From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752318AbbALRXZ (ORCPT ); Mon, 12 Jan 2015 12:23:25 -0500 Received: from mx02.posteo.de ([89.146.194.165]:35418 "EHLO mx02.posteo.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751054AbbALRXX (ORCPT ); Mon, 12 Jan 2015 12:23:23 -0500 From: Martin Kepplinger To: mingo@kernel.org Cc: peterz@infradead.org, paulmck@linux.vnet.ibm.com, tytso@mit.edu, maxime.coquelin@st.com, linux@roeck-us.net, linux-kernel@vger.kernel.org, Martin Kepplinger Subject: [PATCH v2] bitops.h: add sign_extend8(), 16 and 64 functions Date: Mon, 12 Jan 2015 18:22:50 +0100 Message-Id: <1421083370-24924-1-git-send-email-martink@posteo.de> X-Mailer: git-send-email 2.1.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This adds helper functions for sign-extending signed values of any lower (hardware-)given size to s8, s16 or s64 respectively, just like sign_extend32() for s32. Signed-off-by: Martin Kepplinger Suggested-by: Christoph Muellner --- include/linux/bitops.h | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/include/linux/bitops.h b/include/linux/bitops.h index 5d858e0..9c31680 100644 --- a/include/linux/bitops.h +++ b/include/linux/bitops.h @@ -161,6 +161,28 @@ static inline __u8 ror8(__u8 word, unsigned int shift) } /** + * sign_extend8 - sign extend a 8-bit value using specified bit as sign-bit + * @value: value to sign extend + * @index: 0 based bit index (0<=index<8) to sign bit + */ +static inline __s8 sign_extend8(__u8 value, int index) +{ + __u8 shift = 7 - index; + return (__s8)(value << shift) >> shift; +} + +/** + * sign_extend16 - sign extend a 16-bit value using specified bit as sign-bit + * @value: value to sign extend + * @index: 0 based bit index (0<=index<16) to sign bit + */ +static inline __s16 sign_extend16(__u16 value, int index) +{ + __u8 shift = 15 - index; + return (__s16)(value << shift) >> shift; +} + +/** * sign_extend32 - sign extend a 32-bit value using specified bit as sign-bit * @value: value to sign extend * @index: 0 based bit index (0<=index<32) to sign bit @@ -171,6 +193,17 @@ static inline __s32 sign_extend32(__u32 value, int index) return (__s32)(value << shift) >> shift; } +/** + * sign_extend64 - sign extend a 64-bit value using specified bit as sign-bit + * @value: value to sign extend + * @index: 0 based bit index (0<=index<64) to sign bit + */ +static inline __s64 sign_extend64(__u64 value, int index) +{ + __u8 shift = 63 - index; + return (__s64)(value << shift) >> shift; +} + static inline unsigned fls_long(unsigned long l) { if (sizeof(l) == 4) -- 2.1.4