Need some examples using Lookup( I'm playing with led matrix sample code)

[tacbanon]

Hi everyone, I know this is a beginner question but I need help how on how to understand this code(not mine) below and perhaps later on modify it for my application.

Lookup yazi_reg,[30,"HELLO WORLD LED MATRIX DISPLAY "],harf_reg

"LOOKUP statement can be used to retrieve values from a table of 8-bit constants." I got this from the manual but unfortunately I don't really get it yet.
Hope anyone can tell me how the above line should work..and can I make an array variable to place "HELLO WORLD LED MATRIX DISPLAY "? Assuming string of characters was entered from PC - mcu.

The whole code:

porta=0  :  portb=0  :  portc=0  :  portd=0
trisa=0  :  trisb=0  :  trisc=0  :  trisd=0
porte=0  : trise=0
harf_reg var byte
adres_sec var byte
yinele var byte
sutun_reg var byte[300]
veri var byte
yazi_reg var byte 
i VAR BYTE
x var byte
z var byte
y var byte
t var byte
q var byte
sure var byte
yedek var byte
'Define OSC 48
CLEAR  :  portd=255:sure=200 :GOTO oku:
oku:
call yazi  : yazi_reg=yazi_reg+1  :  z=harf_reg
    for i=1 to z
        call yazi  : yazi_reg=yazi_reg+1  : call data_sec
        for y=0 to yinele
            call datalar
            sutun_reg[t]=veri  :  t=t+1
            adres_sec=adres_sec+1
        next y
    next i
t=0
goto gonder
gonder:
FOR Q=0 TO 5
    for i=0 to 15 ' 15
        portb=sutun_reg[t]  :  t=t+1
        porta=i
        portc=111110:pauseus sure:portc=111111
    next i
    for i=0 to 15
        portb=sutun_reg[t]  :  t=t+1
        porta=i
        portc=111101:pauseus sure:portc=111111
    next i
    for i=0 to 15
        portb=sutun_reg[t]  :  t=t+1
        porta=i
        portc=111011:pauseus sure:portc=111111
    next i
    for i=0 to 15
        portb=sutun_reg[t]  :  t=t+1
        porta=i
        portc=110111:pauseus sure:portc=111111
    next i
    for i=0 to 15
        portb=sutun_reg[t]  :  t=t+1
        porta=i
        portc=101111:pauseus sure:portc=111111
    next i
    for i=0 to 15
        portb=sutun_reg[t]  :  t=t+1
        porta=i
        portc=011111:pauseus sure:portc=111111
    next i
    for i=0 to 15
        portb=sutun_reg[t]  :  t=t+1
        porta=i
        portc=111111:pauseus sure:portc=111111
    next i
     for i=0 to 15
        portb=sutun_reg[t]  :  t=t+1
        porta=i
        portc=111111:pauseus sure:portc=111111
    next i
t=0
NEXT Q
goto kaydir
kaydir:
    yedek=sutun_reg[0]
    for i=0 to 239
        sutun_reg[i]=sutun_reg[i+1]
    next i
        sutun_reg[240]=yedek
goto gonder
yazi:
lookup yazi_reg,[30,"HELLO WORLD LED MATRIX DISPLAY "],harf_reg
return


