Avalon: Routine at DF33

This section runs through each spell and checks to see if the player has collected it. If so, the text can be printed on the scroll.

Five spells are always displayed on the scroll in a wraparound vertical scrolling list. If the player has fewer than five spells, one or more will show at least once.

At the start of the game the player only has the 'MOVE' spell, so this appears five times.

Used by the routines at E641 and E699.
Checks each spell in the spell index at 6DFC, to see if Maroc has it. For each spell found (up to 5), prints the spell name text on the scroll, and plays a short sound effect.
DF33	LD A,($EAE2)	Spell list index
DF36	LD ($EAE5),A	Copy spell list index into spell list counter
DF39	LD DE,($EAE3)	Address pointer to the start of spell list text at 6DFC
DF3D	LD A,$01	Scroll text line counter (1-5)
DF3F	LD ($EAC7),A	Scroll text line counter (1-5)
DF42	LD HL,$504A	Screen address of top text line of scroll, 3 characters from the left hand side
DF45	LD ($EADE),HL	Put screen display address in temp store for retrieving later
DF48	LD B,$08	Move address pointer along 8 bytes to get to the first/next spell text (e.g. "MOVE" at 6E04)
DF4A	INC DE
DF4B	DJNZ $DF4A
DF4D	LD ($EAA1),DE	Store spell text address pointer
DF51	LD ($EAA4),HL	Store the screen display address
DF54	LD A,$08	Store length of text string to print - spell texts at 6DFC are padded with spaces to make them all 8 characters long
DF56	LD ($EAA3),A
DF59	CALL $E2E0	Print the spell text on the scroll
DF5C	LD HL,($EAA1)	Retrieve the spell text address pointer - this is now pointing at the data after the spell text, e.g. 6E0C.
This section runs through each spell and checks to see if the player has collected it. If so, the text can be printed on the scroll. Five spells are always displayed on the scroll in a wraparound vertical scrolling list. If the player has fewer than five spells, one or more will show at least once. At the start of the game the player only has the 'MOVE' spell, so this appears five times.
DF5F	LD A,($EB69)	Total number of spells to check - 27
DF62	LD C,A	Total number of spells to check - 27
DF63	LD A,($EAE5)	Spell list counter
DF66	CP C	Check if at the end (spell #27)
DF67	JR NZ,$DF70	Check if at the end (spell #27)
DF69	LD A,$00	If so, reset counter to zero...
DF6B	LD HL,($EB65)	...and return the spell name text address pointer to the start of the list, e.g. 6DFC.
DF6E	JR $DF71
DF70	INC A	If we're not at the end of the list, increment the spell list counter.
DF71	LD ($EAE5),A
DF74	LD A,(HL)	Get the the first byte (after the spell name).
DF75	CP $10	Check if this byte = 16, which indicates the player has collected the spell
DF77	JR Z,$DF7F	If so, jump out and print the spell name
DF79	LD BC,$0010	The player hasn't collected this spell, so move the spell text address pointer along 16 bytes to the next spell and repeat the checking loop.
DF7C	ADD HL,BC
DF7D	JR $DF5F
Spell name to print found (Maroc has this spell). First, play a short sound as the player scrolls through the spell list:
DF7F	OUT ($FE),A	The 'A' register is 16 from previous routine (bit 4 is set), so it's used here to switch the speaker on
DF81	LD A,($EAA6)	Counter (initialized at 5) which is used to determine an incremental series of 5 tones, while the player holds down a key to scroll through the spell list
DF84	CP $00	Counter = 0?
DF86	JR Z,$DF95	If so, skip next routine (this keeps the tone at its highest pitch)
DF88	RLA	Take counter and x 2
DF89	RLA	5 rotates to shift bits 0-2 of the counter into bits 5-7
DF8A	RLA
DF8B	RLA
DF8C	RLA
DF8D	AND $E0	Filter out unwanted bits 0-4
DF8F	LD B,A	Store in B to act as a second counter
DF90	CALL $DB06	Routine that generates a pseudo-random number.
DF93	DJNZ $DF90	...The output from the CALLed routine isn't used, it's just called multiple times to provide a handy short delay for the speaker toggle effect/sound.
Spell text line print checks
DF95	LD A,($EAC7)	Continue to check the spell index (at 6DFC) to see which spells Maroc has, and print them on the scroll
DF98	CP $05	5 spells can be printed on the scroll. Have they all been done?
DF9A	JR Z,$DFBB	If so, jump straight to RET at the end of this routine
DF9C	INC A	Otherwise, increment the scroll text line counter
DF9D	LD ($EAC7),A	...and re-store.
DFA0	CP $03	Are we on spell text line number 3?
DFA2	JR NZ,$DFAD	Are we on spell text line number 3?
DFA4	LD A,($EAE5)	If so, this is the spell in the middle of the scroll, that the selection arrow is pointing at
DFA7	LD ($EAE6),A	So set the 'currently highlighted' spell as this one
DFAA	LD ($EAE7),HL	...and also store the address pointer to this spell's data (6DFC).
Prep for printing next line of text:
DFAD	EX DE,HL	Put the current spell index list address pointer into the DE register, ready for checking/printing any other spells the Maroc might have (from DF45)
DFAE	LD HL,($EADE)	Retrieve the screen display address
DFB1	LD BC,$0120	Move the screen display address down 9 pixels ready for the next line of spell text. 288 is 256 (one pixel line down) plus 32 (8 pixel lines down).
DFB4	ADD HL,BC
DFB5	LD A,$00	Toggle speaker (bit 4) off
DFB7	OUT ($FE),A	Toggle speaker (bit 4) off
DFB9	JR $DF45	Keep checking for spells to print
DFBB	RET	RETurn after 5 spells printed