end */
  73
  74 .Lgot2s = .-.LCTOC1
  75         .long   __GOT2_START__                  /* -mrelocatable GOT pointers start */
  76
  77 .Lgot2e = .-.LCTOC1
  78         .long   __GOT2_END__                    /* -mrelocatable GOT pointers end */
  79
  80 .Lfixups = .-.LCTOC1
  81         .long   __FIXUP_START__                 /* start of .fixup section */
  82
  83 .Lfixupe = .-.LCTOC1
  84         .long   __FIXUP_END__                   /* end of .fixup section */
  85
  86 .Lctors = .-.LCTOC1
  87         .long   __CTOR_LIST__                   /* start of .ctor section */
  88
  89 .Lctore = .-.LCTOC1
  90         .long   __CTOR_END__                    /* end of .ctor section */
  91
  92 .Ldtors = .-.LCTOC1
  93         .long   __DTOR_LIST__                   /* start of .dtor section */
  94
  95 .Ldtore = .-.LCTOC1
  96         .long   __DTOR_END__                    /* end of .dtor section */
  97
  98 .Lexcepts = .-.LCTOC1
  99         .long   __EXCEPT_START__                /* start of .gcc_except_table section */
 100
 101 .Lexcepte = .-.LCTOC1
 102         .long   __EXCEPT_END__                  /* end of .gcc_except_table section */
 103
 104 .Linit = .-.LCTOC1
 105         .long   .Linit_p                        /* address of variable to say we've been called */
 106
 107         .text
 108         .align  2
 109 .Lptr:
 110         .long   .LCTOC1-.Laddr                  /* PC relative pointer to .got2 */
 111 #endif
 112
 113         .data
 114         .align  2
 115 .Linit_p:
 116         .long   0
 117
 118         .text
 119
 120 FUNC_START(__eabi)
 121
 122 /* Eliminate -mrelocatable code if not -mrelocatable, so that this file can
 123    be assembled with other assemblers than GAS.  */
 124
 125 #ifndef _RELOCATABLE
 126         addis   10,0,.Linit_p@ha                /* init flag */
 127         addis   11,0,.LCTOC1@ha                 /* load address of .LCTOC1 */
 128         lwz     9,.Linit_p@l(10)                /* init flag */
 129         addi    11,11,.LCTOC1@l
 130         cmplwi  2,9,0                           /* init flag != 0? */
 131         bnelr   2                               /* return now, if we've been called already */
 132         stw     1,.Linit_p@l(10)                /* store a nonzero value in the done flag */
 133
 134 #else /* -mrelocatable */
 135         mflr    0
 136         bl      .Laddr                          /* get current address */
 137 .Laddr:
 138         mflr    12                              /* real address of .Laddr */
 139         lwz     11,(.Lptr-.Laddr)(12)           /* linker generated address of .LCTOC1 */
 140         add     11,11,12                        /* correct to real pointer */
 141         lwz     12,.Ltable(11)                  /* get linker's idea of where .Laddr is */
 142         lwz     10,.Linit(11)                   /* address of init flag */
 143         subf.   12,12,11                        /* calculate difference */
 144         lwzx    9,10,12                         /* done flag */
 145         cmplwi  2,9,0                           /* init flag != 0? */
 146         mtlr    0                               /* restore in case branch was taken */
 147         bnelr   2                               /* return now, if we've been called already */
 148         stwx    1,10,12                         /* store a nonzero value in the done flag */
 149         beq+    0,.Lsdata                       /* skip if we don't need to relocate */
 150
 151 /* We need to relocate the .got2 pointers.  */
 152
 153         lwz     3,.Lgot2s(11)                   /* GOT2 pointers start */
 154         lwz     4,.Lgot2e(11)                   /* GOT2 pointers end */
 155         add     3,12,3                          /* adjust pointers */
 156         add     4,12,4
 157         bl      FUNC_NAME(__eabi_convert)       /* convert pointers in .got2 section */
 158
 159 /* Fixup the .ctor section for static constructors */
 160
 161         lwz     3,.Lctors(11)                   /* constructors pointers start */
 162         lwz     4,.Lctore(11)                   /* constructors pointers end */
 163         bl      FUNC_NAME(__eabi_convert)       /* convert constructors */
 164
 165 /* Fixup the .dtor section for static destructors */
 166
 167         lwz     3,.Ldtors(11)                   /* destructors pointers start */
 168         lwz     4,.Ldtore(11)                   /* destructors pointers end */
 169         bl      FUNC_NAME(__eabi_convert)       /* convert destructors */
 170
 171 /* Fixup the .gcc_except_table section for G++ exceptions */
 172
 173         lwz     3,.Lexcepts(11)                 /* exception table pointers start */
 174         lwz     4,.Lexcepte(11)                 /* exception table pointers end */
 175         bl      FUNC_NAME(__eabi_convert)       /* convert exceptions */
 176
 177 /* Fixup the addresses in the GOT below _GLOBAL_OFFSET_TABLE_-4 */
 178
 179         lwz     3,.Lgots(11)                    /* GOT table pointers start */
 180         lwz     4,.Lgotm1(11)                   /* GOT table pointers below _GLOBAL_OFFSET_TABLE-4 */
