Hello Ijaz this is the codes.

$NOMOD51
#include <reg52.inc>
;*****************************************************
;program to generate PWM using AT89C52 *
;*****************************************************

RAM EQU 0F000H ;External DATA (RAM) Starts here
RAMEND EQU 0FFFFH ;External DATA (RAM) Ends here

;***************************************************
; SETUP THE NAMES OF THE SEFGMENTS
;***************************************************

BUFF_SEG SEGMENT IDATA
DATA_SEG SEGMENT DATA
CODE_SEG SEGMENT CODE
;****************************
; byte/word variables ;
;****************************
RSEG DATA_SEG
org 0008h
cputick: DS 1
PWM1: DS 2
PWM2: DS 2
time: DS 2


;****************************************************
; stack support ;
;****************************************************
RSEG BUFF_SEG
STACK:
DS 10

;***************************************************
; MAIN PROGRAM INITIALIZATION ;
;***************************************************
RSEG CODE_SEG

USING 0 ; use register block 0
ORG 8000h ;CODE Starts here (normally in ROM)
LJMP start

ORG 800BH
ORL TH0,#0DCh ;reload timer 0 for 10 ms
INC cputick
RETI
;**********************************************************************************
;service timer2 auto reload shift 16-bit PWM pattern to P1.7 and P1.6 every 1/1000 s
;**********************************************************************************
org 802bh
PUSH PSW
PUSH ACC
;********************************************
;PWM1 is for motor 1 shifted through P1.7
;**********************************************
clr C
MOV A,PWM1
RLC A
MOV PWM1,A
MOV A,PWM1+1
RLC A
MOV PWM1+1,A
MOV P1.7,C ;P1.7 for motor 1
MOV A,PWM1
MOV ACC.0,C
MOV PWM1,A
;**********************************************
;PWM2 is for motor 2 shifted through P1.6
;**********************************************
clr C
MOV A,PWM2
RLC A
MOV PWM2,A
MOV A,PWM2+1
RLC A
MOV PWM2+1,A
MOV P1.6,C ;P1.6 for motor 2
MOV A,PWM2
MOV ACC.0,C
MOV PWM2,A

POP ACC
POP PSW
reti
;************************************************************************
;Fixed memory locations for alternate access to the R0-R7 register bank.;
;************************************************************************
?R0 EQU 0 ;Used for "POP" from stack
?R1 EQU ?R0+1 ;Used to load index indirectly
?R2 EQU ?R0+2 ;"" "" "" ""
?R3 EQU ?R0+3 ;Used by some runtime lib functions
?R4 EQU ?R0+4
?R5 EQU ?R0+5
?R6 EQU ?R0+6
?R7 EQU ?R0+7

org 8100
DB 0A5H,0E5H,0E0H,0A5H ;signature bytes
DB 253,255,0,0 ;id 253 = startup
DB 0,0,0,0 ;prompt code vector
DB 0,0,0,0
DB 0,0,0,0
DB 0,0,0,0
DB 0,0,0,0
DB 255,255,255,255 ;length and checksum (255=unused)
DB 'Main Controller',0
ORG 8100+64 ;executable code begins here

start: MOV SP,#stack-1 ;Set up initial stack
CLR A ;Get end of list flag
MOVX @DPTR,A ;Set heap ending address
orl TMOD,#00000001b ;set timer 0 to be counter 16 bit
SETB IE.7 ;set bit EA
SETB IE.1 ;set bit ET0 Enable timer 0 interrupt
SETB TCON.4 ;start timer 0

mov 0c9H,00H ;T2MOD address is $C9
MOV RCAP2H,#0FCh
MOV RCAP2L,#65
mov T2CON,#00000001b ;start timer 2 producing 1kHz signal
SETB IE.5 ;enable timer2 interrupt


end