BizHawk/waterbox/picodrive/pico/sound/mix.c

80 lines
1.3 KiB
C

/*
* some code for sample mixing
* (C) notaz, 2006,2007
*
* This work is licensed under the terms of MAME license.
* See COPYING file in the top-level directory.
*/
#define MAXOUT (+32767)
#define MINOUT (-32768)
/* limitter */
#define Limit(val, max,min) { \
if ( val > max ) val = max; \
else if ( val < min ) val = min; \
}
void mix_32_to_16l_stereo(short *dest, int *src, int count)
{
int l, r;
for (; count > 0; count--)
{
l = r = *dest;
l += *src++;
r += *src++;
Limit( l, MAXOUT, MINOUT );
Limit( r, MAXOUT, MINOUT );
*dest++ = l;
*dest++ = r;
}
}
void mix_32_to_16_mono(short *dest, int *src, int count)
{
int l;
for (; count > 0; count--)
{
l = *dest;
l += *src++;
Limit( l, MAXOUT, MINOUT );
*dest++ = l;
}
}
void mix_16h_to_32(int *dest_buf, short *mp3_buf, int count)
{
while (count--)
{
*dest_buf++ += *mp3_buf++ >> 1;
}
}
void mix_16h_to_32_s1(int *dest_buf, short *mp3_buf, int count)
{
count >>= 1;
while (count--)
{
*dest_buf++ += *mp3_buf++ >> 1;
*dest_buf++ += *mp3_buf++ >> 1;
mp3_buf += 1*2;
}
}
void mix_16h_to_32_s2(int *dest_buf, short *mp3_buf, int count)
{
count >>= 1;
while (count--)
{
*dest_buf++ += *mp3_buf++ >> 1;
*dest_buf++ += *mp3_buf++ >> 1;
mp3_buf += 3*2;
}
}