1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/lib/utils.c Fri Nov 09 21:03:47 2018 +0100
1.3 @@ -0,0 +1,58 @@
1.4 +/*
1.5 + * Some simple utility functions.
1.6 + *
1.7 + * Copyright (C) 2018 Paul Boddie <paul@boddie.org.uk>
1.8 + *
1.9 + * This program is free software: you can redistribute it and/or modify
1.10 + * it under the terms of the GNU General Public License as published by
1.11 + * the Free Software Foundation, either version 3 of the License, or
1.12 + * (at your option) any later version.
1.13 + *
1.14 + * This program is distributed in the hope that it will be useful,
1.15 + * but WITHOUT ANY WARRANTY; without even the implied warranty of
1.16 + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
1.17 + * GNU General Public License for more details.
1.18 + *
1.19 + * You should have received a copy of the GNU General Public License
1.20 + * along with this program. If not, see <http://www.gnu.org/licenses/>.
1.21 + */
1.22 +
1.23 +#include "utils.h"
1.24 +
1.25 +
1.26 +
1.27 +/* A simple busy wait involving a register-based counter. */
1.28 +
1.29 +void wait(uint32_t delay)
1.30 +{
1.31 + uint32_t counter = delay;
1.32 +
1.33 + if (!delay) return;
1.34 + while (counter--) __asm__(""); /* retain loop */
1.35 +}
1.36 +
1.37 +/* Wrap a pointer within the given limits. */
1.38 +
1.39 +uint8_t *wrap_pointer(uint8_t *ptr, uint8_t *lower, uint8_t *upper)
1.40 +{
1.41 + uint32_t size = upper - lower;
1.42 +
1.43 + if (ptr < lower)
1.44 + return upper - (lower - ptr) % size;
1.45 + else if (ptr >= upper)
1.46 + return lower + (ptr - upper) % size;
1.47 + else
1.48 + return ptr;
1.49 +}
1.50 +
1.51 +/* Wrap a value within the bounds [0, limit). */
1.52 +
1.53 +int wrap_value(int value, int limit)
1.54 +{
1.55 + if (value < 0)
1.56 + return limit - (-value % limit);
1.57 + else if (value >= limit)
1.58 + return (value - limit) % limit;
1.59 + else
1.60 + return value;
1.61 +}