f256/f256lib/f_random.c
2024-03-27 19:54:24 -05:00

59 lines
1.7 KiB
C

/*
* Copyright (c) 2024 Scott Duensing, scott@kangaroopunch.com
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#ifndef WITHOUT_RANDOM
#ifndef F256LIB_AMALGAMATED_BUILD
#include "f_random.h"
#endif
uint16_t randomRead(void) {
uint16_t result;
POKE(VKY_RND_CTRL, 1); // Enable.
result = PEEKW(VKY_RNDL);
return result;
}
void randomReset(void) {
struct time_t clock;
// Seed the random number generator from the clock.
kernelArgs->common.buf = &clock;
kernelArgs->common.buflen = sizeof(struct time_t);
kernelCall(Clock.GetTime);
randomSeed(mathUnsignedMultiply(clock.seconds, clock.centis));
}
void randomSeed(uint16_t seed) {
POKEW(VKY_SEEDL, seed);
POKE(VKY_RND_CTRL, 3); // Enable, load seed.
}
#endif