Description
Return sum and carry of three one-bit inputs.
Fixed-width arithmetic can wrap, saturate, shift in sign bits or expose discarded bits. Carry, borrow and signed overflow describe different conditions; a local rounding decision or guard/sticky triplet is one part of an arithmetic operation rather than a complete floating-point result.
Return sum and carry of three one-bit inputs.
When to use this tool
Use Carry Save Adder One Column when evaluating the stated shift, arithmetic flag or rounding convention.
How to use the tool and how it works
- Enter first, second, third. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read sum, carry. Use the output convention below.
Return sum and carry of three one-bit inputs. Require each zero or one; total = first+second+third, sum = total modulo two, carry = floor(total/2).1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| first | First | Required. Safe integer. |
| second | Second | Required. Safe integer. |
| third | Third | Required. Safe integer. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| sum | Sum | Required. Safe integer. |
| carry | Carry | Required. Safe integer. |
{
"input": {
"first": 1,
"second": 1,
"third": 1
},
"output": {
"sum": 1,
"carry": 1
}
}Limitations and assumptions
- Carry belongs to the next-higher position; this is one column, not a ripple adder, word sum or machine flag state.
- 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
Use a complete arithmetic operation with explicit width, signedness, overflow and rounding policy; keep exact integer text when values exceed ordinary numeric precision.
References
Similar or alternative tools
- Bitwise: Single Bit Carry Propagation Mask
Return the carry-propagation mask from adding one selected bit.
- Bitwise: Fixed Width Add Overflow Flags
Return modular sum, unsigned carry and signed overflow independently.