1 % ------------------------------------------------------------------------------
2 % $Id: PrelNum.lhs,v 1.34 2000/09/26 16:45:34 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
48 fromInt :: Int -> a -- partain: Glasgow extension
52 fromInt (I# i#) = fromInteger (S# i#)
53 -- Go via the standard class-op if the
54 -- non-standard one ain't provided
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
93 -- These can't go in PrelBase with the defn of Int, because
94 -- we don't have pairs defined at that time!
96 quotRemInt :: Int -> Int -> (Int, Int)
97 a@(I# _) `quotRemInt` b@(I# _) = (a `quotInt` b, a `remInt` b)
98 -- OK, so I made it a little stricter. Shoot me. (WDP 94/10)
100 divModInt :: Int -> Int -> (Int, Int)
101 divModInt x@(I# _) y@(I# _) = (x `divInt` y, x `modInt` y)
102 -- Stricter. Sorry if you don't like it. (WDP 94/10)
106 %*********************************************************
108 \subsection{The @Integer@ type}
110 %*********************************************************
114 = S# Int# -- small integers
115 | J# Int# ByteArray# -- large integers
118 Convenient boxed Integer PrimOps.
121 zeroInteger :: Integer
124 int2Integer :: Int -> Integer
125 {-# INLINE int2Integer #-}
126 int2Integer (I# i) = S# i
128 integer2Int :: Integer -> Int
129 integer2Int (S# i) = I# i
130 integer2Int (J# s d) = case (integer2Int# s d) of { n# -> I# n# }
132 toBig (S# i) = case int2Integer# i of { (# s, d #) -> J# s d }
137 %*********************************************************
139 \subsection{Dividing @Integers@}
141 %*********************************************************
144 quotRemInteger :: Integer -> Integer -> (Integer, Integer)
145 quotRemInteger a@(S# (-2147483648#)) b = quotRemInteger (toBig a) b
146 quotRemInteger (S# i) (S# j)
147 = case quotRemInt (I# i) (I# j) of ( I# i, I# j ) -> ( S# i, S# j )
148 quotRemInteger i1@(J# _ _) i2@(S# _) = quotRemInteger i1 (toBig i2)
149 quotRemInteger i1@(S# _) i2@(J# _ _) = quotRemInteger (toBig i1) i2
150 quotRemInteger (J# s1 d1) (J# s2 d2)
151 = case (quotRemInteger# s1 d1 s2 d2) of
153 -> (J# s3 d3, J# s4 d4)
155 divModInteger a@(S# (-2147483648#)) b = divModInteger (toBig a) b
156 divModInteger (S# i) (S# j)
157 = case divModInt (I# i) (I# j) of ( I# i, I# j ) -> ( S# i, S# j)
158 divModInteger i1@(J# _ _) i2@(S# _) = divModInteger i1 (toBig i2)
159 divModInteger i1@(S# _) i2@(J# _ _) = divModInteger (toBig i1) i2
160 divModInteger (J# s1 d1) (J# s2 d2)
161 = case (divModInteger# s1 d1 s2 d2) of
163 -> (J# s3 d3, J# s4 d4)
165 remInteger :: Integer -> Integer -> Integer
167 = error "Prelude.Integral.rem{Integer}: divide by 0"
168 remInteger a@(S# (-2147483648#)) b = remInteger (toBig a) b
169 remInteger (S# a) (S# b) = S# (remInt# a b)
170 {- Special case doesn't work, because a 1-element J# has the range
171 -(2^32-1) -- 2^32-1, whereas S# has the range -2^31 -- (2^31-1)
172 remInteger ia@(S# a) (J# sb b)
173 | sb ==# 1# = S# (remInt# a (word2Int# (integer2Word# sb b)))
