- (inst lea result (make-ea :byte :base words :disp
- (+ (1- (ash 1 n-lowtag-bits))
- (* vector-data-offset n-word-bytes))))
- (inst and result (lognot lowtag-mask))
- (pseudo-atomic
- (allocation result result)
- (inst lea result (make-ea :byte :base result :disp other-pointer-lowtag))
- (storew type result 0 other-pointer-lowtag)
- (storew length result vector-length-slot other-pointer-lowtag))))
+ (let ((size (sc-case words
+ (immediate
+ (logandc2 (+ (fixnumize (tn-value words))
+ (+ (1- (ash 1 n-lowtag-bits))
+ (* vector-data-offset n-word-bytes)))
+ lowtag-mask))
+ (t
+ (inst lea result (make-ea :byte :base words :disp
+ (+ (1- (ash 1 n-lowtag-bits))
+ (* vector-data-offset
+ n-word-bytes))))
+ (inst and result (lognot lowtag-mask))
+ result))))
+ (pseudo-atomic
+ (allocation result size)
+ (inst lea result (make-ea :byte :base result :disp other-pointer-lowtag))
+ (sc-case type
+ (immediate
+ (aver (typep (tn-value type) '(unsigned-byte 8)))
+ (storeb (tn-value type) result 0 other-pointer-lowtag))
+ (t
+ (storew type result 0 other-pointer-lowtag)))
+ (sc-case length
+ (immediate
+ (let ((fixnum-length (fixnumize (tn-value length))))
+ (typecase fixnum-length
+ ((unsigned-byte 8)
+ (storeb fixnum-length result
+ vector-length-slot other-pointer-lowtag))
+ (t
+ (storew fixnum-length result
+ vector-length-slot other-pointer-lowtag)))))
+ (t
+ (storew length result vector-length-slot other-pointer-lowtag)))))))