From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Boris V. Guzhov" <borg@int.spb.ru>
To: <ecos-discuss@sourceware.cygnus.com>
Subject: [ECOS] rodata feature :-(
Date: Mon, 20 Nov 2000 06:52:00 -0000
Message-id: <004c01c052fa$badb9bf0$7601a8c0@borg>
X-SW-Source: 2000-11/msg00244.html

Hi All,

There is a very interesting  feature of the "rodata" section.

There is the a.out program that linked with the following linker
script (mlt_i386_pc_ram.ldi):
MEMORY
{
    ram : ORIGIN = 0x0, LENGTH = 0x800000
}

SECTIONS
{
    SECTIONS_BEGIN
    SECTION_vectors (ram, 0x10000, LMA_EQ_VMA)
    SECTION_text (ram, ALIGN (0x4), LMA_EQ_VMA)
    SECTION_fini (ram, ALIGN (0x4), LMA_EQ_VMA)
    SECTION_rodata1 (ram, ALIGN (0x8), LMA_EQ_VMA)
    SECTION_rodata (ram, ALIGN (0x8), LMA_EQ_VMA)
    SECTION_fixup (ram, ALIGN (0x4), LMA_EQ_VMA)
    SECTION_gcc_except_table (ram, ALIGN (0x1), LMA_EQ_VMA)
    SECTION_rel__got (ram, ALIGN (0x1), LMA_EQ_VMA)
    SECTION_data (ram, 0x100000, LMA_EQ_VMA)
    SECTION_sbss (ram, ALIGN (0x4), LMA_EQ_VMA)
    SECTION_bss (ram, ALIGN (0x10), LMA_EQ_VMA)
    SECTIONS_END
}

It's "nm -gn a.out" output:
....
0007a0e0 R bit_first_set8
00092d08 R  Cyg_libc_str_null_mask_1
 00092d10 R Cyg_libc_str_null_mask_2
0009522f R nothrow
00095360 A _EXCEPT_END_
....
There is strange memory hole between "bit_first_set8" and "
Cyg_libc_str_null_mask_1":
0x92d08 - 0x7a0e0 = 0x18C28 (~100 kb).

How can you explain it?

Note that:
- the bit_first_set8 declaration is  "extern const unsigned char
bit_first_set8[256];",
- the bit_first_set8 and Cyg_libc_str_null_mask_*  variables are declared in
different files.

Thanks in advance.

--
Boris Guzhov,
St.Petersburg, Russia