Messages in this thread Patch in this message | | | Date | Thu, 1 Jun 2006 21:28:21 -0400 | From | Chuck Ebbert <> | Subject | [patch 2.6.16-rc5-mm2] i386 memcpy: optimal memcpy for IO |
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From: H. Peter Anvin <hpa@zytor.com>
Optimal memcpy for moves to/from IO space. Does as few moves as possible while keeping transfers optimally aligned.
Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com>
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Andrew, remove i386-memcpy-use-as-few-moves-as.patch from -mm and replace it with this, please.
arch/i386/lib/memcpy.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++++ include/asm-i386/io.h | 11 ++------- 2 files changed, 60 insertions(+), 8 deletions(-)
--- 2.6.17-rc5-32.orig/arch/i386/lib/memcpy.c +++ 2.6.17-rc5-32/arch/i386/lib/memcpy.c @@ -42,3 +42,60 @@ void *memmove(void *dest, const void *sr return dest; } EXPORT_SYMBOL(memmove); + +/* + * The most general form of memory copy to/from I/O space, used for + * devices which can handle arbitrary transactions with appropriate + * handling of byte enables. The goal is to produce the minimum + * number of naturally aligned transactions on the bus. + */ + +#define build_memcpy_io(dst, src, count, align_reg) \ +({ \ +unsigned long d0, d1, d2, d3; \ +asm volatile( \ + "jecxz 1f\n\t" \ + \ + "testl $1, " align_reg "\n\t" \ + "jz 2f\n\t" \ + "movsb\n\t" \ + "decl %2\n" \ +"2:\n\t" \ + "cmpl $2, %2\n\t" \ + "jb 3f\n\t" \ + "testl $2, " align_reg "\n\t" \ + "jz 4f\n\t" \ + "movsw\n\t" \ + "decl %2\n\t" \ + "decl %2\n" \ +"4:\n\t" \ + "movl %2, %3\n\t" \ + "shrl $2, %2\n\t" \ + "jz 5f\n\t" \ + "rep ; movsl\n" \ +"5:\n\t" \ + "movl %3, %2\n\t" \ + "testb $2, %b2\n\t" \ + "jz 3f\n\t" \ + "movsw\n" \ +"3:\n\t" \ + "testb $1, %b2\n\t" \ + "jz 1f\n\t" \ + "movsb\n" \ +"1:" \ + : "=&D" (d0), "=&S" (d1), "=&c" (d2), "=&g" (d3)\ + : "0" (dst), "1" (src), "2" (count) \ + : "memory"); \ +}) + +void memcpy_fromio(void *dst, const volatile void __iomem *src, int count) +{ + build_memcpy_io(dst, src, count, "%%esi"); +} +EXPORT_SYMBOL(memcpy_fromio) + +void memcpy_toio(volatile void __iomem *dst, const void *src, int count) +{ + build_memcpy_io(dst, src, count, "%%edi"); +} +EXPORT_SYMBOL(memcpy_toio) --- 2.6.17-rc5-32.orig/include/asm-i386/io.h +++ 2.6.17-rc5-32/include/asm-i386/io.h @@ -200,14 +200,9 @@ static inline void memset_io(volatile vo { memset((void __force *) addr, val, count); } -static inline void memcpy_fromio(void *dst, const volatile void __iomem *src, int count) -{ - __memcpy(dst, (void __force *) src, count); -} -static inline void memcpy_toio(volatile void __iomem *dst, const void *src, int count) -{ - __memcpy((void __force *) dst, src, count); -} + +extern void memcpy_fromio(void *dst, const volatile void __iomem *src, int count); +extern void memcpy_toio(volatile void __iomem *dst, const void *src, int count); /* * ISA space is 'always mapped' on a typical x86 system, no need to -- Chuck - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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