0.8.3.80:
[sbcl/simd.git] / src / code / numbers.lisp
blob3632cd6e89ac3af615e07303ec7bd99b2196d9f8
1 ;;;; This file contains the definitions of most number functions.
3 ;;;; This software is part of the SBCL system. See the README file for
4 ;;;; more information.
5 ;;;;
6 ;;;; This software is derived from the CMU CL system, which was
7 ;;;; written at Carnegie Mellon University and released into the
8 ;;;; public domain. The software is in the public domain and is
9 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
10 ;;;; files for more information.
12 (in-package "SB!KERNEL")
14 ;;;; the NUMBER-DISPATCH macro
16 (eval-when (:compile-toplevel :load-toplevel :execute)
18 ;;; Grovel an individual case to NUMBER-DISPATCH, augmenting RESULT
19 ;;; with the type dispatches and bodies. Result is a tree built of
20 ;;; alists representing the dispatching off each arg (in order). The
21 ;;; leaf is the body to be executed in that case.
22 (defun parse-number-dispatch (vars result types var-types body)
23 (cond ((null vars)
24 (unless (null types) (error "More types than vars."))
25 (when (cdr result)
26 (error "Duplicate case: ~S." body))
27 (setf (cdr result)
28 (sublis var-types body :test #'equal)))
29 ((null types)
30 (error "More vars than types."))
32 (flet ((frob (var type)
33 (parse-number-dispatch
34 (rest vars)
35 (or (assoc type (cdr result) :test #'equal)
36 (car (setf (cdr result)
37 (acons type nil (cdr result)))))
38 (rest types)
39 (acons `(dispatch-type ,var) type var-types)
40 body)))
41 (let ((type (first types))
42 (var (first vars)))
43 (if (and (consp type) (eq (first type) 'foreach))
44 (dolist (type (rest type))
45 (frob var type))
46 (frob var type)))))))
48 ;;; our guess for the preferred order in which to do type tests
49 ;;; (cheaper and/or more probable first.)
50 (defparameter *type-test-ordering*
51 '(fixnum single-float double-float integer #!+long-float long-float bignum
52 complex ratio))
54 ;;; Should TYPE1 be tested before TYPE2?
55 (defun type-test-order (type1 type2)
56 (let ((o1 (position type1 *type-test-ordering*))
57 (o2 (position type2 *type-test-ordering*)))
58 (cond ((not o1) nil)
59 ((not o2) t)
61 (< o1 o2)))))
63 ;;; Return an ETYPECASE form that does the type dispatch, ordering the
64 ;;; cases for efficiency.
65 (defun generate-number-dispatch (vars error-tags cases)
66 (if vars
67 (let ((var (first vars))
68 (cases (sort cases #'type-test-order :key #'car)))
69 `((typecase ,var
70 ,@(mapcar (lambda (case)
71 `(,(first case)
72 ,@(generate-number-dispatch (rest vars)
73 (rest error-tags)
74 (cdr case))))
75 cases)
76 (t (go ,(first error-tags))))))
77 cases))
79 ) ; EVAL-WHEN
81 ;;; This is a vaguely case-like macro that does number cross-product
82 ;;; dispatches. The Vars are the variables we are dispatching off of.
83 ;;; The Type paired with each Var is used in the error message when no
84 ;;; case matches. Each case specifies a Type for each var, and is
85 ;;; executed when that signature holds. A type may be a list
86 ;;; (FOREACH Each-Type*), causing that case to be repeatedly
87 ;;; instantiated for every Each-Type. In the body of each case, any
88 ;;; list of the form (DISPATCH-TYPE Var-Name) is substituted with the
89 ;;; type of that var in that instance of the case.
90 ;;;
91 ;;; As an alternate to a case spec, there may be a form whose CAR is a
92 ;;; symbol. In this case, we apply the CAR of the form to the CDR and
93 ;;; treat the result of the call as a list of cases. This process is
94 ;;; not applied recursively.
95 (defmacro number-dispatch (var-specs &body cases)
96 (let ((res (list nil))
97 (vars (mapcar #'car var-specs))
98 (block (gensym)))
99 (dolist (case cases)
100 (if (symbolp (first case))
101 (let ((cases (apply (symbol-function (first case)) (rest case))))
102 (dolist (case cases)
103 (parse-number-dispatch vars res (first case) nil (rest case))))
104 (parse-number-dispatch vars res (first case) nil (rest case))))
106 (collect ((errors)
107 (error-tags))
108 (dolist (spec var-specs)
109 (let ((var (first spec))
110 (type (second spec))
111 (tag (gensym)))
112 (error-tags tag)
113 (errors tag)
114 (errors `(return-from
115 ,block
116 (error 'simple-type-error :datum ,var
117 :expected-type ',type
118 :format-control
119 "~@<Argument ~A is not a ~S: ~2I~_~S~:>"
120 :format-arguments
121 (list ',var ',type ,var))))))
123 `(block ,block
124 (tagbody
125 (return-from ,block
126 ,@(generate-number-dispatch vars (error-tags)
127 (cdr res)))
128 ,@(errors))))))
130 ;;;; binary operation dispatching utilities
132 (eval-when (:compile-toplevel :execute)
134 ;;; Return NUMBER-DISPATCH forms for rational X float.
135 (defun float-contagion (op x y &optional (rat-types '(fixnum bignum ratio)))
136 `(((single-float single-float) (,op ,x ,y))
137 (((foreach ,@rat-types)
138 (foreach single-float double-float #!+long-float long-float))
139 (,op (coerce ,x '(dispatch-type ,y)) ,y))
140 (((foreach single-float double-float #!+long-float long-float)
141 (foreach ,@rat-types))
142 (,op ,x (coerce ,y '(dispatch-type ,x))))
143 #!+long-float
144 (((foreach single-float double-float long-float) long-float)
145 (,op (coerce ,x 'long-float) ,y))
146 #!+long-float
147 ((long-float (foreach single-float double-float))
148 (,op ,x (coerce ,y 'long-float)))
149 (((foreach single-float double-float) double-float)
150 (,op (coerce ,x 'double-float) ,y))
151 ((double-float single-float)
152 (,op ,x (coerce ,y 'double-float)))))
154 ;;; Return NUMBER-DISPATCH forms for bignum X fixnum.
155 (defun bignum-cross-fixnum (fix-op big-op)
156 `(((fixnum fixnum) (,fix-op x y))
157 ((fixnum bignum)
158 (,big-op (make-small-bignum x) y))
159 ((bignum fixnum)
160 (,big-op x (make-small-bignum y)))
161 ((bignum bignum)
162 (,big-op x y))))
164 ) ; EVAL-WHEN
166 ;;;; canonicalization utilities
168 ;;; If IMAGPART is 0, return REALPART, otherwise make a complex. This is
169 ;;; used when we know that REALPART and IMAGPART are the same type, but
170 ;;; rational canonicalization might still need to be done.
