Commit 8d8d2e9c authored by Linus Torvalds's avatar Linus Torvalds

Merge branch 'x86-mem-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-mem-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, mem: Optimize memmove for small size and unaligned cases
  x86, mem: Optimize memcpy by avoiding memory false dependece
  x86, mem: Don't implement forward memmove() as memcpy()
parents 2a8b67fb 3b4b682b
......@@ -22,22 +22,187 @@ EXPORT_SYMBOL(memset);
void *memmove(void *dest, const void *src, size_t n)
{
int d0, d1, d2;
if (dest < src) {
memcpy(dest, src, n);
} else {
__asm__ __volatile__(
"std\n\t"
"rep\n\t"
"movsb\n\t"
"cld"
: "=&c" (d0), "=&S" (d1), "=&D" (d2)
:"0" (n),
"1" (n-1+src),
"2" (n-1+dest)
:"memory");
}
return dest;
int d0,d1,d2,d3,d4,d5;
char *ret = dest;
__asm__ __volatile__(
/* Handle more 16bytes 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 16byts 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 16byts 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;
}
EXPORT_SYMBOL(memmove);
......@@ -40,84 +40,132 @@
ENTRY(__memcpy)
ENTRY(memcpy)
CFI_STARTPROC
movq %rdi, %rax
/*
* Put the number of full 64-byte blocks into %ecx.
* Tail portion is handled at the end:
* Use 32bit CMP here to avoid long NOP padding.
*/
movq %rdi, %rax
movl %edx, %ecx
shrl $6, %ecx
jz .Lhandle_tail
cmp $0x20, %edx
jb .Lhandle_tail
.p2align 4
.Lloop_64:
/*
* We decrement the loop index here - and the zero-flag is
* checked at the end of the loop (instructions inbetween do
* not change the zero flag):
* We check whether memory false dependece could occur,
* then jump to corresponding copy mode.
*/
decl %ecx
cmp %dil, %sil
jl .Lcopy_backward
subl $0x20, %edx
.Lcopy_forward_loop:
subq $0x20, %rdx
/*
* Move in blocks of 4x16 bytes:
* Move in blocks of 4x8 bytes:
*/
movq 0*8(%rsi), %r11
movq 1*8(%rsi), %r8
movq %r11, 0*8(%rdi)
movq %r8, 1*8(%rdi)
movq 2*8(%rsi), %r9
movq 3*8(%rsi), %r10
movq %r9, 2*8(%rdi)
movq %r10, 3*8(%rdi)
movq 4*8(%rsi), %r11
movq 5*8(%rsi), %r8
movq %r11, 4*8(%rdi)
movq %r8, 5*8(%rdi)
movq 6*8(%rsi), %r9
movq 7*8(%rsi), %r10
movq %r9, 6*8(%rdi)
movq %r10, 7*8(%rdi)
leaq 64(%rsi), %rsi
leaq 64(%rdi), %rdi
jnz .Lloop_64
movq 0*8(%rsi), %r8
movq 1*8(%rsi), %r9
movq 2*8(%rsi), %r10
movq 3*8(%rsi), %r11
leaq 4*8(%rsi), %rsi
movq %r8, 0*8(%rdi)
movq %r9, 1*8(%rdi)
movq %r10, 2*8(%rdi)
movq %r11, 3*8(%rdi)
leaq 4*8(%rdi), %rdi
jae .Lcopy_forward_loop
addq $0x20, %rdx
jmp .Lhandle_tail
.Lcopy_backward:
/*
* Calculate copy position to tail.
*/
addq %rdx, %rsi
addq %rdx, %rdi
subq $0x20, %rdx
/*
* At most 3 ALU operations in one cycle,
* so append NOPS in the same 16bytes trunk.
*/
.p2align 4
.Lcopy_backward_loop:
subq $0x20, %rdx
movq -1*8(%rsi), %r8
movq -2*8(%rsi), %r9
movq -3*8(%rsi), %r10
movq -4*8(%rsi), %r11
leaq -4*8(%rsi), %rsi
movq %r8, -1*8(%rdi)
movq %r9, -2*8(%rdi)
movq %r10, -3*8(%rdi)
movq %r11, -4*8(%rdi)
leaq -4*8(%rdi), %rdi
jae .Lcopy_backward_loop
/*
* Calculate copy position to head.
