1 % ------------------------------------------------------------------------------
2 % $Id: PrelNum.lhs,v 1.35 2001/02/22 13:17:59 simonpj Exp $
4 % (c) The University of Glasgow, 1994-2000
7 \section[PrelNum]{Module @PrelNum@}
19 {-# OPTIONS -fno-implicit-prelude #-}
23 import {-# SOURCE #-} PrelErr
32 default () -- Double isn't available yet,
33 -- and we shouldn't be using defaults anyway
36 %*********************************************************
38 \subsection{Standard numeric class}
40 %*********************************************************
43 class (Eq a, Show a) => Num a where
44 (+), (-), (*) :: a -> a -> a
47 fromInteger :: Integer -> a
52 fromInt :: Num a => Int -> a
53 -- For backward compatibility
54 fromInt (I# i#) = fromInteger (S# i#)
57 A few small numeric functions
60 subtract :: (Num a) => a -> a -> a
61 {-# INLINE subtract #-}
65 ord_0 = fromInt (ord '0')
69 %*********************************************************
71 \subsection{Instances for @Int@}
73 %*********************************************************
76 instance Num Int where
78 (-) x y = minusInt x y
79 negate x = negateInt x
80 (*) x y = timesInt x y
81 abs n = if n `geInt` 0 then n else (negateInt n)
83 signum n | n `ltInt` 0 = negateInt 1
87 fromInteger n = integer2Int n
92 -- These can't go in PrelBase with the defn of Int, because
93 -- we don't have pairs defined at that time!
95 quotRemInt :: Int -> Int -> (Int, Int)
96 a@(I# _) `quotRemInt` b@(I# _) = (a `quotInt` b, a `remInt` b)
97 -- OK, so I made it a little stricter. Shoot me. (WDP 94/10)
99 divModInt :: Int -> Int -> (Int, Int)
100 divModInt x@(I# _) y@(I# _) = (x `divInt` y, x `modInt` y)
101 -- Stricter. Sorry if you don't like it. (WDP 94/10)
105 %*********************************************************
107 \subsection{The @Integer@ type}
109 %*********************************************************
113 = S# Int# -- small integers
114 | J# Int# ByteArray# -- large integers
117 Convenient boxed Integer PrimOps.
120 zeroInteger :: Integer
123 int2Integer :: Int -> Integer
124 {-# INLINE int2Integer #-}
125 int2Integer (I# i) = S# i
127 integer2Int :: Integer -> Int
128 integer2Int (S# i) = I# i
129 integer2Int (J# s d) = case (integer2Int# s d) of { n# -> I# n# }
131 toBig (S# i) = case int2Integer# i of { (# s, d #) -> J# s d }
136 %*********************************************************
138 \subsection{Dividing @Integers@}
140 %*********************************************************
143 quotRemInteger :: Integer -> Integer -> (Integer, Integer)
144 quotRemInteger a@(S# (-2147483648#)) b = quotRemInteger (toBig a) b
145 quotRemInteger (S# i) (S# j)
146 = case quotRemInt (I# i) (I# j) of ( I# i, I# j ) -> ( S# i, S# j )
147 quotRemInteger i1@(J# _ _) i2@(S# _) = quotRemInteger i1 (toBig i2)
148 quotRemInteger i1@(S# _) i2@(J# _ _) = quotRemInteger (toBig i1) i2
149 quotRemInteger (J# s1 d1) (J# s2 d2)
150 = case (quotRemInteger# s1 d1 s2 d2) of
152 -> (J# s3 d3, J# s4 d4)
154 divModInteger a@(S# (-2147483648#)) b = divModInteger (toBig a) b
155 divModInteger (S# i) (S# j)
156 = case divModInt (I# i) (I# j) of ( I# i, I# j ) -> ( S# i, S# j)
