RULES:
FW = 00.04.04.04.03
                BB GG RR
0xFFFF     = 0x 00 FF FF = YELLOW 
0xFFFF00   = 0x FF FF 00 = CYAN
0xFF00FF   = 0x FF 00 FF = PINK
0xFF8000   = 0x FF 80 00 = BLUE

DISASSEMBLED:
--------------------------------------------------------
P4_rw:400882C8
P4_rw:400882C8 ; =============== S U B R O U T I N E =======================================
P4_rw:400882C8
P4_rw:400882C8
P4_rw:400882C8 GET_CH_COLOR                            ; CODE XREF: sub_400B2CB4+13C↓p
P4_rw:400882C8                                         ; sub_400B2CB4+14C↓p ...
P4_rw:400882C8                 ANDS    R0, R0, #0xFF
P4_rw:400882CC                 CMP     R0, #4
P4_rw:400882D0                 BCC     loc_400882E0
P4_rw:400882D4                 MOV     R0, #0xFFFF
P4_rw:400882DC                 B       locret_40088334
P4_rw:400882E0 ; ---------------------------------------------------------------------------
P4_rw:400882E0
P4_rw:400882E0 loc_400882E0                            ; CODE XREF: GET_CH_COLOR+8↑j
P4_rw:400882E0                 MOV     R1, #0xFFFF
P4_rw:400882E8                 ANDS    R0, R0, #0xFF
P4_rw:400882EC                 CMP     R0, #3          ; switch 4 cases
P4_rw:400882F0                 BHI     def_400882F8    ; jumptable 400882F8 default case
P4_rw:400882F4                 LDRB    R2, [PC,R0]
P4_rw:400882F8                 ADD     PC, PC, R2,LSL#2 ; switch jump
P4_rw:400882F8 ; ---------------------------------------------------------------------------
P4_rw:400882FC jpt_400882F8    DCB 0                   ; jump table for switch statement
P4_rw:400882FD                 DCB 3
P4_rw:400882FE                 DCB 6
P4_rw:400882FF                 DCB 9
P4_rw:40088300 ; ---------------------------------------------------------------------------
P4_rw:40088300
P4_rw:40088300 loc_40088300                            ; CODE XREF: GET_CH_COLOR+30↑j
P4_rw:40088300                 MOV     R1, #0xFFFF     ; jumptable 400882F8 case 0
P4_rw:40088308                 B       def_400882F8    ; jumptable 400882F8 default case
P4_rw:4008830C ; ---------------------------------------------------------------------------
P4_rw:4008830C
P4_rw:4008830C loc_4008830C                            ; CODE XREF: GET_CH_COLOR+30↑j
P4_rw:4008830C                 MOV     R1, #0xFFFF00   ; jumptable 400882F8 case 1
P4_rw:40088314                 B       def_400882F8    ; jumptable 400882F8 default case
P4_rw:40088318 ; ---------------------------------------------------------------------------
P4_rw:40088318
P4_rw:40088318 loc_40088318                            ; CODE XREF: GET_CH_COLOR+30↑j
P4_rw:40088318                 MOV     R1, #0xFF00FF   ; jumptable 400882F8 case 2
P4_rw:40088320                 B       def_400882F8    ; jumptable 400882F8 default case
P4_rw:40088324 ; ---------------------------------------------------------------------------
P4_rw:40088324
P4_rw:40088324 loc_40088324                            ; CODE XREF: GET_CH_COLOR+30↑j
P4_rw:40088324                 MOV     R1, #0xFF8000   ; jumptable 400882F8 case 3
P4_rw:4008832C                 B       def_400882F8    ; jumptable 400882F8 default case
P4_rw:40088330 ; ---------------------------------------------------------------------------
P4_rw:40088330
P4_rw:40088330 def_400882F8                            ; CODE XREF: GET_CH_COLOR+28↑j
P4_rw:40088330                                         ; GET_CH_COLOR+40↑j ...
P4_rw:40088330                 MOVS    R0, R1          ; jumptable 400882F8 default case
P4_rw:40088334
P4_rw:40088334 locret_40088334                         ; CODE XREF: GET_CH_COLOR+14↑j
P4_rw:40088334                 BX      LR
P4_rw:40088334 ; End of function GET_CH_COLOR
P4_rw:40088334




DECOMPILED:
--------------------------------------------------------
signed int __fastcall GET_CH_COLOR(unsigned __int8 a1)
{
  signed int v2; // r1

  if ( a1 >= 4u )
    return 0xFFFF;
  v2 = 0xFFFF;
  switch ( a1 )
  {
    case 0u:	// CH1
      v2 = 0xFFFF;
      break;
    case 1u:	// CH2
      v2 = 0xFFFF00;
      break;
    case 2u:	// CH3
      v2 = 0xFF00FF;
      break;
    case 3u:	// CH4
      v2 = 0xFF8000;
      break;
    default:
      return v2;
  }
  return v2;
}


HEX VIEW (use https://onlinedisassembler.com/odaweb/ for understand, ARCH=armv5te): 
--------------------------------------------------------
v2 = 0xFFFF   CH1  -> ADDRESS: 0x0088374 DATA: FF 10 A0 E3 FF 1C 81 E3
v2 = 0xFFFF00 CH2  -> ADDRESS: 0x0088380 DATA: FF 18 A0 E3 FF 1C 81 E3
v2 = 0xFF00FF CH3  -> ADDRESS: 0x008838C DATA: FF 10 A0 E3 FF 18 81 E3
v2 = 0xFF8000 CH4  -> ADDRESS: 0x0088398 DATA: C0 18 A0 E3 FE 19 81 E3


EXAMPLE (CH3 PINK -> RED):
--------------------------------------------------------
CH3 PINK = FF 10 A0 E3 FF 18 81 E3 @ 0x008838C

FF 10 A0 E3 FF 18 81 E3 means:

mov r1, #255 ; 0xff
orr r1, r1, #16711680 ; 0xff0000

r1 now contain 0xff00ff (ff0000 OR 0000ff = ff00ff), but we need 0x0000ff
So hex for CH3 RED = FF 10 A0 E3 00 18 81 E3