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author R. Belmont <rb6502@users.noreply.github.com>2017-06-25 07:55:14 -0400
committer GitHub <noreply@github.com>2017-06-25 07:55:14 -0400
commit10f74bb2feb6b60a23110787a564dbd2de9c7d1f (patch)
treee8bb86cf13975a963ca8e0c9eb3c90ab4dbdfd11 /docs/source/initialsetup
parent319eb61d0fec64eca6ee72eb824e0531fac552ba (diff)
parent9788f622e2f76c0487e5f0c430e92be75be991ea (diff)
Merge pull request #2409 from 057a3dd61f99517a3afea0051a49cb27994f94d/sdl-callback-fix
Fix sound_sdl::sdl_callback, fill buffer with silence when underflow.
Diffstat (limited to 'docs/source/initialsetup')
0 files changed, 0 insertions, 0 deletions
3 124
// license:BSD-3-Clause
// copyright-holders:Aaron Giles
/***************************************************************************

    coreutil.c

    Miscellaneous utility code

***************************************************************************/

#include "coreutil.h"
#include <assert.h>
#include <zlib.h>


/***************************************************************************
    BINARY CODED DECIMAL HELPERS
***************************************************************************/

int bcd_adjust(int value)
{
	if ((value & 0xf) >= 0xa)
		value = value + 0x10 - 0xa;
	if ((value & 0xf0) >= 0xa0)
		value = value - 0xa0 + 0x100;
	return value;
}


UINT32 dec_2_bcd(UINT32 a)
{
	UINT32 result = 0;
	int shift = 0;

	while (a != 0)
	{
		result |= (a % 10) << shift;
		a /= 10;
		shift += 4;
	}
	return result;
}


UINT32 bcd_2_dec(UINT32 a)
{
	UINT32 result = 0;
	UINT32 scale = 1;

	while (a != 0)
	{
		result += (a & 0x0f) * scale;
		a >>= 4;
		scale *= 10;
	}
	return result;
}



/***************************************************************************
    GREGORIAN CALENDAR HELPERS
***************************************************************************/

int gregorian_is_leap_year(int year)
{
	return !((year % 100) ? (year % 4) : (year % 400));
}


/* months are one counted */

/**
 * @fn  int gregorian_days_in_month(int month, int year)
 *
 * @brief   Gregorian days in month.
 *
 * @param   month   The month.
 * @param   year    The year.
 *
 * @return  An int.
 */

int gregorian_days_in_month(int month, int year)
{
	assert(month >= 1 && month <= 12);

	int days[] = { 31,28,31,30,31,30,31,31,30,31,30,31 };
	days[1] += gregorian_is_leap_year(year) ? 1 : 0;
	return days[month-1];
}


/***************************************************************************
    MISC
***************************************************************************/

/**
 * @fn  void rand_memory(void *memory, size_t length)
 *
 * @brief   Random memory.
 *
 * @param [in,out]  memory  If non-null, the memory.
 * @param   length          The length.
 */

void rand_memory(void *memory, size_t length)
{
	static UINT32 seed = 0;
	UINT8 *bytes = (UINT8 *) memory;
	size_t i;

	for (i = 0; i < length; i++)
	{
		seed = seed * 214013 + 2531011;
		bytes[i] = (UINT8) (seed >> 16);
	}
}


UINT32 core_crc32(UINT32 crc, const UINT8 *buf, UINT32 len)
{
	return crc32(crc, buf, len);
}