Ternary Bitselect One Word Tool

Description

Select one bounded word under a mask.

Bit positions are usually counted from the least-significant bit, while a displayed binary string has its own left-to-right indexing convention. Masks, fields and parity predicates describe a selected region or pattern; local agreement does not validate a complete encoded record.

Select one bounded word under a mask.

When to use this tool

Use Ternary Bitselect One Word when checking the stated mask, field, parity or bit-index convention.

How to use the tool and how it works

Enter mask, first, second, width. Use the units and conventions below.
Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
Read value. Use the output convention below.

Select one bounded word under a mask. Require width 1..32 and all word values in range; value = (mask AND first) OR ((widthMask XOR mask) AND second).^[1]

Input field	Meaning and units	Accepted input
mask	Mask	Required. Safe integer.
first	First	Required. Safe integer.
second	Second	Required. Safe integer.
width	Width under the stated bit, interval or geometry convention; apply the field-specific units and bounds.	Required. Safe integer; minimum 1; maximum 32.

Output field	Interpretation	Returned shape
value	Value	Required. Safe integer.

json

{
  "input": {
    "mask": 15,
    "first": 170,
    "second": 85,
    "width": 8
  },
  "output": {
    "value": 90
  }
}

Limitations and assumptions

A set mask bit chooses first and a clear bit second; no signedness conversion, byte-order interpretation or hardware access occurs.
Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.

Alternative or Complementary methods

Choose an explicit bit order, word width and missing-position policy; use the complete record format and appropriate parsing or checksum methods for full validation.

References

Calculation and input contract: bitwise/ternary-bitselect-one-word — tool.io

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