diff --git a/compiler/old-rt/genesis.lisp b/compiler/old-rt/genesis.lisp index d755cfd3c4d5159c185d8b28a98f25096286afc8..cff8a12d8735722309eb5633272065ba3cf0c6f3 100644 --- a/compiler/old-rt/genesis.lisp +++ b/compiler/old-rt/genesis.lisp @@ -996,7 +996,7 @@ (prepare-for-fast-read-byte *fasl-file* (let* ((len (fast-read-u-integer 4)) (size (fast-read-byte)) - (ac (integer-length size)) + (ac (1- (integer-length size))) (res (%primitive alloc-i-vector len ac))) (done-with-fast-read-byte) (unless (and (<= ac 5) (= size (ash 1 ac)))