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-rw-r--r--arch/x86/lib/memset_64.S133
1 files changed, 133 insertions, 0 deletions
diff --git a/arch/x86/lib/memset_64.S b/arch/x86/lib/memset_64.S
new file mode 100644
index 00000000000..2c5948116bd
--- /dev/null
+++ b/arch/x86/lib/memset_64.S
@@ -0,0 +1,133 @@
+/* Copyright 2002 Andi Kleen, SuSE Labs */
+
+#include <linux/linkage.h>
+#include <asm/dwarf2.h>
+
+/*
+ * ISO C memset - set a memory block to a byte value.
+ *
+ * rdi destination
+ * rsi value (char)
+ * rdx count (bytes)
+ *
+ * rax original destination
+ */
+ ALIGN
+memset_c:
+ CFI_STARTPROC
+ movq %rdi,%r9
+ movl %edx,%r8d
+ andl $7,%r8d
+ movl %edx,%ecx
+ shrl $3,%ecx
+ /* expand byte value */
+ movzbl %sil,%esi
+ movabs $0x0101010101010101,%rax
+ mulq %rsi /* with rax, clobbers rdx */
+ rep stosq
+ movl %r8d,%ecx
+ rep stosb
+ movq %r9,%rax
+ ret
+ CFI_ENDPROC
+ENDPROC(memset_c)
+
+ENTRY(memset)
+ENTRY(__memset)
+ CFI_STARTPROC
+ movq %rdi,%r10
+ movq %rdx,%r11
+
+ /* expand byte value */
+ movzbl %sil,%ecx
+ movabs $0x0101010101010101,%rax
+ mul %rcx /* with rax, clobbers rdx */
+
+ /* align dst */
+ movl %edi,%r9d
+ andl $7,%r9d
+ jnz .Lbad_alignment
+ CFI_REMEMBER_STATE
+.Lafter_bad_alignment:
+
+ movl %r11d,%ecx
+ shrl $6,%ecx
+ jz .Lhandle_tail
+
+ .p2align 4
+.Lloop_64:
+ decl %ecx
+ movq %rax,(%rdi)
+ movq %rax,8(%rdi)
+ movq %rax,16(%rdi)
+ movq %rax,24(%rdi)
+ movq %rax,32(%rdi)
+ movq %rax,40(%rdi)
+ movq %rax,48(%rdi)
+ movq %rax,56(%rdi)
+ leaq 64(%rdi),%rdi
+ jnz .Lloop_64
+
+ /* Handle tail in loops. The loops should be faster than hard
+ to predict jump tables. */
+ .p2align 4
+.Lhandle_tail:
+ movl %r11d,%ecx
+ andl $63&(~7),%ecx
+ jz .Lhandle_7
+ shrl $3,%ecx
+ .p2align 4
+.Lloop_8:
+ decl %ecx
+ movq %rax,(%rdi)
+ leaq 8(%rdi),%rdi
+ jnz .Lloop_8
+
+.Lhandle_7:
+ movl %r11d,%ecx
+ andl $7,%ecx
+ jz .Lende
+ .p2align 4
+.Lloop_1:
+ decl %ecx
+ movb %al,(%rdi)
+ leaq 1(%rdi),%rdi
+ jnz .Lloop_1
+
+.Lende:
+ movq %r10,%rax
+ ret
+
+ CFI_RESTORE_STATE
+.Lbad_alignment:
+ cmpq $7,%r11
+ jbe .Lhandle_7
+ movq %rax,(%rdi) /* unaligned store */
+ movq $8,%r8
+ subq %r9,%r8
+ addq %r8,%rdi
+ subq %r8,%r11
+ jmp .Lafter_bad_alignment
+.Lfinal:
+ CFI_ENDPROC
+ENDPROC(memset)
+ENDPROC(__memset)
+
+ /* Some CPUs run faster using the string instructions.
+ It is also a lot simpler. Use this when possible */
+
+#include <asm/cpufeature.h>
+
+ .section .altinstr_replacement,"ax"
+1: .byte 0xeb /* jmp <disp8> */
+ .byte (memset_c - memset) - (2f - 1b) /* offset */
+2:
+ .previous
+ .section .altinstructions,"a"
+ .align 8
+ .quad memset
+ .quad 1b
+ .byte X86_FEATURE_REP_GOOD
+ .byte .Lfinal - memset
+ .byte 2b - 1b
+ .previous