const RANGE = -384.. -127 proc get_values(): (seq[int8], seq[int16], seq[int32]) = let i8 = -3'i8 let i16 = -3'i16 let i32 = -3'i32 doAssert i8.ze == 0xFD doAssert i8.ze64 == 0xFD doAssert i16.ze == 0xFFFD doAssert i16.ze64 == 0xFFFD result[0] = @[]; result[1] = @[]; result[2] = @[] for offset in RANGE: let i8 = -(1'i64 shl 9) + offset let i16 = -(1'i64 shl 17) + offset let i32 = -(1'i64 shl 33) + offset # higher bits are masked. these should be exactly equal to offset. result[0].add cast[int8](cast[uint64](i8)) result[1].add cast[int16](cast[uint64](i16)) result[2].add cast[int32](cast[uint64](i32)) # these values this computed by VM const COMPILETIME_VALUES = get_values() # these values this computed by compiler let RUNTIME_VALUES = get_values() template check_values(int_type: static[int]) = var index = 0 let cvalues = COMPILETIME_VALUES[int_type] let rvalues = RUNTIME_VALUES[int_type] for offset in RANGE: let moffset = cast[type(rvalues[0])](offset) doAssert(moffset == rvalues[index] and moffset == cvalues[index], "expected: " & $moffset & " got runtime: " & $rvalues[index] & " && compiletime: " & $cvalues[index] ) inc(index) check_values(0) # uint8 check_values(1) # uint16 check_values(2) # uint32