- (loadw header x 0 other-pointer-type)
- (inst srl header (1+ type-bits) header)
- (loadw y x bignum-digits-offset other-pointer-type)
+ (loadw header x 0 other-pointer-lowtag)
+ (inst srl header (1+ n-widetag-bits) header)
+ (loadw y x bignum-digits-offset other-pointer-lowtag)