* RFA: correct size of long double on PPC Linux
@ 2004-03-24 18:10 Jim Blandy
2004-03-26 14:12 ` Kevin Buettner
0 siblings, 1 reply; 6+ messages in thread
From: Jim Blandy @ 2004-03-24 18:10 UTC (permalink / raw)
To: gdb-patches
2004-03-24 Jim Blandy <jimb@redhat.com>
* ppc-linux-tdep.c (ppc_linux_init_abi): Long doubles are eight
bytes long on PPC Linux.
Index: gdb/ppc-linux-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/ppc-linux-tdep.c,v
retrieving revision 1.49
diff -c -r1.49 ppc-linux-tdep.c
*** gdb/ppc-linux-tdep.c 14 Nov 2003 14:16:29 -0000 1.49
--- gdb/ppc-linux-tdep.c 11 Feb 2004 18:59:31 -0000
***************
*** 1042,1047 ****
--- 1042,1049 ----
if (tdep->wordsize == 4)
{
+ set_gdbarch_long_double_bit (gdbarch, 8 * TARGET_CHAR_BIT);
+
/* Until November 2001, gcc did not comply with the 32 bit SysV
R4 ABI requirement that structures less than or equal to 8
bytes should be returned in registers. Instead GCC was using
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: RFA: correct size of long double on PPC Linux
2004-03-24 18:10 RFA: correct size of long double on PPC Linux Jim Blandy
@ 2004-03-26 14:12 ` Kevin Buettner
2004-03-26 15:19 ` Daniel Jacobowitz
0 siblings, 1 reply; 6+ messages in thread
From: Kevin Buettner @ 2004-03-26 14:12 UTC (permalink / raw)
To: Jim Blandy; +Cc: gdb-patches
On 24 Mar 2004 13:10:33 -0500
Jim Blandy <jimb@redhat.com> wrote:
> 2004-03-24 Jim Blandy <jimb@redhat.com>
>
> * ppc-linux-tdep.c (ppc_linux_init_abi): Long doubles are eight
> bytes long on PPC Linux.
Can you provide the ABI reference for this?
According to the documentation that I have (which is the System V ABI
PowerPC Processor Supplement), the size of a long double is 16 bytes.
Kevin
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: RFA: correct size of long double on PPC Linux
2004-03-26 14:12 ` Kevin Buettner
@ 2004-03-26 15:19 ` Daniel Jacobowitz
2004-03-26 15:45 ` Jim Blandy
0 siblings, 1 reply; 6+ messages in thread
From: Daniel Jacobowitz @ 2004-03-26 15:19 UTC (permalink / raw)
To: Kevin Buettner; +Cc: Jim Blandy, gdb-patches
On Thu, Mar 25, 2004 at 10:23:58PM -0700, Kevin Buettner wrote:
> On 24 Mar 2004 13:10:33 -0500
> Jim Blandy <jimb@redhat.com> wrote:
>
> > 2004-03-24 Jim Blandy <jimb@redhat.com>
> >
> > * ppc-linux-tdep.c (ppc_linux_init_abi): Long doubles are eight
> > bytes long on PPC Linux.
>
> Can you provide the ABI reference for this?
>
> According to the documentation that I have (which is the System V ABI
> PowerPC Processor Supplement), the size of a long double is 16 bytes.
Yes - this is one of the known warts in the PPC GNU/Linux ABI. People
have been talking for years about fixing it to match the SysV ABI. GCC
only recently got 128-bit long double support on PPC, so it may be
changing soon; but for all existing PPC GNU/Linux systems I know of,
eight bytes is correct.
--
Daniel Jacobowitz
MontaVista Software Debian GNU/Linux Developer
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: RFA: correct size of long double on PPC Linux
2004-03-26 15:19 ` Daniel Jacobowitz
@ 2004-03-26 15:45 ` Jim Blandy
2004-03-26 16:23 ` Kevin Buettner
0 siblings, 1 reply; 6+ messages in thread
From: Jim Blandy @ 2004-03-26 15:45 UTC (permalink / raw)
To: Daniel Jacobowitz; +Cc: Kevin Buettner, gdb-patches
Daniel Jacobowitz <drow@false.org> writes:
> On Thu, Mar 25, 2004 at 10:23:58PM -0700, Kevin Buettner wrote:
> > On 24 Mar 2004 13:10:33 -0500
> > Jim Blandy <jimb@redhat.com> wrote:
> >
> > > 2004-03-24 Jim Blandy <jimb@redhat.com>
> > >
> > > * ppc-linux-tdep.c (ppc_linux_init_abi): Long doubles are eight
> > > bytes long on PPC Linux.
> >
> > Can you provide the ABI reference for this?
> >
> > According to the documentation that I have (which is the System V ABI
> > PowerPC Processor Supplement), the size of a long double is 16 bytes.
>
> Yes - this is one of the known warts in the PPC GNU/Linux ABI. People
> have been talking for years about fixing it to match the SysV ABI. GCC
> only recently got 128-bit long double support on PPC, so it may be
> changing soon; but for all existing PPC GNU/Linux systems I know of,
> eight bytes is correct.
