Bit manipulation not working with 64 bit values

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#261 0 comments 0 reactions 0 assignees View on GitHub

@asumo-1xts is already working on this.

Since Aug 30, 2026.

  • #278 by @asumo-1xts — open

Assessment

Difficulty
3/5
Estimated time
1-2 days
Newbie friendliness
25/100
Issue type
Feature
Clarity
Mostly clear
Activity status
Stale
Tech stack
cpp
Domain
api, embedded-iot

Research direction

Start by locating the standard bitRead(), bitWrite(), bitSet(), bitClear(), bitToggle(), and bit() macros in the Arduino API. Compare their behavior with the uint64_t examples in the issue and inspect linked pull request #278. Done means 64-bit values are supported without breaking existing compatibility.

Written by the indexing model from the issue text.

Description

I need to manipulate bits in uint64_t variable.
Standard bitRead(), bitWrite(), bitSet(), bitClear(), bitToggle() macros not working. They work only up to 32 bits (uint32_t).

I made quick hack in my code to work with 64 bit variables:

#define bitRead64(value, bit) (((value) >> (bit)) & 0x01ULL)
#define bitSet64(value, bit) ((value) |= (1ULL << (bit)))
#define bitClear64(value, bit) ((value) &= ~(1ULL << (bit)))
#define bitToggle64(value, bit) ((value) ^= (1ULL << (bit)))
#define bitWrite64(value, bit, bitvalue) ((bitvalue) ? bitSet64((value), (bit)) : bitClear64((value), (bit)))

Recommendations: consider to rewrite bitRead(), bitWrite(), bitSet(), bitClear(), bitToggle() and bit() for 64 bit compatibility if possible and hope it will not break global compatibility.

Original post: https://github.com/earlephilhower/arduino-pico/issues/3260

Dominant language
C++
Stars
306
Forks
150
No merged PRs in 30d

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