I 1.1 v J \)v \J b) Tdn s(f
2. Quyet d!nh thu~t toan si'r dl,lllg Thu~t loan la tWIn tlf cae
dl,lllg. Thu~t loan la tWIn tlf cae bu6e x3.e d!nh mQt phuang phap giai quyet van de.
3. The hi~n thu~t toan thong qua lUll do. Hlnh 2.82 biru dicn cae bieu tuqng ehuAn
Chilfnh
Rockwell 6502
Nh~p thanh chua
Nh~p thanh ghi X
Gong vOi cd mang (cany)
Ghuyen logic phai mot bil
Re nhanh neu xoii cd mang (carry)
Nhay den dia chi
Motorola 6809
Nh~p thanh chlIa A
Nh~p thanh ghi chi s6 X
G9n9 vo; cO mang (carry) 10; thanh chua A
Ghuyen logic phai m9t bit
Re nhanh neu xoa cd mang (carry)
Nhay den d!a chi
Intel8035A
Nh~p thanh chua
Ghuyen I(( Ihanh ghi 2 d~n thanh ghi 1
G9n9 vo; cO mang (carry) to; Ihanh r
Quay thanh Ch1I8 ve phia trai
Nhay va dieu ki{m
Nhay co dieu ki$n neu cc Iii dung
I Thu?tnhd - - LOA LOX - AOC LSR BCC JMP LOAA LOX ADGA LSR BCC JMP LOA MOV r1 r2 ADGr RLC JMP Jcc
de the hi¢n lUll do. M6i mQt buoe eila thll~t toan the hi¢n bang mQt ho~e han
mQt bieu tuqng va n6i voi nhau boi cae duemg the hi¢n luong chuang trinh. 4. Chuy~n lUll dol thll~t toan thanh eau l¢nh rna bQ xu If co the thlfe hi¢n.
Tue la viet cae eau l¢nh thea ngon ngu l~p trinh.
5. Ch<;ly thi'r v~ go loi chuang trinh.
II II l-t-
sat dau/ket thuc Thu tl,lC Noi
<> L../~7 •
Qua trinh Quyel dinh Huang chay chuong trinh
ChU(mg trinh chinh
CillIO'llg trlnh ho~t de)ng thea huang SI.f ki~n bAt dau tae dQng, no phfl.n lo~i tac dQng thea rna va xu If tac de)ng. Slf h¢n gay ra tac dQng la cac thiet bi ngo~i vi. do nguai siI dyng dieu khie:n hm~c do ehlnh sl,l' hO':lt uQng clla ban thall chuoog trlnh.
Truac het thiet I~p diu hlnh cang tmac khi co nhu cau truy~n, tiep thea ki~m tra tr':lng thai clla duemg truy~n. Neu duang truycn roi thi viIng d~m duqc ki~m tra. (Vung d¢m luu dO' li~u thea nguyen dc xep hang dqi, dO' li~u co nhu cau gtri truac duqc gui ra h~mg dqi tmac va nguqc h.li). Neu duang lruyen b~n thi tin hi~u chua duqc phep truyen va nhu V(ly khang xdy ra tranh chap trang qua trlnh truyen.
Giao di¢n pMn mem co the xay dl!flg tren ell sa edu true ho~c hrtimg do'i tll(fllg. q.p trlnh cau true la phuoog philp to chu-c, phan chia chLIOOg trlnh thanh cac ham. tM. tyc, chung duqc dung de: xiI Ii dfr ii~u nhung i':li tikh rai cac cau truc dfr li~u. Th6ng qua cac ngan ngfr Foxpra, Pascal, C phuoog phap nay khil quen thuQc doi vm nhfrng nguai lam tin hQc. L~p trinh huang d6i tm;mg dl,l'a tren vi¢c t6 chuoog trlnh thanh cac lap . Khac vm barn va thiJ. tyc, lap la mOt doo vj baa gelm d. du li~u va cac phuoog thuc xu Ii, vi v~y lap co th~ rna tii cac thl,l'c th~ mQt cach chan thl,l'c, day diJ. d. phan dO' li¢u va yeu cau quan If. Tu tuang
I~p trlnh huang d6i tlIqng dLIqc ap dl,lng hau het cho cac ngan ngfr rnai ch~y
tren rnai tflIang Windows nhLI Microsoft Access, Visual Basic, Visual C. L~p trillh cdu trile g6m cac cau truc dfr li¢u (nhLI bien, mango ban ghi) va d.c ham, thll tl,lc l~p thanh mQt clnlllllg (rillll ehillh va cdc chuang trll/h con.
