1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * Generic Reed Solomon encoder / decoder library
 
 
 
 4 *
 5 * Copyright 2002, Phil Karn, KA9Q
 6 * May be used under the terms of the GNU General Public License (GPL)
 7 *
 8 * Adaption to the kernel by Thomas Gleixner (tglx@linutronix.de)
 9 *
10 * Generic data width independent code which is included by the wrappers.
 
 
 
 
 
 
11 */
12{
13	struct rs_codec *rs = rsc->codec;
14	int i, j, pad;
15	int nn = rs->nn;
16	int nroots = rs->nroots;
17	uint16_t *alpha_to = rs->alpha_to;
18	uint16_t *index_of = rs->index_of;
19	uint16_t *genpoly = rs->genpoly;
20	uint16_t fb;
21	uint16_t msk = (uint16_t) rs->nn;
22
23	/* Check length parameter for validity */
24	pad = nn - nroots - len;
25	if (pad < 0 || pad >= nn)
26		return -ERANGE;
27
28	for (i = 0; i < len; i++) {
29		fb = index_of[((((uint16_t) data[i])^invmsk) & msk) ^ par[0]];
30		/* feedback term is non-zero */
31		if (fb != nn) {
32			for (j = 1; j < nroots; j++) {
33				par[j] ^= alpha_to[rs_modnn(rs, fb +
34							 genpoly[nroots - j])];
35			}
36		}
37		/* Shift */
38		memmove(&par[0], &par[1], sizeof(uint16_t) * (nroots - 1));
39		if (fb != nn) {
40			par[nroots - 1] = alpha_to[rs_modnn(rs,
41							    fb + genpoly[0])];
42		} else {
43			par[nroots - 1] = 0;
44		}
45	}
46	return 0;
47}

 
 1/*
 2 * lib/reed_solomon/encode_rs.c
 3 *
 4 * Overview:
 5 *   Generic Reed Solomon encoder / decoder library
 6 *
 7 * Copyright 2002, Phil Karn, KA9Q
 8 * May be used under the terms of the GNU General Public License (GPL)
 9 *
10 * Adaption to the kernel by Thomas Gleixner (tglx@linutronix.de)
11 *
12 * $Id: encode_rs.c,v 1.5 2005/11/07 11:14:59 gleixner Exp $
13 *
14 */
15
16/* Generic data width independent code which is included by the
17 * wrappers.
18 * int encode_rsX (struct rs_control *rs, uintX_t *data, int len, uintY_t *par)
19 */
20{
 
21	int i, j, pad;
22	int nn = rs->nn;
23	int nroots = rs->nroots;
24	uint16_t *alpha_to = rs->alpha_to;
25	uint16_t *index_of = rs->index_of;
26	uint16_t *genpoly = rs->genpoly;
27	uint16_t fb;
28	uint16_t msk = (uint16_t) rs->nn;
29
30	/* Check length parameter for validity */
31	pad = nn - nroots - len;
32	if (pad < 0 || pad >= nn)
33		return -ERANGE;
34
35	for (i = 0; i < len; i++) {
36		fb = index_of[((((uint16_t) data[i])^invmsk) & msk) ^ par[0]];
37		/* feedback term is non-zero */
38		if (fb != nn) {
39			for (j = 1; j < nroots; j++) {
40				par[j] ^= alpha_to[rs_modnn(rs, fb +
41							 genpoly[nroots - j])];
42			}
43		}
44		/* Shift */
45		memmove(&par[0], &par[1], sizeof(uint16_t) * (nroots - 1));
46		if (fb != nn) {
47			par[nroots - 1] = alpha_to[rs_modnn(rs,
48							    fb + genpoly[0])];
49		} else {
50			par[nroots - 1] = 0;
51		}
52	}
53	return 0;
54}