arduino / arduino/ArduinoCore-API

Bit manipulation not working with 64 bit values

Open
#261 0 comments 0 reactions 0 assignees Claimed by @asumo-1xts View on GitHub
Dominant language
C++
Stars
306
Forks
150
PR merge metrics
No merged PRs in 30d

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:

```cpp
#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

Contributor guide

No contributing guide indexed for this repository

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.

Assessment

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

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.