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trying mormords ideas and why its slower

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This commit is contained in:
Richard Thier 2025-09-27 05:18:07 +02:00
parent a6dd3f93cd
commit 42943f4678
1 changed files with 11 additions and 2 deletions
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13
fastrand.h
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@ -125,6 +125,15 @@ static inline uint32_t lcg_ilp(rand_ilp_state *state, RAND_ILP which) {
return state->h; return state->h;
} }
assert(0); assert(0);
return 0;
}
/** Slower for me than lcg_ilp because that gets optimized out in unrolled loop! */
static inline uint32_t lcg_ilp2(rand_ilp_state *state, RAND_ILP which)
{
uint32_t *s = &(state->a) + which;
*s = *s * 1664525u + 1013904223u;
return *s;
} }
/** Pick a "reasonably random" number in [0, until-1] without modulus */ /** Pick a "reasonably random" number in [0, until-1] without modulus */
@ -134,8 +143,8 @@ static inline uint32_t rand_until(rand_state *restrict state, uint32_t until) {
return (uint32_t)(((uint64_t)rand * until) >> 32); return (uint32_t)(((uint64_t)rand * until) >> 32);
} }
uint32_t fastmodlike(uint32_t num, uint32_t m) { static inline uint32_t fastmodlike(uint32_t num, uint32_t m) {
return (((uint64_t) num) * m); return (uint32_t)(((uint64_t) num * m) >> 32);
} }
/** /**