diff options
Diffstat (limited to 'libc/stdlib.c')
| -rw-r--r-- | libc/stdlib.c | 49 |
1 files changed, 32 insertions, 17 deletions
diff --git a/libc/stdlib.c b/libc/stdlib.c index bb30039..57b370c 100644 --- a/libc/stdlib.c +++ b/libc/stdlib.c @@ -35,31 +35,45 @@ char* itoa(int val, int base) return &buf[i+(neg?0:1)]; } -static unsigned long rand_s1 = 18, rand_s2 = 5, rand_s3 = 43; +#define RAND_A1 12 +#define RAND_A2 25 +#define RAND_A3 27 -#define M 1103515245UL -#define A 12345UL +#define RAND_C1 4101842887655102017LL +#define RAND_C2 2685821657736338717LL -/* this is a very fast tausworthe RNG */ +static uint64_t rand_state = RAND_C1; + +uint64_t rand64(void) +{ + /* Marsaglia's Xorshift generator combined with a LCRNG */ + rand_state ^= rand_state >> RAND_A1; + rand_state ^= rand_state << RAND_A2; + rand_state ^= rand_state >> RAND_A3; + return rand_state * RAND_C2; +} + +static uint64_t rand_temp; +static int bytes_left = 0; unsigned int rand(void) { - rand_s1 = (((rand_s1&4294967294)<<12)^(((rand_s1<<13)^rand_s1)>>19)); - rand_s2 = (((rand_s2&4294967288)<< 4)^(((rand_s2<< 2)^rand_s2)>>25)); - rand_s3 = (((rand_s3&4294967280)<<17)^(((rand_s3<< 3)^rand_s3)>>11)); - return (rand_s1 ^ rand_s2 ^ rand_s3); + if(bytes_left < 4) + { + rand_temp = rand64(); + bytes_left = 8; + } + unsigned int ret = rand_temp & 0xFFFFFFFF; + rand_temp >>= 32; + bytes_left -= 4; + return ret; } -void srand(unsigned int seed) +void srand(uint64_t seed) { - if(!seed) - seed = 42; - rand_s1 = seed++; - rand_s2 = seed++; - rand_s3 = seed++; - /* "warm it up" */ - for(int i=0;i<10;++i) - rand(); + if(seed == RAND_C1) + seed = RAND_C1 + 1; + rand_state = RAND_C1 ^ seed; } int abs(int val) @@ -69,6 +83,7 @@ int abs(int val) void *malloc(size_t sz) { + return kmalloc(sz); static uint8_t mallocbuf[1024*1024*16]; static uint8_t *next_ptr = mallocbuf; static int bytes_left = sizeof(mallocbuf); |