The Hobbit (v1.0): Routine at 8009

Looks the special word up in the table at 8029 and jumps to its handler. DE (the word's class and the parser's state) is saved on the stack at 800C and restored at 8027 before the jump.

If the word is not in the table, the jump at 801C goes back into the parser WITHOUT restoring DE, leaving two bytes on the stack. Every special word except DO is in the table, so in practice this happens only when the player types DO - and then the game loses control completely (see the bug note).

The special words are ALL, EXCEPT, IT, ONE, the game commands PRINT, NOPRINT, LOAD, SAVE, QUIT, HELP, SCORE and PAUSE, and a quotation mark (which has class $90 and a word of 0, and matches the first entry, 80CD).

Looks the special word up in the table at 8029 and jumps to its handler. DE (the word's class and the parser's state) is saved on the stack at 800C and restored at 8027 before the jump. If the word is not in the table, the jump at 801C goes back into the parser WITHOUT restoring DE, leaving two bytes on the stack. Every special word except DO is in the table, so in practice this happens only when the player types DO - and then the game loses control completely (see the bug note). The special words are ALL, EXCEPT, IT, ONE, the game commands PRINT, NOPRINT, LOAD, SAVE, QUIT, HELP, SCORE and PAUSE, and a quotation mark (which has class $90 and a word of 0, and matches the first entry, 80CD).
8009	LD HL,$8029	HL = the table of special words
800C	PUSH DE	Save the class and the parser state...
800D	LD D,$0D	Thirteen entries to check
800F	LD A,(HL)	Compare the low byte of the word
8010	INC HL
8011	CP C
8012	JR NZ,$8018	No match: next entry
8014	LD A,(HL)	Compare the high nibble
8015	CP B	Compare the high nibble
8016	JR Z,$801F	Found it
8018	INC HL	Next entry
8019	DEC D
801A	JR NZ,$800F
801C	JP $7C6A	Not in the table: carry on parsing - but DE is never restored, so two bytes are left on the stack (see the bug note)
801F	LD DE,$0019	Found: the handlers are 25 bytes further on
8022	ADD HL,DE	Found: the handlers are 25 bytes further on
8023	LD E,(HL)	HL = the handler
8024	INC HL
8025	LD D,(HL)
8026	EX DE,HL
8027	POP DE	...restore the class and state
8028	JP (HL)	Jump to the handler