Package int256 implements 256-bit signed integer arithmetic for GnoSwap.
256-bit signed integer arithmetic for GnoSwap.
Fixed-size 256-bit signed integer library optimized for AMM calculations.
The unsuffixed Add, Sub, and Mul methods return the low 256 bits
(two's-complement wrap). The AddOverflow, SubOverflow, and MulOverflow
variants additionally report whether the signed operation overflowed.
*Overflow variants 1package main
2
3import i256 "gno.land/p/gnoswap/int256/v1"
4
5func main() {
6 a := i256.NewInt(100)
7 b := i256.MustFromDecimal("-1000")
8 result, overflow := new(i256.Int).AddOverflow(a, b)
9 if overflow {
10 panic("signed addition overflow")
11 }
12 println(result.ToString()) // -900
13}
The type shares a little-endian four-word representation with uint256 and
interoperates with it through conversion methods, but signed arithmetic is
implemented independently.
Package int256 implements 256-bit signed integer arithmetic for GnoSwap.
This package provides an Int type that represents a 256-bit signed integer using two's complement representation. It supports the full range from -(2^255) to 2^255-1. The unsuffixed Add, Sub, and Mul methods return the truncated 256-bit result; AddOverflow, SubOverflow, and MulOverflow also return a signed-overflow flag.
The implementation follows Ethereum's int256 semantics, ensuring compatibility for cross-chain DeFi protocols. Operations are optimized for common AMM calculations including tick math and price computations.
FromDecimal parses a signed decimal string into a 256-bit integer.
Parameters:
Returns:
FromUint256 converts a uint256 to int256. Panics if the uint256 value is greater than MaxInt256 (2^255 - 1).
Parameters:
Returns:
MaxInt256 returns the maximum signed 256-bit integer, 2^255 - 1.
Returns:
MinInt256 returns the minimum signed 256-bit integer, -2^255.
Returns:
MustFromDecimal parses a signed decimal string and panics on invalid input.
Parameters:
Returns:
NewInt constructs a signed 256-bit integer from an int64.
Parameters:
Returns:
One returns a fresh Int representing the signed value 1.
Returns:
Zero returns a fresh Int whose 256 bits are all zero.
Returns:
Abs returns the unsigned magnitude of z.
Returns:
Panics for MinInt256 because NegOverflow cannot represent its positive magnitude as Int.
Add adds x and y modulo 2^256.
Parameters:
Returns:
AddOverflow adds x and y modulo 2^256 and reports signed overflow.
Parameters:
Returns:
And sets z to the bitwise AND of x and y.
Parameters:
Returns:
BitLen returns the number of bits needed to represent z's raw 256-bit pattern.
Returns:
Clear sets every limb of z to zero.
Returns:
Clone returns an independent copy of z.
Returns:
Cmp compares z and x as signed two's-complement int256 values.
Parameters:
Returns:
Div divides signed 256-bit x by y, truncating the quotient toward zero.
Parameters:
Returns:
Panics if y is zero.
Eq reports whether z and x have identical 256-bit representations.
Parameters:
Returns:
Gt reports whether z is greater than x as signed int256 values.
Parameters:
Returns:
Gte reports whether z is greater than or equal to x as signed int256 values.
Parameters:
Returns:
Int64 converts z to int64 after checking its signed range.
Returns:
Panics if z is outside the signed int64 range.
IsInt64 reports whether z can be represented exactly as a signed int64.
Returns:
IsMinI256 reports whether z equals MinInt256.
Returns:
IsNeg reports whether z has its signed two's-complement sign bit set.
Returns:
IsOne reports whether z represents the signed value 1.
Returns:
IsPositive reports whether z is strictly greater than zero.
Returns:
IsUint64 reports whether z fits in an unsigned 64-bit word.
Returns:
IsZero reports whether every limb of z is zero.
Returns:
Lsh sets z to x left-shifted by n bits, truncating to 256 bits.
Parameters:
Returns:
Lt reports whether z is less than x as signed int256 values.
Parameters:
Returns:
Lte reports whether z is less than or equal to x as signed int256 values.
Parameters:
Returns:
Mul multiplies x and y modulo 2^256.
Parameters:
Returns:
MulOverflow multiplies x and y and reports whether the signed product exceeds int256. The returned value is still the wrapped low 256-bit product.
Parameters:
Returns:
Neg computes the two's-complement negation of x modulo 2^256.
Parameters:
Returns:
NegOverflow computes the two's-complement negation of x and rejects the one value whose positive magnitude is outside signed int256.
Parameters:
Returns:
Panics when x is MinInt256.
Neq reports whether z and x have different 256-bit representations.
Parameters:
Returns:
Not sets z to the bitwise complement of x.
Parameters:
Returns:
Or sets z to the bitwise OR of x and y.
Parameters:
Returns:
Rem computes the signed remainder of x divided by y, preserving x's sign.
Parameters:
Returns:
Panics if y is zero.
Rsh shifts x right by n bits using signed arithmetic semantics. Non-negative values receive zero-fill; negative values receive sign extension.
Parameters:
Returns:
Set copies the complete 256-bit value from x into z.
Parameters:
Returns:
SetAllBitsOne sets every bit of z to one, the two's-complement representation of -1.
Returns:
SetBytes32 loads the first 32 bytes of in as a big-endian 256-bit value.
Parameters:
Returns:
Panics if in contains fewer than 32 bytes.
SetInt64 assigns x to z with two's-complement sign extension.
Parameters:
Returns:
SetOne sets z to the signed value 1.
Returns:
SetString parses a signed decimal string into an Int.
Parameters:
Returns:
SetUint64 assigns the non-negative uint64 x to z, clearing its upper limbs.
Parameters:
Returns:
Sign reports the signed sign of z.
Returns:
Sub subtracts y from x modulo 2^256.
Parameters:
Returns:
SubOverflow subtracts y from x modulo 2^256 and reports signed overflow.
Parameters:
Returns:
ToString returns the signed decimal representation of z.
Returns:
Uint64 converts z to uint64 when its upper 192 bits are zero.
Returns:
Panics if any upper limb of z is non-zero.
Xor sets z to the bitwise exclusive OR of x and y.
Parameters:
Returns: