* [PATCH] powerpc: provide __bswapdi2
@ 2013-05-10 21:18 David Woodhouse
2013-05-13 6:48 ` Anton Blanchard
2013-05-13 7:09 ` Michael Neuling
0 siblings, 2 replies; 18+ messages in thread
From: David Woodhouse @ 2013-05-10 21:18 UTC (permalink / raw)
To: linuxppc-dev; +Cc: viro
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From: David Woodhouse <David.Woodhouse@intel.com>
Some versions of GCC apparently expect this to be provided by libgcc.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
---
Untested.
diff --git a/arch/powerpc/kernel/misc_32.S b/arch/powerpc/kernel/misc_32.S
index 19e096b..f077dc2 100644
--- a/arch/powerpc/kernel/misc_32.S
+++ b/arch/powerpc/kernel/misc_32.S
@@ -657,6 +657,17 @@ _GLOBAL(__ucmpdi2)
li r3,2
blr
+_GLOBAL(__bswapdi2)
+ rlwinm 10,4,8,0xffffffff
+ rlwinm 11,3,8,0xffffffff
+ rlwimi 10,4,24,0,7
+ rlwimi 11,3,24,0,7
+ rlwimi 10,4,24,16,23
+ rlwimi 11,3,24,16,23
+ mr 4,11
+ mr 3,10
+ blr
+
_GLOBAL(abs)
srawi r4,r3,31
xor r3,r3,r4
diff --git a/arch/powerpc/kernel/misc_64.S b/arch/powerpc/kernel/misc_64.S
index 5cfa800..3b2e6e8 100644
--- a/arch/powerpc/kernel/misc_64.S
+++ b/arch/powerpc/kernel/misc_64.S
@@ -234,6 +234,18 @@ _GLOBAL(__flush_dcache_icache)
isync
blr
+_GLOBAL(__bswapdi2)
+ srdi 8,3,32
+ rlwinm 7,3,8,0xffffffff
+ rlwimi 7,3,24,0,7
+ rlwinm 9,8,8,0xffffffff
+ rlwimi 7,3,24,16,23
+ rlwimi 9,8,24,0,7
+ rlwimi 9,8,24,16,23
+ sldi 7,7,32
+ or 7,7,9
+ mr 3,7
+ blr
#if defined(CONFIG_PPC_PMAC) || defined(CONFIG_PPC_MAPLE)
/*
diff --git a/arch/powerpc/kernel/ppc_ksyms.c b/arch/powerpc/kernel/ppc_ksyms.c
index 78b8766..c296665 100644
--- a/arch/powerpc/kernel/ppc_ksyms.c
+++ b/arch/powerpc/kernel/ppc_ksyms.c
@@ -143,7 +143,8 @@ EXPORT_SYMBOL(__lshrdi3);
int __ucmpdi2(unsigned long long, unsigned long long);
EXPORT_SYMBOL(__ucmpdi2);
#endif
-
+long long __bswapdi2(long long);
+EXPORT_SYMBOL(__bswapdi2);
EXPORT_SYMBOL(memcpy);
EXPORT_SYMBOL(memset);
EXPORT_SYMBOL(memmove);
--
dwmw2
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^ permalink raw reply related [flat|nested] 18+ messages in thread
* Re: [PATCH] powerpc: provide __bswapdi2
2013-05-10 21:18 [PATCH] powerpc: provide __bswapdi2 David Woodhouse
@ 2013-05-13 6:48 ` Anton Blanchard
2013-05-13 7:20 ` Alan Modra
2013-05-13 7:09 ` Michael Neuling
1 sibling, 1 reply; 18+ messages in thread
From: Anton Blanchard @ 2013-05-13 6:48 UTC (permalink / raw)
To: David Woodhouse; +Cc: linuxppc-dev, viro, amodra
On Fri, 10 May 2013 22:18:27 +0100
David Woodhouse <dwmw2@infradead.org> wrote:
> From: David Woodhouse <David.Woodhouse@intel.com>
>
> Some versions of GCC apparently expect this to be provided by libgcc.
Thanks Dave. We were discussing this with Alan Modra and he doesn't
think the 64bit target should ever emit a call to __bswapdi2. Did you
only see it on 32bit, or 64bit as well?
Alan: I notice Dave is adding calls to __builtin_bswap, perhaps some
versions of the 64bit compiler did emit __bswapdi2 calls for that.
Anton
>
> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
> ---
> Untested.
