Author: mjg Date: Mon Sep 17 15:49:35 2018 New Revision: 338713 URL: https://svnweb.freebsd.org/changeset/base/338713
Log: amd64: depessimize userspace memcpy/memmove/bcopy The change resembles what was done in r334537 for kernel routines. While here take care of i386 variants. Note that primitives remain suboptimal. Reviewed by: kib (previous version) Approved by: re (gjb) Differential Revision: https://reviews.freebsd.org/D17167 Modified: head/lib/libc/amd64/string/bcopy.S head/lib/libc/i386/string/bcopy.S Modified: head/lib/libc/amd64/string/bcopy.S ============================================================================== --- head/lib/libc/amd64/string/bcopy.S Mon Sep 17 15:34:19 2018 (r338712) +++ head/lib/libc/amd64/string/bcopy.S Mon Sep 17 15:49:35 2018 (r338713) @@ -66,6 +66,9 @@ ENTRY(bcopy) movsq movq %rdx,%rcx andq $7,%rcx /* any bytes left? */ + jne 2f + ret +2: rep movsb ret @@ -73,11 +76,13 @@ ENTRY(bcopy) addq %rcx,%rdi /* copy backwards. */ addq %rcx,%rsi std - andq $7,%rcx /* any fractional bytes? */ decq %rdi decq %rsi + andq $7,%rcx /* any fractional bytes? */ + je 3f rep movsb +3: movq %rdx,%rcx /* copy remainder by words */ shrq $3,%rcx subq $7,%rsi Modified: head/lib/libc/i386/string/bcopy.S ============================================================================== --- head/lib/libc/i386/string/bcopy.S Mon Sep 17 15:34:19 2018 (r338712) +++ head/lib/libc/i386/string/bcopy.S Mon Sep 17 15:49:35 2018 (r338713) @@ -64,7 +64,7 @@ ENTRY(bcopy) movl %edi,%edx subl %esi,%edx cmpl %ecx,%edx /* overlapping? */ - jb 1f + jb 2f cld /* nope, copy forwards. */ movl %ecx,%edx shrl $2,%ecx /* copy by words */ @@ -72,21 +72,28 @@ ENTRY(bcopy) movsl movl %edx,%ecx andl $3,%ecx /* any bytes left? */ + jne 1f + popl %edi + popl %esi + ret +1: rep movsb popl %edi popl %esi ret -1: +2: addl %ecx,%edi /* copy backwards. */ addl %ecx,%esi std movl %ecx,%edx - andl $3,%ecx /* any fractional bytes? */ decl %edi decl %esi + andl $3,%ecx /* any fractional bytes? */ + je 3f rep movsb +3: movl %edx,%ecx /* copy remainder by words */ shrl $2,%ecx subl $3,%esi _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
