I have to do a driving system for speed of a d.c. motor.The provider gives me the source code which contains more routine.This program exist in hex format but I tanslated it in asm for 8051(it is the controller which is used).In the code that I have obtained I identified some routines: serial comunication, capture of the speed, the routine of reading and writing of a character on LCD, routine of command with PWM1(curent impulses) and other.I don't know where is the code for regulation(PID calibration in discreet time
u(k)=u(k-1)+u(k-2)
recursive algorithm) and comunication with MATLAB, because the output of speed traductor is displayed and view with MATLAB.For this it exist a MATLAB model whiches block ar written in C.The code which I don't know what it,s doing is displayed below:

X8a68: clr c
mov a,52h
addc a,6bh
mov 52h,a
mov a,53h
addc a,6ah
mov 53h,a
mov a,54h
addc a,#0
mov 54h,a
mov a,55h
addc a,#0
mov 55h,a
ret
;
X8a82: clr c
mov a,52h
addc a,5bh
mov 52h,a
mov a,53h
addc a,5ah
mov 53h,a
mov a,54h
addc a,59h
mov 54h,a
mov a,55h
addc a,58h
mov 55h,a
ret
;
clr c
mov a,52h
subb a,5dh
mov 52h,a
mov a,53h
subb a,5ch
mov 53h,a
mov a,54h
subb a,#0
mov 54h,a
mov a,55h
subb a,#0
mov 55h,a
ret
;
X8ab6: clr c
mov a,52h
subb a,61h
mov 52h,a
mov a,53h
subb a,60h
mov 53h,a
mov a,54h
subb a,5fh
mov 54h,a
mov a,55h
subb a,5eh
mov 55h,a
ret
;
X8ad0: mov a,55h
cpl a
mov 55h,a
mov a,54h
cpl a
mov 54h,a
mov a,53h
cpl a
mov 53h,a
mov a,52h
cpl a
add a,#1
mov 52h,a
mov a,53h
addc a,#0
mov 53h,a
mov a,54h
addc a,#0
mov 54h,a
mov a,55h
addc a,#0
mov 55h,a
ret
;
X8af9: clr 20h.6
clr 20h.7
mov a,55h
mov c,acc.7
mov 20h.6,c
jnc X8b08
lcall X8ad0
X8b08: mov a,68h
mov c,acc.7
mov 20h.7,c
anl c,/20h.6
mov 20h.7,c
mov c,20h.6
anl c,/acc.7
orl c,20h.7
mov 20h.6,c
jnb acc.7,X8b2f
mov a,68h
cpl a
mov 68h,a
mov a,69h
cpl a
add a,#1
mov 69h,a
mov a,68h
addc a,#0
mov 68h,a
X8b2f: mov 6fh,#0
mov 6eh,#0
mov b,52h
mov a,69h
mul ab
mov 6ch,a
mov 6dh,b
mov b,53h
mov a,69h
mul ab
add a,6dh
mov 6dh,a
mov a,b
addc a,6eh
mov 6eh,a
jnc X8b54
inc 6fh
X8b54: mov b,52h
mov a,68h
mul ab
add a,6dh
mov 6dh,a
mov a,b
addc a,6eh
mov 6eh,a
jnc X8b68
inc 6fh
X8b68: mov b,54h
mov a,69h
mul ab
add a,6eh
mov 6eh,a
mov a,b
addc a,6fh
mov 6fh,a
mov b,53h
mov a,68h
mul ab
add a,6eh
mov 6eh,a
mov a,b
addc a,6fh
mov 6fh,a
mov b,55h
mov a,69h
mul ab
add a,6fh
mov 6fh,a
mov b,54h
mov a,68h
mul ab
add a,6fh
mov 6fh,a
mov 52h,6ch
mov 53h,6dh
mov 54h,6eh
mov 55h,6fh
jnb 20h.6,X8bae
lcall X8ad0
X8bae: ret
;
X8baf: clr 20h.6
clr 20h.7
mov a,55h
mov c,acc.7
mov 20h.6,c
