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WITCH program to find first 20 primes
-------------------------------------

CONSTANTS
12	0.0000001
13	00100	Send 1
14	39919 	Initial LOAD_DIV instruction
15	12080	Terminal STORE_PRIME instruction
16	12079	Terminal less 1 STORE_PRIME instruction

WORKING_STORE
17	00100	Candidate prime increment (/100), initially 1
18	00000	Temporary for 22
19		Current divisor (-ve)
20	00200 	Candidate prime (/100), starting at 2
21		Result of division (units in LS digit)
22	40019	Lowest valid LOAD_DIV
23	00100	1 (/100), used to inc 17 and then cleared

FINISH
24	00100	Finish
TRY_NEXT
25	21900	Clear store 19 (current divisor)
LOAD_DIV
26	39919	Load divisor (-ve) to store 19
DO_DIVISION
27	20900	Clear acc
28	08900	Set shift 10e-7
29	32009	Load -ve store 20 (candidate prime) to acc
30	22100	Clear store 21
31	61921	Divide acc by store 19 (current divisor) into 21
32	08900	Set shift 10e-7
33	11209	Add 0.0000001 to acc (becomes +ve only if no remainder,-ve zero)
34	01109	Test acc +ve
35	02251	Jump to NOT_PRIME if so
36	12218	Move last LOAD_DIV to temporary
37	31826	Subtract last LOAD_DIV from current
38	01126	Test > 0 (current > last)
39	21826	Restore LOAD_DIV and clear temporary
40	31326	Subtract one from LOAD_DIV send addr
41	02225 	Goto TRY_NEXT if not reached end
PRINT_PRIME
42	12001	Print prime number
CLEAR_PRIME
43	29900	Clear next prime storage addr
STORE_PRIME
44	12099	Store prime number
45	31544	Subtract terminal STORE_PRIME instruction
46	01244	Test <= 0 (current <= terminal)
47	02224	Goto FINISH if done enough
48	11644	Add terminal less 1 STORE_PRIME (i.e end up with 1 less in recv addr)
49	31322	Subtract one from lowest valid LOAD_DIV send addr
50	31343	Subtract one from CLEAR_PRIME send addr
NOT_PRIME
51	11720	Advance candidate prime
52	22600	Clear LOAD_DIV instruction
53	11426	Reset LOAD_DIV instruction
54	22317	Add 1 to prime increment (first pass only)
55	02125	Goto TRY_NEXT
ENTRY_POINT
56	07400	Set print layout
57	02142   Goto PRINT_PRIME