sim/rx/load.c

   1 /* load.c --- loading object files into the RX simulator.
   2
   3 Copyright (C) 2005, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
   4 Contributed by Red Hat, Inc.
   5
   6 This file is part of the GNU simulators.
   7
   8 This program is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 3 of the License, or
  11 (at your option) any later version.
  12
  13 This program is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21
  22 #include "config.h"
  23 #include <stdlib.h>
  24 #include <stdio.h>
  25 #include <string.h>
  26
  27 #include "bfd.h"
  28 #include "libbfd.h"
  29 #include "cpu.h"
  30 #include "mem.h"
  31 #include "elf/internal.h"
  32 #include "elf/common.h"
  33
  34 /* A note about endianness and swapping...
  35
  36    The RX chip is CISC-like in that the opcodes are variable length
  37    and are read as a stream of bytes.  However, the chip itself shares
  38    the code prefetch block with the data fetch block, so when it's
  39    configured for big endian mode, the memory fetched for opcodes is
  40    word-swapped.  To compensate for this, the ELF file has the code
  41    sections pre-swapped.  Our BFD knows this, and for the convenience
  42    of all the other tools, hides this swapping at a very low level.
  43    I.e.  it swaps words on the way out and on the way back in.
  44
  45    Fortunately the iovector routines are unaffected by this, so we
  46    can use them to read in the segments directly, without having
  47    to worry about byte swapping anything.
  48
  49    However, our opcode decoder and disassemblers need to swap the data
  50    after reading it from the chip memory, just like the chip does.
  51    All in all, the code words are swapped four times between the
  52    assembler and our decoder.
  53
  54    If the chip is running in little-endian mode, no swapping is done
  55    anywhere.  Note also that the *operands* within opcodes are always
  56    encoded in little-endian format.  */
  57
  58 void
  59 rx_load (bfd *prog)
  60 {
  61   unsigned long highest_addr_loaded = 0;
  62   Elf_Internal_Phdr * phdrs;
  63   long sizeof_phdrs;
  64   int num_headers;
  65   int i;
  66
  67   rx_big_endian = bfd_big_endian (prog);
  68
  69   /* Note we load by ELF program header not by BFD sections.
  70      This is because BFD sections get their information from
  71      the ELF section structure, which only includes a VMA value
  72      and not an LMA value.  */
  73   sizeof_phdrs = bfd_get_elf_phdr_upper_bound (prog);
  74   if (sizeof_phdrs == 0)
  75     {
  76       fprintf (stderr, "Failed to get size of program headers\n");
  77       return;
  78     }
  79   phdrs = malloc (sizeof_phdrs);
  80   if (phdrs == NULL)
  81     {
  82       fprintf (stderr, "Failed allocate memory to hold program headers\n");
  83       return;
  84     }
  85   num_headers = bfd_get_elf_phdrs (prog, phdrs);
  86   if (num_headers < 1)
  87     {
  88       fprintf (stderr, "Failed to read program headers\n");
  89       return;
  90     }
  91
  92   for (i = 0; i < num_headers; i++)
  93     {
  94       Elf_Internal_Phdr * p = phdrs + i;
  95       char *buf;
  96       bfd_vma size;
  97       bfd_vma base;
  98       file_ptr offset;
  99
 100       size = p->p_filesz;
 101       if (size <= 0)
 102         continue;
 103
 104       base = p->p_paddr;
 105       if (verbose > 1)
 106         fprintf (stderr, "[load segment: lma=%08x vma=%08x size=%08x]\n",
 107                  (int) base, (int) p->p_vaddr, (int) size);
 108
 109       buf = malloc (size);
 110       if (buf == NULL)
 111         {
 112           fprintf (stderr, "Failed to allocate buffer to hold program segment\n");
 113           continue;
 114         }
 115
 116       offset = p->p_offset;
 117       if (prog->iovec->bseek (prog, offset, SEEK_SET) != 0)
 118         {
 119           fprintf (stderr, "Failed to seek to offset %lx\n", (long) offset);
 120           continue;
 121         }
 122       if (prog->iovec->bread (prog, buf, size) != size)
 123         {
 124           fprintf (stderr, "Failed to read %lx bytes\n", size);
 125           continue;
 126         }
 127
 128       mem_put_blk (base, buf, size);
 129       free (buf);
 130       if (highest_addr_loaded < base + size - 1 && size >= 4)
 131         highest_addr_loaded = base + size - 1;
 132     }
 133
 134   free (phdrs);
 135
 136   regs.r_pc = prog->start_address;
 137
 138   if (strcmp (bfd_get_target (prog), "srec") == 0
 139       || regs.r_pc == 0)
 140     {
 141       regs.r_pc = mem_get_si (0xfffffffc);
 142       heaptop = heapbottom = 0;
 143     }
 144
 145   if (verbose > 1)
 146     fprintf (stderr, "[start pc=%08x %s]\n",
 147              (unsigned int) regs.r_pc,
 148              rx_big_endian ? "BE" : "LE");
 149 }