[avr-gcc-list] avr-g++ 4.3.2 and pgmspace.h

[Kövesdi György]

Hi,

I tried to store some data in flash memory using pgmspace.h.
It works well in C programs but I found that using C++ the things go wrong.
My sample code is:

$> cat x.c

#include <avr/io.h>
#include <avr/pgmspace.h>

prog_uint8_t table[] = {
    0x01,
    0x02,
    0x03
};

uint8_t x;

void test(uint8_t index)
{
    x=pgm_read_byte_near(table+index);
}

int main()
{
}

If it is compiled by avr-gcc, the result seems good:

$> avr-gcc -mmcu=attiny26 -Os x.c -o x
$> avr-objdump -d x

...
00000018 <table>:
  18:   01 02 03 00                                         ....
...
00000052 <test>:
  52:   e8 e1           ldi     r30, 0x18       ; 24
  54:   f0 e0           ldi     r31, 0x00       ; 0
  56:   e8 0f           add     r30, r24
  58:   f1 1d           adc     r31, r1
  5a:   c8 95           lpm
  5c:   e0 2d           mov     r30, r0
  5e:   e0 93 60 00     sts     0x0060, r30
  62:   08 95           ret
...

The table address seems correct here.
But using C++:

$> avr-g++ -mmcu=attiny26 -Os x.c -o x
$> avr-objdump -d x

...
0000004e <_Z4testh>:
  4e:   e0 e6           ldi     r30, 0x60       ; 96
  50:   f0 e0           ldi     r31, 0x00       ; 0
  52:   e8 0f           add     r30, r24
  54:   f1 1d           adc     r31, r1
  56:   c8 95           lpm
  58:   e0 2d           mov     r30, r0
  5a:   e0 93 64 00     sts     0x0064, r30
  5e:   08 95           ret
...

The table seems now stored in the data segment.
Other MCU types give the same result.

Tanx in advance
K. Gy.