This corresponds to $7FA3 in the ZX Spectrum version.

Used by the routines at $292F and $298B. The safe combination itself is stored at $90.

Used by the routines at $34B5, $350B, $3558, $35EF and $365C.

Used by the routines at $0800, $149F, $15B3, $169B, $19A5, $29C8, $2D47, $3472 and $3687. Holds $FF if ERIC is standing up, or $00 otherwise (meaning he's sitting on a chair, a staircase or the floor, or he's lying on his back).

This corresponds to $7FFB in the ZX Spectrum version.

Used by the routines at $0800, $15B3, $169B, $191B, $1BFA, $1EC2, $2696, $2757, $28BC, $290F, $29C8, $2D47 and $3472. If ERIC is doing anything other than walking or standing still, one of the bits here will be set.

Bit	Meaning if set
0	ERIC is firing the catapult.
1	ERIC is jumping.
2	ERIC is hitting.
3	ERIC is writing on a blackboard.
4	ERIC has just been knocked down or unseated.
5	ERIC is being spoken to by little boy no. 10.
6	ERIC is immobilised.
7	Unused.

Used by the routines at $189D, $2BB0, $2D47, $3AD5 and $BD00.

Holds one of the following values to indicate the sound effect currently being played:

Value	Sound effect
0	None
1	A shield has been hit
2	ERIC is jumping
3	Bell is ringing

Used by the routines at $189D, $2BB0, $2D47, $3AD5 and $BD00.

Used by the routines at $0800 at $39C7.

This corresponds to $7FF5 in the ZX Spectrum version.

Used by the routine at $15B3.

This corresponds to $7FF7 in the ZX Spectrum version.

Used by the routines at $0800, $0C31, $0EC2, $149F, $1D4A, $277D, $28BC, $2BB0, $2D47 and $3AD5. The LSB of the lesson clock is at $FD.

This corresponds to $7FF9 in the ZX Spectrum version.

Used by the routines at $2D47 and $3AD5.

This corresponds to $7FEA in the ZX Spectrum version.

Used by the routines at $0800, $176F, $1FA0, $2241, $2573, $2A43, $2BB0, $2D47, $3B46 and $BE09.

Value	Meaning
0	Demo mode.
1	Shields need to be flashed.
2	All shields flashing; safe not open.
3	ERIC has opened the safe; shields need to be unflashed.

The value here is non-zero when ERIC is midstride. Used by the routines at $0800, $15B3, $2D47, $3472 and $365C.

The following byte holds the result of reading the keyboard and joystick, as done by the interrupt routine at $39C7. It holds $00 if there was no input, the ASCII code of the key pressed (if any), or one of the following values if the joystick was moved:

Value	Meaning
$D1	Up ('Q' with bit 7 set)
$C1	Down ('A' with bit 7 set)
$CF	Left ('O' with bit 7 set)
$D0	Right ('P' with bit 7 set)
$46	Fire ('F')

Used by the routines at $0800, $184E, $189D, $290F, $2D47, $3940, $39C7 and $BE09.

This corresponds to $7F00 in the ZX Spectrum version.

Used by the routines at $11CF, $16E9, $2043, $2387, $2D47, $2EE6, $3012, $3072, $3113, $31EA, $322E, $35EF, $39C7 and $3A90.

Used by the routines at $0800, $09E9, $1129, $149F, $15B3, $1640, $17E5, $191B, $1D4A, $1EE3, $1F29, $1FA0, $2241, $2387, $2696, $27D2, $298B, $29C8, $2A43, $2B52, $2D47, $2E13, $3279, $33BF, $3AB4, $3AD5, $3B5E and $BE09.

This corresponds to $7FF4 in the ZX Spectrum version.

Used by the routines at $09E9, $0D91, $149F, $2573 and $3AD5. See the list of lesson descriptors at $8CE0.

This corresponds to $7FF3 in the ZX Spectrum version.

Used by the routine at $149F.

This corresponds to $7FC4 in the ZX Spectrum version.

Used by the routines at $0800, $1D37, $2BB0 and $2E13.

This corresponds to $7FC6 in the ZX Spectrum version.

Used by the routines at $0800, $1D4A and $2E13.

This corresponds to $7FC1 in the ZX Spectrum version.

Used by the main loop at $0800.

Incremented on every pass through the interrupt routine at $39C7, and used by the main loop at $0800 to adjust ERIC's walking speed in demo mode.

This corresponds to $7F9F in the ZX Spectrum version.

Used by the routines at $176F, $1F3A and $292F. The teachers' safe combination letters are stored at $03.

This corresponds to $7F9B in the ZX Spectrum version.

Used by the routines at $1FA0 and $2AAA.

This corresponds to $7F9A in the ZX Spectrum version.

Used by the routines at $2241 and $2AAA.

Used by the routines at $2241 and $3AD5.

This byte holds a copy of the keyboard/joystick reading at $4C. It is copied here by the routine at $0800. Also used by the routines at $290F and $365C.

This corresponds to $7FF2 in the ZX Spectrum version.

Used by the routine at $149F.

Used by the routines at $149F and $3AD5.

Used by the routine at $39C7.

Set by the routine at $169B and then used by the routine at $191B.

Holds $FF if the safe is flashing, $00 otherwise. Used by the routines at $176F, $2BB0 and $39C7.

This corresponds to $7FEB in the ZX Spectrum version.

Used by the routines at $2BB0 and $2D47.

Decremented on each pass through the main loop at $0800. When the timer reaches zero, either ERIC is moved from the midstride position (if he is midstride), or the keyboard/joystick input is checked, whereupon the timer is reset to 4. It is initialised to 1 by the routine at $2D47, and reset to either 2 or 6 by the routine at $365C after moving ERIC midstride.

Used by the routines at $2D47 and $3940.

This corresponds to $7FC2 in the ZX Spectrum version.

Used by the routine at $2E13.

This corresponds to $7FF7 in the ZX Spectrum version.

Used by the routines at $0800, $270D, $292F, $2BB0 and $2D47. The MSB of the lesson clock is at $40.

This corresponds to $7FF6 in the ZX Spectrum version.

Used by the routines at $169B, $17E5, $184E, $189D, $191B and $2D47.