diff options
Diffstat (limited to 'lib/libc/amd64/string/bcmp.S')
| -rw-r--r-- | lib/libc/amd64/string/bcmp.S | 130 |
1 files changed, 112 insertions, 18 deletions
diff --git a/lib/libc/amd64/string/bcmp.S b/lib/libc/amd64/string/bcmp.S index d01b76bc10e5..efdc6d33e4dd 100644 --- a/lib/libc/amd64/string/bcmp.S +++ b/lib/libc/amd64/string/bcmp.S @@ -1,27 +1,121 @@ +/*- + * Copyright (c) 2018 The FreeBSD Foundation + * + * This software was developed by Mateusz Guzik <mjg@FreeBSD.org> + * under sponsorship from the FreeBSD Foundation. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * $FreeBSD$ + */ + #include <machine/asm.h> __FBSDID("$FreeBSD$"); -#if 0 - RCSID("$NetBSD: bcmp.S,v 1.1 2001/06/19 00:25:04 fvdl Exp $") -#endif - ENTRY(bcmp) - cld /* set compare direction forward */ + cmpq $16,%rdx + jae 5f +1: + testq %rdx,%rdx + je 3f + xorl %ecx,%ecx +2: + movzbl (%rdi,%rcx,1),%eax + movzbl (%rsi,%rcx,1),%r8d + cmpb %r8b,%al + jne 4f + addq $1,%rcx + cmpq %rcx,%rdx + jz 3f + movzbl (%rdi,%rcx,1),%eax + movzbl (%rsi,%rcx,1),%r8d + cmpb %r8b,%al + jne 4f + addq $1,%rcx + cmpq %rcx,%rdx + jz 3f + movzbl (%rdi,%rcx,1),%eax + movzbl (%rsi,%rcx,1),%r8d + cmpb %r8b,%al + jne 4f + addq $1,%rcx + cmpq %rcx,%rdx + jz 3f + movzbl (%rdi,%rcx,1),%eax + movzbl (%rsi,%rcx,1),%r8d + cmpb %r8b,%al + jne 4f + addq $1,%rcx + cmpq %rcx,%rdx + jne 2b +3: + xorl %eax,%eax + ret +4: + movl $1,%eax + ret +5: + cmpq $32,%rdx + jae 7f +6: + /* + * 8 bytes + */ + movq (%rdi),%r8 + movq (%rsi),%r9 + cmpq %r8,%r9 + jne 4b + leaq 8(%rdi),%rdi + leaq 8(%rsi),%rsi + subq $8,%rdx + cmpq $8,%rdx + jae 6b + jl 1b + jmp 3b +7: + /* + * 32 bytes + */ + movq (%rsi),%r8 + movq 8(%rsi),%r9 + subq (%rdi),%r8 + subq 8(%rdi),%r9 + or %r8,%r9 + jnz 4b - movq %rdx,%rcx /* compare by words */ - shrq $3,%rcx - repe - cmpsq - jne L1 + movq 16(%rsi),%r8 + movq 24(%rsi),%r9 + subq 16(%rdi),%r8 + subq 24(%rdi),%r9 + or %r8,%r9 + jnz 4b - movq %rdx,%rcx /* compare remainder by bytes */ - andq $7,%rcx - repe - cmpsb -L1: - setne %al - movsbl %al,%eax - ret + leaq 32(%rdi),%rdi + leaq 32(%rsi),%rsi + subq $32,%rdx + cmpq $32,%rdx + jae 7b + jnz 1b + jmp 3b END(bcmp) .section .note.GNU-stack,"",%progbits |