Hi everybody,
I'm writing code for embedded ARM microcontroler using arm-none-eabi-gcc
version 8.3.1 20190703. I'd like to put my static data structure into
FLASH memory to save precious RAM. My code is like this:
---------------------------------
static const char *test_a[] /* __attribute__((section (".rodata"))) */ = {
"test1",
"test2",
};
static const char *test_b[] /* __attribute__((section (".rodata"))) */ = {
"test3",
"test4",
};
static const char *test_c[] /* __attribute__((section (".rodata"))) */ = {
"test5",
"test6",
};
static const struct dict_ports_s {
const char **alias;
const char len;
const char *name;
} ports[] = {
{ .name = "test0", .len = sizeof(test_a), .alias = test_a },
{ .name = "test1", .len = sizeof(test_b), .alias = test_b },
{ .name = "test2", .len = sizeof(test_c), .alias = test_c },
};
int main(int ac, char *av[]) {
int i;
for (i = 0; i < 3; i++) {
printf("%d %s\n", ports[i].len , ports[i].alias[0]);
}
return 0;
}
------------------------------------------------
but neither the "const" words in declarations, nor the explicit
selection of ".RODATA" section make those constant data structure go
into read-only data section. Assembler, that gcc produces with "-S"
option looks like this:
-----------------------------------------
.section .data.test_a,"aw"
.align 2
.set .LANCHOR0,. + 0
.type test_a, %object
.size test_a, 8
test_a:
.word .LC5
.word .LC6
.section .data.test_b,"aw"
.align 2
.set .LANCHOR1,. + 0
.type test_b, %object
.size test_b, 8
test_b:
.word .LC3
.word .LC4
.section .data.test_c,"aw"
.align 2
.set .LANCHOR2,. + 0
.type test_c, %object
.size test_c, 8
test_c:
.word .LC1
.word .LC2
----------------------------------------------------
so the structures are emitted into relevant ".data.test*" sections which
are writable. And that's not what I need.
How do I get them emitted into "a" section (with no "w" attribute)?
BR.
Rafał
PS: I'm not a subscriber of the list, so pls Cc: responses to me directly.
