Basic data types in a compilation

1, Byte (DB) define Byte

A BYTE has a 8-bit binary composition, the highest bit is the 7th bit, and the lowest bit is the No. 0 bit. When representing a signed number, the highest bit is the sign bit.

00001001 =9

10001011 = 11 Signed

= 139 unsigned

Typically, memory is addressed by Byte, and the smallest unit of information read and write memory is a byte.

Var_byte DB 10011101B

Var_bytes DB 41h,42d,61h

Then a byte with a maximum value of 8 bits is 11111111=256 the minimum value is-256

Ah and Al these can store 8-bit values so for the int type value (this cannot be said that the assembly has an int type can only say the range of numbers converted to 10 decimal because the data default is 10 binary) only to-256 256

2. Word (DW) define Word

Consists of 2 bytes of a word, the highest bit is the 15th bit, the lowest bit is the No. 0 bit. A high of 8 bits is called a high byte, and a low 8 bit is called a low byte.

0010101000111100

Var_word DW 4512

Here a word is just a type can't describe a letter representing a word

A word in the assembly is a byte of a character two bytes

3, double Word (DD) define Doubleword

Use 2 words (4 bytes) to compose a double word, its height 16 bits is called the high word, the low 16 bit is called the low word.

The double word has a large data representation range, which is usually the data type to satisfy the data representation range, and can also be used to store far pointers.

Var_dword DD 0f99728h 2H 0ABH

4, four words (DQ)

Consists of 4 words (8 bytes) of a four-word type, it has a total of 64 bits, of course, there is a greater range of data representation, but in assembly language is rarely used in this data type.

5, 10 bytes (DT)

Consisting of 10 bytes of a 10-byte type, it has a total of 80 bits.

6. String (DB)

A string is made up of several bytes, a variable number of bytes, and usually one character per byte. This form of data is another form of data that is often used in assembly language programs.

CHAR_ABC db ' A ', ' B ', ' C '

STRING_ABC db ' ABC '

Basic data types in a compilation