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functor Basic(structure Real : REAL
structure Pack : PACK_REAL
where type real = Real.real) =
struct
open Real
val () = print " Reported\n"
val () = print (" precision: " ^ Int.toString precision ^ "\n")
val {man=_, exp} = toManExp maxFinite
val () = print (" max exponent: " ^ Int.toString exp ^ "\n")
val {man=_, exp} = toManExp minNormalPos
val () = print (" min exponent: " ^ Int.toString exp ^ "\n")
val {man=_, exp} = toManExp minPos
val () = print (" min denormal: " ^ Int.toString exp ^ "\n")
(* Now let's compute the actual mantissa *)
val zero = fromInt 0
val one = fromInt 1
val two = fromInt 2
fun precision eq x =
if eq (x+one, x) then 0 else
Int.+ (1, precision eq (x+x))
fun maxExp eq x =
if eq (x, x+x) then 0 else
Int.+ (1, maxExp eq (x+x))
fun lowBit (1, x) = x
| lowBit (i, x) = lowBit (Int.- (i, 1), x / two)
fun minExp eq x =
if not (eq (x, (x / two) * two)) orelse eq (x, zero) then 1 else
Int.- (minExp eq (x / two), 1)
val eq = ==
val xprecision = precision eq one
val lastBit = one + lowBit (xprecision, one)
val xmaxExp = maxExp eq one
val xminNormalExp = minExp eq lastBit
val xminExp = minExp eq one
val () = print " Actual\n"
val () = print (" precision: " ^ Int.toString xprecision ^ "\n")
val () = print (" max exponent: " ^ Int.toString xmaxExp ^ "\n")
val () = print (" min exponent: " ^ Int.toString xminNormalExp ^ "\n")
val () = print (" min denormal: " ^ Int.toString xminExp ^ "\n")
val a = Word8Array.array (Pack.bytesPerElem, 0w0)
fun id x = (Pack.update (a, 0, x); Pack.subArr (a, 0))
val eq = fn (x, y) => == (id x, id y)
val xprecision = precision eq one
val lastBit = one + lowBit (xprecision, one)
val xmaxExp = maxExp eq one
val xminNormalExp = minExp eq lastBit
val xminExp = minExp eq one
val () = print " Exported\n"
val () = print (" precision: " ^ Int.toString xprecision ^ "\n")
val () = print (" max exponent: " ^ Int.toString xmaxExp ^ "\n")
val () = print (" min exponent: " ^ Int.toString xminNormalExp ^ "\n")
val () = print (" min denormal: " ^ Int.toString xminExp ^ "\n")
end
val () = print "Real32\n"
structure Z = Basic(structure Real = Real32
structure Pack = PackReal32Little)
val () = print "Real64\n"
structure Z = Basic(structure Real = Real64
structure Pack = PackReal64Big)
|
