/*
* Copyright (c) 2005 Apple Computer, Inc. All rights reserved.
*
* @APPLE_LICENSE_HEADER_START@
*
* The contents of this file constitute Original Code as defined in and
* are subject to the Apple Public Source License Version 1.1 (the
* "License"). You may not use this file except in compliance with the
* License. Please obtain a copy of the License at
* http://www.apple.com/publicsource and read it before using this file.
*
* This Original Code and all software distributed under the License are
* distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
* License for the specific language governing rights and limitations
* under the License.
*
* @APPLE_LICENSE_HEADER_END@
*/
#include <machine/cpu_capabilities.h>
/* This file contains the following functions:
*
* void *memset(void *b, int c, size_t len) * void memset_pattern8(void *b, const void *c8, size_t len) *
* Calls of memset() with c==0 are routed to the bzero() routine. Most of the
* others go to _COMM_PAGE_MEMSET_PATTERN, which is entered as follows:
* %edi = ptr to memory to set (aligned)
* %edx = length (which can be short, though we bias in favor of long operands)
* %xmm0 = the pattern to store
* Return conditions:
* %eax, %edi, %esi, %ecx, and %edx all trashed
*
* NB: we avoid "stos" family of instructions (stosl, stosb), as they are very slow
* on P4s and probably other processors.
*/
#define kShort 255 // for nonzero memset(), too short for commpage
.text
.globl _memset
.align 2
_memset: // void *memset(void *b, int c, size_t len) movl 12(%esp),%edx // get length
andl $0xFF,%eax // (c==0) ?
jnz LNonzero // not a bzero
movl $(_COMM_PAGE_BZERO),%eax// map memset(p,0,n) into bzero(p,n)
movl %edx,8(%esp) // put count where bzero() expects it
jmp %eax // enter commpage
// Handle memset of a nonzero value.
LNonzero:
pushl %edi // save a few nonvolatiles
pushl %esi
movl %eax,%esi // replicate byte in %al into all four bytes
movl 12(%esp),%edi // point to operand
shll $8,%esi
orl %esi,%eax
movl %eax,%esi
shll $16,%esi
orl %esi,%eax // now %eax has "c" in all 4 bytes
cmpl $(kShort),%edx // is operand too short for SSE?
ja LCallCommpage // no
// Nonzero memset() too short to call commpage.
// %eax = replicated 4-byte pattern
// %edi = ptr
// %edx = length (<= kShort)
cmpl $16,%edx // long enough to word align?
jge 3f // yes
test %edx,%edx // length==0?
jz 6f
1:
movb %al,(%edi) // pack in a byte
inc %edi
dec %edx
jnz 1b
jmp 6f
2:
movb %al,(%edi) // pack in a byte
inc %edi
dec %edx
3:
test $3,%edi // is ptr doubleword aligned?
jnz 2b // no
movl %edx,%ecx // copy length
shrl $2,%edx // #doublewords to store
4:
movl %eax,(%edi) // store aligned doubleword
addl $4,%edi
dec %edx
jnz 4b
andl $3,%ecx // any leftover bytes?
jz 6f // no
5:
movb %al,(%edi) // pack in a byte
inc %edi
dec %ecx
jnz 5b
6:
movl 12(%esp),%eax // get return value (ie, original ptr)
popl %esi
popl %edi
ret
// Nonzero memset() is long enough to call commpage.
// %eax = replicated 4-byte pattern
// %edi = ptr
// %edx = length (> kShort)
LCallCommpage:
movd %eax,%xmm0 // move %eax to low 4 bytes of %xmm0
pshufd $(0x00),%xmm0,%xmm0 // replicate across the vector
movl %edi,%ecx // copy dest ptr
negl %ecx
andl $15,%ecx // get #bytes to align ptr
jz 2f // skip if already aligned
subl %ecx,%edx // decrement length
1:
movb %al,(%edi) // pack in a byte
inc %edi
dec %ecx
jnz 1b
2: // ptr aligned, length long enough to justify
movl $(_COMM_PAGE_MEMSET_PATTERN),%eax
call %eax // call commpage to do the heavy lifting
movl 12(%esp),%eax // get return value (ie, original ptr)
popl %esi
popl %edi
ret
// Handle memset of a 16-byte pattern.
