Question

In MPLAB IDE what is the sizes of data types (int, unsigned int, float, unsigned float, char...)?

Answer 1

This is hard without knowing for which CPU you want to compile code. Assuming e.g. Microchip s C18 compiler for the PIC18, the User Guide states the following fundamental type sizes:

TYPE                SIZE     RANGE
char(1,2)            8 bits  -128 127
signed char          8 bits  -128 127
unsigned char        8 bits  0 255
int                 16 bits  -32,768 32,767
unsigned int        16 bits  0 65,535
short               16 bits  -32,768 32,767
unsigned short      16 bits  0 65,535
short long          24 bits  -8,388,608 8,388,607
unsigned short long 24 bits  0 16,777,215
long                32 bits  -2,147,483,648 2,147,483,647
unsigned long       32 bits  0 4,294,967,295

Note that this includes some types (short long) that are not standard in C.

Answer 2

Values for int, long, etc., are never standardly defined across all compilers(reference) . For this reason, it is advised to make use of the library:

#include <stdint.h>

To make use of this library for your own purposes, try using the code as follows:

typedef uint8_t    BYTE
typedef uint16_t   WORD
typedef uint32_t   LONG

Then you just use these to define your variables. This method usually makes use of an integer.h file to store these definitions and is included wherever needed.

Answer 3

Here is the implementation of integer data types on different MPLAB XC compilers.

Data Types for 8-bit devices (implementation on XC8 compiler):
Data Types for 16-bit devices (implementation on XC16 compiler):
Data Types for 32-bit devices (implementation on XC32 compiler):

Answer 4

I would be wary of such generalizations. MPLAB is just an IDE - it is suitable for different chips. Microchip has 8-bit controllers like PIC18F, 16-bit and 32-bit controllers. The data types for each may be different and hold serious implications for performance. I.e. for the 8-bit chips the 16 and 32 bit data types may be emulated in software, which isn t always what you want.

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