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floor vs bitwise
(version: 0)
Comparing performance of:
Bitwise vs Floor
Created:
3 years ago
by:
Guest
Jump to the latest result
Script Preparation code:
date = Date.now( ) / 1000
Tests:
Bitwise
y = date >> 8 & 255
Floor
y = date % 256; date = Math.floor( date / 256 )
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
Bitwise
Floor
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
one year ago
)
User agent:
Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/136.0.0.0 Safari/537.36
Browser/OS:
Chrome 136 on Linux
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Embed Benchmark Result
<iframe src="https://measurethat.net/Embed?id=605067" width="100%" height="500px"></iframe>
Test name
Executions per second
Bitwise
16116976.0 Ops/sec
Floor
7801073.0 Ops/sec
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
**Overview** The provided JSON represents a JavaScript microbenchmark on the MeasureThat.net website. The benchmark compares two approaches to calculate the floor of a date value: bitwise and mathematical. **Benchmark Definition** The benchmark definition is not explicitly stated in the provided JSON, but it can be inferred from the test cases. The benchmark measures the performance difference between two functions: 1. `date >> 8 & 255`: This function performs a bitwise right shift operation on the date value (in milliseconds) and then performs a bitwise AND operation with 255 to extract the lower 8 bits. 2. `Math.floor(date / 256)`: This function divides the date value by 256, effectively rounding down to the nearest integer. **Options Compared** The benchmark compares two options: 1. **Bitwise**: Uses a combination of bitwise operations to calculate the floor. 2. **Floor**: Uses the built-in `Math.floor()` function to round down to the nearest integer. **Pros and Cons** **Bitwise:** Pros: * Potential performance advantage due to avoiding overhead of a built-in function call * May be faster for certain types of inputs (e.g., large integers) Cons: * More complex and harder to understand, potentially increasing maintenance costs * Requires manual knowledge of bitwise operations **Floor:** Pros: * Easier to understand and maintain, as it's a well-known and widely used function * Less prone to errors due to its built-in implementation Cons: * May incur overhead from the function call, potentially reducing performance **Other Considerations** The benchmark assumes that the input date value is in milliseconds. The choice of unit (e.g., seconds, minutes) may impact the performance difference between the two approaches. If the input date value were to be in a different unit, the bitwise approach might become more complex and harder to understand. **Library Used** None explicitly mentioned in the provided JSON. However, the `Date` object is used, which is a built-in JavaScript library for working with dates. **Special JS Feature or Syntax** The benchmark uses a feature of JavaScript called "arithmetic shift" (`>>`), which is similar to bitwise right shift but performs arithmetic instead of binary shifting. This allows for faster calculations when dealing with integers. Overall, the benchmark provides valuable insights into the performance characteristics of different approaches to calculating the floor of a date value in JavaScript.
Related benchmarks:
Division by 1000 vs bitwise shifting approximation (1024)
Round float
remainder or floor 2
toFixed vs toPrecision vs Math.round() vs bitwise, also trunc, floor
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