- (mixf result (sxhash (length x)))
- (do* ((i sb!vm:vector-data-offset (+ i 1))
- ;; FIXME: should we respect DEPTHOID? SXHASH on strings
- ;; doesn't seem to...
- (end (+ sb!vm:vector-data-offset
- (ceiling (length x) sb!vm:n-word-bits))))
- ((= i end) result)
- (declare (type index i end))
- (let ((num
- (if (= i (1- end))
- (logand
- (ash (1- (ash 1 (mod (length x) sb!vm:n-word-bits)))
- ,(ecase sb!c:*backend-byte-order*
- (:little-endian 0)
- (:big-endian
- '(- sb!vm:n-word-bits
- (mod (length x) sb!vm:n-word-bits)))))
- (%raw-bits x i))
- (%raw-bits x i))))
- (declare (type (unsigned-byte 32) num))
- (mixf result ,(ecase sb!c:*backend-byte-order*
- (:little-endian '(logand num most-positive-fixnum))
- ;; FIXME: I'm not certain that N-LOWTAG-BITS
- ;; is the clearest way of expressing this:
- ;; it's essentially the difference between
- ;; `(UNSIGNED-BYTE ,SB!VM:N-WORD-BITS) and
- ;; (AND FIXNUM UNSIGNED-BYTE).
- (:big-endian '(ash num (- sb!vm:n-lowtag-bits)))))))))
+ (let ((length (length x)))
+ (cond
+ ((= length 0) (mix result (sxhash 0)))
+ (t
+ (mixf result (sxhash (length x)))
+ (do* ((i 0 (+ i 1))
+ ;; FIXME: should we respect DEPTHOID? SXHASH on
+ ;; strings doesn't seem to...
+ (end-1 (floor (1- length) sb!vm:n-word-bits)))
+ ((= i end-1)
+ (let ((num
+ (logand
+ (ash (1- (ash 1 (mod length sb!vm:n-word-bits)))
+ ,(ecase sb!c:*backend-byte-order*
+ (:little-endian 0)
+ (:big-endian
+ '(- sb!vm:n-word-bits
+ (mod length sb!vm:n-word-bits)))))
+ (%vector-raw-bits x i))))
+ (mix result ,(ecase sb!c:*backend-byte-order*
+ (:little-endian
+ '(logand num most-positive-fixnum))
+ (:big-endian
+ '(ash num (- sb!vm:n-lowtag-bits)))))))
+ (declare (type index i end-1))
+ (let ((num (%vector-raw-bits x i)))
+ (mixf result ,(ecase sb!c:*backend-byte-order*
+ (:little-endian
+ '(logand num most-positive-fixnum))
+ ;; FIXME: I'm not certain that
+ ;; N-LOWTAG-BITS is the clearest way of
+ ;; expressing this: it's essentially the
+ ;; difference between `(UNSIGNED-BYTE
+ ;; ,SB!VM:N-WORD-BITS) and (AND FIXNUM
+ ;; UNSIGNED-BYTE).
+ (:big-endian
+ '(ash num (- sb!vm:n-lowtag-bits))))))))))))