diff options
Diffstat (limited to 'lib/reed_solomon/encode_rs.c')
| -rw-r--r-- | lib/reed_solomon/encode_rs.c | 54 | 
1 files changed, 54 insertions, 0 deletions
diff --git a/lib/reed_solomon/encode_rs.c b/lib/reed_solomon/encode_rs.c new file mode 100644 index 00000000000..237bf65ae88 --- /dev/null +++ b/lib/reed_solomon/encode_rs.c @@ -0,0 +1,54 @@ +/*  + * lib/reed_solomon/encode_rs.c + * + * Overview: + *   Generic Reed Solomon encoder / decoder library + *    + * Copyright 2002, Phil Karn, KA9Q + * May be used under the terms of the GNU General Public License (GPL) + * + * Adaption to the kernel by Thomas Gleixner (tglx@linutronix.de) + * + * $Id: encode_rs.c,v 1.4 2004/10/22 15:41:47 gleixner Exp $ + * + */ + +/* Generic data width independent code which is included by the  + * wrappers. + * int encode_rsX (struct rs_control *rs, uintX_t *data, int len, uintY_t *par) + */ +{ +	int i, j, pad; +	int nn = rs->nn; +	int nroots = rs->nroots; +	uint16_t *alpha_to = rs->alpha_to; +	uint16_t *index_of = rs->index_of; +	uint16_t *genpoly = rs->genpoly; +	uint16_t fb; +	uint16_t msk = (uint16_t) rs->nn; + +	/* Check length parameter for validity */ +	pad = nn - nroots - len; +	if (pad < 0 || pad >= nn) +		return -ERANGE; + +	for (i = 0; i < len; i++) { +		fb = index_of[((((uint16_t) data[i])^invmsk) & msk) ^ par[0]]; +		/* feedback term is non-zero */ +		if (fb != nn) {	 +			for (j = 1; j < nroots; j++) { +				par[j] ^= alpha_to[rs_modnn(rs, fb +  +							 genpoly[nroots - j])]; +			} +		} +		/* Shift */ +		memmove(&par[0], &par[1], sizeof(uint16_t) * (nroots - 1)); +		if (fb != nn) { +			par[nroots - 1] = alpha_to[rs_modnn(rs,  +							    fb + genpoly[0])]; +		} else { +			par[nroots - 1] = 0; +		} +	} +	return 0; +}  |