157 divModInteger i1@(J# _ _) i2@(S# _) = divModInteger i1 (toBig i2)
158 divModInteger i1@(S# _) i2@(J# _ _) = divModInteger (toBig i1) i2
159 divModInteger (J# s1 d1) (J# s2 d2)
160 = case (divModInteger# s1 d1 s2 d2) of
162 -> (J# s3 d3, J# s4 d4)
164 remInteger :: Integer -> Integer -> Integer
166 = error "Prelude.Integral.rem{Integer}: divide by 0"
167 remInteger a@(S# (-2147483648#)) b = remInteger (toBig a) b
168 remInteger (S# a) (S# b) = S# (remInt# a b)
169 {- Special case doesn't work, because a 1-element J# has the range
170 -(2^32-1) -- 2^32-1, whereas S# has the range -2^31 -- (2^31-1)
171 remInteger ia@(S# a) (J# sb b)
172 | sb ==# 1# = S# (remInt# a (word2Int# (integer2Word# sb b)))
173 | sb ==# -1# = S# (remInt# a (0# -# (word2Int# (integer2Word# sb b))))
175 | otherwise = S# (0# -# a)
177 remInteger ia@(S# _) ib@(J# _ _) = remInteger (toBig ia) ib
178 remInteger (J# sa a) (S# b)
179 = case int2Integer# b of { (# sb, b #) ->
180 case remInteger# sa a sb b of { (# sr, r #) ->
181 S# (sr *# (word2Int# (integer2Word# sr r))) }}
182 remInteger (J# sa a) (J# sb b)
183 = case remInteger# sa a sb b of (# sr, r #) -> J# sr r
185 quotInteger :: Integer -> Integer -> Integer
187 = error "Prelude.Integral.quot{Integer}: divide by 0"
188 quotInteger a@(S# (-2147483648#)) b = quotInteger (toBig a) b
189 quotInteger (S# a) (S# b) = S# (quotInt# a b)
190 {- Special case disabled, see remInteger above
191 quotInteger (S# a) (J# sb b)
192 | sb ==# 1# = S# (quotInt# a (word2Int# (integer2Word# sb b)))
193 | sb ==# -1# = S# (quotInt# a (0# -# (word2Int# (integer2Word# sb b))))
194 | otherwise = zeroInteger
196 quotInteger ia@(S# _) ib@(J# _ _) = quotInteger (toBig ia) ib
197 quotInteger (J# sa a) (S# b)
198 = case int2Integer# b of { (# sb, b #) ->
199 case quotInteger# sa a sb b of (# sq, q #) -> J# sq q }
200 quotInteger (J# sa a) (J# sb b)
201 = case quotInteger# sa a sb b of (# sg, g #) -> J# sg g
207 gcdInteger :: Integer -> Integer -> Integer
208 -- SUP: Do we really need the first two cases?
209 gcdInteger a@(S# (-2147483648#)) b = gcdInteger (toBig a) b
210 gcdInteger a b@(S# (-2147483648#)) = gcdInteger a (toBig b)
211 gcdInteger (S# a) (S# b) = case gcdInt (I# a) (I# b) of { I# c -> S# c }
212 gcdInteger ia@(S# 0#) ib@(J# 0# _) = error "PrelNum.gcdInteger: gcd 0 0 is undefined"
213 gcdInteger ia@(S# a) ib@(J# sb b)
216 | otherwise = S# (gcdIntegerInt# absSb b absA)
217 where absA = if a <# 0# then negateInt# a else a
218 absSb = if sb <# 0# then negateInt# sb else sb
219 gcdInteger ia@(J# _ _) ib@(S# _) = gcdInteger ib ia
220 gcdInteger (J# 0# _) (J# 0# _) = error "PrelNum.gcdInteger: gcd 0 0 is undefined"
221 gcdInteger (J# sa a) (J# sb b)
222 = case gcdInteger# sa a sb b of (# sg, g #) -> J# sg g
224 lcmInteger :: Integer -> Integer -> Integer
230 = (divExact aa (gcdInteger aa ab)) * ab
234 divExact :: Integer -> Integer -> Integer
235 divExact a@(S# (-2147483648#)) b = divExact (toBig a) b
236 divExact (S# a) (S# b) = S# (quotInt# a b)
237 divExact (S# a) (J# sb b)
238 = S# (quotInt# a (sb *# (word2Int# (integer2Word# sb b))))
239 divExact (J# sa a) (S# b)
240 = case int2Integer# b of
241 (# sb, b #) -> case divExactInteger# sa a sb b of (# sd, d #) -> J# sd d
