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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <inttypes.h>
/* generic function for 32-bit, 4-bytes at a time */
static inline __attribute__((always_inline))
uint32_t is_char4_outside(uint32_t x, uint8_t min8, uint8_t max8)
{
uint32_t min32 = min8 * 0x01010101U;
uint32_t max32 = max8 * 0x01010101U;
return (((x - min32) | (max32 - x)) & 0x80808080U);
}
/* generic function for 64-bit, 4-bytes at a time */
static inline __attribute__((always_inline))
uint64_t is_char8_outside_by4(uint64_t x, uint8_t min8, uint8_t max8)
{
return is_char4_outside(x, min8, max8) | is_char4_outside(x >> 32, min8, max8);
}
/* generic function for 64-bit, 8-bytes at a time */
static inline __attribute__((always_inline))
uint64_t is_char8_outside_by8(uint64_t x, uint8_t min8, uint8_t max8)
{
uint64_t min64 = min8 * 0x0101010101010101ULL;
uint64_t max64 = max8 * 0x0101010101010101ULL;
return (((x - min64) | (max64 - x)) & 0x8080808080808080ULL);
}
/* generic function for 64-bit, 4- or 8-bytes at a time */
static inline __attribute__((always_inline))
uint64_t is_char8_outside(uint64_t x, uint8_t min8, uint8_t max8)
{
if (sizeof(long) >= 8)
return is_char8_outside_by8(x, min8, max8);
else
return is_char8_outside_by4(x, min8, max8);
}
/* reference function for 32-bit, one byte at a time */
static inline int slow32_ref(uint32_t x)
{
uint8_t a, b, c, d;
a = x >> 0; b = x >> 8; c = x >> 16; d = x >> 24;
return a < 0x24 || a > 0x7e || b < 0x24 || b > 0x7e ||
c < 0x24 || c > 0x7e || d < 0x24 || d > 0x7e;
}
/* reference function for 64-bit, one byte at a time */
static inline int slow64_ref(uint64_t x)
{
uint8_t a, b, c, d, e, f, g, h;
a = x >> 0; b = x >> 8; c = x >> 16; d = x >> 24;
e = x >> 32; f = x >> 40; g = x >> 48; h = x >> 56;
return a < 0x24 || a > 0x7e || b < 0x24 || b > 0x7e ||
c < 0x24 || c > 0x7e || d < 0x24 || d > 0x7e ||
e < 0x24 || e > 0x7e || f < 0x24 || f > 0x7e ||
g < 0x24 || g > 0x7e || h < 0x24 || h > 0x7e;
}
/* optimal function for 32-bit, 4-bytes at a time */
static inline int fast32_gen(uint32_t x)
{
return !!is_char4_outside(x, 0x24, 0x7e);
}
/* optimal function for 64-bit, 4-bytes at a time */
static inline int fast64_gen4(uint64_t x)
{
return !!is_char8_outside_by4(x, 0x24, 0x7e);
}
/* optimal function for 64-bit, 8-bytes at a time */
static inline int fast64_gen8(uint64_t x)
{
return !!is_char8_outside_by8(x, 0x24, 0x7e);
}
/* optimal function for 64-bit, 4- or 8-bytes at a time */
static inline int fast64_gen(uint64_t x)
{
return !!is_char8_outside(x, 0x24, 0x7e);
}
/* specific function for 32-bit, 4- or 8-bytes at a time */
static inline int fast32_spec(uint32_t x)
{
return !!(((x - 0x24242424) | (0x7e7e7e7e - x)) & 0x80808080U);
}
/* specific function for 32-bit, 4- or 8-bytes at a time */
static inline int fast64_spec(uint64_t x)
{
return !!(((x - 0x2424242424242424ULL) | (0x7e7e7e7e7e7e7e7eULL - x)) & 0x8080808080808080ULL);
}
/* xorshift 64-bit PRNG */
#define RND64SEED 0x9876543210abcdefull
static uint64_t rnd64seed = RND64SEED;
static inline uint64_t rnd64()
{
rnd64seed ^= rnd64seed << 13;
rnd64seed ^= rnd64seed >> 7;
rnd64seed ^= rnd64seed << 17;
return rnd64seed;
}
int main(int argc, char **argv)
{
uint32_t base = 0;
uint32_t step = 1;
uint32_t loops = 0;
int size = 32;
int ref;
/* usage: cmd [<bits> [<base> [<step>]]] */
if (argc > 1)
size = atoi(argv[1]);
if (argc > 2)
base = atol(argv[2]);
if (argc > 3)
step = atol(argv[3]);
if (size == 32) {
do {
ref = slow32_ref(base);
if (fast32_gen(base) != ref) {
printf("fast32_gen() fails at 0x%08x: %d / ref=%d\n", base, !ref, ref);
return 1;
}
if (fast32_spec(base) != ref) {
printf("fast32_spec() fails at 0x%08x: %d / ref=%d\n", base, !ref, ref);
return 1;
}
base += step;
loops++;
if (!(loops & 0x7ffff))
printf("0x%08x: 0x%08x\r", loops, base);
} while (base >= step);
}
else if (size == 64) { /* 64-bit on randoms but no more than 2^32 tests */
uint32_t ctr;
uint64_t rnd;
/* offset the RNG if using multiple workers */
for (ctr = 0; ctr < base; ctr++)
rnd64();
do {
rnd = rnd64();
ref = slow64_ref(rnd);
if (fast64_gen(rnd) != ref) {
printf("fast64_gen() fails at 0x%08x: fct(0x%16llx)=%d / ref=%d\n", base, (long long)rnd, !ref, ref);
return 1;
}
if (fast64_gen4(rnd) != ref) {
printf("fast64_gen4() fails at 0x%08x: fct(0x%16llx)=%d / ref=%d\n", base, (long long)rnd, !ref, ref);
return 1;
}
if (fast64_gen8(rnd) != ref) {
printf("fast64_gen8() fails at 0x%08x: fct(0x%16llx)=%d / ref=%d\n", base, (long long)rnd, !ref, ref);
return 1;
}
if (fast64_spec(rnd) != ref) {
printf("fast64_spec() fails at 0x%08x: fct(0x%16llx)=%d / ref=%d\n", base, (long long)rnd, !ref, ref);
return 1;
}
base += step;
loops++;
if (!(loops & 0x7ffff))
printf("0x%08x: 0x%08x -> 0x%16llx\r", loops, base, (long long)rnd);
} while (base >= step);
}
else {
printf("unknown size, usage: %s [<bits> [<base> [<step>]]]\n", argv[0]);
return 1;
}
printf("%llu checks passed. \n",
(unsigned long long)((uint32_t)(base - step) / step) + 1);
return 0;
}
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