From db1ffc32dd0d32ef476c00637efc888ecea8466c Mon Sep 17 00:00:00 2001 From: Mark Cave-Ayland Date: Fri, 25 Jun 2021 07:53:57 +0100 Subject: [PATCH] qemu/bitops.h: add bitrev8 implementation MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This will be required for an upcoming checksum calculation. Signed-off-by: Mark Cave-Ayland Tested-by: Finn Thain Reviewed-by: Philippe Mathieu-Daudé Message-Id: <20210625065401.30170-7-mark.cave-ayland@ilande.co.uk> Signed-off-by: Philippe Mathieu-Daudé --- include/qemu/bitops.h | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/include/qemu/bitops.h b/include/qemu/bitops.h index 03213ce952..110c56e099 100644 --- a/include/qemu/bitops.h +++ b/include/qemu/bitops.h @@ -618,4 +618,26 @@ static inline uint64_t half_unshuffle64(uint64_t x) return x; } +/** + * bitrev8: + * @x: 8-bit value to be reversed + * + * Given an input value with bits:: + * + * ABCDEFGH + * + * return the value with its bits reversed from left to right:: + * + * HGFEDCBA + * + * Returns: the bit-reversed value. + */ +static inline uint8_t bitrev8(uint8_t x) +{ + x = ((x >> 1) & 0x55) | ((x << 1) & 0xaa); + x = ((x >> 2) & 0x33) | ((x << 2) & 0xcc); + x = (x >> 4) | (x << 4) ; + return x; +} + #endif