171 #!-sb-fluid (declaim (inline canonical-complex))
172 (defun canonical-complex (realpart imagpart)
173 (if (eql imagpart 0)
174 realpart
175 (cond #!+long-float
176 ((and (typep realpart 'long-float)
177 (typep imagpart 'long-float))
178 (truly-the (complex long-float) (complex realpart imagpart)))
179 ((and (typep realpart 'double-float)
180 (typep imagpart 'double-float))
181 (truly-the (complex double-float) (complex realpart imagpart)))
182 ((and (typep realpart 'single-float)
183 (typep imagpart 'single-float))
184 (truly-the (complex single-float) (complex realpart imagpart)))
186 (%make-complex realpart imagpart)))))
188 ;;; Given a numerator and denominator with the GCD already divided
189 ;;; out, make a canonical rational. We make the denominator positive,
190 ;;; and check whether it is 1.
191 #!-sb-fluid (declaim (inline build-ratio))
192 (defun build-ratio (num den)
193 (multiple-value-bind (num den)
194 (if (minusp den)
195 (values (- num) (- den))
196 (values num den))
197 (cond
198 ((eql den 0)
199 (error 'division-by-zero
200 :operands (list num den)
201 :operation 'build-ratio))
202 ((eql den 1) num)
203 (t (%make-ratio num den)))))
205 ;;; Truncate X and Y, but bum the case where Y is 1.
206 #!-sb-fluid (declaim (inline maybe-truncate))
207 (defun maybe-truncate (x y)
208 (if (eql y 1)
210 (truncate x y)))
212 ;;;; COMPLEXes
214 (defun upgraded-complex-part-type (spec &optional environment)
215 #!+sb-doc
216 "Return the element type of the most specialized COMPLEX number type that
217 can hold parts of type SPEC."
218 (declare (ignore environment))
219 (cond ((unknown-type-p (specifier-type spec))
220 (error "undefined type: ~S" spec))
221 ((subtypep spec 'single-float)
222 'single-float)
223 ((subtypep spec 'double-float)
224 'double-float)
225 #!+long-float
226 ((subtypep spec 'long-float)
227 'long-float)
228 ((subtypep spec 'rational)
229 'rational)
231 'real)))
233 (defun complex (realpart &optional (imagpart 0))
234 #!+sb-doc
235 "Return a complex number with the specified real and imaginary components."
236 (flet ((%%make-complex (realpart imagpart)
237 (cond #!+long-float
238 ((and (typep realpart 'long-float)
239 (typep imagpart 'long-float))
240 (truly-the (complex long-float)
241 (complex realpart imagpart)))
242 ((and (typep realpart 'double-float)
243 (typep imagpart 'double-float))
244 (truly-the (complex double-float)
245 (complex realpart imagpart)))
246 ((and (typep realpart 'single-float)
247 (typep imagpart 'single-float))
248 (truly-the (complex single-float)
249 (complex realpart imagpart)))
251 (%make-complex realpart imagpart)))))
252 (number-dispatch ((realpart real) (imagpart real))
253 ((rational rational)
254 (canonical-complex realpart imagpart))
255 (float-contagion %%make-complex realpart imagpart (rational)))))
257 (defun realpart (number)
258 #!+sb-doc
259 "Extract the real part of a number."
260 (typecase number
261 #!+long-float
262 ((complex long-float)
263 (truly-the long-float (realpart number)))
264 ((complex double-float)
265 (truly-the double-float (realpart number)))
266 ((complex single-float)
267 (truly-the single-float (realpart number)))
268 ((complex rational)
269 (sb!kernel:%realpart number))
271 number)))
273 (defun imagpart (number)
274 #!+sb-doc
275 "Extract the imaginary part of a number."
276 (typecase number
277 #!+long-float
278 ((complex long-float)
279 (truly-the long-float (imagpart number)))
280 ((complex double-float)
281 (truly-the double-float (imagpart number)))
282 ((complex single-float)
283 (truly-the single-float (imagpart number)))
284 ((complex rational)
285 (sb!kernel:%imagpart number))
286 (float
287 (float 0 number))
289 0)))
291 (defun conjugate (number)
292 #!+sb-doc
293 "Return the complex conjugate of NUMBER. For non-complex numbers, this is
294 an identity."
295 (if (complexp number)
296 (complex (realpart number) (- (imagpart number)))
297 number))
299 (defun signum (number)
300 #!+sb-doc
301 "If NUMBER is zero, return NUMBER, else return (/ NUMBER (ABS NUMBER))."
302 (if (zerop number)
303 number
304 (if (rationalp number)
305 (if (plusp number) 1 -1)
306 (/ number (abs number)))))
308 ;;;; ratios
310 (defun numerator (number)
311 #!+sb-doc
312 "Return the numerator of NUMBER, which must be rational."
313 (numerator number))
315 (defun denominator (number)
316 #!+sb-doc
317 "Return the denominator of NUMBER, which must be rational."
318 (denominator number))
320 ;;;; arithmetic operations
322 (macrolet ((define-arith (op init doc)
323 #!-sb-doc (declare (ignore doc))
324 `(defun ,op (&rest args)
325 #!+sb-doc ,doc
326 (if (null args) ,init
327 (do ((args (cdr args) (cdr args))
328 (result (car args) (,op result (car args))))
329 ((null args) result)
330 ;; to signal TYPE-ERROR when exactly 1 arg of wrong type:
331 (declare (type number result)))))))
332 (define-arith + 0
333 "Return the sum of its arguments. With no args, returns 0.")
334 (define-arith * 1
335 "Return the product of its arguments. With no args, returns 1."))
337 (defun - (number &rest more-numbers)
338 #!+sb-doc
339 "Subtract the second and all subsequent arguments from the first;
340 or with one argument, negate the first argument."
341 (if more-numbers
342 (do ((nlist more-numbers (cdr nlist))
343 (result number))
344 ((atom nlist) result)
345 (declare (list nlist))
346 (setq result (- result (car nlist))))
347 (- number)))
349 (defun / (number &rest more-numbers)
350 #!+sb-doc
351 "Divide the first argument by each of the following arguments, in turn.
352 With one argument, return reciprocal."
353 (if more-numbers
354 (do ((nlist more-numbers (cdr nlist))
355 (result number))
356 ((atom nlist) result)
357 (declare (list nlist))
358 (setq result (/ result (car nlist))))
359 (/ number)))
361 (defun 1+ (number)
362 #!+sb-doc
363 "Return NUMBER + 1."
364 (1+ number))
366 (defun 1- (number)
367 #!+sb-doc
368 "Return NUMBER - 1."