>
> diff --git a/arch/powerpc/kernel/misc_32.S
> b/arch/powerpc/kernel/misc_32.S index 19e096b..f077dc2 100644
> --- a/arch/powerpc/kernel/misc_32.S
> +++ b/arch/powerpc/kernel/misc_32.S
> @@ -657,6 +657,17 @@ _GLOBAL(__ucmpdi2)
> li r3,2
> blr
>
> +_GLOBAL(__bswapdi2)
> + rlwinm 10,4,8,0xffffffff
> + rlwinm 11,3,8,0xffffffff
> + rlwimi 10,4,24,0,7
> + rlwimi 11,3,24,0,7
> + rlwimi 10,4,24,16,23
> + rlwimi 11,3,24,16,23
> + mr 4,11
> + mr 3,10
> + blr
> +
> _GLOBAL(abs)
> srawi r4,r3,31
> xor r3,r3,r4
> diff --git a/arch/powerpc/kernel/misc_64.S
> b/arch/powerpc/kernel/misc_64.S index 5cfa800..3b2e6e8 100644
> --- a/arch/powerpc/kernel/misc_64.S
> +++ b/arch/powerpc/kernel/misc_64.S
> @@ -234,6 +234,18 @@ _GLOBAL(__flush_dcache_icache)
> isync
> blr
>
> +_GLOBAL(__bswapdi2)
> + srdi 8,3,32
> + rlwinm 7,3,8,0xffffffff
> + rlwimi 7,3,24,0,7
> + rlwinm 9,8,8,0xffffffff
> + rlwimi 7,3,24,16,23
> + rlwimi 9,8,24,0,7
> + rlwimi 9,8,24,16,23
> + sldi 7,7,32
> + or 7,7,9
> + mr 3,7
> + blr
>
> #if defined(CONFIG_PPC_PMAC) || defined(CONFIG_PPC_MAPLE)
> /*
> diff --git a/arch/powerpc/kernel/ppc_ksyms.c
> b/arch/powerpc/kernel/ppc_ksyms.c index 78b8766..c296665 100644
> --- a/arch/powerpc/kernel/ppc_ksyms.c
> +++ b/arch/powerpc/kernel/ppc_ksyms.c
> @@ -143,7 +143,8 @@ EXPORT_SYMBOL(__lshrdi3);
> int __ucmpdi2(unsigned long long, unsigned long long);
> EXPORT_SYMBOL(__ucmpdi2);
> #endif
> -
> +long long __bswapdi2(long long);
> +EXPORT_SYMBOL(__bswapdi2);
> EXPORT_SYMBOL(memcpy);
> EXPORT_SYMBOL(memset);
> EXPORT_SYMBOL(memmove);
>
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] powerpc: provide __bswapdi2
2013-05-10 21:18 [PATCH] powerpc: provide __bswapdi2 David Woodhouse
2013-05-13 6:48 ` Anton Blanchard
@ 2013-05-13 7:09 ` Michael Neuling
2013-05-13 7:20 ` [PATCH v2] " Michael Neuling
` (3 more replies)
1 sibling, 4 replies; 18+ messages in thread
From: Michael Neuling @ 2013-05-13 7:09 UTC (permalink / raw)
To: David Woodhouse; +Cc: linuxppc-dev, viro
David Woodhouse <dwmw2@infradead.org> wrote:
> From: David Woodhouse <David.Woodhouse@intel.com>
>
> Some versions of GCC apparently expect this to be provided by libgcc.
>
> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
> ---
> Untested.
>
> diff --git a/arch/powerpc/kernel/misc_32.S b/arch/powerpc/kernel/misc_32.S
> index 19e096b..f077dc2 100644
> --- a/arch/powerpc/kernel/misc_32.S
> +++ b/arch/powerpc/kernel/misc_32.S
> @@ -657,6 +657,17 @@ _GLOBAL(__ucmpdi2)
> li r3,2
> blr
>
> +_GLOBAL(__bswapdi2)
> + rlwinm 10,4,8,0xffffffff
> + rlwinm 11,3,8,0xffffffff
> + rlwimi 10,4,24,0,7
> + rlwimi 11,3,24,0,7
> + rlwimi 10,4,24,16,23
> + rlwimi 11,3,24,16,23
> + mr 4,11
> + mr 3,10
> + blr
> +
This doesn't work for me but the below does:
_GLOBAL(__bswapdi2)
rotlwi r9,r4,8
rotlwi r10,r3,8
rlwimi r9,r4,24,0,7
rlwimi r10,r3,24,0,7
rlwimi r9,r4,24,16,23
rlwimi r10,r3,24,16,23
mr r4,r10
mr r3,r9
blr
stolen from GCC -02 output of:
unsigned long long __bswapdi2(unsigned long long x)
{
return ((x & 0x00000000000000ffULL) << 56) |
((x & 0x000000000000ff00ULL) << 40) |
((x & 0x0000000000ff0000ULL) << 24) |
((x & 0x00000000ff000000ULL) << 8) |
((x & 0x000000ff00000000ULL) >> 8) |
((x & 0x0000ff0000000000ULL) >> 24) |
((x & 0x00ff000000000000ULL) >> 40) |
((x & 0xff00000000000000ULL) >> 56);
}
> _GLOBAL(abs)
> srawi r4,r3,31
> xor r3,r3,r4
> diff --git a/arch/powerpc/kernel/misc_64.S b/arch/powerpc/kernel/misc_64.S
> index 5cfa800..3b2e6e8 100644
> --- a/arch/powerpc/kernel/misc_64.S
> +++ b/arch/powerpc/kernel/misc_64.S
> @@ -234,6 +234,18 @@ _GLOBAL(__flush_dcache_icache)
> isync
> blr
>
> +_GLOBAL(__bswapdi2)
> + srdi 8,3,32
> + rlwinm 7,3,8,0xffffffff
> + rlwimi 7,3,24,0,7
> + rlwinm 9,8,8,0xffffffff
> + rlwimi 7,3,24,16,23
> + rlwimi 9,8,24,0,7
> + rlwimi 9,8,24,16,23
> + sldi 7,7,32
> + or 7,7,9
> + mr 3,7
> + blr
This works but we should add "r" to the register names.
I'll repost
Mikey
>
> #if defined(CONFIG_PPC_PMAC) || defined(CONFIG_PPC_MAPLE)
> /*
> diff --git a/arch/powerpc/kernel/ppc_ksyms.c b/arch/powerpc/kernel/ppc_ksyms.c
> index 78b8766..c296665 100644
> --- a/arch/powerpc/kernel/ppc_ksyms.c
> +++ b/arch/powerpc/kernel/ppc_ksyms.c
> @@ -143,7 +143,8 @@ EXPORT_SYMBOL(__lshrdi3);
> int __ucmpdi2(unsigned long long, unsigned long long);
> EXPORT_SYMBOL(__ucmpdi2);
> #endif
> -
> +long long __bswapdi2(long long);
> +EXPORT_SYMBOL(__bswapdi2);
> EXPORT_SYMBOL(memcpy);
> EXPORT_SYMBOL(memset);
> EXPORT_SYMBOL(memmove);
>
> --
> dwmw2
>
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@lists.ozlabs.org
> https://lists.ozlabs.org/listinfo/linuxppc-dev
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] powerpc: provide __bswapdi2
2013-05-13 6:48 ` Anton Blanchard
@ 2013-05-13 7:20 ` Alan Modra
2013-05-13 10:27 ` David Woodhouse
0 siblings, 1 reply; 18+ messages in thread
From: Alan Modra @ 2013-05-13 7:20 UTC (permalink / raw)
To: Anton Blanchard; +Cc: linuxppc-dev, David Woodhouse, viro
On Mon, May 13, 2013 at 04:48:19PM +1000, Anton Blanchard wrote:
> On Fri, 10 May 2013 22:18:27 +0100
> David Woodhouse <dwmw2@infradead.org> wrote:
>
> > From: David Woodhouse <David.Woodhouse@intel.com>
> >
> > Some versions of GCC apparently expect this to be provided by libgcc.
