[z-machine] set_attr opcode

[Mose Wingert]

Can someone tell me how the set_attr opcode works?  The Z-machine doc just
says
2OP:11 B set_attr object attribute
Make *object* have the attribute numbered *attribute*

My thought was that if I saw three bytes, say 11, 12, 13, that that would
mean "set attribute 13 for object 12" (11 being the set_attr command).  But
that doesn't seem to be right, because when I'm looking at the very
beginning of the z-code for Zork 1, byte 6 is 72 (so I set the PC to 72),
then bytes 72, 73, and 74 are 11, 212, and 232, which by my interpretation
would be "set attribute 232 for object 212".  But there are only 32
attributes...so obviously something is wrong.

What am I missing?