improved unsigned support

lib/core/unsigned.nim

@@ -0,0 +1,59 @@
+#
+#
+#            Nimrod's Runtime Library
+#        (c) Copyright 2012 Andreas Rumpf
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+## This module implements basic arithmetic operators for unsigned integers.
+## To discourage users from using ``unsigned``, it's not part of ``system``,
+## but an extra import.
+
+type
+  SomeUInt = uint|uint8|uint16|uint32|uint64
+
+proc `not`*[T: SomeUInt](x: T): T {.magic: "BitnotI", noSideEffect.}
+  ## computes the `bitwise complement` of the integer `x`.
+
+proc `shr`*[T: SomeUInt](x, y: T): T {.magic: "ShrI", noSideEffect.}
+  ## computes the `shift right` operation of `x` and `y`.
+
+proc `shl`*[T: SomeUInt](x, y: T): T {.magic: "ShlI", noSideEffect.}
+  ## computes the `shift left` operation of `x` and `y`.
+
+proc `and`*[T: SomeUInt](x, y: T): T {.magic: "BitandI", noSideEffect.}
+  ## computes the `bitwise and` of numbers `x` and `y`.
+
+proc `or`*[T: SomeUInt](x, y: T): T {.magic: "BitorI", noSideEffect.}
+  ## computes the `bitwise or` of numbers `x` and `y`.
+
+proc `xor`*[T: SomeUInt](x, y: T): T {.magic: "BitxorI", noSideEffect.}
+  ## computes the `bitwise xor` of numbers `x` and `y`.
+
+proc `==`*[T: SomeUInt](x, y: T): bool {.magic: "EqI", noSideEffect.}
+  ## Compares two unsigned integers for equality.
+
+proc `+`*[T: SomeUInt](x, y: T): T {.magic: "AddU", noSideEffect.}
+  ## Binary `+` operator for unsigned integers.
+
+proc `-`*[T: SomeUInt](x, y: T): T {.magic: "SubU", noSideEffect.}
+  ## Binary `-` operator for unsigned integers.
+
+proc `*`*[T: SomeUInt](x, y: T): T {.magic: "MulU", noSideEffect.}
+  ## Binary `*` operator for unsigned integers.
+
+proc `div`*[T: SomeUInt](x, y: T): T {.magic: "DivU", noSideEffect.}
+  ## computes the integer division. This is roughly the same as
+  ## ``floor(x/y)``.
+
+proc `mod`*[T: SomeUInt](x, y: T): T {.magic: "ModU", noSideEffect.}
+  ## computes the integer modulo operation. This is the same as
+  ## ``x - (x div y) * y``.
+
+proc `<=`*[T: SomeUInt](x, y: SomeUInt): bool {.magic: "LeU", noSideEffect.}
+  ## Returns true iff ``x <= y``.
+
+proc `<`*[T: SomeUInt](x, y: T): bool {.magic: "LtU", noSideEffect.}
+  ## Returns true iff ``unsigned(x) < unsigned(y)``.