>
> Thanks Dave. We were discussing this with Alan Modra and he doesn't
> think the 64bit target should ever emit a call to __bswapdi2. Did you
> only see it on 32bit, or 64bit as well?
>
> Alan: I notice Dave is adding calls to __builtin_bswap, perhaps some
> versions of the 64bit compiler did emit __bswapdi2 calls for that.
I did a little digging, and it looks like gcc-4.4 will emit __bswapdi2
calls. Support in rs6000.md appeared 2009-06-25.
--
Alan Modra
Australia Development Lab, IBM
^ permalink raw reply [flat|nested] 18+ messages in thread
* [PATCH v2] powerpc: provide __bswapdi2
2013-05-13 7:09 ` Michael Neuling
@ 2013-05-13 7:20 ` Michael Neuling
2013-05-13 7:33 ` [PATCH] " Gabriel Paubert
` (2 subsequent siblings)
3 siblings, 0 replies; 18+ messages in thread
From: Michael Neuling @ 2013-05-13 7:20 UTC (permalink / raw)
To: benh, David Woodhouse; +Cc: linuxppc-dev, viro
From: David Woodhouse <David.Woodhouse@intel.com>
Some versions of GCC apparently expect this to be provided by libgcc.
Updates from Mikey to fix 32 bit version and adding "r" to registers.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Michael Neuling <mikey@neuling.org>
diff --git a/arch/powerpc/kernel/misc_32.S b/arch/powerpc/kernel/misc_32.S
index 19e096b..3bcaa7ee 100644
--- a/arch/powerpc/kernel/misc_32.S
+++ b/arch/powerpc/kernel/misc_32.S
@@ -657,6 +657,17 @@ _GLOBAL(__ucmpdi2)
li r3,2
blr
+_GLOBAL(__bswapdi2)
+ rotlwi r9,r4,8
+ rotlwi r10,r3,8
+ rlwimi r9,r4,24,0,7
+ rlwimi r10,r3,24,0,7
+ rlwimi r9,r4,24,16,23
+ rlwimi r10,r3,24,16,23
+ mr r4,r10
+ mr r3,r9
+ blr
+
_GLOBAL(abs)
srawi r4,r3,31
xor r3,r3,r4
diff --git a/arch/powerpc/kernel/misc_64.S b/arch/powerpc/kernel/misc_64.S
index 5cfa800..637bd82 100644
--- a/arch/powerpc/kernel/misc_64.S
+++ b/arch/powerpc/kernel/misc_64.S
@@ -234,6 +234,18 @@ _GLOBAL(__flush_dcache_icache)
isync
blr
+_GLOBAL(__bswapdi2)
+ srdi r8,r3,32
+ rlwinm r7,r3,8,0xffffffff
+ rlwimi r7,r3,24,0,7
+ rlwinm r9,r8,8,0xffffffff
+ rlwimi r7,r3,24,16,23
+ rlwimi r9,r8,24,0,7
+ rlwimi r9,r8,24,16,23
+ sldi r7,r7,32
+ or r7,r7,r9
+ mr r3,r7
+ blr
#if defined(CONFIG_PPC_PMAC) || defined(CONFIG_PPC_MAPLE)
/*
diff --git a/arch/powerpc/kernel/ppc_ksyms.c b/arch/powerpc/kernel/ppc_ksyms.c
index 78b8766..c296665 100644
--- a/arch/powerpc/kernel/ppc_ksyms.c
+++ b/arch/powerpc/kernel/ppc_ksyms.c
@@ -143,7 +143,8 @@ EXPORT_SYMBOL(__lshrdi3);
int __ucmpdi2(unsigned long long, unsigned long long);
EXPORT_SYMBOL(__ucmpdi2);
#endif
-
+long long __bswapdi2(long long);
+EXPORT_SYMBOL(__bswapdi2);
EXPORT_SYMBOL(memcpy);
EXPORT_SYMBOL(memset);
EXPORT_SYMBOL(memmove);
^ permalink raw reply related [flat|nested] 18+ messages in thread
* Re: [PATCH] powerpc: provide __bswapdi2
2013-05-13 7:09 ` Michael Neuling
2013-05-13 7:20 ` [PATCH v2] " Michael Neuling
@ 2013-05-13 7:33 ` Gabriel Paubert
2013-05-13 10:23 ` [PATCH v3] " Michael Neuling
2013-05-13 10:33 ` [PATCH] " David Woodhouse
2013-05-14 1:09 ` Stephen Rothwell
3 siblings, 1 reply; 18+ messages in thread
From: Gabriel Paubert @ 2013-05-13 7:33 UTC (permalink / raw)
To: Michael Neuling; +Cc: linuxppc-dev, David Woodhouse, viro
On Mon, May 13, 2013 at 05:09:59PM +1000, Michael Neuling wrote:
> David Woodhouse <dwmw2@infradead.org> wrote:
>
> > From: David Woodhouse <David.Woodhouse@intel.com>
> >
> > Some versions of GCC apparently expect this to be provided by libgcc.
> >
> > Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
> > ---
> > Untested.
