MacBook Pro

I got my work supplied MacBook Pro last week, and I've got two words... AWE-SOME! It's waaaay fast. On my dual 2GHz G5, Firefox bounces the dock icon about 5-8 times before opening. With the new universal Firefox binary, it bounces 1-2x on my MBP! That's friggin' fast! Now, I don't actually use Firefox (mostly because it's historically been too slow to start), but it's still an interesting measure.

Here's a few other interesting little tid-bits I came across on my first run through the new system:

• You can tell if an application is universal by looking at the "Get Info" window in the Finder, or by using the file command from the Terminal. And you can tell if a process is actually running under Rosetta at runtime because /usr/libexec/oah/translate will be mapped into its address space. Just

  lsof -p PID | grep translate

  
  



• 
  You can run an application under Rosetta from the command line by using the command /usr/libexec/oah/translate. For example:

  /usr/libexec/oah/translate /bin/ls

  
  



• On PPC functions arguments are passed in CPU registers starting with $r3. So, the function call foo(1, 2, 3) would have 0x1 in $r3, 0x2 in $r4, etc. On Intel function arguments are passed on the stack, so the function call foo(1, 2, 3) would have 0x1 at $ebp+8, 0x2 at $ebp+12, etc.
  



• 
  In Objective-C, a method call like [foo add:5] actually gets compiled into a C function call like

  objc_msgSend(self, @selector(add:), 5)

  And as we just saw, Intel Macs pass function arguments on the stack. So, the standard way to print "self" in gdb on a PPC Mac is

  po $r3

  (remember, $r3 has the first argument on PPC -- "self"), but on Intel it turns into

  po *(int *)($ebp+8)

  (po is print-object).
  



• 
  If you need to debug (using gdb) a PPC binary on an Intel Mac, you can do some basic stuff by setting the OAH_GDB environment variable to YES, then starting the application. Then in a new window, start gdb like

  gdb --oah

  then use gdb's attach command to attach to the running process like normal. This will even show you PPC style registers and stuff in gdb. Pretty cool for basic debugging.