From: Gabriel Paubert <paubert@iram.es>
To: Scott Wood <scottwood@freescale.com>
Cc: linuxppc-dev@ozlabs.org, Michael Neuling <mikey@neuling.org>,
Paul Mackerras <paulus@samba.org>
Subject: Re: [PATCH 2/9] powerpc: Add macros to access floating point registers in thread_struct.
Date: Wed, 25 Jun 2008 18:12:55 +0200 [thread overview]
Message-ID: <20080625161255.GA12165@iram.es> (raw)
In-Reply-To: <48626588.8050202@freescale.com>
On Wed, Jun 25, 2008 at 10:34:32AM -0500, Scott Wood wrote:
> Kumar Gala wrote:
> >>+/* Macros to workout the correct index for the FPR in the thread
> >>struct */
> >>+#define FPRNUMBER(i) (((i) - PT_FPR0) >> 1)
> >>+#define FPRHALF(i) (((i) - PT_FPR0) % 2)
> >
> >Have you looked at what the compiler spits out here to make sure we
> >aren't getting a divide? Seems like we could use '& 0x1'.
>
> GCC's not *that* dumb. However, you may get some unnecessary
> sign-twiddling if "i" is signed.
Not for modulo 2, it's only an even/odd choice and GCC
implements that efficiently IIRC. For other powers of 2,
making the left hand side unsigned helps the compiler.
The right shift OTOH might be faster if "i" is unsigned
since right signed right shifts affect the carry on PPC (I really
don't know if srawi is slower than srwi on some processors,
srwi is a form of rlwinm which is always fast).
Gabriel
next prev parent reply other threads:[~2008-06-25 16:44 UTC|newest]
Thread overview: 106+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-06-18 0:47 [PATCH 0/9] powerpc: Add kernel support for POWER7 VSX Michael Neuling
2008-06-18 0:47 ` [PATCH 1/9] powerpc: Fix msr setting in 32 bit signal code Michael Neuling
2008-06-18 14:53 ` Kumar Gala
2008-06-18 23:55 ` Michael Neuling
2008-06-18 0:47 ` [PATCH 4/9] powerpc: Make load_up_fpu and load_up_altivec callable Michael Neuling
2008-06-18 0:47 ` [PATCH 2/9] powerpc: Add macros to access floating point registers in thread_struct Michael Neuling
2008-06-18 0:47 ` [PATCH 3/9] powerpc: Move altivec_unavailable Michael Neuling
2008-06-18 0:47 ` [PATCH 5/9] powerpc: Introduce VSX thread_struct and CONFIG_VSX Michael Neuling
2008-06-18 19:35 ` Kumar Gala
2008-06-18 22:58 ` Paul Mackerras
2008-06-19 4:13 ` Kumar Gala
2008-06-19 4:30 ` Michael Neuling
2008-06-19 4:22 ` Kumar Gala
2008-06-19 4:35 ` Michael Neuling
2008-06-19 4:58 ` Kumar Gala
2008-06-19 5:37 ` Michael Neuling
2008-06-19 5:47 ` Kumar Gala
2008-06-19 6:01 ` Michael Neuling
2008-06-19 6:10 ` Kumar Gala
2008-06-19 9:33 ` Benjamin Herrenschmidt
2008-06-19 13:24 ` Kumar Gala
2008-06-18 0:47 ` [PATCH 9/9] powerpc: Add CONFIG_VSX config option Michael Neuling
2008-06-18 0:47 ` [PATCH 7/9] powerpc: Add VSX assembler code macros Michael Neuling
2008-06-18 0:47 ` [PATCH 6/9] powerpc: Add VSX CPU feature Michael Neuling
2008-06-18 16:28 ` Joel Schopp
2008-06-19 6:51 ` David Woodhouse
2008-06-19 7:00 ` Michael Neuling
