#598 Possible Bug in Modulo Implementation - Signed / Unsigned Values

[r.f.]

Possible bug in modulo implementation? Example - 100% reproducible

1) Defining a value and calling mod() function yields correct result.

--> number = 7
number = 7
--> typeof(number)
ans = double
--> mod(number, 2)
ans = 1

2) Casting the value to unsigned and calling mod() function gives 0 as result.

--> number = uint8(number)
number = 7
--> typeof(number)
ans = uint8
--> mod(number, 2)
ans = 0

--> number = uint16(number)
number = 7
--> typeof(number)
ans = uint16
--> mod(number, 2)
ans = 0

--> number = uint32(number)
number = 7
--> typeof(number)
ans = uint32
--> mod(number, 2)
ans = 0

3) Casting the value to signed and calling mod() function gives negative result.

--> number = int8(number)
number = 7
--> typeof(number)
ans = int8
--> mod(number, 2)
ans = -1

--> number = int16(number)
number = 7
--> typeof(number)
ans = int16
--> mod(number, 2)
ans = -1

--> number = int32(number)
number = 7
--> typeof(number)
ans = int32
--> mod(number, 2)
ans = -1

4) Casting the value back to double and calling mod() yields correct result again.

--> number = double(number)
number = 7
--> typeof(number)
ans = double
--> mod(number, 2)
ans = 1

[r.f.]

Same test in Matlab with mod() working like expected:

--> number = 7
number = 7
--> class(number)
ans = double
--> mod(number,2)
ans = 1

--> number = uint8(number)
number = 7
--> class(number)
ans = uint8
--> mod(number,2)
ans = 1

--> number = uint16(number)
number = 7
--> class(number)
ans = uint16
--> mod(number,2)
ans = 1

--> number = uint32(number)
number = 7
--> class(number)
ans = uint32
--> mod(number,2)
ans = 1

--> number = int8(number)
number = 7
--> class(number)
ans = int8
--> mod(number,2)
ans = 1

--> number = int16(number)
number = 7
--> class(number)
ans = int16
--> mod(number,2)
ans = 1

--> number = int32(number)
number = 7
--> class(number)
ans = int32
--> mod(number,2)
ans = 1

--> number = double(number)
number = 7
--> class(number)
ans = double
--> mod(number,2)
ans = 1