Add unary minus test

hardy/ct_primitives.nim

@@ -51,6 +51,11 @@ func `*`*[T: HardBase](x, y: T): T {.magic: "MulU".}
 # We don't implement div/mod as we can't assume the hardware implementation
 # is constant-time
 
+func `-`*(x: HardBase): HardBase {.inline.}=
+  ## Unary minus returns the two-complement representation
+  ## of an unsigned integer
+  {.emit:"`result` = -`x`;".}
+
 # ############################################################
 #
 #             Hardened Boolean primitives
@@ -61,11 +66,6 @@ func `not`*(ctl: HardBool): HardBool {.inline.}=
   ## Negate a constant-time boolean
   ctl xor 1
 
-func `-`*(x: HardBase): HardBase {.inline.}=
-  ## Unary minus returns the two-complement representation
-  ## of an unsigned integer
-  {.emit:"`result` = -`x`;".}
-
 func select*[T: HardBase](ctl: HardBool[T], x, y: T): T {.inline.}=
   ## Multiplexer / selector
   ## Returns x if ctl == 1

hardy/datatypes.nim

@@ -30,10 +30,6 @@ func htrue*(T: type(BaseUint)): auto {.compileTime.}=
 func hfalse*(T: type(BaseUint)): auto {.compileTime.}=
   (HardBool[HardBase[T]])(false)
 
-template hard*(x: static int, T: type BaseUint): HardBase[T] =
-  ## For int literals
-  (HardBase[T])(x)
-
 func hard*[T: BaseUint](x: T): HardBase[T] {.inline.}=
   (HardBase[T])(x)
 

tests/all_tests.nim

@@ -113,3 +113,22 @@ suite "Hardened unsigned integers":
     operator_check(`+`)
     operator_check(`-`)
     operator_check(`*`)
+
+  test "Unary `-`, returning the 2-complement of an unsigned integer":
+    let x1 = rand(high(int)).uint64
+    let y1 = rand(high(int)).uint64
+    let x2 = rand(high(int)).uint64
+    let y2 = rand(high(int)).uint64
+    let x3 = rand(high(int)).uint64
+    let y3 = rand(high(int)).uint64
+    check:
+      (-hard(0'u32)).undistinct == 0
+      (-high(HardBase[uint32])).undistinct == 1'u32
+      (-hard(0x80000000'u32)).undistinct == 0x80000000'u32 # This is low(int32) == 0b10000..0000
+
+      undistinct(-x1.hard) == undistinct(not(x1.hard) + hard(1'u64))
+      undistinct(-x2.hard) == undistinct(not(x2.hard) + hard(1'u64))
+      undistinct(-x3.hard) == undistinct(not(x3.hard) + hard(1'u64))
+      undistinct(-y1.hard) == undistinct(not(y1.hard) + hard(1'u64))
+      undistinct(-y2.hard) == undistinct(not(y2.hard) + hard(1'u64))
+      undistinct(-y3.hard) == undistinct(not(y3.hard) + hard(1'u64))