Class new title: MachineDouble
	subclassof: Number
	fields: 'high low'
	declare: 'high8 low4 low8 high4 '

< t1 
	[high = t1 high  [low < t1 low]
	high < t1 high]

asInt | t1 t2 
	[(high lshift: 8) lor: low]

classInit 
	[low4 _ 64.
	high4 _ 68]

decreaseby: t1 | t2 
	[t2 _ low - t1.
	[t2 < 0  [high _ high - 1 land: 255]].
	low _ t2 land: 255]

extract | t1 
	[t1 _ low.
	low _ high.
	high _ [(low land: 128) = 0  [0]
			255].
	t1]

gets: t1 mtimes: t2 | t3 t4 t5 t6 t7 t8 
	[t3 _ t1 lshift: 4.
	t4 _ t1 land: 15.
	t5 _ t2 lshift: 4.
	t6 _ t2 land: 15.
	low _ t6 * t4.
	high _ t5 * t3.
	t8 _ t5 * t4.
	t7 _ t8 + (t6 * t3).
	high _ high + (t7 lshift: 4).
	low _ ((t7 land: 15) lshift: 4) + low.
	low  256 
		[high _ high + 1.
		low _ low - 256]]

high [high]

high_ t1 
	[high _ t1]

increaseby: t1 | t2 
	[t2 _ low + t1.
	[t2 > 255  [high _ high + 1 land: 255]].
	low _ t2 land: 255]

init 
	[low _ 0.
	high _ 0]

low [low]

low_ t1 
	[low _ t1]

mdiv: t1 | t2 
	[high > t1  [user notify: 'illegal MachineDouble division']
	high < 64 
		[t2 _ high * 256 + low.
		high _ t2 \ t1.
		t2 / t1]
	high < 128 
		[t2 _ (high lshift: 2) + (low lshift: 6) - t1.
		high _ t2 lshift: 2.
		low _ low field: 38 _ t2.
		(self mdiv: t1) + 64]
	t2 _ (high lshift: 1) + (low lshift: 7) - t1.
	high _ t2 lshift: 1.
	low _ low field: 23 _ t2.
	(self mdiv: t1) + 128]

printon: t1 
	[t1 append: '[MachineDouble 0'.
	high printon: t1 base: 8.
	t1 append: ' 0'.
	low printon: t1 base: 8.
	t1 append: ']']