1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
4  * Copyright (c) 2006-2009 Ariff Abdullah <ariff@FreeBSD.org>
6  * Copyright (c) 2024-2025 The FreeBSD Foundation
45  * Automatically turn on 64bit arithmetic on suitable archs
46  * (amd64 64bit, etc..) for wider 32bit samples / integer processing.
76 /* 32bit fixed point shift */
80 #define PCM_S8_MIN	 -0x80
82 #define PCM_S16_MIN	 -0x8000
84 #define PCM_S24_MIN	 -0x800000
88 #define PCM_S32_MIN	 -0x80000000L
91 #define PCM_S32_MIN	 -0x80000000LL
95 #define PCM_S32_MIN	(-0x7fffffff - 1)
98 /* Bytes-per-sample definition */
180 		    (int8_t)src[3] << 24);  in pcm_sample_read()
184 		    (int8_t)src[0] << 24);  in pcm_sample_read()
188 		    (int8_t)(src[3] ^ 0x80) << 24);  in pcm_sample_read()
192 		    (int8_t)(src[0] ^ 0x80) << 24);  in pcm_sample_read()
198 			    (int8_t)src[3] << 24);  in pcm_sample_read()
201 			    (int8_t)src[0] << 24);  in pcm_sample_read()
204 		/* NaN, +/- Inf  or too small */  in pcm_sample_read()
215 		e += 8 - 127;  in pcm_sample_read()
217 			m >>= -e;  in pcm_sample_read()
220 		v = INTPCM_T((s == 0) ? m : -m);  in pcm_sample_read()
232  * Read sample and normalize to 32-bit magnitude.
237 	return (pcm_sample_read(src, fmt) << (32 - AFMT_BIT(fmt)));  in pcm_sample_read_norm()
241  * Read sample and restrict magnitude to 24 bits.
254 	 * 16bit = 96db (close enough)  in pcm_sample_read_calc()
255 	 * 24bit = 144db (perfect)  in pcm_sample_read_calc()
256 	 * 32bit = 196db (way too much)  in pcm_sample_read_calc()
258 	 * 24bit is pretty much sufficient for our signed integer processing.  in pcm_sample_read_calc()
259 	 * Also, to avoid overflow, we truncate 32bit (and only 32bit) samples  in pcm_sample_read_calc()
260 	 * down to 24bit (see below for the reason), unless SND_PCM_64 is  in pcm_sample_read_calc()
288 				v = -v;  in pcm_sample_write()
290 			e = 127 - 8;  in pcm_sample_write()
297 				e--;  in pcm_sample_write()
362 		dst[3] = v >> 24;  in pcm_sample_write()
369 		dst[0] = v >> 24;  in pcm_sample_write()
375 		dst[3] = (v >> 24) ^ 0x80;  in pcm_sample_write()
381 		dst[0] = (v >> 24) ^ 0x80;  in pcm_sample_write()
395 	pcm_sample_write(dst, v >> (32 - AFMT_BIT(fmt)), fmt);  in pcm_sample_write_norm()
405 	/* Shift back to 32-bit magnitude. */  in pcm_sample_write_calc()
424 	case 24:  in pcm_clamp()