174 | sb ==# -1# = S# (remInt# a (0# -# (word2Int# (integer2Word# sb b))))
176 | otherwise = S# (0# -# a)
178 remInteger ia@(S# _) ib@(J# _ _) = remInteger (toBig ia) ib
179 remInteger (J# sa a) (S# b)
180 = case int2Integer# b of { (# sb, b #) ->
181 case remInteger# sa a sb b of { (# sr, r #) ->
182 S# (sr *# (word2Int# (integer2Word# sr r))) }}
183 remInteger (J# sa a) (J# sb b)
184 = case remInteger# sa a sb b of (# sr, r #) -> J# sr r
186 quotInteger :: Integer -> Integer -> Integer
188 = error "Prelude.Integral.quot{Integer}: divide by 0"
189 quotInteger a@(S# (-2147483648#)) b = quotInteger (toBig a) b
190 quotInteger (S# a) (S# b) = S# (quotInt# a b)
191 {- Special case disabled, see remInteger above
192 quotInteger (S# a) (J# sb b)
193 | sb ==# 1# = S# (quotInt# a (word2Int# (integer2Word# sb b)))
194 | sb ==# -1# = S# (quotInt# a (0# -# (word2Int# (integer2Word# sb b))))
195 | otherwise = zeroInteger
197 quotInteger ia@(S# _) ib@(J# _ _) = quotInteger (toBig ia) ib
198 quotInteger (J# sa a) (S# b)
199 = case int2Integer# b of { (# sb, b #) ->
200 case quotInteger# sa a sb b of (# sq, q #) -> J# sq q }
201 quotInteger (J# sa a) (J# sb b)
202 = case quotInteger# sa a sb b of (# sg, g #) -> J# sg g
208 gcdInteger :: Integer -> Integer -> Integer
209 -- SUP: Do we really need the first two cases?
210 gcdInteger a@(S# (-2147483648#)) b = gcdInteger (toBig a) b
211 gcdInteger a b@(S# (-2147483648#)) = gcdInteger a (toBig b)
212 gcdInteger (S# a) (S# b) = case gcdInt (I# a) (I# b) of { I# c -> S# c }
213 gcdInteger ia@(S# 0#) ib@(J# 0# _) = error "PrelNum.gcdInteger: gcd 0 0 is undefined"
214 gcdInteger ia@(S# a) ib@(J# sb b)
217 | otherwise = S# (gcdIntegerInt# absSb b absA)
218 where absA = if a <# 0# then negateInt# a else a
219 absSb = if sb <# 0# then negateInt# sb else sb
220 gcdInteger ia@(J# _ _) ib@(S# _) = gcdInteger ib ia
221 gcdInteger (J# 0# _) (J# 0# _) = error "PrelNum.gcdInteger: gcd 0 0 is undefined"
222 gcdInteger (J# sa a) (J# sb b)
223 = case gcdInteger# sa a sb b of (# sg, g #) -> J# sg g
225 lcmInteger :: Integer -> Integer -> Integer
231 = (divExact aa (gcdInteger aa ab)) * ab
235 divExact :: Integer -> Integer -> Integer
236 divExact a@(S# (-2147483648#)) b = divExact (toBig a) b
237 divExact (S# a) (S# b) = S# (quotInt# a b)
238 divExact (S# a) (J# sb b)
239 = S# (quotInt# a (sb *# (word2Int# (integer2Word# sb b))))
240 divExact (J# sa a) (S# b)
241 = case int2Integer# b of
242 (# sb, b #) -> case divExactInteger# sa a sb b of (# sd, d #) -> J# sd d
243 divExact (J# sa a) (J# sb b)
244 = case divExactInteger# sa a sb b of (# sd, d #) -> J# sd d
248 %*********************************************************
250 \subsection{The @Integer@ instances for @Eq@, @Ord@}
252 %*********************************************************
255 instance Eq Integer where
256 (S# i) == (S# j) = i ==# j
257 (S# i) == (J# s d) = cmpIntegerInt# s d i ==# 0#
258 (J# s d) == (S# i) = cmpIntegerInt# s d i ==# 0#