> >
> > diff --git a/arch/powerpc/kernel/misc_32.S b/arch/powerpc/kernel/misc_32.S
> > index 19e096b..f077dc2 100644
> > --- a/arch/powerpc/kernel/misc_32.S
> > +++ b/arch/powerpc/kernel/misc_32.S
> > @@ -657,6 +657,17 @@ _GLOBAL(__ucmpdi2)
> > li r3,2
> > blr
> >
> > +_GLOBAL(__bswapdi2)
> > + rlwinm 10,4,8,0xffffffff
> > + rlwinm 11,3,8,0xffffffff
> > + rlwimi 10,4,24,0,7
> > + rlwimi 11,3,24,0,7
> > + rlwimi 10,4,24,16,23
> > + rlwimi 11,3,24,16,23
> > + mr 4,11
> > + mr 3,10
> > + blr
> > +
>
> This doesn't work for me but the below does:
>
> _GLOBAL(__bswapdi2)
> rotlwi r9,r4,8
> rotlwi r10,r3,8
> rlwimi r9,r4,24,0,7
> rlwimi r10,r3,24,0,7
> rlwimi r9,r4,24,16,23
> rlwimi r10,r3,24,16,23
> mr r4,r10
> mr r3,r9
> blr
>
Actually, I'd swap the two mr instructions to never
have an instruction that uses the result from the
previous one.
> stolen from GCC -02 output of:
> unsigned long long __bswapdi2(unsigned long long x)
> {
> return ((x & 0x00000000000000ffULL) << 56) |
> ((x & 0x000000000000ff00ULL) << 40) |
> ((x & 0x0000000000ff0000ULL) << 24) |
> ((x & 0x00000000ff000000ULL) << 8) |
> ((x & 0x000000ff00000000ULL) >> 8) |
> ((x & 0x0000ff0000000000ULL) >> 24) |
> ((x & 0x00ff000000000000ULL) >> 40) |
> ((x & 0xff00000000000000ULL) >> 56);
> }
>
> > _GLOBAL(abs)
> > srawi r4,r3,31
> > xor r3,r3,r4
> > diff --git a/arch/powerpc/kernel/misc_64.S b/arch/powerpc/kernel/misc_64.S
> > index 5cfa800..3b2e6e8 100644
> > --- a/arch/powerpc/kernel/misc_64.S
> > +++ b/arch/powerpc/kernel/misc_64.S
> > @@ -234,6 +234,18 @@ _GLOBAL(__flush_dcache_icache)
> > isync
> > blr
> >
> > +_GLOBAL(__bswapdi2)
> > + srdi 8,3,32
> > + rlwinm 7,3,8,0xffffffff
> > + rlwimi 7,3,24,0,7
> > + rlwinm 9,8,8,0xffffffff
> > + rlwimi 7,3,24,16,23
> > + rlwimi 9,8,24,0,7
> > + rlwimi 9,8,24,16,23
> > + sldi 7,7,32
> > + or 7,7,9
> > + mr 3,7
> > + blr
>
> This works but we should add "r" to the register names.
>
And merge the last two instructions as a single "or r3,r7,r9".
Gabriel
^ permalink raw reply [flat|nested] 18+ messages in thread
* [PATCH v3] powerpc: provide __bswapdi2
2013-05-13 7:33 ` [PATCH] " Gabriel Paubert
@ 2013-05-13 10:23 ` Michael Neuling
0 siblings, 0 replies; 18+ messages in thread
From: Michael Neuling @ 2013-05-13 10:23 UTC (permalink / raw)
To: Benjamin Herrenschmidt
Cc: mikey, David Woodhouse, linuxppc-dev, viro, David Woodhouse
From: David Woodhouse <David.Woodhouse@intel.com>
Some versions of GCC apparently expect this to be provided by libgcc.
Updates from Mikey to fix 32 bit version and adding "r" to registers.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Michael Neuling <mikey@neuling.org>
---
Fixes from Gabriel.
arch/powerpc/kernel/misc_32.S | 11 +++++++++++
arch/powerpc/kernel/misc_64.S | 11 +++++++++++
arch/powerpc/kernel/ppc_ksyms.c | 3 ++-
3 files changed, 24 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/kernel/misc_32.S b/arch/powerpc/kernel/misc_32.S
index 19e096b..e469f30 100644
--- a/arch/powerpc/kernel/misc_32.S
+++ b/arch/powerpc/kernel/misc_32.S
@@ -657,6 +657,17 @@ _GLOBAL(__ucmpdi2)
li r3,2
blr
+_GLOBAL(__bswapdi2)
+ rotlwi r9,r4,8
+ rotlwi r10,r3,8
+ rlwimi r9,r4,24,0,7
+ rlwimi r10,r3,24,0,7
+ rlwimi r9,r4,24,16,23
+ rlwimi r10,r3,24,16,23
+ mr r3,r9
+ mr r4,r10
+ blr
+
_GLOBAL(abs)
srawi r4,r3,31
xor r3,r3,r4
diff --git a/arch/powerpc/kernel/misc_64.S b/arch/powerpc/kernel/misc_64.S
index 5cfa800..6820e45 100644
--- a/arch/powerpc/kernel/misc_64.S
+++ b/arch/powerpc/kernel/misc_64.S
@@ -234,6 +234,17 @@ _GLOBAL(__flush_dcache_icache)
isync
blr
+_GLOBAL(__bswapdi2)
+ srdi r8,r3,32
+ rlwinm r7,r3,8,0xffffffff
+ rlwimi r7,r3,24,0,7
+ rlwinm r9,r8,8,0xffffffff
+ rlwimi r7,r3,24,16,23
+ rlwimi r9,r8,24,0,7
+ rlwimi r9,r8,24,16,23
+ sldi r7,r7,32
+ or r3,r7,r9
+ blr
#if defined(CONFIG_PPC_PMAC) || defined(CONFIG_PPC_MAPLE)
/*
diff --git a/arch/powerpc/kernel/ppc_ksyms.c b/arch/powerpc/kernel/ppc_ksyms.c
index 78b8766..c296665 100644
--- a/arch/powerpc/kernel/ppc_ksyms.c
+++ b/arch/powerpc/kernel/ppc_ksyms.c
@@ -143,7 +143,8 @@ EXPORT_SYMBOL(__lshrdi3);
int __ucmpdi2(unsigned long long, unsigned long long);
EXPORT_SYMBOL(__ucmpdi2);
#endif
-
+long long __bswapdi2(long long);
+EXPORT_SYMBOL(__bswapdi2);
EXPORT_SYMBOL(memcpy);
EXPORT_SYMBOL(memset);
EXPORT_SYMBOL(memmove);
--
1.7.10.4
^ permalink raw reply related [flat|nested] 18+ messages in thread
* Re: [PATCH] powerpc: provide __bswapdi2
2013-05-13 7:20 ` Alan Modra
@ 2013-05-13 10:27 ` David Woodhouse
2013-05-13 16:47 ` Segher Boessenkool
0 siblings, 1 reply; 18+ messages in thread
From: David Woodhouse @ 2013-05-13 10:27 UTC (permalink / raw)
To: Alan Modra; +Cc: linuxppc-dev, Anton Blanchard, viro
[-- Attachment #1: Type: text/plain, Size: 480 bytes --]
On Mon, 2013-05-13 at 16:50 +0930, Alan Modra wrote:
> I did a little digging, and it looks like gcc-4.4 will emit __bswapdi2
> calls. Support in rs6000.md appeared 2009-06-25.