369 (1- number))
371 (eval-when (:compile-toplevel)
373 (sb!xc:defmacro two-arg-+/- (name op big-op)
374 `(defun ,name (x y)
375 (number-dispatch ((x number) (y number))
376 (bignum-cross-fixnum ,op ,big-op)
377 (float-contagion ,op x y)
379 ((complex complex)
380 (canonical-complex (,op (realpart x) (realpart y))
381 (,op (imagpart x) (imagpart y))))
382 (((foreach bignum fixnum ratio single-float double-float
383 #!+long-float long-float) complex)
384 (complex (,op x (realpart y)) (,op (imagpart y))))
385 ((complex (or rational float))
386 (complex (,op (realpart x) y) (imagpart x)))
388 (((foreach fixnum bignum) ratio)
389 (let* ((dy (denominator y))
390 (n (,op (* x dy) (numerator y))))
391 (%make-ratio n dy)))
392 ((ratio integer)
393 (let* ((dx (denominator x))
394 (n (,op (numerator x) (* y dx))))
395 (%make-ratio n dx)))
396 ((ratio ratio)
397 (let* ((nx (numerator x))
398 (dx (denominator x))
399 (ny (numerator y))
400 (dy (denominator y))
401 (g1 (gcd dx dy)))
402 (if (eql g1 1)
403 (%make-ratio (,op (* nx dy) (* dx ny)) (* dx dy))
404 (let* ((t1 (,op (* nx (truncate dy g1)) (* (truncate dx g1) ny)))
405 (g2 (gcd t1 g1))
406 (t2 (truncate dx g1)))
407 (cond ((eql t1 0) 0)
408 ((eql g2 1)
409 (%make-ratio t1 (* t2 dy)))
410 (T (let* ((nn (truncate t1 g2))
411 (t3 (truncate dy g2))
412 (nd (if (eql t2 1) t3 (* t2 t3))))
413 (if (eql nd 1) nn (%make-ratio nn nd))))))))))))
415 ) ; EVAL-WHEN
417 (two-arg-+/- two-arg-+ + add-bignums)
418 (two-arg-+/- two-arg-- - subtract-bignum)
420 (defun two-arg-* (x y)
421 (flet ((integer*ratio (x y)
422 (if (eql x 0) 0
423 (let* ((ny (numerator y))
424 (dy (denominator y))
425 (gcd (gcd x dy)))
426 (if (eql gcd 1)
427 (%make-ratio (* x ny) dy)
428 (let ((nn (* (truncate x gcd) ny))
429 (nd (truncate dy gcd)))
430 (if (eql nd 1)
432 (%make-ratio nn nd)))))))
433 (complex*real (x y)
434 (canonical-complex (* (realpart x) y) (* (imagpart x) y))))
435 (number-dispatch ((x number) (y number))
436 (float-contagion * x y)
438 ((fixnum fixnum) (multiply-fixnums x y))
439 ((bignum fixnum) (multiply-bignum-and-fixnum x y))
440 ((fixnum bignum) (multiply-bignum-and-fixnum y x))
441 ((bignum bignum) (multiply-bignums x y))
443 ((complex complex)
444 (let* ((rx (realpart x))
445 (ix (imagpart x))
446 (ry (realpart y))
447 (iy (imagpart y)))
448 (canonical-complex (- (* rx ry) (* ix iy)) (+ (* rx iy) (* ix ry)))))
449 (((foreach bignum fixnum ratio single-float double-float
450 #!+long-float long-float)
451 complex)
452 (complex*real y x))
453 ((complex (or rational float))
454 (complex*real x y))
456 (((foreach bignum fixnum) ratio) (integer*ratio x y))
457 ((ratio integer) (integer*ratio y x))
458 ((ratio ratio)
459 (let* ((nx (numerator x))
460 (dx (denominator x))
461 (ny (numerator y))
462 (dy (denominator y))
463 (g1 (gcd nx dy))
464 (g2 (gcd dx ny)))
465 (build-ratio (* (maybe-truncate nx g1)
466 (maybe-truncate ny g2))
467 (* (maybe-truncate dx g2)
468 (maybe-truncate dy g1))))))))
470 ;;; Divide two integers, producing a canonical rational. If a fixnum,
471 ;;; we see whether they divide evenly before trying the GCD. In the
472 ;;; bignum case, we don't bother, since bignum division is expensive,
473 ;;; and the test is not very likely to succeed.
474 (defun integer-/-integer (x y)
475 (if (and (typep x 'fixnum) (typep y 'fixnum))
476 (multiple-value-bind (quo rem) (truncate x y)
477 (if (zerop rem)
479 (let ((gcd (gcd x y)))
480 (declare (fixnum gcd))
481 (if (eql gcd 1)
482 (build-ratio x y)
483 (build-ratio (truncate x gcd) (truncate y gcd))))))
484 (let ((gcd (gcd x y)))
485 (if (eql gcd 1)
486 (build-ratio x y)
487 (build-ratio (truncate x gcd) (truncate y gcd))))))
489 (defun two-arg-/ (x y)
490 (number-dispatch ((x number) (y number))
491 (float-contagion / x y (ratio integer))
493 ((complex complex)
494 (let* ((rx (realpart x))
495 (ix (imagpart x))
496 (ry (realpart y))
497 (iy (imagpart y)))
498 (if (> (abs ry) (abs iy))
499 (let* ((r (/ iy ry))
500 (dn (* ry (+ 1 (* r r)))))
501 (canonical-complex (/ (+ rx (* ix r)) dn)
502 (/ (- ix (* rx r)) dn)))
503 (let* ((r (/ ry iy))
504 (dn (* iy (+ 1 (* r r)))))
505 (canonical-complex (/ (+ (* rx r) ix) dn)
506 (/ (- (* ix r) rx) dn))))))
507 (((foreach integer ratio single-float double-float) complex)
508 (let* ((ry (realpart y))
509 (iy (imagpart y)))
510 (if (> (abs ry) (abs iy))
511 (let* ((r (/ iy ry))
512 (dn (* ry (+ 1 (* r r)))))
513 (canonical-complex (/ x dn)
514 (/ (- (* x r)) dn)))
515 (let* ((r (/ ry iy))
516 (dn (* iy (+ 1 (* r r)))))
517 (canonical-complex (/ (* x r) dn)
518 (/ (- x) dn))))))
519 ((complex (or rational float))
520 (canonical-complex (/ (realpart x) y)
521 (/ (imagpart x) y)))
523 ((ratio ratio)
524 (let* ((nx (numerator x))
525 (dx (denominator x))
526 (ny (numerator y))
527 (dy (denominator y))
528 (g1 (gcd nx ny))
529 (g2 (gcd dx dy)))
530 (build-ratio (* (maybe-truncate nx g1) (maybe-truncate dy g2))
531 (* (maybe-truncate dx g2) (maybe-truncate ny g1)))))
533 ((integer integer)
534 (integer-/-integer x y))
536 ((integer ratio)
537 (if (zerop x)
539 (let* ((ny (numerator y))
540 (dy (denominator y))
541 (gcd (gcd x ny)))
542 (build-ratio (* (maybe-truncate x gcd) dy)
543 (maybe-truncate ny gcd)))))
545 ((ratio integer)
546 (let* ((nx (numerator x))
547 (gcd (gcd nx y)))
548 (build-ratio (maybe-truncate nx gcd)
549 (* (maybe-truncate y gcd) (denominator x)))))))
551 (defun %negate (n)
552 (number-dispatch ((n number))
553 (((foreach fixnum single-float double-float #!+long-float long-float))
554 (%negate n))
555 ((bignum)
556 (negate-bignum n))
557 ((ratio)
558 (%make-ratio (- (numerator n)) (denominator n)))
559 ((complex)
560 (complex (- (realpart n)) (- (imagpart n))))))
562 ;;;; TRUNCATE and friends
564 (defun truncate (number &optional (divisor 1))
565 #!+sb-doc
566 "Return number (or number/divisor) as an integer, rounded toward 0.