259 (J# s1 d1) == (J# s2 d2) = (cmpInteger# s1 d1 s2 d2) ==# 0#
261 (S# i) /= (S# j) = i /=# j
262 (S# i) /= (J# s d) = cmpIntegerInt# s d i /=# 0#
263 (J# s d) /= (S# i) = cmpIntegerInt# s d i /=# 0#
264 (J# s1 d1) /= (J# s2 d2) = (cmpInteger# s1 d1 s2 d2) /=# 0#
266 ------------------------------------------------------------------------
267 instance Ord Integer where
268 (S# i) <= (S# j) = i <=# j
269 (J# s d) <= (S# i) = cmpIntegerInt# s d i <=# 0#
270 (S# i) <= (J# s d) = cmpIntegerInt# s d i >=# 0#
271 (J# s1 d1) <= (J# s2 d2) = (cmpInteger# s1 d1 s2 d2) <=# 0#
273 (S# i) > (S# j) = i ># j
274 (J# s d) > (S# i) = cmpIntegerInt# s d i ># 0#
275 (S# i) > (J# s d) = cmpIntegerInt# s d i <# 0#
276 (J# s1 d1) > (J# s2 d2) = (cmpInteger# s1 d1 s2 d2) ># 0#
278 (S# i) < (S# j) = i <# j
279 (J# s d) < (S# i) = cmpIntegerInt# s d i <# 0#
280 (S# i) < (J# s d) = cmpIntegerInt# s d i ># 0#
281 (J# s1 d1) < (J# s2 d2) = (cmpInteger# s1 d1 s2 d2) <# 0#
283 (S# i) >= (S# j) = i >=# j
284 (J# s d) >= (S# i) = cmpIntegerInt# s d i >=# 0#
285 (S# i) >= (J# s d) = cmpIntegerInt# s d i <=# 0#
286 (J# s1 d1) >= (J# s2 d2) = (cmpInteger# s1 d1 s2 d2) >=# 0#
288 compare (S# i) (S# j)
292 compare (J# s d) (S# i)
293 = case cmpIntegerInt# s d i of { res# ->
294 if res# <# 0# then LT else
295 if res# ># 0# then GT else EQ
297 compare (S# i) (J# s d)
298 = case cmpIntegerInt# s d i of { res# ->
299 if res# ># 0# then LT else
300 if res# <# 0# then GT else EQ
302 compare (J# s1 d1) (J# s2 d2)
303 = case cmpInteger# s1 d1 s2 d2 of { res# ->
304 if res# <# 0# then LT else
305 if res# ># 0# then GT else EQ
310 %*********************************************************
312 \subsection{The @Integer@ instances for @Num@}
314 %*********************************************************
317 instance Num Integer where
321 negate = negateInteger
323 fromInt (I# i) = S# i
325 -- ORIG: abs n = if n >= 0 then n else -n
326 abs (S# (-2147483648#)) = 2147483648
327 abs (S# i) = case abs (I# i) of I# j -> S# j
328 abs n@(J# s d) = if (s >=# 0#) then n else J# (negateInt# s) d
330 signum (S# i) = case signum (I# i) of I# j -> S# j
333 cmp = cmpIntegerInt# s d 0#
335 if cmp ># 0# then S# 1#
336 else if cmp ==# 0# then S# 0#
337 else S# (negateInt# 1#)
339 plusInteger i1@(S# i) i2@(S# j) = case addIntC# i j of { (# r, c #) ->
340 if c ==# 0# then S# r
341 else toBig i1 + toBig i2 }
342 plusInteger i1@(J# _ _) i2@(S# _) = i1 + toBig i2
343 plusInteger i1@(S# _) i2@(J# _ _) = toBig i1 + i2
344 plusInteger (J# s1 d1) (J# s2 d2) = case plusInteger# s1 d1 s2 d2 of (# s, d #) -> J# s d
346 minusInteger i1@(S# i) i2@(S# j) = case subIntC# i j of { (# r, c #) ->
347 if c ==# 0# then S# r
348 else toBig i1 - toBig i2 }
349 minusInteger i1@(J# _ _) i2@(S# _) = i1 - toBig i2
350 minusInteger i1@(S# _) i2@(J# _ _) = toBig i1 - i2
351 minusInteger (J# s1 d1) (J# s2 d2) = case minusInteger# s1 d1 s2 d2 of (# s, d #) -> J# s d
