+;;; * For FreeBSD, the requirement of user and kernel space are
+;;; getting larger, and users tend to extend them.
+;;; If MAXDSIZ is extended from 512MB to 1GB, we can't use up to
+;;; around 0x50000000.
+;;; And if KVA_PAGES is extended from 1GB to 1.5GB, we can't use
+;;; down to around 0xA0000000.
+;;; So we use 0x58000000--0x98000000 for dynamic space.
+;;; * OpenBSD address space changes for W^X as well as malloc
+;;; randomization made the old addresses unsafe. The only range
+;;; that is really safe is between the end of the text segment (it
+;;; starts at #x3C000000) and #x7C000000. However if the -Z linker
+;;; option is used then the safe range is (probably) #x00001000 to
+;;; #x48048000, with the text and data segments at #x08048000.