The minus operation for long integer

src/longlonguint.jl

@@ -79,7 +79,24 @@ function _sadd(x::NTuple{C,UInt}, y::NTuple{C,UInt}, c::Bool) where {C}
         return (_sadd(x[1:C-1], y[1:C-1], c1)..., v1)
     end
 end
+function Base.:(-)(x::LongLongUInt{C}, y::LongLongUInt{C}) where {C}
+    return LongLongUInt(_ssub(x.content, y.content, false))
+end
+function _ssub(x::NTuple{1,UInt}, y::NTuple{1,UInt}, c::Bool)
+    return (x[1] - y[1] - c,)
+end
+function _ssub(x::NTuple{C,UInt}, y::NTuple{C,UInt}, c::Bool) where {C}
+    v1, c1 = Base.sub_with_overflow(x[C], y[C])
+    if c
+        v2, c2 = Base.sub_with_overflow(v1, c)
+        c = c1 || c2
+        return (_ssub(x[1:C-1], y[1:C-1], c)..., v2)
+    else
+        return (_ssub(x[1:C-1], y[1:C-1], c1)..., v1)
+    end
+end
 Base.count_ones(x::LongLongUInt) = sum(count_ones, x.content)
+Base.bitstring(x::LongLongUInt) = join(bitstring.(x.content), "")
 
 function longinttype(n::Int, D::Int)
     N = ceil(Int, n * log2(D))

test/longlonguint.jl

@@ -5,8 +5,10 @@ using Test, BitBasis
     @test Int(x) === 3
     @test bsizeof(x) == 64
     @test BitBasis.nint(x) == 1
+    @test bitstring(x) == "0000000000000000000000000000000000000000000000000000000000000011"
 
     x = LongLongUInt((3, 6))
+    @test bitstring(x) == "00000000000000000000000000000000000000000000000000000000000000110000000000000000000000000000000000000000000000000000000000000110"
     @test zero(x) == LongLongUInt((0, 0))
     @test x << 1 == LongLongUInt((6, 12))
     @test x >> 1 == LongLongUInt((UInt(1), UInt(3) + UInt(1)<<63))
@@ -19,6 +21,8 @@ using Test, BitBasis
     @test x | y == LongLongUInt((7, 7))
     @test x ⊻ y == LongLongUInt((6, 1))
     @test x + y == LongLongUInt((8, 13))
+    z = LongLongUInt((5, 4))
+    @test z - x == LongLongUInt((UInt64(1), typemax(UInt64)-1))
 
     # add with overflow
     z = LongLongUInt((UInt(17), typemax(UInt)-1))
@@ -77,4 +81,9 @@ end
     @test readbit(x, 66) == 1
     @test readbit(x, 67) == 0
     @test readbit(BitStr{78}(x), 66) == 1
+end
+
+@testset "bmask" begin
+    @test bmask(LongLongUInt{1}, 1:1) == LongLongUInt((UInt64(1),))
+    @test bmask(LongLongUInt{2}, 1:65) == LongLongUInt((UInt64(1), typemax(UInt64)))
 end