I went to the Linux Standards Base, and it said that programs that use
'long double' on PPC Linux are non-conformant. So I figured the best
I could do was to make GDB match GCC.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: RFA: correct size of long double on PPC Linux
2004-03-26 15:45 ` Jim Blandy
@ 2004-03-26 16:23 ` Kevin Buettner
2004-03-26 21:05 ` Jim Blandy
0 siblings, 1 reply; 6+ messages in thread
From: Kevin Buettner @ 2004-03-26 16:23 UTC (permalink / raw)
To: Jim Blandy; +Cc: gdb-patches, Daniel Jacobowitz
On 26 Mar 2004 10:45:13 -0500
Jim Blandy <jimb@redhat.com> wrote:
> Daniel Jacobowitz <drow@false.org> writes:
>
> > On Thu, Mar 25, 2004 at 10:23:58PM -0700, Kevin Buettner wrote:
> > > On 24 Mar 2004 13:10:33 -0500
> > > Jim Blandy <jimb@redhat.com> wrote:
> > >
> > > > 2004-03-24 Jim Blandy <jimb@redhat.com>
> > > >
> > > > * ppc-linux-tdep.c (ppc_linux_init_abi): Long doubles are eight
> > > > bytes long on PPC Linux.
> > >
> > > Can you provide the ABI reference for this?
> > >
> > > According to the documentation that I have (which is the System V ABI
> > > PowerPC Processor Supplement), the size of a long double is 16 bytes.
> >
> > Yes - this is one of the known warts in the PPC GNU/Linux ABI. People
> > have been talking for years about fixing it to match the SysV ABI. GCC
> > only recently got 128-bit long double support on PPC, so it may be
> > changing soon; but for all existing PPC GNU/Linux systems I know of,
> > eight bytes is correct.
>
> I went to the Linux Standards Base, and it said that programs that use
> 'long double' on PPC Linux are non-conformant. So I figured the best
> I could do was to make GDB match GCC.
Okay, this patch is approved then, so long as you add a suitable comment
about PPC Linux deviating from the System V ABI on this matter.
Thanks!
Kevin
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: RFA: correct size of long double on PPC Linux
2004-03-26 16:23 ` Kevin Buettner
@ 2004-03-26 21:05 ` Jim Blandy
0 siblings, 0 replies; 6+ messages in thread
From: Jim Blandy @ 2004-03-26 21:05 UTC (permalink / raw)
To: Kevin Buettner; +Cc: gdb-patches, Daniel Jacobowitz
Kevin Buettner <kevinb@redhat.com> writes:
> On 26 Mar 2004 10:45:13 -0500
> Jim Blandy <jimb@redhat.com> wrote:
>
> > Daniel Jacobowitz <drow@false.org> writes:
> >
> > > On Thu, Mar 25, 2004 at 10:23:58PM -0700, Kevin Buettner wrote:
> > > > On 24 Mar 2004 13:10:33 -0500
> > > > Jim Blandy <jimb@redhat.com> wrote:
> > > >
> > > > > 2004-03-24 Jim Blandy <jimb@redhat.com>
> > > > >
> > > > > * ppc-linux-tdep.c (ppc_linux_init_abi): Long doubles are eight
> > > > > bytes long on PPC Linux.
> > > >
> > > > Can you provide the ABI reference for this?
> > > >
> > > > According to the documentation that I have (which is the System V ABI
> > > > PowerPC Processor Supplement), the size of a long double is 16 bytes.
> > >
> > > Yes - this is one of the known warts in the PPC GNU/Linux ABI. People
> > > have been talking for years about fixing it to match the SysV ABI. GCC
> > > only recently got 128-bit long double support on PPC, so it may be
> > > changing soon; but for all existing PPC GNU/Linux systems I know of,
> > > eight bytes is correct.
> >
> > I went to the Linux Standards Base, and it said that programs that use
> > 'long double' on PPC Linux are non-conformant. So I figured the best
> > I could do was to make GDB match GCC.
>
> Okay, this patch is approved then, so long as you add a suitable comment
> about PPC Linux deviating from the System V ABI on this matter.
Okay, thanks. I've committed the following:
2004-03-24 Jim Blandy <jimb@redhat.com>
* ppc-linux-tdep.c (ppc_linux_init_abi): Long doubles are eight
bytes long on PPC Linux.
Index: ppc-linux-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/ppc-linux-tdep.c,v
retrieving revision 1.54
retrieving revision 1.55
diff -c -c -F'^(' -r1.54 -r1.55
*** ppc-linux-tdep.c 23 Mar 2004 14:47:56 -0000 1.54
--- ppc-linux-tdep.c 26 Mar 2004 20:59:38 -0000 1.55
***************
*** 1076,1081 ****
--- 1076,1090 ----
if (tdep->wordsize == 4)
{
+ /* NOTE: jimb/2004-03-26: The System V ABI PowerPC Processor
+ Supplement says that long doubles are sixteen bytes long.
+ However, as one of the known warts of its ABI, PPC GNU/Linux
+ uses eight-byte long doubles. GCC only recently got 128-bit
+ long double support on PPC, so it may be changing soon. The
+ Linux Standards Base says that programs that use 'long
+ double' on PPC GNU/Linux are non-conformant. */
+ set_gdbarch_long_double_bit (gdbarch, 8 * TARGET_CHAR_BIT);
+
/* Until November 2001, gcc did not comply with the 32 bit SysV
R4 ABI requirement that structures less than or equal to 8
bytes should be returned in registers. Instead GCC was using
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2004-03-26 21:05 UTC | newest]
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2004-03-24 18:10 RFA: correct size of long double on PPC Linux Jim Blandy
2004-03-26 14:12 ` Kevin Buettner
2004-03-26 15:19 ` Daniel Jacobowitz
2004-03-26 15:45 ` Jim Blandy
2004-03-26 16:23 ` Kevin Buettner
2004-03-26 21:05 ` Jim Blandy
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