That's where it was seen. I don't have anything that ancient any more so
it didn't show up in my testing, but Al saw it on a Debian system.
--
David Woodhouse Open Source Technology Centre
David.Woodhouse@intel.com Intel Corporation
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^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] powerpc: provide __bswapdi2
2013-05-13 7:09 ` Michael Neuling
2013-05-13 7:20 ` [PATCH v2] " Michael Neuling
2013-05-13 7:33 ` [PATCH] " Gabriel Paubert
@ 2013-05-13 10:33 ` David Woodhouse
2013-05-13 10:38 ` David Woodhouse
2013-05-13 16:55 ` Segher Boessenkool
2013-05-14 1:09 ` Stephen Rothwell
3 siblings, 2 replies; 18+ messages in thread
From: David Woodhouse @ 2013-05-13 10:33 UTC (permalink / raw)
To: Michael Neuling; +Cc: linuxppc-dev, viro
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On Mon, 2013-05-13 at 17:09 +1000, Michael Neuling wrote:
>
> This doesn't work for me but the below does:
...
>
> stolen from GCC -02 output of:
> unsigned long long __bswapdi2(unsigned long long x)
Hm, so was mine:
[dwmw2@i7 ~]$ powerpc64-linux-gnu-gcc -O2 -S -o- bswapdi2.c -m32
.file "bswapdi2.c"
.section ".text"
.align 2
.p2align 4,,15
.globl __bswapdi2
.type __bswapdi2, @function
__bswapdi2:
rlwinm 10,4,8,0xffffffff
rlwinm 11,3,8,0xffffffff
rlwimi 10,4,24,0,7
rlwimi 11,3,24,0,7
rlwimi 10,4,24,16,23
rlwimi 11,3,24,16,23
mr 4,11
mr 3,10
blr
.size __bswapdi2,.-__bswapdi2
.ident "GCC: (GNU) 4.7.2 20121105 (Red Hat 4.7.2-2.aa.20121114svn)"
On Mon, 2013-05-13 at 09:33 +0200, Gabriel Paubert wrote:
> Actually, I'd swap the two mr instructions to never
> have an instruction that uses the result from the
> previous one.
Bad GCC. No biscuit.
Should we file a PR?
--
David Woodhouse Open Source Technology Centre
David.Woodhouse@intel.com Intel Corporation
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^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] powerpc: provide __bswapdi2
2013-05-13 10:33 ` [PATCH] " David Woodhouse
@ 2013-05-13 10:38 ` David Woodhouse
2013-05-13 10:51 ` Joakim Tjernlund
2013-05-13 13:12 ` Gabriel Paubert
2013-05-13 16:55 ` Segher Boessenkool
1 sibling, 2 replies; 18+ messages in thread
From: David Woodhouse @ 2013-05-13 10:38 UTC (permalink / raw)
To: Michael Neuling; +Cc: linuxppc-dev, viro
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On Mon, 2013-05-13 at 11:33 +0100, David Woodhouse wrote:
>
> On Mon, 2013-05-13 at 09:33 +0200, Gabriel Paubert wrote:
> > Actually, I'd swap the two mr instructions to never
> > have an instruction that uses the result from the
> > previous one.
>
> Bad GCC. No biscuit.
>
> Should we file a PR?