Chucmg trlnh can la mOt philn clla ehLIcmg trinh dung de thl,l'C hi¢n mQt ehtIc nang nhat djnh va duqe d~t rieng sao cho nhicu dO':ln ChLIcmg trlnh e6 the Slr
dyng duqe no. Chuang trlnh can dam nhi¢m nhfrng cang vi¢e can den thLIang xuycn nhu nh~p s6 li~u, in ket qua hay thl,l'c hi¢n rnQt s6 tinh toan, thtl tye ho~c ham can co d6i va eac bien, mang C!,le be) danh rieng eha ham. Vi¢e trao d6i dfr
Ji~u giua d.e ham thong qua cae do; va bien toan b(J.
Ujp trillh f1lr/fIll!. d.61' 'wmg co trung tam la lop (cla.\·s). C6 th~ xem lap la sl,l' kct hqp cae thanh philn dfr li~u va cae h~lm ho~c la Slf rna r¢ng cau truc (struct) bang each dLIa them cae plullll/g tlllfC (metha) hay con gQi Iii. hii.m thanh vien. Me)t lap dLIqe djnh nghia nhLI sau:
IIKhai bao cae thanh philn dG' li~u
II Khlll b,to e~e phuang thuc I
Yeu du eua modun phan mem Ii ngoai vi~e thoa man cac yeu eau cl,l th6 eua b(l xV I~' thl con can d~ sil dl,lng va dap ling chue nang, khi nang thich nghi. kha naIlg rna rl)ng va gia thanh.
ChllO'ng trinh con (Subrountines)
Chuang trinh con hi m¢t phan cua chuang trinh dung d~ thlfc hi¢n m¢l chuc nang nhat dinh va dUQ'c d~t rieng sao cho nhieu do,!-n chuang trlnh co the Slr
dl,lng duQ'c n6. Chuang lrlnh con dam nhi~m nhCi'ng eong vi¢c can den thuang
xuyen, vi dl,!, I~p phan chuang trlnh d~ t;:.tO m¢t thai gian tn~, v ... v. va chung dUQ'c I~p ue sao c6 th~ duQ'c gQi tlr nhieu diem trong m¢t chuang trinh.
Yeu call cua modun phan mem I3. ngoai vi~c thoa man cac yeu call Cl,! the cua b¢ vi xU If thl con can de su dl.Jng va dap ll'ng ehuc nang. co khi nang thieh nghi. kha nang rna r¢ng va gia thanh h';1.
2.7.5. ThiH ke mOdun philn mem:
Thiet ke' philn mem eho m(Jt h¢ thong co di~n tiI. quan tn:mg nhat In nhin nh~n dUQ'c thu b£).c yeu cau trang h¢ thong (hinh 2.83) . Ph~m vi yell cau til "cae doi hoi cua h~ th6ng" den "cac sensor, phan cung ..... thuQc cac lap phl,lc vl,I cac ml,lc dieh khac nhau. Quan tr9ng nhat dn tach rieng chue nang co di~n tu khoi SlJ thi Mnh, nhu v~y lap tren kh6ng bi lien quan den cong vi~e thlJc hi¢n boi lap duoi Moi m¢t lap, thay vi hUOng tn!c tiep van lap tren thl no nh~n d!eh Vl;! va tinh tr4ng eua lap ngay duOi. M¢t kg thu~t l~p trlnh
di qua nhicu lap co the gay ra d.c file roi trong qua trlnh sau nay. L~p trinh cho h¢ th6ng co di¢n tu la mQt van d6 kha trim tuQ'ng. Vi dl;!. m¢t thay doi trang giao di~n sensor ho~c actuator chi phai yell cau thay doi moi 16'p ngay trcn do, lap h¢ dieu khien tru yen