Patch a bug on writing to stdout, and add clearer error on openning data files

pkg/obifp/unint.go

@@ -0,0 +1,41 @@
+package obifp
+
+type FPUint[T Uint64 | Uint128 | Uint256] interface {
+	Zero() T
+	Set64(v uint64) T
+
+	IsZero() bool
+	LeftShift(n uint) T
+	RightShift(n uint) T
+
+	Add(v T) T
+	Sub(v T) T
+	Mul(v T) T
+	//Div(v T) T
+
+	And(v T) T
+	Or(v T) T
+	Xor(v T) T
+	Not() T
+
+	LessThan(v T) bool
+	LessThanOrEqual(v T) bool
+	GreaterThan(v T) bool
+	GreaterThanOrEqual(v T) bool
+
+	AsUint64() uint64
+
+	Uint64 | Uint128 | Uint256
+}
+
+func ZeroUint[T FPUint[T]]() T {
+	return *new(T)
+}
+
+func OneUint[T FPUint[T]]() T {
+	return ZeroUint[T]().Set64(1)
+}
+
+func From64[T FPUint[T]](v uint64) T {
+	return ZeroUint[T]().Set64(v)
+}