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#include <cstdint>
#include <klibc/string.hpp>
void* klibc::memcpy(void *__restrict dest, const void *__restrict src, std::size_t n) {
#if defined(__x86_64__)
asm volatile(
"rep movsb"
: "+D"(dest), "+S"(src), "+c"(n)
:
: "memory"
);
return dest;
#else
std::uint8_t *__restrict pdest = static_cast<std::uint8_t *__restrict>(dest);
const std::uint8_t *__restrict psrc = static_cast<const std::uint8_t *__restrict>(src);
for (std::size_t i = 0; i < n; i++) {
pdest[i] = psrc[i];
}
return dest;
#endif
}
void* klibc::memset(void *s, int c, std::size_t n) {
#if defined(__x86_64__)
void* original_s = s;
asm volatile(
"rep stosb"
: "+D"(s), "+c"(n)
: "a"((std::uint8_t)c)
: "memory"
);
return original_s;
#else
std::uint8_t *p = static_cast<std::uint8_t *>(s);
for (std::size_t i = 0; i < n; i++) {
p[i] = static_cast<std::uint8_t>(c);
}
return s;
#endif
}
void* klibc::memmove(void *dest, const void *src, std::size_t n) {
std::uint8_t *pdest = static_cast<std::uint8_t *>(dest);
const std::uint8_t *psrc = static_cast<const std::uint8_t *>(src);
if (reinterpret_cast<std::uintptr_t>(src) > reinterpret_cast<std::uintptr_t>(dest)) {
for (std::size_t i = 0; i < n; i++) {
pdest[i] = psrc[i];
}
} else if (reinterpret_cast<std::uintptr_t>(src) < reinterpret_cast<std::uintptr_t>(dest)) {
for (std::size_t i = n; i > 0; i--) {
pdest[i-1] = psrc[i-1];
}
}
return dest;
}
int klibc::memcmp(const void *s1, const void *s2, std::size_t n) {
const std::uint8_t *p1 = static_cast<const std::uint8_t *>(s1);
const std::uint8_t *p2 = static_cast<const std::uint8_t *>(s2);
for (std::size_t i = 0; i < n; i++) {
if (p1[i] != p2[i]) {
return p1[i] < p2[i] ? -1 : 1;
}
}
return 0;
}
int klibc::strlen(const char *str) {
int len = 0;
while (str[len] != '\0') {
len++;
}
return len;
}
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