242 divExact (J# sa a) (J# sb b)
243 = case divExactInteger# sa a sb b of (# sd, d #) -> J# sd d
247 %*********************************************************
249 \subsection{The @Integer@ instances for @Eq@, @Ord@}
251 %*********************************************************
254 instance Eq Integer where
255 (S# i) == (S# j) = i ==# j
256 (S# i) == (J# s d) = cmpIntegerInt# s d i ==# 0#
257 (J# s d) == (S# i) = cmpIntegerInt# s d i ==# 0#
258 (J# s1 d1) == (J# s2 d2) = (cmpInteger# s1 d1 s2 d2) ==# 0#
260 (S# i) /= (S# j) = i /=# j
261 (S# i) /= (J# s d) = cmpIntegerInt# s d i /=# 0#
262 (J# s d) /= (S# i) = cmpIntegerInt# s d i /=# 0#
263 (J# s1 d1) /= (J# s2 d2) = (cmpInteger# s1 d1 s2 d2) /=# 0#
265 ------------------------------------------------------------------------
266 instance Ord Integer where
267 (S# i) <= (S# j) = i <=# j
268 (J# s d) <= (S# i) = cmpIntegerInt# s d i <=# 0#
269 (S# i) <= (J# s d) = cmpIntegerInt# s d i >=# 0#
270 (J# s1 d1) <= (J# s2 d2) = (cmpInteger# s1 d1 s2 d2) <=# 0#
272 (S# i) > (S# j) = i ># j
273 (J# s d) > (S# i) = cmpIntegerInt# s d i ># 0#
274 (S# i) > (J# s d) = cmpIntegerInt# s d i <# 0#
275 (J# s1 d1) > (J# s2 d2) = (cmpInteger# s1 d1 s2 d2) ># 0#
277 (S# i) < (S# j) = i <# j
278 (J# s d) < (S# i) = cmpIntegerInt# s d i <# 0#
279 (S# i) < (J# s d) = cmpIntegerInt# s d i ># 0#
280 (J# s1 d1) < (J# s2 d2) = (cmpInteger# s1 d1 s2 d2) <# 0#
282 (S# i) >= (S# j) = i >=# j
283 (J# s d) >= (S# i) = cmpIntegerInt# s d i >=# 0#
284 (S# i) >= (J# s d) = cmpIntegerInt# s d i <=# 0#
285 (J# s1 d1) >= (J# s2 d2) = (cmpInteger# s1 d1 s2 d2) >=# 0#
287 compare (S# i) (S# j)
291 compare (J# s d) (S# i)
292 = case cmpIntegerInt# s d i of { res# ->
293 if res# <# 0# then LT else
294 if res# ># 0# then GT else EQ
296 compare (S# i) (J# s d)
297 = case cmpIntegerInt# s d i of { res# ->
298 if res# ># 0# then LT else
299 if res# <# 0# then GT else EQ
301 compare (J# s1 d1) (J# s2 d2)
302 = case cmpInteger# s1 d1 s2 d2 of { res# ->
303 if res# <# 0# then LT else
304 if res# ># 0# then GT else EQ
309 %*********************************************************
311 \subsection{The @Integer@ instances for @Num@}
313 %*********************************************************
316 instance Num Integer where
320 negate = negateInteger
323 -- ORIG: abs n = if n >= 0 then n else -n
324 abs (S# (-2147483648#)) = 2147483648
325 abs (S# i) = case abs (I# i) of I# j -> S# j
326 abs n@(J# s d) = if (s >=# 0#) then n else J# (negateInt# s) d
328 signum (S# i) = case signum (I# i) of I# j -> S# j
331 cmp = cmpIntegerInt# s d 0#
333 if cmp ># 0# then S# 1#
334 else if cmp ==# 0# then S# 0#
335 else S# (negateInt# 1#)
337 plusInteger i1@(S# i) i2@(S# j) = case addIntC# i j of { (# r, c #) ->
338 if c ==# 0# then S# r
339 else toBig i1 + toBig i2 }
340 plusInteger i1@(J# _ _) i2@(S# _) = i1 + toBig i2
341 plusInteger i1@(S# _) i2@(J# _ _) = toBig i1 + i2
342 plusInteger (J# s1 d1) (J# s2 d2) = case plusInteger# s1 d1 s2 d2 of (# s, d #) -> J# s d
344 minusInteger i1@(S# i) i2@(S# j) = case subIntC# i j of { (# r, c #) ->
345 if c ==# 0# then S# r
346 else toBig i1 - toBig i2 }
347 minusInteger i1@(J# _ _) i2@(S# _) = i1 - toBig i2