.globl _memset_pattern16
.align 2, 0x90
_memset_pattern16: // void memset_pattern16(void *b, const void *c16, size_t len) pushl %esi
movl 20(%esp),%edx // get length
movl 16(%esp),%esi // get ptr to 16-byte pattern
movl 12(%esp),%edi // point to operand
movdqu (%esi),%xmm0 // load the pattern
jmp LAlignPtr
// Handle memset of an 8-byte pattern.
.globl _memset_pattern8
.align 2, 0x90
_memset_pattern8: // void memset_pattern8(void *b, const void *c8, size_t len) pushl %esi
movl 20(%esp),%edx // get length
movl 16(%esp),%esi // get ptr to 8-byte pattern
movl 12(%esp),%edi // point to operand
movq (%esi),%xmm0 // load pattern into low 8 bytes
punpcklqdq %xmm0,%xmm0 // replicate into all 16
jmp LAlignPtr
// Handle memset of a 4-byte pattern.
.globl _memset_pattern4
.align 2, 0x90
_memset_pattern4: // void memset_pattern4(void *b, const void *c4, size_t len) pushl %esi
movl 20(%esp),%edx // get length
movl 16(%esp),%esi // get ptr to 4-byte pattern
movl 12(%esp),%edi // point to operand
movd (%esi),%xmm0 // load pattern into low 4 bytes
pshufd $(0x00),%xmm0,%xmm0 // replicate the 4 bytes across the vector
// Align ptr if necessary. We must rotate the pattern right for each byte we
// store while aligning the ptr. Since there is no rotate instruction in SSE3,
// we have to synthesize the rotates.
// %edi = ptr
// %edx = length
// %xmm0 = pattern
LAlignPtr: // NB: can drop down to here!
cmpl $100,%edx // long enough to bother aligning ptr?
movl %edi,%ecx // copy ptr
jb LReady // not long enough
negl %ecx
andl $15,%ecx // get #bytes to align ptr
jz LReady // already aligned
subl %ecx,%edx // adjust length
test $1,%cl // 1-byte store required?
movd %xmm0,%eax // get 4 low bytes in %eax
jz 2f // no
movdqa %xmm0,%xmm1 // copy pattern so we can shift in both directions
movb %al,(%edi) // pack in the low-order byte
psrldq $1,%xmm0 // shift pattern right 1 byte
inc %edi
pslldq $15,%xmm1 // shift pattern left 15 bytes
shrl $8,%eax // in case 2-byte store is required
por %xmm1,%xmm0 // complete right rotate of pattern by 1 byte
2:
test $2,%cl // 2-byte store required?
jz 4f // no
psrldq $2,%xmm0 // shift pattern down 2 bytes
movw %ax,(%edi) // pack in next two bytes
pinsrw $7,%eax,%xmm0 // insert low word of %eax into high word of %xmm0
addl $2,%edi // adjust ptr
4:
test $4,%cl // 4-byte store required?
jz 8f // no
movd %xmm0,(%edi) // store low 4 bytes of %xmm0
pshufd $(0x39),%xmm0,%xmm0 // rotate %xmm0 right 4 bytes (mask == 00 11 10 01)
addl $4,%edi // adjust ptr
8:
test $8,%cl // 8-byte store required?
jz LReady // no
movq %xmm0,(%edi) // store low 8 bytes of %xmm0
pshufd $(0x4e),%xmm0,%xmm0 // rotate %xmm0 right 8 bytes (mask == 01 00 11 10)
addl $8,%edi // adjust ptr
// Ptr is aligned if practical, we're ready to call commpage to do the heavy lifting.
LReady:
movl $(_COMM_PAGE_MEMSET_PATTERN),%eax
call %eax // call commpage to do the heavy lifting
popl %esi
popl %edi
ret