353 timesInteger i1@(S# i) i2@(S# j) = case mulIntC# i j of { (# r, c #) ->
354 if c ==# 0# then S# r
355 else toBig i1 * toBig i2 }
356 timesInteger i1@(J# _ _) i2@(S# _) = i1 * toBig i2
357 timesInteger i1@(S# _) i2@(J# _ _) = toBig i1 * i2
358 timesInteger (J# s1 d1) (J# s2 d2) = case timesInteger# s1 d1 s2 d2 of (# s, d #) -> J# s d
360 negateInteger (S# (-2147483648#)) = 2147483648
361 negateInteger (S# i) = S# (negateInt# i)
362 negateInteger (J# s d) = J# (negateInt# s) d
366 %*********************************************************
368 \subsection{The @Integer@ instance for @Enum@}
370 %*********************************************************
373 instance Enum Integer where
376 toEnum n = int2Integer n
377 fromEnum n = integer2Int n
379 {-# INLINE enumFrom #-}
380 {-# INLINE enumFromThen #-}
381 {-# INLINE enumFromTo #-}
382 {-# INLINE enumFromThenTo #-}
383 enumFrom x = efdInteger x 1
384 enumFromThen x y = efdInteger x (y-x)
385 enumFromTo x lim = efdtInteger x 1 lim
386 enumFromThenTo x y lim = efdtInteger x (y-x) lim
389 efdInteger = enumDeltaIntegerList
390 efdtInteger = enumDeltaToIntegerList
393 "efdInteger" forall x y. efdInteger x y = build (\c _ -> enumDeltaIntegerFB c x y)
394 "efdtInteger" forall x y l.efdtInteger x y l = build (\c n -> enumDeltaToIntegerFB c n x y l)
395 "enumDeltaInteger" enumDeltaIntegerFB (:) = enumDeltaIntegerList
396 "enumDeltaToInteger" enumDeltaToIntegerFB (:) [] = enumDeltaToIntegerList
399 enumDeltaIntegerFB :: (Integer -> b -> b) -> Integer -> Integer -> b
400 enumDeltaIntegerFB c x d = x `c` enumDeltaIntegerFB c (x+d) d
402 enumDeltaIntegerList :: Integer -> Integer -> [Integer]
403 enumDeltaIntegerList x d = x : enumDeltaIntegerList (x+d) d
405 enumDeltaToIntegerFB c n x delta lim
406 | delta >= 0 = up_fb c n x delta lim
407 | otherwise = dn_fb c n x delta lim
409 enumDeltaToIntegerList x delta lim
410 | delta >= 0 = up_list x delta lim
411 | otherwise = dn_list x delta lim
413 up_fb c n x delta lim = go (x::Integer)
416 | otherwise = x `c` go (x+delta)
417 dn_fb c n x delta lim = go (x::Integer)
420 | otherwise = x `c` go (x+delta)
422 up_list x delta lim = go (x::Integer)
425 | otherwise = x : go (x+delta)
426 dn_list x delta lim = go (x::Integer)
429 | otherwise = x : go (x+delta)
434 %*********************************************************
436 \subsection{The @Integer@ instances for @Show@}
438 %*********************************************************
441 instance Show Integer where
442 showsPrec x = showSignedInteger x
443 showList = showList__ (showsPrec 0)
445 showSignedInteger :: Int -> Integer -> ShowS
446 showSignedInteger p n r
447 | n < 0 && p > 6 = '(':jtos n (')':r)
448 | otherwise = jtos n r
450 jtos :: Integer -> String -> String
452 | i < 0 = '-' : jtos' (-i) rs
453 | otherwise = jtos' i rs
455 jtos' :: Integer -> String -> String
457 | n < 10 = chr (fromInteger n + (ord_0::Int)) : cs
458 | otherwise = jtos' q (chr (integer2Int r + (ord_0::Int)) : cs)
460 (q,r) = n `quotRemInteger` 10