Bring in a faster memmove() from Linux 4.7. This speeds up scrolling on the display.
Signed-off-by: Simon Glass sjg@chromium.org ---
Changes in v2: - Move the code into string.c - Fix multi-line comments that should not be
arch/x86/include/asm/string.h | 2 +- arch/x86/lib/string.c | 161 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 162 insertions(+), 1 deletion(-)
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/string.c b/arch/x86/lib/string.c index 6c66431..5343c2b 100644 --- a/arch/x86/lib/string.c +++ b/arch/x86/lib/string.c @@ -130,3 +130,164 @@ void *memcpy(void *dstpp, const void *srcpp, size_t len)
return dstpp; } + +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 */ + "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; +}