Cirrus Logic CS485 Bedienungsanleitung PDF herunterladen (Seite 5)

CS485G Spring 2015 5

6. What is the largest signed integer you can store in 16 bits? (Answer:

− 1 = 32767)

7. How many bits do you need to store 4893? It’s about 4 × 10

, so

about 12 bits. (The right answer is 13 bits, but in a 2’s complement

representation, at least 14 bits.)

6 C types and their sizes

1. Unfortunately, C declarations are machine-speciﬁc. Here is the size

in bytes of various declarations.

C declaration x86 x86-64

char 1 1

short 2 2

int 4 4

long 4 8 !

long long 8 8

float 4 4

double 8 8

long double 12 16 !

pointer 4 8 !

7 Byte ordering

1. If a word has more than one byte, what is the order?

2. Example: 19088743 = 01234567

3. Big-endian: Least signiﬁcant byte has the highest address. (Sun,

PPC, Mac, Internet). The bytes, in order, are 0x01, 0x23, 0x45, 0x67.

4. Little-endian: Least signiﬁcant byte has the lowest address. (x86).

The bytes, in order, are 0x67, 0x45, 0x23, 0x01.

5. You can use the od program to show a ﬁle in bytes, characters, inte-

gers, ...

6. Lecture 4, 1/23/2015 Lab 2

7. Lecture 5, 1/26/2015

1 2 3 4 5 6 7 8 9 10 ... 66 67

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Cirrus Logic CS485 Bedienungsanleitung Seite 5