;; Index into the Next vector chaining together free slots in the KV
;; vector.
(next-free-kv 0 :type index)
+ ;; A cache that is either nil or is an index into the hash table
+ ;; that should be checked first
+ (cache nil :type (or null index))
;; The index vector. This may be larger than the hash size to help
;; reduce collisions.
(index-vector (missing-arg)
;; This table parallels the KV table, and can be used to store the
;; hash associated with the key, saving recalculation. Could be
;; useful for EQL, and EQUAL hash tables. This table is not needed
- ;; for EQ hash tables, and when present the value of #x80000000
- ;; represents EQ-based hashing on the respective key.
+ ;; for EQ hash tables, and when present the value of
+ ;; +MAGIC-HASH-VECTOR-VALUE+ represents EQ-based hashing on the
+ ;; respective key.
(hash-vector nil :type (or null (simple-array (unsigned-byte
#.sb!vm:n-word-bits) (*)))))
+
+;; as explained by pmai on openprojects #lisp IRC 2002-07-30: #x80000000
+;; is bigger than any possible nonEQ hash value, and thus indicates an
+;; empty slot; and EQ hash tables don't use HASH-TABLE-HASH-VECTOR.
+;; The previous sentence was written when SBCL was 32-bit only. The value
+;; now depends on the word size. It is propagated to C in genesis because
+;; the generational garbage collector needs to know it.
+(defconstant +magic-hash-vector-value+ (ash 1 (1- sb!vm:n-word-bits)))
+
\f
(defmacro-mundanely with-hash-table-iterator ((function hash-table) &body body)
#!+sb-doc