Re: [U-Boot] [PATCH 02/12] x86: Add an accelerated memmove() function

Hi Simon,

On Mon, Oct 3, 2016 at 11:12 AM, Simon Glass sjg@chromium.org wrote:

Bring in a faster memmove() from Linux 4.7. This speeds up scrolling on the display.

Signed-off-by: Simon Glass sjg@chromium.org

arch/x86/include/asm/string.h | 2 +- arch/x86/lib/Makefile | 1 + arch/x86/lib/memmove.c | 193 ++++++++++++++++++++++++++++++++++++++++++

Other optimized routines are put in arch/x86/lib/string.c. Can we put this memmove() there too?

3 files changed, 195 insertions(+), 1 deletion(-) create mode 100644 arch/x86/lib/memmove.c

diff --git a/arch/x86/include/asm/string.h b/arch/x86/include/asm/string.h index 0ad612f..38afd23 100644 --- a/arch/x86/include/asm/string.h +++ b/arch/x86/include/asm/string.h @@ -17,7 +17,7 @@ extern char * strchr(const char * s, int c); #define __HAVE_ARCH_MEMCPY extern void * memcpy(void *, const void *, __kernel_size_t);

-#undef __HAVE_ARCH_MEMMOVE +#define __HAVE_ARCH_MEMMOVE extern void * memmove(void *, const void *, __kernel_size_t);

#undef __HAVE_ARCH_MEMCHR diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile index e17f0bb..b380d62 100644 --- a/arch/x86/lib/Makefile +++ b/arch/x86/lib/Makefile @@ -17,6 +17,7 @@ obj-y += gcc.o obj-y += init_helpers.o obj-y += interrupts.o obj-y += lpc-uclass.o +obj-y += memmove.o obj-y += mpspec.o obj-$(CONFIG_ENABLE_MRC_CACHE) += mrccache.o obj-y += cmd_mtrr.o diff --git a/arch/x86/lib/memmove.c b/arch/x86/lib/memmove.c new file mode 100644 index 0000000..504a184 --- /dev/null +++ b/arch/x86/lib/memmove.c @@ -0,0 +1,193 @@ +/*

• • Copyright (c) 2016 Google, Inc
• • Taken from Linux v4.7. There is no copyright notice on the original file.
• • SPDX-License-Identifier: GPL-2.0+
• */

+#include <common.h>

+void *memmove(void *dest, const void *src, size_t n) +{

•   int d0, d1, d2, d3, d4, d5;
  

•   char *ret = dest;
  

•   __asm__ __volatile__(
  

•           /* Handle more 16 bytes in loop */
  

•           "cmp $0x10, %0\n\t"
  

•           "jb     1f\n\t"
  

•           /* Decide forward/backward copy mode */
  

•           "cmp %2, %1\n\t"
  

•           "jb     2f\n\t"
  

•           /*
  

•            * movs instruction have many startup latency
  

•            * so we handle small size by general register.
  

•            */
  

•           "cmp  $680, %0\n\t"
  

•           "jb 3f\n\t"
  

•           /*
  

•            * movs instruction is only good for aligned case.
  

•            */
  

nits: use single line comment format. Please fix this globally in this file.

•           "mov %1, %3\n\t"
  

•           "xor %2, %3\n\t"
  

•           "and $0xff, %3\n\t"
  

•           "jz 4f\n\t"
  

•           "3:\n\t"
  

•           "sub $0x10, %0\n\t"
  

•           /*
  

•            * We gobble 16 bytes forward in each loop.
  

•            */
  

•           "3:\n\t"
  

•           "sub $0x10, %0\n\t"
  

•           "mov 0*4(%1), %3\n\t"
  

•           "mov 1*4(%1), %4\n\t"
  

•           "mov  %3, 0*4(%2)\n\t"
  

•           "mov  %4, 1*4(%2)\n\t"
  

•           "mov 2*4(%1), %3\n\t"
  

•           "mov 3*4(%1), %4\n\t"
  

•           "mov  %3, 2*4(%2)\n\t"
  

•           "mov  %4, 3*4(%2)\n\t"
  

•           "lea  0x10(%1), %1\n\t"
  

•           "lea  0x10(%2), %2\n\t"
  

•           "jae 3b\n\t"
  

•           "add $0x10, %0\n\t"
  

•           "jmp 1f\n\t"
  

•           /*
  

•            * Handle data forward by movs.
  

•            */
  

•           ".p2align 4\n\t"
  

•           "4:\n\t"
  

•           "mov -4(%1, %0), %3\n\t"
  

•           "lea -4(%2, %0), %4\n\t"
  

•           "shr $2, %0\n\t"
  

•           "rep movsl\n\t"
  

•           "mov %3, (%4)\n\t"
  

•           "jmp 11f\n\t"
  

•           /*
  

•            * Handle data backward by movs.
  

