From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Robert Cragie" <rcc@jennic.com>
To: <ecos-discuss@sources.redhat.com>
Subject: [ECOS] Declaring new section
Date: Fri, 10 Aug 2001 03:40:00 -0000
Message-id: <NDBBLOIOMLKELOJBAPAGGEBDCIAA.rcc@jennic.com>
X-SW-Source: 2001-08/msg00305.html

I needed to declare a new section for a specific SRAM device on my board. I
did this by the adding the following lines in the .ldi file:

// eCos memory layout - Tue Feb 29 14:25:49 2000

// This is a generated file - do not edit

#include <cyg/infra/cyg_type.inc>

MEMORY
{
    ram : ORIGIN = 0, LENGTH = 0x4000000
    rom : ORIGIN = 0x24000000, LENGTH = 0x80000
Added this line --->        sram : ORIGIN = 0x28001000, LENGTH = 0x0003F000
}

SECTIONS
{
    SECTIONS_BEGIN
    SECTION_rom_vectors (rom, 0x24000000, LMA_EQ_VMA)
    SECTION_text (rom, ALIGN (0x4), LMA_EQ_VMA)
    SECTION_fini (rom, ALIGN (0x4), LMA_EQ_VMA)
    SECTION_rodata (rom, ALIGN (0x4), LMA_EQ_VMA)
    SECTION_rodata1 (rom, ALIGN (0x4), LMA_EQ_VMA)
    SECTION_fixup (rom, ALIGN (0x4), LMA_EQ_VMA)
    SECTION_gcc_except_table (rom, ALIGN (0x4), LMA_EQ_VMA)
    SECTION_fixed_vectors (ram, 0x20, LMA_EQ_VMA)
    SECTION_data (ram, 0x800, FOLLOWING (.gcc_except_table))
    SECTION_bss (ram, ALIGN (0x4), LMA_EQ_VMA)
    CYG_LABEL_DEFN(__heap1) = ALIGN (0x8);
Added this line --->    SECTION_sram (sram, 0x28001000, LMA_EQ_VMA)
    SECTIONS_END
}

This worked fine, but when I came to generate an S-record file (using
"arm-elf-objcopy -S -O srec myfile myfile.srec") for downloading, it added
in loads of S-records at 0x28000000, all 0. This screws up the ARM Boot
Monitor flash downloader, as it somehow assumes these should go where the
flash is at 0x24000000. I noticed that the .sram section (according to
"arm-elf-objdump -h myfile") is of type CONTENTS, ALLOC, LOAD, DATA.

There is obviously a bit of magick going on between the .ldi file and
target.ld - is there any way I can make the .sram section like the .bss
section, i.e. so it is cleared to zero and doesn't appear as downloadable?

Also, whilst we're on the subject, is there anyway to link in .a files
without having to physically include them in target.ld?

TIA

Robert Cragie
Design Engineer
Jennic Ltd.
Furnival Street
Sheffield
S1 4QT
United Kingdom
Tel: +44 (0) 114 281 4512
Fax: +44 (0) 114 281 2951
Mob: +44 (0) 7940 558520
mailto:rcc@jennic.com
http://www.jennic.com