Hoi ve so thuc nhi phan.

Khi doi tu so thap phan xang so thuc nhi phan, voi nhung so la luy thua cua 2 thi viec chuyen doi don gian. VD: (1/2)=>0.1
(1/4)=>0.01
(1/8)=>0.001
...........
Nhung voi nhung so khong phai luy thua cua 2, thi ta phai tru dan cho 1/2;1/4;1/8;......
Vi du voi so 0.2 ta lam nhu sau:

starting: 0.200000000000

1
2
3 subtracting 0.125000000000
remainder = 0.075000000000
4 subtracting 0.062500000000
remainder = 0.012500000000
5
6
7 subtracting 0.007812500000
remainder = 0.004687500000
8 subtracting 0.003906250000
remainder = 0.000781250000
9
10
11 subtracting 0.000488281250
remainder = 0.000292968750
12 subtracting 0.000244140625
remainder = 0.000048828125
13
14
15 subtracting 0.000030517578
remainder = 0.000018310547

16 subtracting 0.000015258789
remainder = 0.000003051758
17
18
19 subtracting 0.000001907349
remainder = 0.000001144409
20 subtracting 0.000000953674
remainder = 0.000000190735
21
22
23 subtracting 0.000000119209
remainder = 0.000000071526


Mantissa: .00110011001100110011001

Dieu minh muon hoi cac ban la: doi voi so thuc nhi phan duoc tao ra (co 23 bit sau dau phay), thi do chinh xac chi den con so thu 7 ma khong phai la ca 23 so ????
Cam on,

Khi chuyen tu binary sang decimal toi thuong lam nhu the nay:
VD nhu convert 0.234 sang binary
0.234 * 2
0.468
0.936
1.872 * 2 -> lay phan le nhan 2
1.744
Tuy yeu cau cua bai toan la lay chinh xac den so hang thu may thi ta tinh them, trong th nay lay den so thu 4. ket qua la
%0.0011
Neu ban convert sang IEE 754 thi exponent se bieu dien duoi dang 8 bit binary excess 127 format, con mantissa se chiem so bit con lai, vd nhu trong truong hop ban noi la Single precision la 32bit thi mantissa chiem 23 bit (23 + 8 = 31 + 1 bit sign la 32)
Do chinh xac tuy vao ban lay den bao nhieu chu khogn nhat thiet la 7 so!
I'll always assume no responce means you agree with me![/size=4]