can you convert this programme to 3x4 kaypad programme?????



1st column - RB0
2nd column - RB1
3rd column - RB2
1st row - RB3
2nd row - RB4
3rd row - RB5
4th row - RB6


DEFINE LOADER_USED 1
i VAR byte
col VAR byte
row VAR byte
num VAR byte
PIN VAR byte[4]
ADMIN VAR byte[4]
GREEN VAR PORTA.2
YELLOW VAR PORTA.1
BUZZER VAR PORTA.3
OPTION_REG.7 = 0
DATA 0,..............??????? I don't know how to write this part!!!

SETPIN:
SETPIN:
i = 0 WHILE i<4 PIN = 0 GOSUB KEYPAD LET PIN = num i = i + 1
WEND

CHKAMD:
WRITE 1, PIN
PAUSE 200
READ 0, ADMIN
PAUSE 200
IF PIN4 = ADMIN THEN
GREEN = 1
END
ELSE
GOTO SETPIN
ENDIF
KEYPAD:
PAUSE 50

NO_KEY:
TRISB = %01111000
PORTB = 0
IF ((PORTB >> 3)!= %1111)THEN GOTO NO_KEY
PAUSE 50

GOTKEY:
FOR col = 0 to 2
row = 0 TRISB = (dcd col)^%11111111
PORTB = 1
row = PORTB>>3
IF (row!= %1111)THEN CAL_NUM
NEXT col
GOTO GOTKEY

CAL_NUM:
YELLOW = 1
SOUND BUZZER,[100,10]
PAUSE 500
YELLOW = 0
num = (col*3) + (ncd (row^$F))
RETURN