Value macros for high and low characters

I. Definition

In VC6.0 's Microsoft Visual studio/vc98/include/windef.h, the Byte,word,dword is defined

typedef unsigned long DWORD;

typedef unsigned char BYTE;

typedef unsigned short WORD;

In Visual C + + 6.0, the char length is 1 bytes, the short length is 2 bytes, the int and long lengths are 4 bytes, so you can assume that byte and word,dword-defined variables have 1 bytes, 2 bytes, and 4 bytes of memory, respectively. is consistent with the literal meaning of byte and Word,dword.

That

byte=unsigned char (exact equivalent): 8 bits

word=unsigned short (completely equivalent): 16 bits

dword=unsigned long (completely equivalent): 32 bits

Here are some of the more commonly used macros:

Second, Window macros

1.LOBYTE (extract the Low-order byte from the given 16-bit value)

BYTE Lobyte (

WORD Wvalue//value from which low-order the byte is retrieved

);

#define Lobyte (W) ((BYTE) (W))

such as: WORD w=-0x1234;//w in memory in the complement form storage: 0XEDCC, that is, 0XCC (low address) 0xed (high address)

printf ("W Low byte:%x/n", Lobyte (w));//output: W Low byte: CC

2.HIBYTE (extract high byte from a given 16-bit value)

BYTE Hibyte (

WORD Wvalue//value from which high-order the byte is retrieved

);

#define Hibyte (W) ((WORD) (W) >> 8) & 0xFF)

such as: printf ("W's High Byte:%x/n", Hibyte (w));//output: W's high byte: Ed

3.LOWORD (extract low word from a given 32-bit value)

WORD LoWord (

DWORD dwvalue//value from which Low-order word is retrieved

);

#define LOWORD ((WORD) (L))

For example: DWORD l = 0x12345678;//l is stored in memory as: 0x78,0x56,0x34,0x12

printf ("L's low word:%x/n", LoWord (L));//output: L low word: 5678

4.HIWORD (extract high word from a given 32-bit value)

WORD HiWord (

DWORD dwvalue//value from which High-order word is retrieved

);

#define HIWORD (L) (WORD) ((DWORD) (L) >>) & 0xFFFF)

such as: printf ("L High word:%x/n", HiWord (L));//output: L's high word: 1234

5.MAKEWORD (concatenate two given unsigned character values into a 16-bit integer)

WORD Makeword (

BYTE BLow,//Low-order byte of short value

BYTE bhigh//High-order byte of short value

);

#define Makeword (A, B)/

((WORD) ((BYTE) (a)) | ((WORD) ((BYTE) (b))) << 8))

such as: BYTE blow=0x34,bhigh=0x12;

printf ("Makeword (%x,%x) =%x/n", Blow,bhigh,makeword (Blow,bhigh));

The output is: Makeword (34,12) =1234

6.MAKELONG (connecting two given 16-bit values into a 32-bit integer)

DWORD Makelong (

Word wlow,//Low-order Word of Long value

Word whigh//High-order Word of Long value

);

#define Makelong (A, B)/

(LONG) ((WORD) (a)) | ((DWORD) (WORD) (b)) << 16))

such as: WORD vlow=0x5678,vhigh=0x1234;

printf ("Makelong (%x,%x) =%x/n", Vlow,vhigh,makelong (Vlow,vhigh));

Output result: Makelong (5678,1234) =12345678