Maybe not. If you tell it to tune for an in-order machine like Cell, it
swaps them round. Although now I'm confused about which of POWER[567]
were in-order:
[dwmw2@i7 ~]$ powerpc64-linux-gnu-gcc -O2 -S -o- bswapdi2.c -m32 | grep -B1 mr
rlwimi 11,3,24,16,23
mr 4,11
mr 3,10
[dwmw2@i7 ~]$ powerpc64-linux-gnu-gcc -O2 -S -o- bswapdi2.c -m32 -mtune=cell | grep -B1 mr
rlwimi 11,3,24,16,23
mr 3,10
mr 4,11
[dwmw2@i7 ~]$ powerpc64-linux-gnu-gcc -O2 -S -o- bswapdi2.c -m32 -mtune=power5 | grep -B1 mr
rlwimi 11,3,24,16,23
mr 3,10
mr 4,11
[dwmw2@i7 ~]$ powerpc64-linux-gnu-gcc -O2 -S -o- bswapdi2.c -m32 -mtune=power6 | grep -B1 mr
rlwimi 11,3,24,16,23
mr 4,11
mr 3,10
[dwmw2@i7 ~]$ powerpc64-linux-gnu-gcc -O2 -S -o- bswapdi2.c -m32 -mtune=power7 | grep -B1 mr
rlwimi 11,3,24,16,23
mr 4,11
mr 3,10
--
David Woodhouse Open Source Technology Centre
David.Woodhouse@intel.com Intel Corporation
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^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] powerpc: provide __bswapdi2
2013-05-13 10:38 ` David Woodhouse
@ 2013-05-13 10:51 ` Joakim Tjernlund
2013-05-13 11:12 ` Joakim Tjernlund
2013-05-13 13:12 ` Gabriel Paubert
1 sibling, 1 reply; 18+ messages in thread
From: Joakim Tjernlund @ 2013-05-13 10:51 UTC (permalink / raw)
To: David Woodhouse; +Cc: linuxppc-dev, Michael Neuling, viro
"Linuxppc-dev"
<linuxppc-dev-bounces+joakim.tjernlund=transmode.se@lists.ozlabs.org>
wrote 2013/05/13 12:38:13:
>
> On Mon, 2013-05-13 at 11:33 +0100, David Woodhouse wrote:
> >
> > On Mon, 2013-05-13 at 09:33 +0200, Gabriel Paubert wrote:
> > > Actually, I'd swap the two mr instructions to never
> > > have an instruction that uses the result from the
> > > previous one.
> >
> > Bad GCC. No biscuit.
> >
> > Should we file a PR?
>
> Maybe not. If you tell it to tune for an in-order machine like Cell, it
> swaps them round. Although now I'm confused about which of POWER[567]
> were in-order:
>
> [dwmw2@i7 ~]$ powerpc64-linux-gnu-gcc -O2 -S -o- bswapdi2.c -m32 | grep
-B1 mr
> rlwimi 11,3,24,16,23
> mr 4,11
> mr 3,10
> [dwmw2@i7 ~]$ powerpc64-linux-gnu-gcc -O2 -S -o- bswapdi2.c -m32
-mtune=cell | grep -B1 mr
> rlwimi 11,3,24,16,23
> mr 3,10
> mr 4,11
> [dwmw2@i7 ~]$ powerpc64-linux-gnu-gcc -O2 -S -o- bswapdi2.c -m32
-mtune=power5 | grep -B1 mr
> rlwimi 11,3,24,16,23
> mr 3,10
> mr 4,11
> [dwmw2@i7 ~]$ powerpc64-linux-gnu-gcc -O2 -S -o- bswapdi2.c -m32
-mtune=power6 | grep -B1 mr
> rlwimi 11,3,24,16,23
> mr 4,11
> mr 3,10
> [dwmw2@i7 ~]$ powerpc64-linux-gnu-gcc -O2 -S -o- bswapdi2.c -m32
-mtune=power7 | grep -B1 mr
> rlwimi 11,3,24,16,23
> mr 4,11
> mr 3,10
A bit rusty on the ppc asm but can you not remove the mr completely:
rlwimi 10,4,24,16,23
rlwimi 11,3,24,16,23
mr 4,11
mr 3,10
to
rlwimi 4,4,24,16,23
rlwimi 3,3,24,16,23
Jocke
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] powerpc: provide __bswapdi2
2013-05-13 10:51 ` Joakim Tjernlund
@ 2013-05-13 11:12 ` Joakim Tjernlund
0 siblings, 0 replies; 18+ messages in thread
From: Joakim Tjernlund @ 2013-05-13 11:12 UTC (permalink / raw)
Cc: linuxppc-dev, Michael Neuling, David Woodhouse, viro
"Linuxppc-dev"
<linuxppc-dev-bounces+joakim.tjernlund=transmode.se@lists.ozlabs.org>
wrote on 2013/05/13 12:51:59:
>
> "Linuxppc-dev"
> <linuxppc-dev-bounces+joakim.tjernlund=transmode.se@lists.ozlabs.org>
> wrote 2013/05/13 12:38:13:
> >
> > On Mon, 2013-05-13 at 11:33 +0100, David Woodhouse wrote:
> > >
> > > On Mon, 2013-05-13 at 09:33 +0200, Gabriel Paubert wrote:
> > > > Actually, I'd swap the two mr instructions to never
> > > > have an instruction that uses the result from the
> > > > previous one.
> > >
> > > Bad GCC. No biscuit.
> > >
> > > Should we file a PR?
> >
> > Maybe not. If you tell it to tune for an in-order machine like Cell,
it
> > swaps them round. Although now I'm confused about which of POWER[567]
> > were in-order:
> >
> > [dwmw2@i7 ~]$ powerpc64-linux-gnu-gcc -O2 -S -o- bswapdi2.c -m32 |
grep
> -B1 mr
> > rlwimi 11,3,24,16,23
> > mr 4,11
> > mr 3,10
> > [dwmw2@i7 ~]$ powerpc64-linux-gnu-gcc -O2 -S -o- bswapdi2.c -m32
> -mtune=cell | grep -B1 mr
> > rlwimi 11,3,24,16,23
> > mr 3,10
> > mr 4,11
> > [dwmw2@i7 ~]$ powerpc64-linux-gnu-gcc -O2 -S -o- bswapdi2.c -m32
> -mtune=power5 | grep -B1 mr
> > rlwimi 11,3,24,16,23
> > mr 3,10
> > mr 4,11
> > [dwmw2@i7 ~]$ powerpc64-linux-gnu-gcc -O2 -S -o- bswapdi2.c -m32
> -mtune=power6 | grep -B1 mr
> > rlwimi 11,3,24,16,23
> > mr 4,11
> > mr 3,10
> > [dwmw2@i7 ~]$ powerpc64-linux-gnu-gcc -O2 -S -o- bswapdi2.c -m32
> -mtune=power7 | grep -B1 mr
> > rlwimi 11,3,24,16,23
> > mr 4,11
> > mr 3,10
>
> A bit rusty on the ppc asm but can you not remove the mr completely:
> rlwimi 10,4,24,16,23
> rlwimi 11,3,24,16,23
> mr 4,11
> mr 3,10
> to
> rlwimi 4,4,24,16,23
> rlwimi 3,3,24,16,23
Oops, that got twisted. Forget my comment.
