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Kernel: Fix memcpy and memset for x86_64

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Those size_ts sure are growing up fast.
This commit is contained in:
Gunnar Beutner 2021-06-26 01:00:16 +02:00 • committed by Andreas Kling
parent c4acfdc0fb
commit f5cd366006
1 changed files with 16 additions and 0 deletions
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16
Kernel/StdLib.cpp
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@ -243,11 +243,19 @@ void* memcpy(void* dest_ptr, const void* src_ptr, size_t n)
// FIXME: Support starting at an unaligned address.
if (!(dest & 0x3) && !(src & 0x3) && n >= 12) {
size_t size_ts = n / sizeof(size_t);
#if ARCH(I386)
asm volatile(
"rep movsl\n"
: "=S"(src), "=D"(dest)
: "S"(src), "D"(dest), "c"(size_ts)
: "memory");
#else
asm volatile(
"rep movsq\n"
: "=S"(src), "=D"(dest)
: "S"(src), "D"(dest), "c"(size_ts)
: "memory");
#endif
n -= size_ts * sizeof(size_t);
if (n == 0)
return dest_ptr;
@ -296,11 +304,19 @@ void* memset(void* dest_ptr, int c, size_t n)
if (!(dest & 0x3) && n >= 12) {
size_t size_ts = n / sizeof(size_t);
size_t expanded_c = explode_byte((u8)c);
#if ARCH(I386)
asm volatile(
"rep stosl\n"
: "=D"(dest)
: "D"(dest), "c"(size_ts), "a"(expanded_c)
: "memory");
#else
asm volatile(
"rep stosq\n"
: "=D"(dest)
: "D"(dest), "c"(size_ts), "a"(expanded_c)
: "memory");
#endif
n -= size_ts * sizeof(size_t);
if (n == 0)
return dest_ptr;