Modified by the routines at 24576 and 24731.

Used by the routine at 24843.

Used by the (unused) routine at 25830.

Used by the routines at 27008, 27026, 28807, 29394 and 29735. Each byte of the SRB corresponds to a segment of 8 character squares on the screen, the leftmost of which will be at x=0, x=8, x=16 or x=24. Each bit set in an SRB byte corresponds to a character square in the segment that needs refreshing. Bit 0 corresponds to the leftmost character square in the segment, bit 7 to the rightmost character square.

Used by the routines at 29518 and 29746.

Used by the routines at 29518 and 29746.

Used by the routine at 30890.

Used by the routine at 63829.

Used by the routines at 63573 and 63779.

Used by the routines at 63191 and 63573. Holds a copy of the battle-year message corresponding to CREAK's birth.

Used by the routines at 63270 and 63573. Holds the ASCII codes of the letters in the safe combination (in the right order). The teachers' safe combination letters are stored at 32675.

Used by the routines at 63573 and 63829. Holds the ASCII codes of the teachers' safe combination letters. The safe combination itself is stored at 32671.

Used by the routine at 63270.

Used by the routine at 63270.

Used by the routine at 63270.

Used by the routine at 62938 while in demo mode.

Used by the routines at 27406 and 32470.

Used by the routine at 27387.

Used by the routines at 30464 and 63931.

Various status flags for the current lesson.

Bit(s)	Meaning
0	End of lesson/playtime (always reset)
1-3	Unused
4	Next lines reprimand for the teacher fetching the truant ERIC (toggled by 30636)
5	Set after a teacher has found the truant ERIC (see 30636)
6	Set after a classroom lesson has started with ERIC present (see 62208) (checked by 30636; reset by 26342)
7	Set after EINSTEIN has had a chance to grass on the absent ERIC (see 62208), or after dinner has started (see 31854) (checked by 30636; reset by 26342)

Bits 0-3 are used by the classroom-based command lists to indicate that or check whether a teacher has arrived at the classroom door to start the lesson.

Bit(s)	Meaning if set
0	Teacher has arrived at the Map Room
1	Teacher has arrived at the Reading Room
2	Teacher has arrived at the Exam Room
3	Teacher has arrived at the White Room
4-6	Unused
7	EINSTEIN is speaking (set by 31919; checked by 31162 and 31944; reset by 31178)

These flags are set and reset by command list 204, and checked by command list 206.

Bit(s)	Meaning if set
0	Little boy no. 1 is ready to stampede
1	Little boy no. 1 is ready to stampede again
2-7	Unused

These flags are used during the special playtimes (when EINSTEIN is going to tell MR WACKER what ERIC's up to, BOY WANDER has hidden a pea-shooter on the fire escape, or ANGELFACE has mumps).

Bit(s)	Meaning if set
0	Little boy no. 10 is waiting for ERIC to respond to the message just delivered (set and reset by 63488; checked by 63352)
1	Unused
2	EINSTEIN is ready (set by command list 212; checked by command list 208)
	BOY WANDER is ready (set and reset by command list 216; checked by command lists 208 and 218)
3	MR WACKER is ready (set by command lists 214 and 218; checked by command list 208)
4	Little boy no. 10 has told ERIC about EINSTEIN (set by command list 208; checked by command list 212)
	Little boy no. 10 has told ERIC about BOY WANDER (set by command list 208; checked by command list 216)
	Little boy no. 10 has told ERIC about ANGELFACE (set by command list 210; checked by command list 220)
5	EINSTEIN has grassed on ERIC (set by command list 212; checked by command list 214)
	ERIC has mumps (set by 64042; checked by command list 222)
6-7	Unused

Used by the routine at 63779, and reset at the start of each lesson by the routine at 26342. Holds 0 if MR CREAK has not yet asked the birth year question during the current lesson, or 1 otherwise.

Decremented by the main loop at 26471; when it becomes zero, the keyboard is checked and ERIC is moved accordingly (see also 25856, 25916, 25962 and 26880).

Zero unless ERIC is midstride or has his arm raised while writing on a board (see 25916); if non-zero, the value is copied to the main action timer at 32744 after ERIC has lowered his arm or moved from the midstride position (see 25856).

Used by the routine at 28143.

Value	Meaning
0	Demo mode
1	Shields need to be flashed
2	All shields flashing; ERIC needs to find the safe combination
3	Shields need to be unflashed

Used by the routine at 28143.

Used by the routines at 28994, 29160 and 63270.

Used by the routines at 29160, 29284, 63056 and 64016. Holds 0 if the board is clean.

Used by the routines at 28994, 29160 and 63270.

Used by the routines at 29160, 29284, 63056 and 64016. Holds 0 if the board is clean.

Used by the routines at 28994, 29160 and 63270.

Used by the routines at 29160, 29284 and 63056. Holds 0 if the board is clean.

Used by the routine at 30636.

Used by the routine at 30636.

Used by the routines at 26342, 30636, 31040, 31188 and 32178. The room ID is stored in bits 0-3, and the teacher ID in bits 4-7. See the list of lesson descriptors at 44256.

Used by the routine at 27303.

Used by the routines at 62495, 62628 and 62771 to coordinate ERIC's movements while firing his catapult, hitting, or jumping.

Decremented in the main loop at 26471. When it reaches 0, it is reset to 5376 by the routine at 26342. It is also checked by the routines at 30636 and 31807, and modified by the routines at 26880, 63456, 63488, 63668, 63931 and 64004.

Used by the routines at 26342 and 31815. Holds the index (0-63) into the main timetable. It is adjusted by the routine at 26880 before starting a new game.

Stores the value of the LSB of the system variable FRAMES as it stood at the end of the last pass through the main loop (see 26471).

If ERIC is doing anything other than walking or standing still, one of the bits here will be set.

Bit	Meaning if set	Handler	Checked by
0	ERIC is firing the catapult	62495	27353
1	ERIC is hitting	62628	27353
2	ERIC is jumping	62771	27353, 30636, 30890, 31229
3	ERIC is being spoken to by little boy no. 10	63352	27353
4	ERIC has just been knocked down or unseated	27303	27353
5	ERIC is writing on a blackboard	63146	26471
6	Unused (always reset)		25983, 26084, 26194
7	ERIC is sitting or lying down (set by 27303 or 27823)		25956, 62574, 62938, 63056

Holds the ASCII code of the last key pressed. Set by the routines at 26471 and 63056; checked by the routines at 25916 and 26194.

Used by the routine at 25126.

Used by the routine at 24993.