jnc X8bbe
lcall X8ad0
X8bbe: mov a,56h
mov c,acc.7
mov 20h.7,c
anl c,/20h.6
mov 20h.7,c
mov c,20h.6
anl c,/acc.7
orl c,20h.7
mov 20h.6,c
jnb acc.7,X8be5
mov a,56h
cpl a
mov 56h,a
mov a,57h
cpl a
add a,#1
mov 57h,a
mov a,56h
addc a,#0
mov 56h,a
X8be5: mov r7,#0
mov r6,#0
mov 6ch,#0
mov 6dh,#0
mov 6eh,#0
mov 6fh,#0
mov r1,56h
mov r0,57h
mov r5,#20h
X8bfb: lcall X8c34
mov a,r6
rlc a
mov r6,a
mov a,r7
rlc a
mov r7,a
clr c
mov a,r7
subb a,r1
jc X8c1b
jnz X8c10
clr c
mov a,r6
subb a,r0
jc X8c1b
X8c10: clr c
mov a,r6
subb a,r0
mov r6,a
mov a,r7
subb a,r1
mov r7,a
setb c
ljmp X8c1c
;
X8c1b: clr c
X8c1c: lcall X8c60
djnz r5,X8bfb
mov 52h,6ch
mov 53h,6dh
mov 54h,6eh
mov 55h,6fh
jnb 20h.6,X8c33
lcall X8ad0
X8c33: ret
;
X8c34: clr c
mov a,52h
rlc a
mov 52h,a
mov a,53h
rlc a
mov 53h,a
mov a,54h
rlc a
mov 54h,a
mov a,55h
rlc a
mov 55h,a
ret
;
clr c
mov a,55h
rrc a
mov 55h,a
mov a,54h
rrc a
mov 54h,a
mov a,53h
rrc a
mov 53h,a
mov a,52h
rrc a
mov 52h,a
ret
;
X8c60: mov a,6ch
rlc a
mov 6ch,a
mov a,6dh
rlc a
mov 6dh,a
mov a,6eh
rlc a
mov 6eh,a
mov a,6fh
rlc a
mov 6fh,a
ret
;
X8c75: mov 52h,37h
mov 53h,38h
mov 54h,#0
mov 55h,#0
mov 69h,#0c8h
mov 68h,#0
lcall X8af9
mov 44h,53h
mov 45h,52h
mov 52h,33h
mov 53h,34h
mov 54h,#0
mov 55h,#0
mov 69h,#64h
mov 68h,#0
lcall X8af9
mov 6bh,45h
mov 6ah,44h
lcall X8a68
mov 44h,53h
mov 45h,52h
mov 52h,#88h
mov 53h,#13h
mov 54h,#0
mov 55h,#0
mov 57h,35h
mov 56h,36h
lcall X8baf
mov 6bh,45h
mov 6ah,44h
lcall X8a68
mov 57h,#64h
mov 56h,#0
lcall X8baf
mov 44h,53h
mov 45h,52h
mov 52h,37h
mov 53h,38h
mov 54h,#0
mov 55h,#0
mov 69h,#4
mov 68h,#0
lcall X8af9
mov 6bh,33h
mov 6ah,34h
lcall X8a68
lcall X8ad0
mov 46h,53h
mov 47h,52h
mov 52h,37h
mov 53h,38h
mov 54h,#0
mov 55h,#0
mov 69h,#2
mov 68h,#0
lcall X8af9
mov 48h,53h
mov 49h,52h
ret
;
X8d24: mov 52h,45h
mov 53h,44h
mov 54h,#0
mov 55h,#0
mov a,44h
jnb acc.7,X8d3b
mov 54h,#0ffh
mov 55h,#0ffh
X8d3b: mov a,39h
mov 69h,39h
mov 68h,#0
jnb acc.7,X8d49
mov 68h,#0ffh
X8d49: lcall X8af9
mov 4eh,52h
mov 4fh,53h
mov 50h,54h
mov 51h,55h
mov 52h,47h
mov 53h,46h
mov 54h,#0
mov 55h,#0
mov a,46h
jnb acc.7,X8d6f
mov 54h,#0ffh
mov 55h,#0ffh
X8d6f: mov a,3ah
mov 69h,3ah
mov 68h,#0
jnb acc.7,X8d7d
mov 68h,#0ffh
X8d7d: lcall X8af9
mov 5bh,4eh
mov 5ah,4fh
mov 59h,50h
mov 58h,51h
lcall X8a82
mov 4eh,52h
mov 4fh,53h
mov 50h,54h
mov 51h,55h
mov 52h,49h
mov 53h,48h
mov 54h,#0
mov 55h,#0
mov a,48h
jnb acc.7,X8db2
mov 54h,#0ffh
mov 55h,#0ffh
X8db2: mov a,3bh
mov 69h,3bh
mov 68h,#0
jnb acc.7,X8dc0
mov 68h,#0ffh
X8dc0: lcall X8af9
mov 5bh,4eh
mov 5ah,4fh
mov 59h,50h