•            */
  

•           ".p2align 4\n\t"
  

•           "6:\n\t"
  

•           "mov (%1), %3\n\t"
  

•           "mov %2, %4\n\t"
  

•           "lea -4(%1, %0), %1\n\t"
  

•           "lea -4(%2, %0), %2\n\t"
  

•           "shr $2, %0\n\t"
  

•           "std\n\t"
  

•           "rep movsl\n\t"
  

•           "mov %3,(%4)\n\t"
  

•           "cld\n\t"
  

•           "jmp 11f\n\t"
  

•           /*
  

•            * Start to prepare for backward copy.
  

•            */
  

•           ".p2align 4\n\t"
  

•           "2:\n\t"
  

•           "cmp  $680, %0\n\t"
  

•           "jb 5f\n\t"
  

•           "mov %1, %3\n\t"
  

•           "xor %2, %3\n\t"
  

•           "and $0xff, %3\n\t"
  

•           "jz 6b\n\t"
  

•           /*
  

•            * Calculate copy position to tail.
  

•            */
  

•           "5:\n\t"
  

•           "add %0, %1\n\t"
  

•           "add %0, %2\n\t"
  

•           "sub $0x10, %0\n\t"
  

•           /*
  

•            * We gobble 16 bytes backward in each loop.
  

•            */
  

•           "7:\n\t"
  

•           "sub $0x10, %0\n\t"
  

•           "mov -1*4(%1), %3\n\t"
  

•           "mov -2*4(%1), %4\n\t"
  

•           "mov  %3, -1*4(%2)\n\t"
  

•           "mov  %4, -2*4(%2)\n\t"
  

•           "mov -3*4(%1), %3\n\t"
  

•           "mov -4*4(%1), %4\n\t"
  

•           "mov  %3, -3*4(%2)\n\t"
  

•           "mov  %4, -4*4(%2)\n\t"
  

•           "lea  -0x10(%1), %1\n\t"
  

•           "lea  -0x10(%2), %2\n\t"
  

•           "jae 7b\n\t"
  

•           /*
  

•            * Calculate copy position to head.
  

•            */
  

•           "add $0x10, %0\n\t"
  

•           "sub %0, %1\n\t"
  

•           "sub %0, %2\n\t"
  

•           /*
  

•            * Move data from 8 bytes to 15 bytes.
  

•            */
  

•           ".p2align 4\n\t"
  

•           "1:\n\t"
  

•           "cmp $8, %0\n\t"
  

•           "jb 8f\n\t"
  

•           "mov 0*4(%1), %3\n\t"
  

•           "mov 1*4(%1), %4\n\t"
  

•           "mov -2*4(%1, %0), %5\n\t"
  

•           "mov -1*4(%1, %0), %1\n\t"
  

•           "mov  %3, 0*4(%2)\n\t"
  

•           "mov  %4, 1*4(%2)\n\t"
  

•           "mov  %5, -2*4(%2, %0)\n\t"
  

•           "mov  %1, -1*4(%2, %0)\n\t"
  

•           "jmp 11f\n\t"
  

•           /*
  

•            * Move data from 4 bytes to 7 bytes.
  

•            */
  

•           ".p2align 4\n\t"
  

•           "8:\n\t"
  

•           "cmp $4, %0\n\t"
  

•           "jb 9f\n\t"
  

•           "mov 0*4(%1), %3\n\t"
  

•           "mov -1*4(%1, %0), %4\n\t"
  

•           "mov  %3, 0*4(%2)\n\t"
  

•           "mov  %4, -1*4(%2, %0)\n\t"
  

•           "jmp 11f\n\t"
  

•           /*
  

•            * Move data from 2 bytes to 3 bytes.
  

•            */
  

•           ".p2align 4\n\t"
  

•           "9:\n\t"
  

•           "cmp $2, %0\n\t"
  

•           "jb 10f\n\t"
  

•           "movw 0*2(%1), %%dx\n\t"
  

•           "movw -1*2(%1, %0), %%bx\n\t"
  

•           "movw %%dx, 0*2(%2)\n\t"
  

•           "movw %%bx, -1*2(%2, %0)\n\t"
  

•           "jmp 11f\n\t"
  

•           /*
  

•            * Move data for 1 byte.
  

•            */
  

•           ".p2align 4\n\t"
  

•           "10:\n\t"
  

•           "cmp $1, %0\n\t"
  

•           "jb 11f\n\t"
  

•           "movb (%1), %%cl\n\t"
  

•           "movb %%cl, (%2)\n\t"
  

•           ".p2align 4\n\t"
  

•           "11:"
  

•           : "=&c" (d0), "=&S" (d1), "=&D" (d2),
  

•             "=r" (d3), "=r" (d4), "=r"(d5)
  

•           : "0" (n),
  

•            "1" (src),
  

•            "2" (dest)
  

•           : "memory");
  

•   return ret;
  

+}

Regards, Bin