On 2014-01-28 20:15, Ian Lance Taylor wrote:
On Tue, Jan 28, 2014 at 7:49 AM, Sebastian Huber
<sebastian.huber@xxxxxxxxxxxxxxxxxx> wrote:
it seems GCC uses this ColdFire TLS ABI:
https://lists.debian.org/debian-68k/2007/11/msg00071.html
Here we have a function
void *__m68k_read_tp(void)
which must return the thread pointer in register a0.
I have to implement this function. Is there a way to instruct GCC to return
the value in register a0 instead of d0 or do I have to use assembler to
implement this function?
I believe that on m68k GNU/Linux a function that returns a pointer
will normally return the value in a0.
Ian
The function
void *__m68k_read_tp(void)
{
const Thread_Control *executing = _Thread_Get_executing();
return (char *) executing->Start.tls_area +
_TLS_Get_thread_control_block_area_size((uintptr_t) _TLS_Alignment)
+ 0x7000;
}
translates to
__m68k_read_tp:
move.l #_TLS_Alignment,%d0
moveq #8,%d1
move.l _Per_CPU_Information+18,%a0
cmp.l %d0,%d1
jls .L2
moveq #8,%d0
.L2:
add.l #28672,%d0
add.l 194(%a0),%d0
rts
I use now:
void __m68k_read_tp(void)
{
const Thread_Control *executing = _Thread_Get_executing();
void *tp = (char *) executing->Start.tls_area +
_TLS_Get_thread_control_block_area_size((uintptr_t) _TLS_Alignment)
+ 0x7000;
__asm__ volatile (
"move.l %0, %%a0"
:
: "d" (tp)
);
}
--
Sebastian Huber, embedded brains GmbH
Address : Dornierstr. 4, D-82178 Puchheim, Germany
Phone : +49 89 189 47 41-16
Fax : +49 89 189 47 41-09
E-Mail : sebastian.huber@xxxxxxxxxxxxxxxxxx
PGP : Public key available on request.
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