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Index: sys/amd64/amd64/machdep.c
===================================================================
--- sys/amd64/amd64/machdep.c
+++ sys/amd64/amd64/machdep.c
@@ -131,6 +131,7 @@
#include <machine/trap.h>
#include <machine/tss.h>
#include <x86/ucode.h>
+#include <x86/ifunc.h>
#ifdef SMP
#include <machine/smp.h>
#endif
@@ -2661,3 +2662,34 @@
}
#endif /* KDB */
+
+#undef memset
+#undef memmove
+#undef memcpy
+
+void *memset_std(void *buf, int c, size_t len);
+void *memset_erms(void *buf, int c, size_t len);
+DEFINE_IFUNC(, void *, memset, (void *, int, size_t), static)
+{
+
+ return ((cpu_stdext_feature & CPUID_STDEXT_ERMS) != 0 ?
+ memset_erms : memset_std);
+}
+
+void *memmove_std(void * _Nonnull dst, const void * _Nonnull src, size_t len);
+void *memmove_erms(void * _Nonnull dst, const void * _Nonnull src, size_t len);
+DEFINE_IFUNC(, void *, memmove, (void * _Nonnull, const void * _Nonnull, size_t), static)
+{
+
+ return ((cpu_stdext_feature & CPUID_STDEXT_ERMS) != 0 ?
+ memmove_erms : memmove_std);
+}
+
+void *memcpy_std(void * _Nonnull dst, const void * _Nonnull src, size_t len);
+void *memcpy_erms(void * _Nonnull dst, const void * _Nonnull src, size_t len);
+DEFINE_IFUNC(, void *, memcpy, (void * _Nonnull, const void * _Nonnull, size_t), static)
+{
+
+ return ((cpu_stdext_feature & CPUID_STDEXT_ERMS) != 0 ?
+ memcpy_erms : memcpy_std);
+}
Index: sys/amd64/amd64/support.S
===================================================================
--- sys/amd64/amd64/support.S
+++ sys/amd64/amd64/support.S
@@ -96,7 +96,7 @@
* Adapted from bcopy written by:
* ws@tools.de (Wolfgang Solfrank, TooLs GmbH) +49-228-985800
*/
-ENTRY(memmove)
+ENTRY(memmove_std)
PUSH_FRAME_POINTER
movq %rdi,%r9
movq %rdx,%rcx
@@ -142,7 +142,7 @@
movq %r9,%rax
POP_FRAME_POINTER
ret
-END(memmove)
+END(memmove_std)
/*
* memcpy(dst, src, len)
@@ -150,7 +150,7 @@
*
* Note: memcpy does not support overlapping copies
*/
-ENTRY(memcpy)
+ENTRY(memcpy_std)
PUSH_FRAME_POINTER
movq %rdi,%rax
movq %rdx,%rcx
@@ -167,13 +167,13 @@
movsb
POP_FRAME_POINTER
ret
-END(memcpy)
+END(memcpy_std)
/*
* memset(dst, c, len)
* rdi, rsi, rdx
*/
-ENTRY(memset)
+ENTRY(memset_std)
PUSH_FRAME_POINTER
movq %rdi,%r9
movq %rdx,%rcx
@@ -195,7 +195,7 @@
movq %r9,%rax
POP_FRAME_POINTER
ret
-END(memset)
+END(memset_std)
/* fillw(pat, base, cnt) */
/* %rdi,%rsi, %rdx */
@@ -1265,3 +1265,74 @@
ret
#undef L1D_FLUSH_SIZE
END(flush_l1d_sw)
+
+/* Variants utilizing Enhanced REP MOVSB/STOSB, commonly found on Intel CPUs. */
+
+/*
+ * memmove(dst, src, cnt)
+ * rdi, rsi, rdx
+ * Adapted from bcopy written by:
+ * ws@tools.de (Wolfgang Solfrank, TooLs GmbH) +49-228-985800
+ */
+ENTRY(memmove_erms)
+ PUSH_FRAME_POINTER
+ movq %rdi,%r9
+ movq %rdx,%rcx
+
+ movq %rdi,%rax
+ subq %rsi,%rax
+ cmpq %rcx,%rax /* overlapping && src < dst? */
+ jb 1f
+
+ rep
+ movsb
+ movq %r9,%rax
+ POP_FRAME_POINTER
+ ret
+
+ /* ALIGN_TEXT */
+1:
+ addq %rcx,%rdi /* copy backwards */
+ addq %rcx,%rsi
+ decq %rdi
+ decq %rsi
+ std
+ rep
+ movsb
+ cld
+ movq %r9,%rax
+ POP_FRAME_POINTER
+ ret
+END(memmove_erms)
+
+/*
+ * memcpy(dst, src, len)
+ * rdi, rsi, rdx
+ *
+ * Note: memcpy does not support overlapping copies
+ */
+ENTRY(memcpy_erms)
+ PUSH_FRAME_POINTER
+ movq %rdi,%rax
+ movq %rdx,%rcx
+ rep
+ movsb
+ POP_FRAME_POINTER
+ ret
+END(memcpy)
+
+/*
+ * memset(dst, c, len)
+ * rdi, rsi, rdx
+ */
+ENTRY(memset_erms)
+ PUSH_FRAME_POINTER
+ movq %rdi,%r9
+ movq %rdx,%rcx
+ movb %sil,%al
+ rep
+ stosb
+ movq %r9,%rax
+ POP_FRAME_POINTER
+ ret
+END(memset_erms)

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