567 The second returned value is the remainder."
568 (macrolet ((truncate-float (rtype)
569 `(let* ((float-div (coerce divisor ',rtype))
570 (res (%unary-truncate (/ number float-div))))
571 (values res
572 (- number
573 (* (coerce res ',rtype) float-div))))))
574 (number-dispatch ((number real) (divisor real))
575 ((fixnum fixnum) (truncate number divisor))
576 (((foreach fixnum bignum) ratio)
577 (let ((q (truncate (* number (denominator divisor))
578 (numerator divisor))))
579 (values q (- number (* q divisor)))))
580 ((fixnum bignum)
581 (bignum-truncate (make-small-bignum number) divisor))
582 ((ratio (or float rational))
583 (let ((q (truncate (numerator number)
584 (* (denominator number) divisor))))
585 (values q (- number (* q divisor)))))
586 ((bignum fixnum)
587 (bignum-truncate number (make-small-bignum divisor)))
588 ((bignum bignum)
589 (bignum-truncate number divisor))
591 (((foreach single-float double-float #!+long-float long-float)
592 (or rational single-float))
593 (if (eql divisor 1)
594 (let ((res (%unary-truncate number)))
595 (values res (- number (coerce res '(dispatch-type number)))))
596 (truncate-float (dispatch-type number))))
597 #!+long-float
598 ((long-float (or single-float double-float long-float))
599 (truncate-float long-float))
600 #!+long-float
601 (((foreach double-float single-float) long-float)
602 (truncate-float long-float))
603 ((double-float (or single-float double-float))
604 (truncate-float double-float))
605 ((single-float double-float)
606 (truncate-float double-float))
607 (((foreach fixnum bignum ratio)
608 (foreach single-float double-float #!+long-float long-float))
609 (truncate-float (dispatch-type divisor))))))
611 ;;; Declare these guys inline to let them get optimized a little.
612 ;;; ROUND and FROUND are not declared inline since they seem too
613 ;;; obscure and too big to inline-expand by default. Also, this gives
614 ;;; the compiler a chance to pick off the unary float case. Similarly,
615 ;;; CEILING and FLOOR are only maybe-inline for now, so that the
616 ;;; power-of-2 CEILING and FLOOR transforms get a chance.
617 #!-sb-fluid (declaim (inline rem mod fceiling ffloor ftruncate))
618 (declaim (maybe-inline ceiling floor))
620 (defun floor (number &optional (divisor 1))
621 #!+sb-doc
622 "Return the greatest integer not greater than number, or number/divisor.
623 The second returned value is (mod number divisor)."
624 ;; If the numbers do not divide exactly and the result of
625 ;; (/ NUMBER DIVISOR) would be negative then decrement the quotient
626 ;; and augment the remainder by the divisor.
627 (multiple-value-bind (tru rem) (truncate number divisor)
628 (if (and (not (zerop rem))
629 (if (minusp divisor)
630 (plusp number)
631 (minusp number)))
632 (values (1- tru) (+ rem divisor))
633 (values tru rem))))
635 (defun ceiling (number &optional (divisor 1))
636 #!+sb-doc
637 "Return the smallest integer not less than number, or number/divisor.
638 The second returned value is the remainder."
639 ;; If the numbers do not divide exactly and the result of
640 ;; (/ NUMBER DIVISOR) would be positive then increment the quotient
641 ;; and decrement the remainder by the divisor.
642 (multiple-value-bind (tru rem) (truncate number divisor)
643 (if (and (not (zerop rem))
644 (if (minusp divisor)
645 (minusp number)
646 (plusp number)))
647 (values (+ tru 1) (- rem divisor))
648 (values tru rem))))
650 (defun round (number &optional (divisor 1))
651 #!+sb-doc
652 "Rounds number (or number/divisor) to nearest integer.
653 The second returned value is the remainder."
654 (if (eql divisor 1)
655 (round number)
656 (multiple-value-bind (tru rem) (truncate number divisor)
657 (if (zerop rem)
658 (values tru rem)
659 (let ((thresh (/ (abs divisor) 2)))
660 (cond ((or (> rem thresh)
661 (and (= rem thresh) (oddp tru)))
662 (if (minusp divisor)
663 (values (- tru 1) (+ rem divisor))
664 (values (+ tru 1) (- rem divisor))))
665 ((let ((-thresh (- thresh)))
666 (or (< rem -thresh)
667 (and (= rem -thresh) (oddp tru))))
668 (if (minusp divisor)
669 (values (+ tru 1) (- rem divisor))
670 (values (- tru 1) (+ rem divisor))))
671 (t (values tru rem))))))))
673 (defun rem (number divisor)
674 #!+sb-doc
675 "Return second result of TRUNCATE."
676 (multiple-value-bind (tru rem) (truncate number divisor)
677 (declare (ignore tru))
678 rem))
680 (defun mod (number divisor)
681 #!+sb-doc
682 "Return second result of FLOOR."
683 (let ((rem (rem number divisor)))
684 (if (and (not (zerop rem))
685 (if (minusp divisor)
686 (plusp number)
687 (minusp number)))
688 (+ rem divisor)
689 rem)))
691 (defmacro !define-float-rounding-function (name op doc)
692 `(defun ,name (number &optional (divisor 1))
693 ,doc
694 (multiple-value-bind (res rem) (,op number divisor)
695 (values (float res (if (floatp rem) rem 1.0)) rem))))
697 (!define-float-rounding-function ffloor floor
698 "Same as FLOOR, but returns first value as a float.")
699 (!define-float-rounding-function fceiling ceiling
700 "Same as CEILING, but returns first value as a float." )
701 (!define-float-rounding-function ftruncate truncate
702 "Same as TRUNCATE, but returns first value as a float.")
703 (!define-float-rounding-function fround round
704 "Same as ROUND, but returns first value as a float.")
