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[Core] quantum: util: add bit and bitmask helpers (#24229)

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quantum: util: add bit and bitmask helpers

These helpers are handy and can prevent off-by-one errors when working
with registers and general low level bit manipulation tasks. The macros
themself are inspired by the bits.h macros from the linux kernel source
code.

Signed-off-by: Stefan Kerkmann <karlk90@pm.me>
Co-authored-by: Pascal Getreuer <50221757+getreuer@users.noreply.github.com>
This commit is contained in:
Stefan Kerkmann 2024-10-12 18:48:00 +02:00 committed by GitHub
parent 6fa11bf219
commit 5478051d74
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2 changed files with 34 additions and 0 deletions
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33
quantum/bits.h Normal file
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/* SPDX-License-Identifier: GPL-2.0 */
#pragma once
#include <stdint.h>
/* Remove these once we transitioned to C23 across all platfroms */
#define UINT32_WIDTH 32
#define UINT64_WIDTH 64
/**
* @brief Mask for the little endian nth bit (0-31) in a 32-bit integer.
*/
#define BIT32(n) (UINT32_C(1) << (n))
/**
* @brief Mask for the little endian nth bit (0-63) in a 64-bit integer.
*/
#define BIT64(n) (UINT64_C(1) << (n))
/**
* @brief Create a contiguous 32-bit wide bitmask starting at bit position @l
* and ending at position @h. The range is inclusive, meaning GENMASK32(20, 10)
* gives us the 32-bit mask 0x001ffc00.
*/
#define GENMASK32(h, l) (((~UINT32_C(0)) - (UINT32_C(1) << (l)) + 1) & (~UINT32_C(0) >> (UINT32_WIDTH - 1 - (h))))
/**
* @brief Create a contiguous 64-bit wide bitmask starting at bit position @l
* and ending at position @h. The range is inclusive, meaning GENMASK64(39, 21)
* gives us the 64-bit mask 0x000000ffffe00000.
*/
#define GENMASK64(h, l) (((~UINT64_C(0)) - (UINT64_C(1) << (l)) + 1) & (~UINT64_C(0) >> (UINT64_WIDTH - 1 - (h))))

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quantum/util.h
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#pragma once
#include "bits.h"
#include "bitwise.h"
// convert to string