First, a quote from 2004.

   "[18 07 ??] - Unspeakable horror."

(Okay, it's not actually that bad.)
[18 07 XX XX XX XX YY]
Compare a constant XX against a text system memory YY



C1/528D: C2 31        REP #$31                  Flags and direct page manipulation.
C1/528F: 0B           PHD 
C1/5290: 48           PHA 
C1/5291: 7B           TDC 
C1/5292: 69 EC FF     ADC #$FFEC
C1/5295: 5B           TCD 
C1/5296: 68           PLA 
C1/5297: 86 12        STX $12                   $12 = Last argument
C1/5299: AD CA 97     LDA $97CA                 Argument gathering loop
C1/529C: C9 04 00     CMP #$0004
C1/529F: B0 14        BCS $52B5
C1/52A1: 8A           TXA 
C1/52A2: E2 20        SEP #$20
C1/52A4: AE CA 97     LDX $97CA
C1/52A7: 9D BA 97     STA $97BA,X
C1/52AA: C2 20        REP #$20
C1/52AC: EE CA 97     INC $97CA
C1/52AF: A9 8D 52     LDA #$528D
C1/52B2: 4C 82 53     JMP $5382                 End of argument gathering loop
C1/52B5: E2 20        SEP #$20
C1/52B7: A9 08        LDA #$08
C1/52B9: E2 10        SEP #$10
C1/52BB: A8           TAY                       Y = 0x8
C1/52BC: AD BB 97     LDA $97BB
C1/52BF: 85 06        STA $06                   $06 = arg2
C1/52C1: 64 07        STZ $07
C1/52C3: 64 08        STZ $08
C1/52C5: 64 09        STZ $09
C1/52C7: C2 20        REP #$20
C1/52C9: 22 46 92 C0  JSR $C09246               $06 = arg2 << 8
C1/52CD: E2 20        SEP #$20
C1/52CF: AD BA 97     LDA $97BA
C1/52D2: 85 0A        STA $0A                   $0A = arg1
C1/52D4: 64 0B        STZ $0B
C1/52D6: 64 0C        STZ $0C
C1/52D8: 64 0D        STZ $0D
C1/52DA: C2 20        REP #$20
C1/52DC: A5 0A        LDA $0A
C1/52DE: 05 06        ORA $06
C1/52E0: 85 0A        STA $0A                   $0A = (arg2 << 8) + arg1
C1/52E2: A5 0C        LDA $0C
C1/52E4: 05 08        ORA $08
C1/52E6: 85 0C        STA $0C
C1/52E8: E2 20        SEP #$20
C1/52EA: A9 10        LDA #$10
C1/52EC: A8           TAY                       Y = 0x10
C1/52ED: AD BC 97     LDA $97BC
C1/52F0: 85 06        STA $06                   $06 = arg3
C1/52F2: 64 07        STZ $07
C1/52F4: 64 08        STZ $08
C1/52F6: 64 09        STZ $09
C1/52F8: C2 20        REP #$20
C1/52FA: 22 46 92 C0  JSR $C09246               $06 = 0x0000, $08 = arg3
C1/52FE: A5 0A        LDA $0A
C1/5300: 05 06        ORA $06
C1/5302: 85 0A        STA $0A                   $0A = (arg2 << 8) + arg1
C1/5304: A5 0C        LDA $0C
C1/5306: 05 08        ORA $08
C1/5308: 85 0C        STA $0C                   $0C = arg3
C1/530A: E2 20        SEP #$20
C1/530C: A9 18        LDA #$18
C1/530E: A8           TAY                       Y = 0x18
C1/530F: AD BD 97     LDA $97BD
C1/5312: 85 06        STA $06                   $06 = arg4
C1/5314: 64 07        STZ $07
C1/5316: 64 08        STZ $08
C1/5318: 64 09        STZ $09
C1/531A: C2 20        REP #$20
C1/531C: 22 46 92 C0  JSR $C09246               $06 = 0x0000, $08 = (arg4 << 8)
C1/5320: A5 0A        LDA $0A
C1/5322: 05 06        ORA $06
C1/5324: 85 0A        STA $0A                   $0A = (arg2 << 8) + arg1
C1/5326: A5 0C        LDA $0C
C1/5328: 05 08        ORA $08
C1/532A: 85 0C        STA $0C                   $0C = (arg4 << 8) + arg3

Whew!
So passes another [0A]-style verbosity special.
The practical upshot:

   $0A+0C = First four argument bytes (constant)

C1/532C: C2 10        REP #$10
C1/532E: A6 12        LDX $12                   X = Last argument
C1/5330: D0 05        BNE $5337                 
C1/5332: 20 0A 04     JSR $040A                 arglast == 0x00: Store working memory in $06+08
C1/5335: 80 11        BRA $5348

C1/5337: E0 01 00     CPX #$0001
C1/533A: D0 05        BNE $5341
C1/533C: 20 DC 03     JSR $03DC                 arglast == 0x01: Store argumentary memory in $06+08
C1/533F: 80 07        BRA $5348

C1/5341: 20 00 04     JSR $0400
C1/5344: 85 06        STA $06
C1/5346: 64 08        STZ $08                   arglast other: Store secondary memory in $06+08

The last argument byte seems to choose what to compare.

   00  = Working memory      ("result")
   01  = Argumentary memory  ("argument")
  else = Secondary memory    ("counter")

C1/5348: A5 06        LDA $06
C1/534A: C5 0A        CMP $0A
C1/534C: A5 08        LDA $08
C1/534E: E5 0C        SBC $0C
C1/5350: B0 05        BCS $5357
C1/5352: A9 00 00     LDA #$0000
C1/5355: 80 15        BRA $536C
C1/5357: A5 0C        LDA $0C
C1/5359: C5 08        CMP $08
C1/535B: D0 04        BNE $5361
C1/535D: A5 0A        LDA $0A
C1/535F: C5 06        CMP $06
C1/5361: D0 05        BNE $5368
C1/5363: A2 01 00     LDX #$0001
C1/5366: 80 03        BRA $536B
C1/5368: A2 02 00     LDX #$0002
C1/536B: 8A           TXA 

C1/536C: 85 06        STA $06
C1/536E: 64 08        STZ $08
C1/5370: 10 02        BPL $5374
C1/5372: C6 08        DEC $08
C1/5374: A5 06        LDA $06
C1/5376: 85 0E        STA $0E
C1/5378: A5 08        LDA $08
C1/537A: 85 10        STA $10
C1/537C: 20 5D 04     JSR $045D                 Store return value in working memory.
C1/537F: A9 00 00     LDA #$0000
C1/5382: 2B           PLD 
C1/5383: 60           RTS 

Memory >= Constant: Nonzero (true)
Memory <  Constant: Zero    (false)

.