706 ;;;; comparisons
708 (defun = (number &rest more-numbers)
709 #!+sb-doc
710 "Return T if all of its arguments are numerically equal, NIL otherwise."
711 (do ((nlist more-numbers (cdr nlist)))
712 ((atom nlist) T)
713 (declare (list nlist))
714 (if (not (= (car nlist) number)) (return nil))))
716 (defun /= (number &rest more-numbers)
717 #!+sb-doc
718 "Return T if no two of its arguments are numerically equal, NIL otherwise."
719 (do* ((head number (car nlist))
720 (nlist more-numbers (cdr nlist)))
721 ((atom nlist) t)
722 (declare (list nlist))
723 (unless (do* ((nl nlist (cdr nl)))
724 ((atom nl) T)
725 (declare (list nl))
726 (if (= head (car nl)) (return nil)))
727 (return nil))))
729 (defun < (number &rest more-numbers)
730 #!+sb-doc
731 "Return T if its arguments are in strictly increasing order, NIL otherwise."
732 (do* ((n number (car nlist))
733 (nlist more-numbers (cdr nlist)))
734 ((atom nlist) t)
735 (declare (list nlist))
736 (if (not (< n (car nlist))) (return nil))))
738 (defun > (number &rest more-numbers)
739 #!+sb-doc
740 "Return T if its arguments are in strictly decreasing order, NIL otherwise."
741 (do* ((n number (car nlist))
742 (nlist more-numbers (cdr nlist)))
743 ((atom nlist) t)
744 (declare (list nlist))
745 (if (not (> n (car nlist))) (return nil))))
747 (defun <= (number &rest more-numbers)
748 #!+sb-doc
749 "Return T if arguments are in strictly non-decreasing order, NIL otherwise."
750 (do* ((n number (car nlist))
751 (nlist more-numbers (cdr nlist)))
752 ((atom nlist) t)
753 (declare (list nlist))
754 (if (not (<= n (car nlist))) (return nil))))
756 (defun >= (number &rest more-numbers)
757 #!+sb-doc
758 "Return T if arguments are in strictly non-increasing order, NIL otherwise."
759 (do* ((n number (car nlist))
760 (nlist more-numbers (cdr nlist)))
761 ((atom nlist) t)
762 (declare (list nlist))
763 (if (not (>= n (car nlist))) (return nil))))
765 (defun max (number &rest more-numbers)
766 #!+sb-doc
767 "Return the greatest of its arguments."
768 (do ((nlist more-numbers (cdr nlist))
769 (result number))
770 ((null nlist) (return result))
771 (declare (list nlist))
772 (declare (type real number result))
773 (if (> (car nlist) result) (setq result (car nlist)))))
775 (defun min (number &rest more-numbers)
776 #!+sb-doc
777 "Return the least of its arguments."
778 (do ((nlist more-numbers (cdr nlist))
779 (result number))
780 ((null nlist) (return result))
781 (declare (list nlist))
782 (declare (type real number result))
783 (if (< (car nlist) result) (setq result (car nlist)))))
785 (eval-when (:compile-toplevel :execute)
787 ;;; The INFINITE-X-FINITE-Y and INFINITE-Y-FINITE-X args tell us how
788 ;;; to handle the case when X or Y is a floating-point infinity and
789 ;;; the other arg is a rational. (Section 12.1.4.1 of the ANSI spec
790 ;;; says that comparisons are done by converting the float to a
791 ;;; rational when comparing with a rational, but infinities can't be
792 ;;; converted to a rational, so we show some initiative and do it this
793 ;;; way instead.)
794 (defun basic-compare (op &key infinite-x-finite-y infinite-y-finite-x)
795 `(((fixnum fixnum) (,op x y))
797 ((single-float single-float) (,op x y))
798 #!+long-float
799 (((foreach single-float double-float long-float) long-float)
800 (,op (coerce x 'long-float) y))
801 #!+long-float
802 ((long-float (foreach single-float double-float))
803 (,op x (coerce y 'long-float)))
804 (((foreach single-float double-float) double-float)
805 (,op (coerce x 'double-float) y))
806 ((double-float single-float)
807 (,op x (coerce y 'double-float)))
808 (((foreach single-float double-float #!+long-float long-float) rational)
809 (if (eql y 0)
810 (,op x (coerce 0 '(dispatch-type x)))
811 (if (float-infinity-p x)
812 ,infinite-x-finite-y
813 (,op (rational x) y))))
814 (((foreach bignum fixnum ratio) float)
815 (if (float-infinity-p y)
816 ,infinite-y-finite-x
817 (,op x (rational y))))))
818 ) ; EVAL-WHEN
820 (macrolet ((def-two-arg-</> (name op ratio-arg1 ratio-arg2 &rest cases)
821 `(defun ,name (x y)
822 (number-dispatch ((x real) (y real))
823 (basic-compare
825 :infinite-x-finite-y
826 (,op x (coerce 0 '(dispatch-type x)))
827 :infinite-y-finite-x
828 (,op (coerce 0 '(dispatch-type y)) y))
829 (((foreach fixnum bignum) ratio)
830 (,op x (,ratio-arg2 (numerator y)
831 (denominator y))))
832 ((ratio integer)
833 (,op (,ratio-arg1 (numerator x)
834 (denominator x))
836 ((ratio ratio)
837 (,op (* (numerator (truly-the ratio x))
838 (denominator (truly-the ratio y)))
839 (* (numerator (truly-the ratio y))
840 (denominator (truly-the ratio x)))))
841 ,@cases))))
842 (def-two-arg-</> two-arg-< < floor ceiling
843 ((fixnum bignum)
844 (bignum-plus-p y))
845 ((bignum fixnum)
846 (not (bignum-plus-p x)))
847 ((bignum bignum)
848 (minusp (bignum-compare x y))))
849 (def-two-arg-</> two-arg-> > ceiling floor
850 ((fixnum bignum)
851 (not (bignum-plus-p y)))
852 ((bignum fixnum)
853 (bignum-plus-p x))
854 ((bignum bignum)
855 (plusp (bignum-compare x y)))))
857 (defun two-arg-= (x y)
858 (number-dispatch ((x number) (y number))
859 (basic-compare =
860 ;; An infinite value is never equal to a finite value.
861 :infinite-x-finite-y nil
862 :infinite-y-finite-x nil)
863 ((fixnum (or bignum ratio)) nil)
865 ((bignum (or fixnum ratio)) nil)
866 ((bignum bignum)
867 (zerop (bignum-compare x y)))
869 ((ratio integer) nil)
870 ((ratio ratio)
871 (and (eql (numerator x) (numerator y))
872 (eql (denominator x) (denominator y))))
874 ((complex complex)
875 (and (= (realpart x) (realpart y))
876 (= (imagpart x) (imagpart y))))
877 (((foreach fixnum bignum ratio single-float double-float
878 #!+long-float long-float) complex)
879 (and (= x (realpart y))
880 (zerop (imagpart y))))
881 ((complex (or float rational))
882 (and (= (realpart x) y)
883 (zerop (imagpart x))))))
885 (defun eql (obj1 obj2)
886 #!+sb-doc
887 "Return T if OBJ1 and OBJ2 represent the same object, otherwise NIL."
