From patchwork Mon Sep 23 02:04:41 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anton Blanchard X-Patchwork-Id: 277050 X-Patchwork-Delegate: benh@kernel.crashing.org Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from ozlabs.org (localhost [IPv6:::1]) by ozlabs.org (Postfix) with ESMTP id 92C402C07D4 for ; Mon, 23 Sep 2013 12:13:58 +1000 (EST) Received: by ozlabs.org (Postfix, from userid 1010) id 80D392C014C; Mon, 23 Sep 2013 12:06:40 +1000 (EST) From: Anton Blanchard To: Benjamin Herrenschmidt , Paul Mackerras Subject: [PATCH 07/39] powerpc: Add little endian support for word-at-a-time functions Date: Mon, 23 Sep 2013 12:04:41 +1000 Message-Id: <1379901913-5945-8-git-send-email-anton@samba.org> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1379901913-5945-1-git-send-email-anton@samba.org> References: <1379901913-5945-1-git-send-email-anton@samba.org> Cc: linuxppc-dev@lists.ozlabs.org X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.16rc2 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" The powerpc word-at-a-time functions are big endian specific. Bring in the x86 version in order to support little endian builds. Signed-off-by: Anton Blanchard --- arch/powerpc/include/asm/word-at-a-time.h | 71 +++++++++++++++++++++++++++++++ 1 file changed, 71 insertions(+) diff --git a/arch/powerpc/include/asm/word-at-a-time.h b/arch/powerpc/include/asm/word-at-a-time.h index d0b6d4a..213a5f2 100644 --- a/arch/powerpc/include/asm/word-at-a-time.h +++ b/arch/powerpc/include/asm/word-at-a-time.h @@ -8,6 +8,8 @@ #include #include +#ifdef __BIG_ENDIAN__ + struct word_at_a_time { const unsigned long high_bits, low_bits; }; @@ -38,4 +40,73 @@ static inline bool has_zero(unsigned long val, unsigned long *data, const struct return (val + c->high_bits) & ~rhs; } +#else + +/* + * This is largely generic for little-endian machines, but the + * optimal byte mask counting is probably going to be something + * that is architecture-specific. If you have a reliably fast + * bit count instruction, that might be better than the multiply + * and shift, for example. + */ +struct word_at_a_time { + const unsigned long one_bits, high_bits; +}; + +#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) } + +#ifdef CONFIG_64BIT + +/* + * Jan Achrenius on G+: microoptimized version of + * the simpler "(mask & ONEBYTES) * ONEBYTES >> 56" + * that works for the bytemasks without having to + * mask them first. + */ +static inline long count_masked_bytes(unsigned long mask) +{ + return mask*0x0001020304050608ul >> 56; +} + +#else /* 32-bit case */ + +/* Carl Chatfield / Jan Achrenius G+ version for 32-bit */ +static inline long count_masked_bytes(long mask) +{ + /* (000000 0000ff 00ffff ffffff) -> ( 1 1 2 3 ) */ + long a = (0x0ff0001+mask) >> 23; + /* Fix the 1 for 00 case */ + return a & mask; +} + +#endif + +/* Return nonzero if it has a zero */ +static inline unsigned long has_zero(unsigned long a, unsigned long *bits, const struct word_at_a_time *c) +{ + unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits; + *bits = mask; + return mask; +} + +static inline unsigned long prep_zero_mask(unsigned long a, unsigned long bits, const struct word_at_a_time *c) +{ + return bits; +} + +static inline unsigned long create_zero_mask(unsigned long bits) +{ + bits = (bits - 1) & ~bits; + return bits >> 7; +} + +/* The mask we created is directly usable as a bytemask */ +#define zero_bytemask(mask) (mask) + +static inline unsigned long find_zero(unsigned long mask) +{ + return count_masked_bytes(mask); +} +#endif + #endif /* _ASM_WORD_AT_A_TIME_H */