Use a hash table for word lookup

Specifically, a hash table with 32 buckets and the hash function name => ((length(name) << 2) ^ name[0] ^ name[1] ^ name[2]) & 0x1F, where name[k] evaluates to 0 if length(name) < k. 32 buckets seemed like a sane choice because the 5 LSB of human ASCII input tends to be the most varied.

The buckets reside at find_hashtable and hold heads to linked lists that work the exact same way var_latest worked, except find traverses the list in the appropriate bucket and create appends to the list in the appropriate bucket. var_latest is thus reduced in function to pointing to the most recently defined word, rather than to a linked list of all existing words.

This means the relatively easy to manage static linked list of words is now a set of 32 such linked lists, which is slightly more difficult to manage, but still not unbearably so: a Lua (5.1 + bit module = luajit) script is provided to check the consistency of the hash table and its linked lists, intended to be used as follows:

	$ path/to/tptasm/main.lua model=R2... target=prog.bin export_labels=prog.labels prog.asm
	$ path/to/htcheck.lua prog.bin prog.labels
	all 112 links are good

The script either succeeds as above, or fails and provides advice on how to achieve consistency, such as:

	star_link is in bucket 0x00, should be in bucket 0x16

in which case star_link would have to be unlinked from the list that starts at find_hashtable.b00 and appended to the list that starts at find_hashtable.b16.

The original linked list was converted to the set of new linked lists simply by initializing all of find_hashtable to 0, copying the original value of var_latest to find_hashtable.b00, and repeatedly running htcheck.lua and fixing links until it reported success.

Also migrate to tptasm (amounts to adding an %include "common" up at the top) and remove references to the unused word_ptr, one of which would produce a warning.

Author: LBPHacker