V8_MEMORY_PAGE_MASK
((V8_MEMORY_PAGE_SIZE - (paddr & V8_MEMORY_PAGE_MASK)) > buflen \
? buflen : (V8_MEMORY_PAGE_SIZE - (paddr & V8_MEMORY_PAGE_MASK)))
(addr & V8_MEMORY_PAGE_MASK) |
(addr & V8_MEMORY_PAGE_MASK) |