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] powerpc: provide __bswapdi2
2013-05-13 10:38 ` David Woodhouse
2013-05-13 10:51 ` Joakim Tjernlund
@ 2013-05-13 13:12 ` Gabriel Paubert
1 sibling, 0 replies; 18+ messages in thread
From: Gabriel Paubert @ 2013-05-13 13:12 UTC (permalink / raw)
To: David Woodhouse; +Cc: linuxppc-dev, Michael Neuling, viro
On Mon, May 13, 2013 at 11:38:13AM +0100, David Woodhouse wrote:
> On Mon, 2013-05-13 at 11:33 +0100, David Woodhouse wrote:
> >
> > On Mon, 2013-05-13 at 09:33 +0200, Gabriel Paubert wrote:
> > > Actually, I'd swap the two mr instructions to never
> > > have an instruction that uses the result from the
> > > previous one.
> >
> > Bad GCC. No biscuit.
> >
> > Should we file a PR?
>
> Maybe not. If you tell it to tune for an in-order machine like Cell, it
> swaps them round. Although now I'm confused about which of POWER[567]
> were in-order:
It was Power6 IIRC. On this kind of fine point, don't rely too much
on what GCC produces.
>
> [dwmw2@i7 ~]$ powerpc64-linux-gnu-gcc -O2 -S -o- bswapdi2.c -m32 | grep -B1 mr
> rlwimi 11,3,24,16,23
> mr 4,11
> mr 3,10
> [dwmw2@i7 ~]$ powerpc64-linux-gnu-gcc -O2 -S -o- bswapdi2.c -m32 -mtune=cell | grep -B1 mr
> rlwimi 11,3,24,16,23
> mr 3,10
> mr 4,11
> [dwmw2@i7 ~]$ powerpc64-linux-gnu-gcc -O2 -S -o- bswapdi2.c -m32 -mtune=power5 | grep -B1 mr
> rlwimi 11,3,24,16,23
> mr 3,10
> mr 4,11
> [dwmw2@i7 ~]$ powerpc64-linux-gnu-gcc -O2 -S -o- bswapdi2.c -m32 -mtune=power6 | grep -B1 mr
> rlwimi 11,3,24,16,23
> mr 4,11
> mr 3,10
> [dwmw2@i7 ~]$ powerpc64-linux-gnu-gcc -O2 -S -o- bswapdi2.c -m32 -mtune=power7 | grep -B1 mr
> rlwimi 11,3,24,16,23
> mr 4,11
> mr 3,10
I don't know of any processor in which putting the mr 3,10 first can cause stalls, so
even a generic tuning should put it first.
Gabriel
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] powerpc: provide __bswapdi2
2013-05-13 10:27 ` David Woodhouse
@ 2013-05-13 16:47 ` Segher Boessenkool
0 siblings, 0 replies; 18+ messages in thread
From: Segher Boessenkool @ 2013-05-13 16:47 UTC (permalink / raw)
To: David Woodhouse; +Cc: linuxppc-dev, Anton Blanchard, viro, Alan Modra
>> I did a little digging, and it looks like gcc-4.4 will emit
>> __bswapdi2
>> calls. Support in rs6000.md appeared 2009-06-25.
>
> That's where it was seen. I don't have anything that ancient any
> more so
> it didn't show up in my testing, but Al saw it on a Debian system.
It should never happen on 32-bit -- it is broken into two bswapsi's --
although, old compiler, who knows. Lack of testing makes some people
nervous though ;-)
Segher
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] powerpc: provide __bswapdi2
2013-05-13 10:33 ` [PATCH] " David Woodhouse
2013-05-13 10:38 ` David Woodhouse
@ 2013-05-13 16:55 ` Segher Boessenkool
1 sibling, 0 replies; 18+ messages in thread
From: Segher Boessenkool @ 2013-05-13 16:55 UTC (permalink / raw)
To: David Woodhouse; +Cc: linuxppc-dev, Michael Neuling, viro
> rlwinm 10,4,8,0xffffffff
> rlwinm 11,3,8,0xffffffff
> rlwimi 10,4,24,0,7
> rlwimi 11,3,24,0,7
> rlwimi 10,4,24,16,23
> rlwimi 11,3,24,16,23
> mr 4,11
> mr 3,10
>> Actually, I'd swap the two mr instructions to never
>> have an instruction that uses the result from the
>> previous one.
>
> Bad GCC. No biscuit.
>
> Should we file a PR?
This is scheduled just fine. Every pair of instructions here can
execute together (on most CPUs, if not all); all instructions after
it are dependent on previous instructions. There also is no issue
(group) restriction that makes this scheduling suboptimal afaics.
Segher
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] powerpc: provide __bswapdi2
2013-05-13 7:09 ` Michael Neuling
` (2 preceding siblings ...)