mov 58h,51h
lcall X8a82
mov 57h,#0ah
mov 56h,#0
lcall X8baf
mov 4dh,52h
mov 4ch,53h
mov 4bh,54h
mov 4ah,55h
ret
;
X8de8: mov 52h,2bh
mov 53h,2ch
mov 54h,#0
mov 55h,#0
mov 4eh,52h
mov 4fh,53h
mov 50h,54h
mov 51h,55h
mov 57h,#0ah
mov 56h,#0
lcall X8baf
mov 5bh,52h
mov 5ah,53h
mov 59h,54h
mov 58h,55h
mov 69h,#0ah
mov 68h,#0
lcall X8af9
mov 61h,52h
mov 60h,53h
mov 5fh,54h
mov 5eh,55h
mov 52h,4eh
mov 53h,4fh
mov 54h,50h
mov 55h,51h
lcall X8ab6
mov a,52h
push acc
mov 52h,5bh
mov 53h,5ah
mov 54h,59h
mov 55h,58h
mov 4eh,52h
mov 4fh,53h
mov 50h,54h
mov 51h,55h
mov 57h,#0ah
mov 56h,#0
lcall X8baf
mov 5bh,52h
mov 5ah,53h
mov 59h,54h
mov 58h,55h
mov 69h,#0ah
mov 68h,#0
lcall X8af9
mov 61h,52h
mov 60h,53h
mov 5fh,54h
mov 5eh,55h
mov 52h,4eh
mov 53h,4fh
mov 54h,50h
mov 55h,51h
lcall X8ab6
mov a,52h
push acc
mov 52h,5bh
mov 53h,5ah
mov 54h,59h
mov 55h,58h
mov 4eh,52h
mov 4fh,53h
mov 50h,54h
mov 51h,55h
mov 57h,#0ah
mov 56h,#0
lcall X8baf
mov 5bh,52h
mov 5ah,53h
mov 59h,54h
mov 58h,55h
mov 69h,#0ah
mov 68h,#0
lcall X8af9
mov 61h,52h
mov 60h,53h
mov 5fh,54h
mov 5eh,55h
mov 52h,4eh
mov 53h,4fh
mov 54h,50h
mov 55h,51h
lcall X8ab6
mov a,52h
push acc
mov 52h,5bh
mov 53h,5ah
mov 54h,59h
mov 55h,58h
mov 4eh,52h
mov 4fh,53h
mov 50h,54h
mov 51h,55h
mov 57h,#0ah
mov 56h,#0
lcall X8baf
mov 5bh,52h
mov 5ah,53h
mov 59h,54h
mov 58h,55h
mov 69h,#0ah
mov 68h,#0
lcall X8af9
mov 61h,52h
mov 60h,53h
mov 5fh,54h
mov 5eh,55h
mov 52h,4eh
mov 53h,4fh
mov 54h,50h
mov 55h,51h
lcall X8ab6
mov a,52h
push acc
mov dptr,#0952bh
pop acc
lcall X8f84
movx @dptr,a
inc dptr
pop acc
lcall X8f84
movx @dptr,a
inc dptr
pop acc
lcall X8f84
movx @dptr,a
inc dptr
pop acc
lcall X8f84
movx @dptr,a
ret
;
mov dptr,#0952bh
mov a,2ch
anl a,#0f0h
swap a
lcall X8f84
movx @dptr,a
inc dptr
mov a,2ch
anl a,#0fh
lcall X8f84
movx @dptr,a
inc dptr
mov a,2bh
anl a,#0f0h
swap a
lcall X8f84
movx @dptr,a
inc dptr
mov a,2bh
anl a,#0fh
lcall X8f84
movx @dptr,a
ret
;
X8f84: anl a,#0fh
jnb acc.3,X8f91
jb acc.2,X8f8f
jnb acc.1,X8f91
X8f8f: add a,#7
X8f91: add a,#30h
ret
;
X8f94: push dph
push dpl
mov dptr,#08fa3h
anl a,#0fh
movc a,@a+dptr
pop dpl
pop dph
ret
;
jnb 26h.1,X8fd8
rlc a
addc a,#35h
addc a,@r0
addc a,@r1
addc a,r0
addc a,r1
ajmp X8a42
;
orl 44h,#45h
orl a,@r0
X8fb3: clr a
movx a,@dptr
inc dptr
mov r0,a
cjne r0,#24h,X8fbb
ret
;
X8fbb: lcall X8ff6
sjmp X8fb3
;
push acc
mov 6ch,a
swap a
lcall X8f94
lcall X8ff6
mov a,6ch
lcall X8f94
lcall X8ff6
pop acc
ret
;
push acc
X8fd8: mov a,#20h
lcall X8ff6
lcall X8ff6
pop acc
ret
;
mov a,#0dh
lcall X8ff6
mov a,#0ah
lcall X8ff6
ret