how to control multiplexed 4x7-seg by atmega32

I have some project in school and I need some help. So project is make an asm code (asemmbly code)for 4 digit x 7-segment(4 digit multiplexed 7-seg) some thing like driver...so I have to control digits by PORTC (bits 0,1,2,3) and control segment's leds by PORTB (B0,...,B7), by using timer0 overflow interrup and ATmega32..:!!interrupt time is about 4 ms. so how to show as example 0x1101 number on my segments?
I have done some code but I don't know how to continue::
here is my code

;----------------------------------------------
;7-Segment


;----------------------------------------------

.include "m32def.inc"

.equ Nbr_of_digits=4
.equ A=0x0111

.dseg
.org 0x60
t0_ovf_cnt: .byte 2 ;timer 0 overflow counter(16-bit)
B: .byte 2

.org 0x100
Result: .byte 20

.cseg
.org 0
jmp Reset

jmp EXT_INT0_SVC
jmp EXT_INT1_SVC
jmp EXT_INT2_SVC

jmp TIMER2_COMP_SVC
jmp TIMER2_OVF_SVC
jmp TIMER2_CAPT_SVC

jmp TIMER1_COMPA_SVC
jmp TIMER1_COMPB_SVC
jmp TIMER1_CVF_SVC

jmp TIMER0_COMP_SVC
jmp TIMER0_OVF_SVC

jmp ST_COMPLETE_SVC ;serial transfer complete
jmp RX_COMPLETE_SVC
jmp DR_EMPTY_SVC ;USART DATA Reg Empty
jmp TX_COMPLETE_SVC

jmp AD_READY_SVC
jmp EEPROM_READY_SVC

jmp ANA_COMA_SVC
jmp TWI_SVC ;2 Wire Serial Interface
jmp SPM_READY_SVC

RESET:
ldi r16, LOW(RAMEND)
out spl,r16
ldi r16,HIGH(RAMEND)
out sph,r16

ldi YL,LOW ( Result )
ldi YH,HIGH( Result )



call TIMER0_OVF_SVC_INIT
call ShowHex


sei ;Global Interrupt Enable


LOOP:
rjmp LOOP

TIMER0_OVF_SVC_INIT:


in r16,TCCR0
ori r16,(1<<CS00)
;ori r16,(1<<CS02)|(1<<CS00)
out TCCR0, r16

in r16,TIMSK
ori r16,(1<<TOIE0)
out TIMSK,r16

clr r16
sts t0_ovf_cnt,r16
sts t0_ovf_cnt+1,r16

ret

TIMER0_OVF_SVC:

push r24
in r24,SREG
push r24
push r25

lds r24,t0_ovf_cnt
lds r25,t0_ovf_cnt+1
adiw r25:r24,1
sts t0_ovf_cnt,r24
sts t0_ovf_cnt+1,r25


pop r25
pop r24
out SREG,r24
pop r24
sei
ldi r19,Nbr_of_digits
dec r19
breq TIMER0_OVF_SVC_INIT


reti

EXT_INT0_SVC:
EXT_INT1_SVC:
EXT_INT2_SVC:
TIMER2_COMP_SVC:
TIMER2_OVF_SVC:
TIMER2_CAPT_SVC:
TIMER1_COMPA_SVC:
TIMER1_COMPB_SVC:
TIMER1_CVF_SVC:
TIMER0_COMP_SVC:
;TIMER0_OVF_SVC:
ST_COMPLETE_SVC:
RX_COMPLETE_SVC:
DR_EMPTY_SVC:
TX_COMPLETE_SVC:
AD_READY_SVC:
EEPROM_READY_SVC:
ANA_COMA_SVC:
TWI_SVC:
SPM_READY_SVC:

reti

Hex2Bin:

ldi ZL,LOW ( ConvTbl<<1 )
ldi ZH,HIGH( ConvTbl<<1 )

andi r16,0x0f
clr r17

add ZL,r16
adc ZH,r17

lpm r16,Z
st Y+,r16
ret
.org 0x200
ConvTbl:
.db 0b00111111,0b00000110,0b01011011,0b01001111,0b01100110,0b01101101
.db 0b01111100,0b00000111,0b01111111,0b01100111,0b00001010,0b00001011
.db 0b00001100,0b00001101,0b00001110,0b00001111

ShowHex:
ldi r16,LOW(A)
ldi r17,high(A)

sts B,r16
sts B+1,r17
call Hex2Bin

ret