preprocessor-macros

Backlinks

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Source: samek-embedded

Manual definition of macros

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#define RCGCGPIO *((unsigned int *)0x400FE608U)

#define GPIOF_BASE 0x40025000u
#define GPIOF_DIR (*((unsigned int *)( GPIOF_BASE + 0x400U)))
#define GPIOF_DEN (*((unsigned int *)( GPIOF_BASE + 0x51CU)))

int main() {
	RCGCGPIO |= 0x20U;
	GPIODIR |= 0xEU;
	GPIOF_DEN |= 0xEU;
	...
}

Notes:

Macros can also be partial statements
Calculations within the macros don’t lead to runtime overheads

Header files

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#include <stdint.h>
#include "lm4f120h5qr.h"

int main() {
	...
}