; Unknown operators (lenient mode). Always return NIL.
; cost_function is encoded in the top 2 bits of the last opcode byte:
;   unknown         = 0 (constant cost)
;   unknown_add     = 1 (add-like)
;   unknown_mul     = 2 (mul-like)
;   unknown_concat  = 3 (concat-like)
; Names without a suffix use multiplier 0; *_x2 use multiplier 1 (cost *= 2).
; Costs must not regress.

; cost_function 0: ignores arguments (including pairs)
unknown => ( ) | 1
unknown 1 => ( ) | 1
unknown 1 2 3 => ( ) | 1
unknown ( 1 2 ) => ( ) | 1
unknown "foobar" 0xabcd => ( ) | 1
unknown_x2 => ( ) | 2
unknown_x2 1 2 3 => ( ) | 2
unknown_x2 ( 1 2 ) => ( ) | 2

; cost_function 1: add-like (old cost model)
unknown_add => ( ) | 99
unknown_add 1 => ( ) | 422
unknown_add 0 => ( ) | 419
unknown_add "" => ( ) | 419
unknown_add 1 2 => ( ) | 745
unknown_add 1 2 3 4 => ( ) | 1391
unknown_add 0x1234 0x56 => ( ) | 748
unknown_add "foobar" => ( ) | 437
unknown_add 0x00 0x00 0x7f0000 0x00 => ( ) | 1397
unknown_add 0x010000000000000000 0x010000000000000000 => ( ) | 793
unknown_add ( 1 ) => FAIL
unknown_add 1 ( 2 ) => FAIL
unknown_add_x2 => ( ) | 198
unknown_add_x2 1 => ( ) | 844
unknown_add_x2 1 2 => ( ) | 1490
unknown_add_x2 1 2 3 4 => ( ) | 2782
unknown_add_x2 "foobar" => ( ) | 874
unknown_add_x2 ( 1 ) => FAIL

; cost_function 2: mul-like (old cost model)
unknown_mul => ( ) | 92
unknown_mul 1 => ( ) | 92
unknown_mul 7 2 => ( ) | 989
unknown_mul 1 2 3 4 => ( ) | 2801
unknown_mul "ab" "cd" => ( ) | 1001
unknown_mul 0x010000 0x010000 => ( ) | 1013
unknown_mul 0x000000000000000007 0x000000000000000002 => ( ) | 1085
unknown_mul ( 1 ) => FAIL
unknown_mul 1 ( 2 ) => FAIL
unknown_mul_x2 => ( ) | 184
unknown_mul_x2 1 => ( ) | 184
unknown_mul_x2 7 2 => ( ) | 1978
unknown_mul_x2 1 2 3 4 => ( ) | 5602
unknown_mul_x2 "ab" "cd" => ( ) | 2002
unknown_mul_x2 ( 1 ) => FAIL

; cost_function 3: concat-like (same for old and new cost model)
unknown_concat => ( ) | 142
unknown_concat "" => ( ) | 277
unknown_concat "a" => ( ) | 280
unknown_concat "a" "b" => ( ) | 418
unknown_concat "a" "b" "c" => ( ) | 556
unknown_concat 0xff 0x00 => ( ) | 418
unknown_concat "foo" "bar" => ( ) | 430
unknown_concat "" "a" "" => ( ) | 550
unknown_concat ( 1 ) => FAIL
unknown_concat "a" ( 2 ) => FAIL
unknown_concat_x2 => ( ) | 284
unknown_concat_x2 "" => ( ) | 554
unknown_concat_x2 "a" => ( ) | 560
unknown_concat_x2 "a" "b" => ( ) | 836
unknown_concat_x2 "foo" "bar" => ( ) | 860
unknown_concat_x2 ( 1 ) => FAIL