348 minusInteger i1@(S# _) i2@(J# _ _) = toBig i1 - i2
349 minusInteger (J# s1 d1) (J# s2 d2) = case minusInteger# s1 d1 s2 d2 of (# s, d #) -> J# s d
351 timesInteger i1@(S# i) i2@(S# j) = case mulIntC# i j of { (# r, c #) ->
352 if c ==# 0# then S# r
353 else toBig i1 * toBig i2 }
354 timesInteger i1@(J# _ _) i2@(S# _) = i1 * toBig i2
355 timesInteger i1@(S# _) i2@(J# _ _) = toBig i1 * i2
356 timesInteger (J# s1 d1) (J# s2 d2) = case timesInteger# s1 d1 s2 d2 of (# s, d #) -> J# s d
358 negateInteger (S# (-2147483648#)) = 2147483648
359 negateInteger (S# i) = S# (negateInt# i)
360 negateInteger (J# s d) = J# (negateInt# s) d
364 %*********************************************************
366 \subsection{The @Integer@ instance for @Enum@}
368 %*********************************************************
371 instance Enum Integer where
374 toEnum n = int2Integer n
375 fromEnum n = integer2Int n
377 {-# INLINE enumFrom #-}
378 {-# INLINE enumFromThen #-}
379 {-# INLINE enumFromTo #-}
380 {-# INLINE enumFromThenTo #-}
381 enumFrom x = efdInteger x 1
382 enumFromThen x y = efdInteger x (y-x)
383 enumFromTo x lim = efdtInteger x 1 lim
384 enumFromThenTo x y lim = efdtInteger x (y-x) lim
387 efdInteger = enumDeltaIntegerList
388 efdtInteger = enumDeltaToIntegerList
391 "efdInteger" forall x y. efdInteger x y = build (\c _ -> enumDeltaIntegerFB c x y)
392 "efdtInteger" forall x y l.efdtInteger x y l = build (\c n -> enumDeltaToIntegerFB c n x y l)
393 "enumDeltaInteger" enumDeltaIntegerFB (:) = enumDeltaIntegerList
394 "enumDeltaToInteger" enumDeltaToIntegerFB (:) [] = enumDeltaToIntegerList
397 enumDeltaIntegerFB :: (Integer -> b -> b) -> Integer -> Integer -> b
398 enumDeltaIntegerFB c x d = x `c` enumDeltaIntegerFB c (x+d) d
400 enumDeltaIntegerList :: Integer -> Integer -> [Integer]
401 enumDeltaIntegerList x d = x : enumDeltaIntegerList (x+d) d
403 enumDeltaToIntegerFB c n x delta lim
404 | delta >= 0 = up_fb c n x delta lim
405 | otherwise = dn_fb c n x delta lim
407 enumDeltaToIntegerList x delta lim
408 | delta >= 0 = up_list x delta lim
409 | otherwise = dn_list x delta lim
411 up_fb c n x delta lim = go (x::Integer)
414 | otherwise = x `c` go (x+delta)
415 dn_fb c n x delta lim = go (x::Integer)
418 | otherwise = x `c` go (x+delta)
420 up_list x delta lim = go (x::Integer)
423 | otherwise = x : go (x+delta)
424 dn_list x delta lim = go (x::Integer)
427 | otherwise = x : go (x+delta)
432 %*********************************************************
434 \subsection{The @Integer@ instances for @Show@}
436 %*********************************************************
439 instance Show Integer where
440 showsPrec x = showSignedInteger x
441 showList = showList__ (showsPrec 0)
443 showSignedInteger :: Int -> Integer -> ShowS
444 showSignedInteger p n r
445 | n < 0 && p > 6 = '(':jtos n (')':r)
446 | otherwise = jtos n r
448 jtos :: Integer -> String -> String
450 | i < 0 = '-' : jtos' (-i) rs
451 | otherwise = jtos' i rs
453 jtos' :: Integer -> String -> String
455 | n < 10 = chr (fromInteger n + (ord_0::Int)) : cs
456 | otherwise = jtos' q (chr (integer2Int r + (ord_0::Int)) : cs)
458 (q,r) = n `quotRemInteger` 10