On Thu, Aug 30, 2007 at 04:55:02PM +1000, Erik Christiansen wrote:
> On Thu, Aug 30, 2007 at 07:16:24AM +0200, Joerg Wunsch wrote:
> > If all else fails, we could still opt for differently named input
> > section (lfuse, hfuse, efuse), and combine them in the linker script
> > into one output section. Again, that would be similar to combining
> > .eeprom* input sections into just one .eeprom output section right
> > now.
>
> Actually, I think that's neater, not least because the magic addresses
> are not seen in the assembler source, but reside only in the linker
> script, where they belong.
The attached does it more neatly, doesn't it? :-)
Erik
P.S. If there's any assembler macro mucky-stuff left to do, I'm
available. (Week after next. :-)
# avr-as -alcmns fuse_demo.s -o fuse_demo.o > fuse_demo.lst
# avr-ld -T fuse_demo.ld -M -o fuse_demo.elf fuse_demo.o > fuse_demo.map
.global lfuse, hfuse, efuse, lock, sig
.section .avr_fuses,"a"
lfuse: .byte 0x11
hfuse: .byte 0x22
efuse: .byte 0x33
.section .avr_lock,"a"
lock: .byte 0x44
.section .avr_sig,"a"
sig: .byte 0x55
/* Based on avr-gcc's default linker script, for normal executables */
OUTPUT_FORMAT("elf32-avr","elf32-avr","elf32-avr")
OUTPUT_ARCH(avr:4)
/* ATmega64 Constants */
RAMEND = 0x20 + 0xE0 + 0x1000 - 1 ; /* Registers + I/O + RAM */
MEMORY
{
text (rx) : ORIGIN = 0, LENGTH = 62K
boot (rx) : ORIGIN = 62K, LENGTH = 2K
data (rw!x) : ORIGIN = 0x800100, LENGTH = 4K
eeprom (rw!x) : ORIGIN = 0x810000, LENGTH = 2K
fuses (rw!x) : ORIGIN = 0x910000, LENGTH = 1K
}
/* This time we're being less profligate with the address space. */
SECTIONS
{
.fuse_stuff :
{
*(.avr_fuses)
. = ALIGN (0x10);
*(.avr_lock)
. = ALIGN (0x10);
*(.avr_sig)
} > fuses
}
fuse_demo.elf: file format elf32-avr
Disassembly of section .fuse_stuff:
00910000 <lfuse>:
910000: 11 22 and r1, r17
00910001 <hfuse>:
910001: 22 33 cpi r18, 0x32 ; 50
00910002 <efuse>:
910002: 33 00 .word 0x0033 ; ????
...
00910010 <lock>:
910010: 44 00 .word 0x0044 ; ????
...
00910020 <sig>:
910020: 55 00 Address 0x00910020 is out of bounds.
.word 0xffff ; ????
/* Note: The above info message is of no import. */
Memory Configuration
Name Origin Length Attributes
text 0x00000000 0x0000f800 xr
boot 0x0000f800 0x00000800 xr
data 0x00800100 0x00001000 rw !x
eeprom 0x00810000 0x00000800 rw !x
fuses 0x00910000 0x00000400 rw !x
Linker script and memory map
0x000010ff RAMEND = 0x10ff
.fuse_stuff 0x00910000 0x21
*(.avr_fuses)
.avr_fuses 0x00910000 0x3 fuse_demo.o
0x00910001 hfuse
0x00910002 efuse
0x00910000 lfuse
0x00910010 . = ALIGN (0x10)
*fill* 0x00910003 0xd 00
*(.avr_lock)
.avr_lock 0x00910010 0x1 fuse_demo.o
0x00910010 lock
0x00910020 . = ALIGN (0x10)
*fill* 0x00910011 0xf 00
*(.avr_sig)
.avr_sig 0x00910020 0x1 fuse_demo.o
0x00910020 sig
LOAD fuse_demo.o
OUTPUT(fuse_demo.elf elf32-avr)
.text 0x00000000 0x0
.data 0x00800100 0x0
.bss 0x00800100 0x0
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