888 (or (eq obj1 obj2)
889 (if (or (typep obj2 'fixnum)
890 (not (typep obj2 'number)))
892 (macrolet ((foo (&rest stuff)
893 `(typecase obj2
894 ,@(mapcar (lambda (foo)
895 (let ((type (car foo))
896 (fn (cadr foo)))
897 `(,type
898 (and (typep obj1 ',type)
899 (,fn obj1 obj2)))))
900 stuff))))
901 (foo
902 (single-float eql)
903 (double-float eql)
904 #!+long-float
905 (long-float eql)
906 (bignum
907 (lambda (x y)
908 (zerop (bignum-compare x y))))
909 (ratio
910 (lambda (x y)
911 (and (eql (numerator x) (numerator y))
912 (eql (denominator x) (denominator y)))))
913 (complex
914 (lambda (x y)
915 (and (eql (realpart x) (realpart y))
916 (eql (imagpart x) (imagpart y))))))))))
918 ;;;; logicals
920 (defun logior (&rest integers)
921 #!+sb-doc
922 "Return the bit-wise or of its arguments. Args must be integers."
923 (declare (list integers))
924 (if integers
925 (do ((result (pop integers) (logior result (pop integers))))
926 ((null integers) result)
927 (declare (integer result)))
930 (defun logxor (&rest integers)
931 #!+sb-doc
932 "Return the bit-wise exclusive or of its arguments. Args must be integers."
933 (declare (list integers))
934 (if integers
935 (do ((result (pop integers) (logxor result (pop integers))))
936 ((null integers) result)
937 (declare (integer result)))
940 (defun logand (&rest integers)
941 #!+sb-doc
942 "Return the bit-wise and of its arguments. Args must be integers."
943 (declare (list integers))
944 (if integers
945 (do ((result (pop integers) (logand result (pop integers))))
946 ((null integers) result)
947 (declare (integer result)))
948 -1))
950 (defun logeqv (&rest integers)
951 #!+sb-doc
952 "Return the bit-wise equivalence of its arguments. Args must be integers."
953 (declare (list integers))
954 (if integers
955 (do ((result (pop integers) (logeqv result (pop integers))))
956 ((null integers) result)
957 (declare (integer result)))
958 -1))
960 (defun lognot (number)
961 #!+sb-doc
962 "Return the bit-wise logical not of integer."
963 (etypecase number
964 (fixnum (lognot (truly-the fixnum number)))
965 (bignum (bignum-logical-not number))))
967 (macrolet ((def (name op big-op &optional doc)
968 `(defun ,name (integer1 integer2)
969 ,@(when doc
970 (list doc))
971 (let ((x integer1)
972 (y integer2))
973 (number-dispatch ((x integer) (y integer))
974 (bignum-cross-fixnum ,op ,big-op))))))
975 (def two-arg-and logand bignum-logical-and)
976 (def two-arg-ior logior bignum-logical-ior)
977 (def two-arg-xor logxor bignum-logical-xor)
978 ;; BIGNUM-LOGICAL-{AND,IOR,XOR} need not return a bignum, so must
979 ;; call the generic LOGNOT...
980 (def two-arg-eqv logeqv (lambda (x y) (lognot (bignum-logical-xor x y))))
981 (def lognand lognand
982 (lambda (x y) (lognot (bignum-logical-and x y)))
983 #!+sb-doc "Complement the logical AND of INTEGER1 and INTEGER2.")
984 (def lognor lognor
985 (lambda (x y) (lognot (bignum-logical-ior x y)))
986 #!+sb-doc "Complement the logical AND of INTEGER1 and INTEGER2.")
987 ;; ... but BIGNUM-LOGICAL-NOT on a bignum will always return a bignum
988 (def logandc1 logandc1
989 (lambda (x y) (bignum-logical-and (bignum-logical-not x) y))
990 #!+sb-doc "Bitwise AND (LOGNOT INTEGER1) with INTEGER2.")
991 (def logandc2 logandc2
992 (lambda (x y) (bignum-logical-and x (bignum-logical-not y)))
993 #!+sb-doc "Bitwise AND INTEGER1 with (LOGNOT INTEGER2).")
994 (def logorc1 logorc1
995 (lambda (x y) (bignum-logical-ior (bignum-logical-not x) y))
996 #!+sb-doc "Bitwise OR (LOGNOT INTEGER1) with INTEGER2.")
997 (def logorc2 logorc2
998 (lambda (x y) (bignum-logical-ior x (bignum-logical-not y)))
999 #!+sb-doc "Bitwise OR INTEGER1 with (LOGNOT INTEGER2)."))
1001 (defun logcount (integer)
1002 #!+sb-doc
1003 "Count the number of 1 bits if INTEGER is positive, and the number of 0 bits
1004 if INTEGER is negative."
1005 (etypecase integer
1006 (fixnum
1007 (logcount (truly-the (integer 0
1008 #.(max sb!xc:most-positive-fixnum
1009 (lognot sb!xc:most-negative-fixnum)))
1010 (if (minusp (truly-the fixnum integer))
1011 (lognot (truly-the fixnum integer))
1012 integer))))
1013 (bignum
1014 (bignum-logcount integer))))
1016 (defun logtest (integer1 integer2)
1017 #!+sb-doc
1018 "Predicate which returns T if logand of integer1 and integer2 is not zero."
1019 (logtest integer1 integer2))
1021 (defun logbitp (index integer)
1022 #!+sb-doc
1023 "Predicate returns T if bit index of integer is a 1."
1024 (number-dispatch ((index integer) (integer integer))
1025 ((fixnum fixnum) (if (> index #.(- sb!vm:n-word-bits sb!vm:n-lowtag-bits))
1026 (minusp integer)
1027 (not (zerop (logand integer (ash 1 index))))))
1028 ((fixnum bignum) (bignum-logbitp index integer))
1029 ((bignum (foreach fixnum bignum)) (minusp integer))))
1031 (defun ash (integer count)
1032 #!+sb-doc
1033 "Shifts integer left by count places preserving sign. - count shifts right."
