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sys: util: add a sign_extend and sign_extend_64 functions

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Add a sign_extend and sign_extend_64 functions, same as the Linux
sign_extend32 and sign_extend64 one. This is useful for sign extending
values smaller than 32 bits.

Signed-off-by: Fabio Baltieri <fabiobaltieri@google.com>
This commit is contained in:
Fabio Baltieri 2024-02-09 23:32:54 +00:00 committed by Fabio Baltieri
parent cbad8eff46
commit 5bb9b129de
1 changed files with 31 additions and 0 deletions
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31
include/zephyr/sys/util.h
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@ -24,6 +24,7 @@
#ifndef _ASMLANGUAGE
#include <zephyr/sys/__assert.h>
#include <zephyr/types.h>
#include <stddef.h>
#include <stdint.h>
@ -567,6 +568,36 @@ static inline uint8_t bin2bcd(uint8_t bin)
*/
uint8_t u8_to_dec(char *buf, uint8_t buflen, uint8_t value);
/**
* @brief Sign extend an 8, 16 or 32 bit value using the index bit as sign bit.
*
* @param value The value to sign expand.
* @param index 0 based bit index to sign bit (0 to 31)
*/
static inline int32_t sign_extend(uint32_t value, uint8_t index)
{
__ASSERT_NO_MSG(index <= 31);
uint8_t shift = 31 - index;
return (int32_t)(value << shift) >> shift;
}
/**
* @brief Sign extend a 64 bit value using the index bit as sign bit.
*
* @param value The value to sign expand.
* @param index 0 based bit index to sign bit (0 to 63)
*/
static inline int64_t sign_extend_64(uint64_t value, uint8_t index)
{
__ASSERT_NO_MSG(index <= 63);
uint8_t shift = 63 - index;
return (int64_t)(value << shift) >> shift;
}
/**
* @brief Properly truncate a NULL-terminated UTF-8 string
*