2008-06-18 0:47 ` [PATCH 8/9] powerpc: Add VSX context save/restore, ptrace and signal support Michael Neuling
2008-06-18 13:05 ` [PATCH 0/9] powerpc: Add kernel support for POWER7 VSX Kumar Gala
2008-06-18 23:54 ` Michael Neuling
2008-06-20 4:13 ` Michael Neuling
2008-06-20 4:13 ` [PATCH 1/9] powerpc: Fix msr setting in 32 bit signal code Michael Neuling
2008-06-20 6:35 ` Kumar Gala
2008-06-20 4:13 ` [PATCH 7/9] powerpc: Add VSX assembler code macros Michael Neuling
2008-06-20 4:13 ` [PATCH 5/9] powerpc: Introduce VSX thread_struct and CONFIG_VSX Michael Neuling
2008-06-20 6:44 ` Kumar Gala
2008-06-20 4:13 ` [PATCH 6/9] powerpc: Add VSX CPU feature Michael Neuling
2008-06-20 4:13 ` [PATCH 3/9] powerpc: Move altivec_unavailable Michael Neuling
2008-06-20 4:13 ` [PATCH 8/9] powerpc: Add VSX context save/restore, ptrace and signal support Michael Neuling
2008-06-20 4:13 ` [PATCH 4/9] powerpc: Make load_up_fpu and load_up_altivec callable Michael Neuling
2008-06-20 4:13 ` [PATCH 2/9] powerpc: Add macros to access floating point registers in thread_struct Michael Neuling
2008-06-20 6:39 ` Kumar Gala
2008-06-22 11:29 ` Michael Neuling
2008-06-20 4:13 ` [PATCH 9/9] powerpc: Add CONFIG_VSX config option Michael Neuling
2008-06-20 6:37 ` [PATCH 0/9] powerpc: Add kernel support for POWER7 VSX Kumar Gala
2008-06-20 8:15 ` Michael Neuling
2008-06-23 5:31 ` Michael Neuling
2008-06-23 5:31 ` [PATCH 1/9] powerpc: Fix msr setting in 32 bit signal code Michael Neuling
2008-06-23 5:31 ` [PATCH 3/9] powerpc: Move altivec_unavailable Michael Neuling
2008-06-23 5:31 ` [PATCH 4/9] powerpc: Make load_up_fpu and load_up_altivec callable Michael Neuling
2008-06-23 5:31 ` [PATCH 2/9] powerpc: Add macros to access floating point registers in thread_struct Michael Neuling
2008-06-23 5:31 ` [PATCH 9/9] powerpc: Add CONFIG_VSX config option Michael Neuling
2008-06-23 5:31 ` [PATCH 5/9] powerpc: Introduce VSX thread_struct and CONFIG_VSX Michael Neuling
2008-06-23 5:31 ` [PATCH 7/9] powerpc: Add VSX assembler code macros Michael Neuling
2008-06-23 5:31 ` [PATCH 6/9] powerpc: Add VSX CPU feature Michael Neuling
2008-06-23 5:31 ` [PATCH 8/9] powerpc: Add VSX context save/restore, ptrace and signal support Michael Neuling
2008-06-23 7:38 ` [PATCH 0/9] powerpc: Add kernel support for POWER7 VSX Michael Neuling
2008-06-23 7:38 ` [PATCH 1/9] powerpc: Fix msr setting in 32 bit signal code Michael Neuling
2008-06-23 14:46 ` Kumar Gala
2008-06-23 7:38 ` [PATCH 2/9] powerpc: Add macros to access floating point registers in thread_struct Michael Neuling
2008-06-23 7:38 ` [PATCH 9/9] powerpc: Add CONFIG_VSX config option Michael Neuling
2008-06-23 7:38 ` [PATCH 5/9] powerpc: Introduce VSX thread_struct and CONFIG_VSX Michael Neuling
2008-06-23 7:38 ` [PATCH 3/9] powerpc: Move altivec_unavailable Michael Neuling
2008-06-23 7:38 ` [PATCH 6/9] powerpc: Add VSX CPU feature Michael Neuling