1034 (declare (integer integer count))
1035 (etypecase integer
1036 (fixnum
1037 (cond ((zerop integer)
1039 ((fixnump count)
1040 (let ((length (integer-length (truly-the fixnum integer)))
1041 (count (truly-the fixnum count)))
1042 (declare (fixnum length count))
1043 (cond ((and (plusp count)
1044 (> (+ length count)
1045 (integer-length most-positive-fixnum)))
1046 (bignum-ashift-left (make-small-bignum integer) count))
1048 (truly-the fixnum
1049 (ash (truly-the fixnum integer) count))))))
1050 ((minusp count)
1051 (if (minusp integer) -1 0))
1053 (bignum-ashift-left (make-small-bignum integer) count))))
1054 (bignum
1055 (if (plusp count)
1056 (bignum-ashift-left integer count)
1057 (bignum-ashift-right integer (- count))))))
1059 (defun integer-length (integer)
1060 #!+sb-doc
1061 "Return the number of significant bits in the absolute value of integer."
1062 (etypecase integer
1063 (fixnum
1064 (integer-length (truly-the fixnum integer)))
1065 (bignum
1066 (bignum-integer-length integer))))
1068 ;;;; BYTE, bytespecs, and related operations
1070 (defun byte (size position)
1071 #!+sb-doc
1072 "Return a byte specifier which may be used by other byte functions
1073 (e.g. LDB)."
1074 (byte size position))
1076 (defun byte-size (bytespec)
1077 #!+sb-doc
1078 "Return the size part of the byte specifier bytespec."
1079 (byte-size bytespec))
1081 (defun byte-position (bytespec)
1082 #!+sb-doc
1083 "Return the position part of the byte specifier bytespec."
1084 (byte-position bytespec))
1086 (defun ldb (bytespec integer)
1087 #!+sb-doc
1088 "Extract the specified byte from integer, and right justify result."
1089 (ldb bytespec integer))
1091 (defun ldb-test (bytespec integer)
1092 #!+sb-doc
1093 "Return T if any of the specified bits in integer are 1's."
1094 (ldb-test bytespec integer))
1096 (defun mask-field (bytespec integer)
1097 #!+sb-doc
1098 "Extract the specified byte from integer, but do not right justify result."
1099 (mask-field bytespec integer))
1101 (defun dpb (newbyte bytespec integer)
1102 #!+sb-doc
1103 "Return new integer with newbyte in specified position, newbyte is right justified."
1104 (dpb newbyte bytespec integer))
1106 (defun deposit-field (newbyte bytespec integer)
1107 #!+sb-doc
1108 "Return new integer with newbyte in specified position, newbyte is not right justified."
1109 (deposit-field newbyte bytespec integer))
1111 (defun %ldb (size posn integer)
1112 (logand (ash integer (- posn))
1113 (1- (ash 1 size))))
1115 (defun %mask-field (size posn integer)
1116 (logand integer (ash (1- (ash 1 size)) posn)))
1118 (defun %dpb (newbyte size posn integer)
1119 (let ((mask (1- (ash 1 size))))
1120 (logior (logand integer (lognot (ash mask posn)))
1121 (ash (logand newbyte mask) posn))))
1123 (defun %deposit-field (newbyte size posn integer)
1124 (let ((mask (ash (ldb (byte size 0) -1) posn)))
1125 (logior (logand newbyte mask)
1126 (logand integer (lognot mask)))))
1128 ;;;; BOOLE
1130 ;;; The boole function dispaches to any logic operation depending on
1131 ;;; the value of a variable. Presently, legal selector values are [0..15].
1132 ;;; boole is open coded for calls with a constant selector. or with calls
1133 ;;; using any of the constants declared below.
1135 (defconstant boole-clr 0
1136 #!+sb-doc
1137 "Boole function op, makes BOOLE return 0.")
1139 (defconstant boole-set 1
1140 #!+sb-doc
1141 "Boole function op, makes BOOLE return -1.")
1143 (defconstant boole-1 2
1144 #!+sb-doc
1145 "Boole function op, makes BOOLE return integer1.")
1147 (defconstant boole-2 3
1148 #!+sb-doc
1149 "Boole function op, makes BOOLE return integer2.")
1151 (defconstant boole-c1 4
1152 #!+sb-doc
1153 "Boole function op, makes BOOLE return complement of integer1.")
1155 (defconstant boole-c2 5
1156 #!+sb-doc
1157 "Boole function op, makes BOOLE return complement of integer2.")
1159 (defconstant boole-and 6
1160 #!+sb-doc
1161 "Boole function op, makes BOOLE return logand of integer1 and integer2.")
1163 (defconstant boole-ior 7
1164 #!+sb-doc
1165 "Boole function op, makes BOOLE return logior of integer1 and integer2.")
1167 (defconstant boole-xor 8
1168 #!+sb-doc
1169 "Boole function op, makes BOOLE return logxor of integer1 and integer2.")
1171 (defconstant boole-eqv 9
1172 #!+sb-doc
1173 "Boole function op, makes BOOLE return logeqv of integer1 and integer2.")
1175 (defconstant boole-nand 10
1176 #!+sb-doc
1177 "Boole function op, makes BOOLE return log nand of integer1 and integer2.")
1179 (defconstant boole-nor 11
1180 #!+sb-doc
1181 "Boole function op, makes BOOLE return lognor of integer1 and integer2.")
1183 (defconstant boole-andc1 12
1184 #!+sb-doc
1185 "Boole function op, makes BOOLE return logandc1 of integer1 and integer2.")
1187 (defconstant boole-andc2 13
1188 #!+sb-doc
1189 "Boole function op, makes BOOLE return logandc2 of integer1 and integer2.")
1191 (defconstant boole-orc1 14
1192 #!+sb-doc
1193 "Boole function op, makes BOOLE return logorc1 of integer1 and integer2.")
1195 (defconstant boole-orc2 15
1196 #!+sb-doc
1197 "Boole function op, makes BOOLE return logorc2 of integer1 and integer2.")
1199 (defun boole (op integer1 integer2)
1200 #!+sb-doc
1201 "Bit-wise boolean function on two integers. Function chosen by OP:
1202 0 BOOLE-CLR
1203 1 BOOLE-SET
1204 2 BOOLE-1
1205 3 BOOLE-2
1206 4 BOOLE-C1
1207 5 BOOLE-C2
1208 6 BOOLE-AND
1209 7 BOOLE-IOR
1210 8 BOOLE-XOR
1211 9 BOOLE-EQV
1212 10 BOOLE-NAND
1213 11 BOOLE-NOR
1214 12 BOOLE-ANDC1
1215 13 BOOLE-ANDC2
1216 14 BOOLE-ORC1
1217 15 BOOLE-ORC2"
1218 (case op
1219 (0 (boole 0 integer1 integer2))
1220 (1 (boole 1 integer1 integer2))
1221 (2 (boole 2 integer1 integer2))
1222 (3 (boole 3 integer1 integer2))
1223 (4 (boole 4 integer1 integer2))
1224 (5 (boole 5 integer1 integer2))
1225 (6 (boole 6 integer1 integer2))
1226 (7 (boole 7 integer1 integer2))
1227 (8 (boole 8 integer1 integer2))
1228 (9 (boole 9 integer1 integer2))
1229 (10 (boole 10 integer1 integer2))
1230 (11 (boole 11 integer1 integer2))
1231 (12 (boole 12 integer1 integer2))
1232 (13 (boole 13 integer1 integer2))
1233 (14 (boole 14 integer1 integer2))
1234 (15 (boole 15 integer1 integer2))
1235 (t (error 'type-error :datum op :expected-type '(mod 16)))))
1237 ;;;; GCD and LCM
1239 (defun gcd (&rest numbers)
1240 #!+sb-doc
1241 "Return the greatest common divisor of the arguments, which must be
1242 integers. Gcd with no arguments is defined to be 0."
