The Hobbit (v1.0): Routine at A2EC

Taking the ring off (also done automatically when timer 6 runs out, A9D4). If the ring is visible it is not being worn: '<actor> is not wearing the ring.' Otherwise the ring and its wearer become visible again, the wearer's strength is multiplied by 4, and timer 6 is stopped.

Because putting the ring on divided the strength by 4 with SRL and taking it off multiplies it by 4 with SLA, the two lowest bits are lost each time: a strength of 74, for example, comes back as 72. Each use of the ring can cost Bilbo up to 3 points of strength.

Taking the ring off (also done automatically when timer 6 runs out, A9D4). If the ring is visible it is not being worn: '<actor> is not wearing the ring.' Otherwise the ring and its wearer become visible again, the wearer's strength is multiplied by 4, and timer 6 is stopped. Because putting the ring on divided the strength by 4 with SRL and taking it off multiplies it by 4 with SLA, the two lowest bits are lost each time: a strength of 74, for example, comes back as 72. Each use of the ring can cost Bilbo up to 3 points of strength.
A2EC	LD IX,($B5FC)	IX = the wearer's record
A2F0	LD IY,$C209	IY = the ring's record
A2F4	BIT 7,(IY+$07)	Is the ring visible (not being worn)?
A2F8	LD HL,$AF66	"you are not wearing the ring."
A2FB	JP NZ,$72D4	Yes: say so
A2FE	CALL $9C99	Dry run? Then stop: it would work
A301	SET 7,(IY+$07)	The ring can be seen again...
A305	SET 7,(IX+$07)	...and so can the wearer...
A309	SLA (IX+$05)	...whose strength is multiplied by 4 (the bottom two bits lost on the way in are gone)
A30D	SLA (IX+$05)
A311	SUB A	Stop timer 6
A312	LD ($C99E),A
A315	RET