*/
addq $0x20, %rdx
subq %rdx, %rsi
subq %rdx, %rdi
.Lhandle_tail:
movl %edx, %ecx
andl $63, %ecx
shrl $3, %ecx
jz .Lhandle_7
cmpq $16, %rdx
jb .Lless_16bytes
/*
* Move data from 16 bytes to 31 bytes.
*/
movq 0*8(%rsi), %r8
movq 1*8(%rsi), %r9
movq -2*8(%rsi, %rdx), %r10
movq -1*8(%rsi, %rdx), %r11
movq %r8, 0*8(%rdi)
movq %r9, 1*8(%rdi)
movq %r10, -2*8(%rdi, %rdx)
movq %r11, -1*8(%rdi, %rdx)
retq
.p2align 4
.Lloop_8:
decl %ecx
movq (%rsi), %r8
movq %r8, (%rdi)
leaq 8(%rdi), %rdi
leaq 8(%rsi), %rsi
jnz .Lloop_8
.Lhandle_7:
movl %edx, %ecx
andl $7, %ecx
jz .Lend
.Lless_16bytes:
cmpq $8, %rdx
jb .Lless_8bytes
/*
* Move data from 8 bytes to 15 bytes.
*/
movq 0*8(%rsi), %r8
movq -1*8(%rsi, %rdx), %r9
movq %r8, 0*8(%rdi)
movq %r9, -1*8(%rdi, %rdx)
retq
.p2align 4
.Lless_8bytes:
cmpq $4, %rdx
jb .Lless_3bytes
/*
* Move data from 4 bytes to 7 bytes.
*/
movl (%rsi), %ecx
movl -4(%rsi, %rdx), %r8d
movl %ecx, (%rdi)
movl %r8d, -4(%rdi, %rdx)
retq
.p2align 4
.Lless_3bytes:
cmpl $0, %edx
je .Lend
/*
* Move data from 1 bytes to 3 bytes.
*/
.Lloop_1:
movb (%rsi), %r8b
movb %r8b, (%rdi)
incq %rdi
incq %rsi
decl %ecx
decl %edx
jnz .Lloop_1
.Lend:
ret
retq
CFI_ENDPROC
ENDPROC(memcpy)
ENDPROC(__memcpy)
......
......@@ -8,14 +8,185 @@
#undef memmove
void *memmove(void *dest, const void *src, size_t count)
{
if (dest < src) {
return memcpy(dest, src, count);
} else {
char *p = dest + count;
const char *s = src + count;
while (count--)
*--p = *--s;
}
return dest;
unsigned long d0,d1,d2,d3,d4,d5,d6,d7;
char *ret;
__asm__ __volatile__(
/* Handle more 32bytes in loop */
"mov %2, %3\n\t"
"cmp $0x20, %0\n\t"
"jb 1f\n\t"
/* Decide forward/backward copy mode */
"cmp %2, %1\n\t"
"jb 2f\n\t"
/*
* movsq instruction have many startup latency
* so we handle small size by general register.
*/
"cmp $680, %0\n\t"
"jb 3f\n\t"
/*
* movsq instruction is only good for aligned case.
*/
"cmpb %%dil, %%sil\n\t"
"je 4f\n\t"
"3:\n\t"
"sub $0x20, %0\n\t"
/*
* We gobble 32byts forward in each loop.
*/
"5:\n\t"
"sub $0x20, %0\n\t"
"movq 0*8(%1), %4\n\t"
"movq 1*8(%1), %5\n\t"
"movq 2*8(%1), %6\n\t"
"movq 3*8(%1), %7\n\t"
"leaq 4*8(%1), %1\n\t"
"movq %4, 0*8(%2)\n\t"
"movq %5, 1*8(%2)\n\t"
"movq %6, 2*8(%2)\n\t"
"movq %7, 3*8(%2)\n\t"
"leaq 4*8(%2), %2\n\t"
"jae 5b\n\t"
"addq $0x20, %0\n\t"
"jmp 1f\n\t"
/*
* Handle data forward by movsq.
*/
".p2align 4\n\t"
"4:\n\t"
"movq %0, %8\n\t"
"movq -8(%1, %0), %4\n\t"
"lea -8(%2, %0), %5\n\t"
"shrq $3, %8\n\t"
"rep movsq\n\t"
"movq %4, (%5)\n\t"
"jmp 13f\n\t"
/*
* Handle data backward by movsq.
