Date: Mon, 7 May 2018 15:07:28 +0000 (UTC) From: Mateusz Guzik <mjg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r333324 - in head/sys: amd64/amd64 conf Message-ID: <201805071507.w47F7SOs035073@repo.freebsd.org>
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Author: mjg Date: Mon May 7 15:07:28 2018 New Revision: 333324 URL: https://svnweb.freebsd.org/changeset/base/333324 Log: amd64: replace libkern's memset and memmove with assembly variants memmove is repurposed bcopy (arguments swapped, return value added) The libkern variant is a wrapper around bcopy, so this is a big improvement. memset is repurposed memcpy. The librkern variant is doing fishy stuff, including branching on 0 and calling bzero. Both functions are rather crude and subject to partial depessimization. This is a soft prerequisite to adding variants utilizing the 'Enhanced REP MOVSB/STOSB' bit and let the kernel patch at runtime. Modified: head/sys/amd64/amd64/support.S head/sys/conf/files.amd64 Modified: head/sys/amd64/amd64/support.S ============================================================================== --- head/sys/amd64/amd64/support.S Mon May 7 15:07:26 2018 (r333323) +++ head/sys/amd64/amd64/support.S Mon May 7 15:07:28 2018 (r333324) @@ -162,6 +162,58 @@ ENTRY(bcopy) END(bcopy) /* + * memmove(dst, src, cnt) + * rdi, rsi, rdx + * Original by: + * ws@tools.de (Wolfgang Solfrank, TooLs GmbH) +49-228-985800 + */ +ENTRY(memmove) + PUSH_FRAME_POINTER + movq %rdi,%r9 + movq %rdx,%rcx + + movq %rdi,%rax + subq %rsi,%rax + cmpq %rcx,%rax /* overlapping && src < dst? */ + jb 1f + + shrq $3,%rcx /* copy by 64-bit words */ + rep + movsq + movq %rdx,%rcx + andq $7,%rcx /* any bytes left? */ + rep + movsb + movq %r9,%rax + POP_FRAME_POINTER + ret + + /* ALIGN_TEXT */ +1: + addq %rcx,%rdi /* copy backwards */ + addq %rcx,%rsi + decq %rdi + decq %rsi + andq $7,%rcx /* any fractional bytes? */ + std + rep + movsb + movq %rdx,%rcx /* copy remainder by 32-bit words */ + shrq $3,%rcx + subq $7,%rsi + subq $7,%rdi + rep + movsq + cld + movq %r9,%rax + POP_FRAME_POINTER + ret +END(memmove) + +/* + * memcpy(dst, src, len) + * rdi, rsi, rdx + * * Note: memcpy does not support overlapping copies */ ENTRY(memcpy) @@ -178,6 +230,27 @@ ENTRY(memcpy) POP_FRAME_POINTER ret END(memcpy) + +/* + * memset(dst, c, len) + * rdi, rsi, rdx + */ +ENTRY(memset) + PUSH_FRAME_POINTER + movq %rdi,%r9 + movq %rdx,%rcx + movq %rsi,%rax + shrq $3,%rcx + rep + stosq + movq %rdx,%rcx + andq $7,%rcx + rep + stosb + movq %r9,%rax + POP_FRAME_POINTER + ret +END(memset) /* * pagecopy(%rdi=from, %rsi=to) Modified: head/sys/conf/files.amd64 ============================================================================== --- head/sys/conf/files.amd64 Mon May 7 15:07:26 2018 (r333323) +++ head/sys/conf/files.amd64 Mon May 7 15:07:28 2018 (r333324) @@ -620,8 +620,6 @@ isa/vga_isa.c optional vga kern/kern_clocksource.c standard kern/link_elf_obj.c standard libkern/x86/crc32_sse42.c standard -libkern/memmove.c standard -libkern/memset.c standard # # IA32 binary support #
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