WILD GUESS ALERT! I'm guessing that this is for byte-alignment on big-endian versus little-endian...
So it's more like 11110000 and 00001111 as masks to flip-flop bytes by some binary logic / magic. The -1 is to "wrap" the byte to binary inversion. You might want to grep the code and see how they are actually used. That helps me a lot when I'm totally lost what the Magic Numbers are used for. Not knowing what the initial value of ZEND_MM_ALIGNMENT is in the first place, this is just wild guess... On Thu, March 1, 2012 10:22 am, Adi Mutu wrote: > > > Hello, > > I want to understand how Zend MM works, so i'm looking trought the > sources and i see this: > > #define ZEND_MM_ALIGNMENT_MASK ~(ZEND_MM_ALIGNMENT-1) #define > ZEND_MM_ALIGNED_SIZE(size) (((size) + ZEND_MM_ALIGNMENT - 1) & > ZEND_MM_ALIGNMENT_MASK) > > > I understand that the first define will create something like 11111000 > ( it will clear last 3 bits) > but what does the 2nd define? Before clearing the last 3 bytes why > does it add ZEND_MM_ALIGNMENT- 1 > to size? > > Thanks, -- brain cancer update: http://richardlynch.blogspot.com/search/label/brain%20tumor Donate: https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=FS9NLTNEEKWBE -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
