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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/utsname.h>
#if defined(__linux__) && defined(HAVE_SYS_AUXV_H)
# include <sys/auxv.h>
#endif
#include "zbuild.h"
#include "riscv_features.h"
#define ISA_V_HWCAP (1 << ('v' - 'a'))
int Z_INTERNAL is_kernel_version_greater_or_equal_to_6_5() {
struct utsname buffer;
if (uname(&buffer) == -1) {
// uname failed
return 0;
}
int major, minor;
if (sscanf(buffer.release, "%d.%d", &major, &minor) != 2) {
// Something bad with uname()
return 0;
}
if (major > 6 || (major == 6 && minor >= 5))
return 1;
return 0;
}
void Z_INTERNAL riscv_check_features_compile_time(struct riscv_cpu_features *features) {
#if defined(__riscv_v) && defined(__linux__)
features->has_rvv = 1;
#else
features->has_rvv = 0;
#endif
}
void Z_INTERNAL riscv_check_features_runtime(struct riscv_cpu_features *features) {
#if defined(__linux__) && defined(HAVE_SYS_AUXV_H)
unsigned long hw_cap = getauxval(AT_HWCAP);
#else
unsigned long hw_cap = 0;
#endif
features->has_rvv = hw_cap & ISA_V_HWCAP;
}
void Z_INTERNAL riscv_check_features(struct riscv_cpu_features *features) {
if (is_kernel_version_greater_or_equal_to_6_5())
riscv_check_features_runtime(features);
else
riscv_check_features_compile_time(features);
if (features->has_rvv) {
size_t e8m1_vec_len;
intptr_t vtype_reg_val;
// Check that a vuint8m1_t vector is at least 16 bytes and that tail
// agnostic and mask agnostic mode are supported
//
__asm__ volatile(
"vsetvli %0, zero, e8, m1, ta, ma\n\t"
"csrr %1, vtype"
: "=r"(e8m1_vec_len), "=r"(vtype_reg_val));
// The RVV target is supported if the VILL bit of VTYPE (the MSB bit of
// VTYPE) is not set and the length of a vuint8m1_t vector is at least 16
// bytes
features->has_rvv = (vtype_reg_val >= 0 && e8m1_vec_len >= 16);
}
}
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