2013-05-13 10:33 ` [PATCH] " David Woodhouse
@ 2013-05-14 1:09 ` Stephen Rothwell
2013-05-14 1:25 ` Michael Neuling
3 siblings, 1 reply; 18+ messages in thread
From: Stephen Rothwell @ 2013-05-14 1:09 UTC (permalink / raw)
To: Michael Neuling; +Cc: linuxppc-dev, David Woodhouse, viro
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Hi Mikey,
On Mon, 13 May 2013 17:09:59 +1000 Michael Neuling <mikey@neuling.org> wrote:
>
> This doesn't work for me but the below does:
>
> _GLOBAL(__bswapdi2)
> rotlwi r9,r4,8
> rotlwi r10,r3,8
> rlwimi r9,r4,24,0,7
> rlwimi r10,r3,24,0,7
> rlwimi r9,r4,24,16,23
> rlwimi r10,r3,24,16,23
> mr r4,r10
> mr r3,r9
> blr
>
> stolen from GCC -02 output of:
> unsigned long long __bswapdi2(unsigned long long x)
> {
> return ((x & 0x00000000000000ffULL) << 56) |
> ((x & 0x000000000000ff00ULL) << 40) |
> ((x & 0x0000000000ff0000ULL) << 24) |
> ((x & 0x00000000ff000000ULL) << 8) |
> ((x & 0x000000ff00000000ULL) >> 8) |
> ((x & 0x0000ff0000000000ULL) >> 24) |
> ((x & 0x00ff000000000000ULL) >> 40) |
> ((x & 0xff00000000000000ULL) >> 56);
> }
So, if we are just stealing the output of gcc, why not just use the C
version (at least for 32 bit)?
--
Cheers,
Stephen Rothwell sfr@canb.auug.org.au
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^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] powerpc: provide __bswapdi2
2013-05-14 1:09 ` Stephen Rothwell
@ 2013-05-14 1:25 ` Michael Neuling
2013-05-14 6:59 ` David Woodhouse
0 siblings, 1 reply; 18+ messages in thread
From: Michael Neuling @ 2013-05-14 1:25 UTC (permalink / raw)
To: Stephen Rothwell; +Cc: Linux PPC dev, David Woodhouse, viro
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On 14 May 2013 11:09, "Stephen Rothwell" <sfr@canb.auug.org.au> wrote:
>
> Hi Mikey,
>
> On Mon, 13 May 2013 17:09:59 +1000 Michael Neuling <mikey@neuling.org>
wrote:
> >
> > This doesn't work for me but the below does:
> >
> > _GLOBAL(__bswapdi2)
> > rotlwi r9,r4,8
> > rotlwi r10,r3,8
> > rlwimi r9,r4,24,0,7
> > rlwimi r10,r3,24,0,7
> > rlwimi r9,r4,24,16,23
> > rlwimi r10,r3,24,16,23
> > mr r4,r10
> > mr r3,r9
> > blr
> >
> > stolen from GCC -02 output of:
> > unsigned long long __bswapdi2(unsigned long long x)
> > {
> > return ((x & 0x00000000000000ffULL) << 56) |
> > ((x & 0x000000000000ff00ULL) << 40) |
> > ((x & 0x0000000000ff0000ULL) << 24) |
> > ((x & 0x00000000ff000000ULL) << 8) |
> > ((x & 0x000000ff00000000ULL) >> 8) |
> > ((x & 0x0000ff0000000000ULL) >> 24) |
> > ((x & 0x00ff000000000000ULL) >> 40) |
> > ((x & 0xff00000000000000ULL) >> 56);
> > }
>
> So, if we are just stealing the output of gcc, why not just use the C
> version (at least for 32 bit)?
Woodhouse: can we just do this?
Mikey
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^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] powerpc: provide __bswapdi2
2013-05-14 1:25 ` Michael Neuling
@ 2013-05-14 6:59 ` David Woodhouse
0 siblings, 0 replies; 18+ messages in thread
From: David Woodhouse @ 2013-05-14 6:59 UTC (permalink / raw)
To: Michael Neuling; +Cc: Stephen Rothwell, viro, Linux PPC dev
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On Tue, 2013-05-14 at 11:25 +1000, Michael Neuling wrote:
>
> > So, if we are just stealing the output of gcc, why not just use the C
> > version (at least for 32 bit)?
>
> Woodhouse: can we just do this?
Sure, if you don't mind GCC optimising the contents of your C function
by turning it into a call to libgcc's __bswapdi2() :)
OK, you might be able to do some archaeology and determine that the only
compiler that emits calls to __bswapdi2() is GCC 4.4, and furthermore
that the same compiler *doesn't* have the wit to notice that the
contents of the function are a 64-bit byteswap, so it's never going to
happen. But I don't like that approach. I'd feel I have to sacrifice a
goat *anyway*, and I don't have a spare goat.
Although now I come to explicitly explain why I did it that way... it
occurs to me that the libgcc version is just written in C, and the
compiler evidently trusts itself not to optimise that into a recursive
call. Is there a compiler switch which guarantees that, which we could
use without other unwanted side-effects?
--
David Woodhouse Open Source Technology Centre
David.Woodhouse@intel.com Intel Corporation
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^ permalink raw reply [flat|nested] 18+ messages in thread
end of thread, other threads:[~2013-05-14 6:59 UTC | newest]
Thread overview: 18+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2013-05-10 21:18 [PATCH] powerpc: provide __bswapdi2 David Woodhouse
2013-05-13 6:48 ` Anton Blanchard
2013-05-13 7:20 ` Alan Modra
2013-05-13 10:27 ` David Woodhouse
2013-05-13 16:47 ` Segher Boessenkool
2013-05-13 7:09 ` Michael Neuling
2013-05-13 7:20 ` [PATCH v2] " Michael Neuling
2013-05-13 7:33 ` [PATCH] " Gabriel Paubert
2013-05-13 10:23 ` [PATCH v3] " Michael Neuling
2013-05-13 10:33 ` [PATCH] " David Woodhouse
2013-05-13 10:38 ` David Woodhouse
2013-05-13 10:51 ` Joakim Tjernlund
2013-05-13 11:12 ` Joakim Tjernlund
2013-05-13 13:12 ` Gabriel Paubert
2013-05-13 16:55 ` Segher Boessenkool
2013-05-14 1:09 ` Stephen Rothwell
2013-05-14 1:25 ` Michael Neuling
2013-05-14 6:59 ` David Woodhouse
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