*/
".p2align 4\n\t"
"7:\n\t"
"movq %0, %8\n\t"
"movq (%1), %4\n\t"
"movq %2, %5\n\t"
"leaq -8(%1, %0), %1\n\t"
"leaq -8(%2, %0), %2\n\t"
"shrq $3, %8\n\t"
"std\n\t"
"rep movsq\n\t"
"cld\n\t"
"movq %4, (%5)\n\t"
"jmp 13f\n\t"
/*
* Start to prepare for backward copy.
*/
".p2align 4\n\t"
"2:\n\t"
"cmp $680, %0\n\t"
"jb 6f \n\t"
"cmp %%dil, %%sil\n\t"
"je 7b \n\t"
"6:\n\t"
/*
* Calculate copy position to tail.
*/
"addq %0, %1\n\t"
"addq %0, %2\n\t"
"subq $0x20, %0\n\t"
/*
* We gobble 32byts backward in each loop.
*/
"8:\n\t"
"subq $0x20, %0\n\t"
"movq -1*8(%1), %4\n\t"
"movq -2*8(%1), %5\n\t"
"movq -3*8(%1), %6\n\t"
"movq -4*8(%1), %7\n\t"
"leaq -4*8(%1), %1\n\t"
"movq %4, -1*8(%2)\n\t"
"movq %5, -2*8(%2)\n\t"
"movq %6, -3*8(%2)\n\t"
"movq %7, -4*8(%2)\n\t"
"leaq -4*8(%2), %2\n\t"
"jae 8b\n\t"
/*
* Calculate copy position to head.
*/
"addq $0x20, %0\n\t"
"subq %0, %1\n\t"
"subq %0, %2\n\t"
"1:\n\t"
"cmpq $16, %0\n\t"
"jb 9f\n\t"
/*
* Move data from 16 bytes to 31 bytes.
*/
"movq 0*8(%1), %4\n\t"
"movq 1*8(%1), %5\n\t"
"movq -2*8(%1, %0), %6\n\t"
"movq -1*8(%1, %0), %7\n\t"
"movq %4, 0*8(%2)\n\t"
"movq %5, 1*8(%2)\n\t"
"movq %6, -2*8(%2, %0)\n\t"
"movq %7, -1*8(%2, %0)\n\t"
"jmp 13f\n\t"
".p2align 4\n\t"
"9:\n\t"
"cmpq $8, %0\n\t"
"jb 10f\n\t"
/*
* Move data from 8 bytes to 15 bytes.
*/
"movq 0*8(%1), %4\n\t"
"movq -1*8(%1, %0), %5\n\t"
"movq %4, 0*8(%2)\n\t"
"movq %5, -1*8(%2, %0)\n\t"
"jmp 13f\n\t"
"10:\n\t"
"cmpq $4, %0\n\t"
"jb 11f\n\t"
/*
* Move data from 4 bytes to 7 bytes.
*/
"movl (%1), %4d\n\t"
"movl -4(%1, %0), %5d\n\t"
"movl %4d, (%2)\n\t"
"movl %5d, -4(%2, %0)\n\t"
"jmp 13f\n\t"
"11:\n\t"
"cmp $2, %0\n\t"
"jb 12f\n\t"
/*
* Move data from 2 bytes to 3 bytes.
*/
"movw (%1), %4w\n\t"
"movw -2(%1, %0), %5w\n\t"
"movw %4w, (%2)\n\t"
"movw %5w, -2(%2, %0)\n\t"
"jmp 13f\n\t"
"12:\n\t"
"cmp $1, %0\n\t"
"jb 13f\n\t"
/*
* Move data for 1 byte.
*/
"movb (%1), %4b\n\t"
"movb %4b, (%2)\n\t"
"13:\n\t"
: "=&d" (d0), "=&S" (d1), "=&D" (d2), "=&a" (ret) ,
"=r"(d3), "=r"(d4), "=r"(d5), "=r"(d6), "=&c" (d7)
:"0" (count),
"1" (src),
"2" (dest)
:"memory");
return ret;
}
EXPORT_SYMBOL(memmove);
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