data_sec:
select case harf_reg
case "A"
adres_sec=0  :  yinele=5  :  return
case "B"
adres_sec=6  :  yinele=5  :  return
case "C"
adres_sec=12  :  yinele=5  :  return
case "D"
adres_sec=18  :  yinele=5  :  return
case "E"
adres_sec=24  :  yinele=5  :  return
case "F"
adres_sec=30  :  yinele=5  :  return
case "G"
adres_sec=36  :  yinele=5  :  return
case "H"
adres_sec=42  :  yinele=5  :  return
case "I"
adres_sec=48  :  yinele=3  :  return
case "i"
adres_sec=52  :  yinele=3  :  return
case "J"
adres_sec=56  :  yinele=5  :  return
case "K"
adres_sec=62  :  yinele=5  :  return
case "L"
adres_sec=68  :  yinele=5  :  return
case "M"
adres_sec=74  :  yinele=5  :  return
case "N"
adres_sec=80  :  yinele=5  :  return
case "O"
adres_sec=86  :  yinele=5  :  return
case "P"
adres_sec=92  :  yinele=5  :  return
case "Q"
adres_sec=98  :  yinele=5  :  return
case "R"
adres_sec=104  :  yinele=5  :  return
case "S"
adres_sec=110  :  yinele=5  :  return
case "T"
adres_sec=116  :  yinele=5  :  return
case "U"
adres_sec=122  :  yinele=5  :  return
case "ü"
adres_sec=128  :  yinele=5  :  return
case "V"
adres_sec=134  :  yinele=5  :  return
case "W"
adres_sec=140  :  yinele=5  :  return
case "X"
adres_sec=146  :  yinele=5  :  return
case "Y"
adres_sec=152  :  yinele=5  :  return
case "Z"
adres_sec=158  :  yinele=5  :  return
case " "
adres_sec=164  :  yinele=5  :  return
case "0"
adres_sec=170  :  yinele=5  :  return
case "1"
adres_sec=176  :  yinele=3  :  return
case "2"
adres_sec=180  :  yinele=5  :  return
case "3"
adres_sec=186  :  yinele=5  :  return
case "4"
adres_sec=192  :  yinele=5  :  return
case "5"
adres_sec=198  :  yinele=5  :  return
case "6"
adres_sec=204  :  yinele=5  :  return
case "7"
adres_sec=210  :  yinele=5  :  return
case "8"
adres_sec=216  :  yinele=5  :  return
case "9"
adres_sec=222  :  yinele=5  :  return
end select


datalar:


 lookup adres_sec,[$7C,$0A,$09,$0A,$7C,0_      ;A
                   ,$7F,$49,$49,$49,$36,0_      ;B
                   ,$3E,$41,$41,$41,$22,0_      ;C
                   ,$7F,$41,$41,$41,$3E,0_      ;D
                   ,$7F,$49,$49,$49,$41,0_      ;E
                   ,$7F,$09,$09,$09,$01,0_      ;F
                   ,$3E,$41,$49,$49,$3A,0_      ;G
                   ,$7F,$08,$08,$08,$7F,0_      ;H
                   ,$41,$7F,$41,0_              ;I
                   ,$44,$7D,$44,0_              ;Ý
                   ,$20,$40,$41,$3F,$01,0_      ;J
                   ,$7F,$08,$14,$22,$41,0_      ;K
                   ,$7F,$40,$40,$40,$40,0_      ;L
                   ,$7F,$02,$04,$02,$7F,0_      ;M
                   ,$7F,$04,$08,$10,$7F,0_      ;N
                   ,$3E,$41,$41,$41,$3E,0_      ;O
                   ,$7F,$09,$09,$09,$06,0_      ;P
                   ,$3E,$41,$51,$61,$3E,0_      ;Q
                   ,$7F,$09,$19,$29,$46,0_      ;R
                   ,$26,$49,$49,$49,$32,0_      ;S
                   ,$01,$01,$7F,$01,$01,0_      ;T
                   ,$3F,$40,$40,$40,$3F,0_      ;U
                   ,$1E,$41,$01,$41,$1E,0_      ;Ü
                   ,$1F,$20,$40,$20,$1F,0_      ;V
                   ,$3F,$40,$30,$40,$3F,0_      ;W
                   ,$63,$14,$08,$14,$63,0_      ;X
                   ,$07,$08,$70,$08,$07,0_      ;Y
                   ,$61,$51,$49,$45,$43,0_      ;Z
                   ,$00,$00,$00,$00,$00,0_      ;Space
                   ,$3E,$51,$49,$45,$3E,0_      ;0
                   ,$42,$7F,$40,0_              ;1
                   ,$62,$51,$49,$45,$42,0_      ;2    
                   ,$22,$49,$49,$49,$36,0_      ;3
                   ,$18,$14,$12,$7F,$10,0_      ;4
                   ,$2F,$49,$49,$49,$31,0_      ;5
                   ,$3E,$49,$49,$49,$32,0_      ;6
                   ,$61,$11,$09,$05,$03,0_      ;7
                   ,$36,$49,$49,$49,$36,0_      ;8
                   ,$26,$49,$49,$49,$3E,0],veri ;9
                   
return

Thanks in advance,
tacbanon