view miscutil/bitmanip.c @ 129:b722fcb52926

gsmfr-preproc usage msg: call it input.gsmx instead of input.gsm
author Mychaela Falconia <falcon@freecalypso.org>
date Sun, 11 Dec 2022 04:02:00 +0000
parents 41f1ae68d253
children
line wrap: on
line source

/*
 * This module provides two utility functions that serve as building blocks
 * for frame bit reordering operations.
 */

#include <stdint.h>

msb_get_bit(buf, bn)
	uint8_t *buf;
{
	int pos_byte = bn >> 3;
	int pos_bit  = 7 - (bn & 7);

	return (buf[pos_byte] >> pos_bit) & 1;
}

msb_set_bit(buf, bn, bit)
	uint8_t *buf;
{
	int pos_byte = bn >> 3;
	int pos_bit  = 7 - (bn & 7);

	if (bit)
		buf[pos_byte] |= (1 << pos_bit);
	else
		buf[pos_byte] &= ~(1 << pos_bit);
}