'(,fun num (or state *random-state*)))))
(frob %random-single-float single-float)
(frob %random-double-float double-float))
-
-;;; Mersenne Twister RNG
-;;;
-;;; FIXME: It's unpleasant to have RANDOM functionality scattered
-;;; through the code this way. It would be nice to move this into the
-;;; same file as the other RANDOM definitions.
-(deftransform random ((num &optional state)
- ((integer 1 #.(expt 2 sb!vm::n-word-bits)) &optional *))
- ;; FIXME: I almost conditionalized this as #!+sb-doc. Find some way
- ;; of automatically finding #!+sb-doc in proximity to DEFTRANSFORM
- ;; to let me scan for places that I made this mistake and didn't
- ;; catch myself.
- "use inline (UNSIGNED-BYTE 32) operations"
- (let ((type (lvar-type num))
- (limit (expt 2 sb!vm::n-word-bits))
- (random-chunk (ecase sb!vm::n-word-bits
- (32 'random-chunk)
- (64 'sb!kernel::big-random-chunk))))
- (if (numeric-type-p type)
- (let ((num-high (numeric-type-high (lvar-type num))))
- (aver num-high)
- (cond ((constant-lvar-p num)
- ;; Check the worst case sum absolute error for the
- ;; random number expectations.
- (let ((rem (rem limit num-high)))
- (unless (< (/ (* 2 rem (- num-high rem))
- num-high limit)
- (expt 2 (- sb!kernel::random-integer-extra-bits)))
- (give-up-ir1-transform
- "The random number expectations are inaccurate."))
- (if (= num-high limit)
- `(,random-chunk (or state *random-state*))
- #!-(or x86 x86-64)
- `(rem (,random-chunk (or state *random-state*)) num)
- #!+(or x86 x86-64)
- ;; Use multiplication, which is faster.
- `(values (sb!bignum::%multiply
- (,random-chunk (or state *random-state*))
- num)))))
- ((> num-high random-fixnum-max)
- (give-up-ir1-transform
- "The range is too large to ensure an accurate result."))
- #!+(or x86 x86-64)
- ((< num-high limit)
- `(values (sb!bignum::%multiply
- (,random-chunk (or state *random-state*))
- num)))
- (t
- `(rem (,random-chunk (or state *random-state*)) num))))
- ;; KLUDGE: a relatively conservative treatment, but better
- ;; than a bug (reported by PFD sbcl-devel towards the end of
- ;; 2004-11.
- '(rem (random-chunk (or state *random-state*)) num))))
\f
;;;; float accessors