2008-06-23 7:38 ` [PATCH 8/9] powerpc: Add VSX context save/restore, ptrace and signal support Michael Neuling
2008-06-23 7:38 ` [PATCH 4/9] powerpc: Make load_up_fpu and load_up_altivec callable Michael Neuling
2008-06-23 7:38 ` [PATCH 7/9] powerpc: Add VSX assembler code macros Michael Neuling
2008-06-24 10:57 ` [PATCH 0/9] powerpc: Add kernel support for POWER7 VSX Michael Neuling
2008-06-24 10:57 ` [PATCH 3/9] powerpc: Move altivec_unavailable Michael Neuling
2008-06-24 10:57 ` [PATCH 1/9] powerpc: Fix msr setting in 32 bit signal code Michael Neuling
2008-06-24 13:47 ` Kumar Gala
2008-06-24 10:57 ` [PATCH 2/9] powerpc: Add macros to access floating point registers in thread_struct Michael Neuling
2008-06-24 14:07 ` Kumar Gala
2008-06-24 16:33 ` Segher Boessenkool
2008-06-25 0:25 ` Michael Neuling
2008-06-24 10:57 ` [PATCH 9/9] powerpc: Add CONFIG_VSX config option Michael Neuling
2008-06-24 14:19 ` Kumar Gala
2008-06-24 10:57 ` [PATCH 5/9] powerpc: Introduce VSX thread_struct and CONFIG_VSX Michael Neuling
2008-06-24 10:57 ` [PATCH 7/9] powerpc: Add VSX assembler code macros Michael Neuling
2008-06-24 14:06 ` Kumar Gala
2008-06-25 0:06 ` Michael Neuling
2008-06-25 2:19 ` Kumar Gala
2008-06-24 10:57 ` [PATCH 6/9] powerpc: Add VSX CPU feature Michael Neuling
2008-06-24 14:19 ` Kumar Gala
2008-06-24 10:57 ` [PATCH 4/9] powerpc: Make load_up_fpu and load_up_altivec callable Michael Neuling
2008-06-24 14:01 ` Kumar Gala
2008-06-24 10:57 ` [PATCH 8/9] powerpc: Add VSX context save/restore, ptrace and signal support Michael Neuling
2008-06-25 4:07 ` [PATCH 0/9] powerpc: Add kernel support for POWER7 VSX Michael Neuling
2008-06-25 4:07 ` [PATCH 1/9] powerpc: Fix msr setting in 32 bit signal code Michael Neuling
2008-06-25 4:07 ` [PATCH 2/9] powerpc: Add macros to access floating point registers in thread_struct Michael Neuling
2008-06-25 14:08 ` Kumar Gala
2008-06-25 15:34 ` Scott Wood
2008-06-25 16:12 ` Gabriel Paubert [this message]
2008-06-25 16:17 ` Scott Wood
2008-06-25 17:07 ` Kumar Gala
2008-06-26 0:09 ` Michael Neuling
2008-06-26 7:07 ` [PATCH] " Michael Neuling
2008-06-26 10:44 ` [PATCH 2/9] " Gabriel Paubert
2008-06-25 17:08 ` Andreas Schwab
2008-06-25 4:07 ` [PATCH 6/9] powerpc: Add VSX CPU feature Michael Neuling
2008-06-25 4:07 ` [PATCH 3/9] powerpc: Move altivec_unavailable Michael Neuling
2008-06-25 4:07 ` [PATCH 9/9] powerpc: Add CONFIG_VSX config option Michael Neuling
2008-06-25 4:07 ` [PATCH 7/9] powerpc: Add VSX assembler code macros Michael Neuling
2008-06-25 4:07 ` [PATCH 4/9] powerpc: Make load_up_fpu and load_up_altivec callable Michael Neuling
2008-06-25 4:07 ` [PATCH 8/9] powerpc: Add VSX context save/restore, ptrace and signal support Michael Neuling
2008-06-25 4:07 ` [PATCH 5/9] powerpc: Introduce VSX thread_struct and CONFIG_VSX Michael Neuling
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