1243 (cond ((null numbers) 0)
1244 ((null (cdr numbers)) (abs (the integer (car numbers))))
1246 (do ((gcd (the integer (car numbers))
1247 (gcd gcd (the integer (car rest))))
1248 (rest (cdr numbers) (cdr rest)))
1249 ((null rest) gcd)
1250 (declare (integer gcd)
1251 (list rest))))))
1253 (defun lcm (&rest numbers)
1254 #!+sb-doc
1255 "Return the least common multiple of one or more integers. LCM of no
1256 arguments is defined to be 1."
1257 (cond ((null numbers) 1)
1258 ((null (cdr numbers)) (abs (the integer (car numbers))))
1260 (do ((lcm (the integer (car numbers))
1261 (lcm lcm (the integer (car rest))))
1262 (rest (cdr numbers) (cdr rest)))
1263 ((null rest) lcm)
1264 (declare (integer lcm) (list rest))))))
1266 (defun two-arg-lcm (n m)
1267 (declare (integer n m))
1268 (if (or (zerop n) (zerop m))
1270 ;; KLUDGE: I'm going to assume that it was written this way
1271 ;; originally for a reason. However, this is a somewhat
1272 ;; complicated way of writing the algorithm in the CLHS page for
1273 ;; LCM, and I don't know why. To be investigated. -- CSR,
1274 ;; 2003-09-11
1275 (let ((m (abs m))
1276 (n (abs n)))
1277 (multiple-value-bind (max min)
1278 (if (> m n)
1279 (values m n)
1280 (values n m))
1281 (* (truncate max (gcd n m)) min)))))
1283 ;;; Do the GCD of two integer arguments. With fixnum arguments, we use the
1284 ;;; binary GCD algorithm from Knuth's seminumerical algorithms (slightly
1285 ;;; structurified), otherwise we call BIGNUM-GCD. We pick off the special case
1286 ;;; of 0 before the dispatch so that the bignum code doesn't have to worry
1287 ;;; about "small bignum" zeros.
1288 (defun two-arg-gcd (u v)
1289 (cond ((eql u 0) (abs v))
1290 ((eql v 0) (abs u))
1292 (number-dispatch ((u integer) (v integer))
1293 ((fixnum fixnum)
1294 (locally
1295 (declare (optimize (speed 3) (safety 0)))
1296 (do ((k 0 (1+ k))
1297 (u (abs u) (ash u -1))
1298 (v (abs v) (ash v -1)))
1299 ((oddp (logior u v))
1300 (do ((temp (if (oddp u) (- v) (ash u -1))
1301 (ash temp -1)))
1302 (nil)
1303 (declare (fixnum temp))
1304 (when (oddp temp)
1305 (if (plusp temp)
1306 (setq u temp)
1307 (setq v (- temp)))
1308 (setq temp (- u v))
1309 (when (zerop temp)
1310 (let ((res (ash u k)))
1311 (declare (type (signed-byte 31) res)
1312 (optimize (inhibit-warnings 3)))
1313 (return res))))))
1314 (declare (type (mod 30) k)
1315 (type (signed-byte 31) u v)))))
1316 ((bignum bignum)
1317 (bignum-gcd u v))
1318 ((bignum fixnum)
1319 (bignum-gcd u (make-small-bignum v)))
1320 ((fixnum bignum)
1321 (bignum-gcd (make-small-bignum u) v))))))
1323 ;;; From discussion on comp.lang.lisp and Akira Kurihara.
1324 (defun isqrt (n)
1325 #!+sb-doc
1326 "Return the root of the nearest integer less than n which is a perfect
1327 square."
1328 (declare (type unsigned-byte n) (values unsigned-byte))
1329 ;; Theoretically (> n 7), i.e., n-len-quarter > 0.
1330 (if (and (fixnump n) (<= n 24))
1331 (cond ((> n 15) 4)
1332 ((> n 8) 3)
1333 ((> n 3) 2)
1334 ((> n 0) 1)
1335 (t 0))
1336 (let* ((n-len-quarter (ash (integer-length n) -2))
1337 (n-half (ash n (- (ash n-len-quarter 1))))
1338 (n-half-isqrt (isqrt n-half))
1339 (init-value (ash (1+ n-half-isqrt) n-len-quarter)))
1340 (loop
1341 (let ((iterated-value
1342 (ash (+ init-value (truncate n init-value)) -1)))
1343 (unless (< iterated-value init-value)
1344 (return init-value))
1345 (setq init-value iterated-value))))))
1347 ;;;; miscellaneous number predicates
1349 (macrolet ((def (name doc)
1350 `(defun ,name (number) ,doc (,name number))))
1351 (def zerop "Is this number zero?")
1352 (def plusp "Is this real number strictly positive?")
1353 (def minusp "Is this real number strictly negative?")
1354 (def oddp "Is this integer odd?")
1355 (def evenp "Is this integer even?"))
1357 ;;;; modular functions
1359 (collect ((forms))
1360 (flet ((definition (name lambda-list width pattern)
1361 (assert (sb!xc:subtypep `(unsigned-byte ,width)
1362 'bignum-element-type))
1363 `(defun ,name ,lambda-list
1364 (flet ((prepare-argument (x)
1365 (declare (integer x))
1366 (etypecase x
1367 ((unsigned-byte ,width) x)
1368 (bignum-element-type (logand x ,pattern))
1369 (fixnum (logand x ,pattern))
1370 (bignum (logand (%bignum-ref x 0) ,pattern)))))
1371 (,name ,@(loop for arg in lambda-list
1372 collect `(prepare-argument ,arg)))))))
1373 (loop for infos being each hash-value of sb!c::*modular-funs*
1374 ;; FIXME: We need to process only "toplevel" functions
1375 unless (eq infos :good)
1376 do (loop for info in infos
1377 for name = (sb!c::modular-fun-info-name info)
1378 and width = (sb!c::modular-fun-info-width info)
1379 and lambda-list = (sb!c::modular-fun-info-lambda-list info)
1380 for pattern = (1- (ash 1 width))
1381 do (forms (definition name lambda-list width pattern)))))
1382 `(progn ,@(forms)))