MPLAB C Compiler for PIC24 MCUs and dsPIC DSCs ... - Microchip

5.1 INTRODUCTION
5.2 HIGHLIGHTS
MPLAB ® C COMPILER FOR
PIC24 MCUs AND dsPIC ® DSCs
USER’S GUIDE
Chapter 5. Data Types
This section discusses the MPLAB C Compiler for PIC24 MCUs and dsPIC ® DSCs
(formerly MPLAB C30) data types.
Items discussed in this chapter are:
• Data Representation
• Integer
• Floating Point
• Pointers
5.3 DATA REPRESENTATION
5.4 INTEGER
Multibyte quantities are stored in “little endian” format, which means:
• The least significant byte is stored at the lowest address
• The least significant bit is stored at the lowest-numbered bit position
As an example, the long value of 0x12345678 is stored at address 0x100 as follows:
0x100 0x101 0x102 0X103
0x78 0x56 0x34 0x12
As another example, the long value of 0x12345678 is stored in registers w4 and w5:
w4 w5
0x5678 0x1234
Table 5-1 shows integer data types are supported in the compiler.
TABLE 5-1: INTEGER DATA TYPES
Type Bits Min Max
char, signed char 8 -128 127
unsigned char 8 0 255
short, signed short 16 -32768 32767
unsigned short 16 0 65535
int, signed int 16 -32768 32767
unsigned int 16 0 65535
long, signed long 32 -2 31
2 31 - 1
unsigned long 32 0 2 32 - 1
long long**, signed long long** 64 -2 63
2 63 - 1
unsigned long long** 64 0 2 64 ** ANSI-89 extension
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© 2008 Microchip Technology Inc. DS51284H-page 79