 181         bl      FUNC_NAME(__eabi_convert)       /* convert lower GOT */
 182
 183 /* Fixup the addresses in the GOT above _GLOBAL_OFFSET_TABLE_+12 */
 184
 185         lwz     3,.Lgotm2(11)                   /* GOT table pointers above _GLOBAL_OFFSET_TABLE+12 */
 186         lwz     4,.Lgote(11)                    /* GOT table pointers end */
 187         bl      FUNC_NAME(__eabi_convert)       /* convert lower GOT */
 188
 189 /* Fixup any user initialized pointers now (the compiler drops pointers to */
 190 /* each of the relocs that it does in the .fixup section).  */
 191
 192 .Lfix:
 193         lwz     3,.Lfixups(11)                  /* fixup pointers start */
 194         lwz     4,.Lfixupe(11)                  /* fixup pointers end */
 195         bl      FUNC_NAME(__eabi_uconvert)      /* convert user initialized pointers */
 196
 197 .Lsdata:
 198         mtlr    0                               /* restore link register */
 199 #endif /* _RELOCATABLE */
 200
 201 /* Only load up register 13 if there is a .sdata and/or .sbss section */
 202         lwz     3,.Lsdas(11)                    /* start of .sdata/.sbss section */
 203         lwz     4,.Lsdae(11)                    /* end of .sdata/.sbss section */
 204         cmpw    1,3,4                           /* .sdata/.sbss section non-empty? */
 205         beq-    1,.Lsda2l                       /* skip loading r13 */
 206
 207         lwz     13,.Lsda(11)                    /* load r13 with _SDA_BASE_ address */
 208
 209 /* Only load up register 2 if there is a .sdata2 and/or .sbss2 section */
 210
 211 .Lsda2l:
 212         lwz     3,.Lsda2s(11)                   /* start of .sdata/.sbss section */
 213         lwz     4,.Lsda2e(11)                   /* end of .sdata/.sbss section */
 214         cmpw    1,3,4                           /* .sdata/.sbss section non-empty? */
 215         beq+    1,.Ldone                        /* skip loading r2 */
 216
 217         lwz     2,.Lsda2(11)                    /* load r2 with _SDA2_BASE_ address */
 218
 219 /* Done adjusting pointers, return by way of doing the C++ global constructors.  */
 220
 221 .Ldone:
 222         b       FUNC_NAME(__init)       /* do any C++ global constructors (which returns to caller) */
 223 FUNC_END(__eabi)
 224
 225 /* Special subroutine to convert a bunch of pointers directly.
 226    r0           has original link register
 227    r3           has low pointer to convert
 228    r4           has high pointer to convert
 229    r5 .. r10    are scratch registers
 230    r11          has the address of .LCTOC1 in it.
 231    r12          has the value to add to each pointer
 232    r13 .. r31   are unchanged */
 233 #ifdef _RELOCATABLE
 234 FUNC_START(__eabi_convert)
 235         cmplw   1,3,4                           /* any pointers to convert? */
 236         subf    5,3,4                           /* calculate number of words to convert */
 237         bclr    4,4                             /* return if no pointers */
 238
 239         srawi   5,5,2
 240         addi    3,3,-4                          /* start-4 for use with lwzu */
 241         mtctr   5
 242
 243 .Lcvt:
 244         lwzu    6,4(3)                          /* pointer to convert */
 245         cmpwi   0,6,0
 246         beq-    .Lcvt2                          /* if pointer is null, don't convert */
 247
 248         add     6,6,12                          /* convert pointer */
 249         stw     6,0(3)
 250 .Lcvt2:
 251         bdnz+   .Lcvt
 252         blr
 253
 254 FUNC_END(__eabi_convert)
 255
 256 /* Special subroutine to convert the pointers the user has initialized.  The
 257    compiler has placed the address of the initialized pointer into the .fixup
 258    section.
 259
 260    r0           has original link register
 261    r3           has low pointer to convert
 262    r4           has high pointer to convert
 263    r5 .. r10    are scratch registers
 264    r11          has the address of .LCTOC1 in it.
 265    r12          has the value to add to each pointer
 266    r13 .. r31   are unchanged */
 267
 268 FUNC_START(__eabi_uconvert)
 269         cmplw   1,3,4                           /* any pointers to convert? */
 270         subf    5,3,4                           /* calculate number of words to convert */
 271         bclr    4,4                             /* return if no pointers */
 272
 273         srawi   5,5,2
 274         addi    3,3,-4                          /* start-4 for use with lwzu */
 275         mtctr   5
 276
 277 .Lucvt:
 278         lwzu    6,4(3)                          /* next pointer to pointer to convert */
 279         add     6,6,12                          /* adjust pointer */
 280         lwz     7,0(6)                          /* get the pointer it points to */
 281         stw     6,0(3)                          /* store adjusted pointer */
 282         add     7,7,12                          /* adjust */
 283         stw     7,0(6)
 284         bdnz+   .Lucvt
 285         blr
 286
 287 FUNC_END(__eabi_uconvert)
 288 #endif
 289 #endif