/*-
 * Copyright (c) 2018-2019 The FreeBSD Foundation
 * Copyright (c) 2003 Peter Wemm.
 * Copyright (c) 1993 The Regents of the University of California.
 * All rights reserved.
 *
 * Portions of this software were developed by
 * Konstantin Belousov <kib@FreeBSD.org> under sponsorship from
 * the FreeBSD Foundation.
 *
 * Primarily rewritten and redeveloped by Mateusz Guzik
 *
 * 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.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 *
 * $FreeBSD$
 */
/*
 * Macros to help implement memcmp(), bcmp(),
 *                          bzero(), memset(),
 *                          memcpy(), bcopy(), memmove()
 */

/*
 * memcmp(b1, b2, len)
 *        rdi,rsi,rdx
 */
.macro MEMCMP end
        xorl    %eax,%eax
10:
        cmpq    $16,%rdx
        ja      101632f

100816:
        cmpb    $8,%dl
        jl      100408f
        movq    (%rdi),%r8
        movq    (%rsi),%r9
        cmpq    %r8,%r9
        jne     80f
        movq    -8(%rdi,%rdx),%r8
        movq    -8(%rsi,%rdx),%r9
        cmpq    %r8,%r9
        jne     10081608f
        \end
100408:
        cmpb    $4,%dl
        jl      100204f
        movl    (%rdi),%r8d
        movl    (%rsi),%r9d
        cmpl    %r8d,%r9d
        jne     80f
        movl    -4(%rdi,%rdx),%r8d
        movl    -4(%rsi,%rdx),%r9d
        cmpl    %r8d,%r9d
        jne     10040804f
        \end
100204:
        cmpb    $2,%dl
        jl      100001f
        movzwl  (%rdi),%r8d
        movzwl  (%rsi),%r9d
        cmpl    %r8d,%r9d
        jne     1f
        movzwl  -2(%rdi,%rdx),%r8d
        movzwl  -2(%rsi,%rdx),%r9d
        cmpl    %r8d,%r9d
        jne     1f
        \end
100001:
        cmpb    $1,%dl
        jl      100000f
        movzbl  (%rdi),%eax
        movzbl  (%rsi),%r8d
        subl    %r8d,%eax
100000:
        \end
ALIGN_TEXT
101632:
        cmpq    $32,%rdx
        ja      103200f
        movq    (%rdi),%r8
        movq    (%rsi),%r9
        cmpq    %r8,%r9
        jne     80f
        movq    8(%rdi),%r8
        movq    8(%rsi),%r9
        cmpq    %r8,%r9
        jne     10163208f
        movq    -16(%rdi,%rdx),%r8
        movq    -16(%rsi,%rdx),%r9
        cmpq    %r8,%r9
        jne     10163216f
        movq    -8(%rdi,%rdx),%r8
        movq    -8(%rsi,%rdx),%r9
        cmpq    %r8,%r9
        jne     10163224f
        \end
ALIGN_TEXT
103200:
        movq    (%rdi),%r8
        movq    8(%rdi),%r9
        subq    (%rsi),%r8
        subq    8(%rsi),%r9
        orq     %r8,%r9
        jnz     10320000f

        movq    16(%rdi),%r8
        movq    24(%rdi),%r9
        subq    16(%rsi),%r8
        subq    24(%rsi),%r9
        orq     %r8,%r9
        jnz     10320016f

        leaq    32(%rdi),%rdi
        leaq    32(%rsi),%rsi
        subq    $32,%rdx
        cmpq    $32,%rdx
        jae     103200b
        cmpb    $0,%dl
        jne     10b
        \end

/*
 * Mismatch was found.
 *
 * Before we compute it we narrow down the range (16 -> 8 -> 4 bytes).
 */
ALIGN_TEXT
10320016:
        leaq    16(%rdi),%rdi
        leaq    16(%rsi),%rsi
10320000:
        movq    (%rdi),%r8
        movq    (%rsi),%r9
        cmpq    %r8,%r9
        jne     80f
        leaq    8(%rdi),%rdi
        leaq    8(%rsi),%rsi
        jmp     80f
ALIGN_TEXT
10081608:
10163224:
        leaq    -8(%rdi,%rdx),%rdi
        leaq    -8(%rsi,%rdx),%rsi
        jmp     80f
ALIGN_TEXT
10163216:
        leaq    -16(%rdi,%rdx),%rdi
        leaq    -16(%rsi,%rdx),%rsi
        jmp     80f
ALIGN_TEXT
10163208:
        leaq    8(%rdi),%rdi
        leaq    8(%rsi),%rsi
        jmp     80f
ALIGN_TEXT
10040804:
        leaq    -4(%rdi,%rdx),%rdi
        leaq    -4(%rsi,%rdx),%rsi
        jmp     1f

ALIGN_TEXT
80:
        movl    (%rdi),%r8d
        movl    (%rsi),%r9d
        cmpl    %r8d,%r9d
        jne     1f
        leaq    4(%rdi),%rdi
        leaq    4(%rsi),%rsi

/*
 * We have up to 4 bytes to inspect.
 */
1:
        movzbl  (%rdi),%eax
        movzbl  (%rsi),%r8d
        cmpb    %r8b,%al
        jne     2f

        movzbl  1(%rdi),%eax
        movzbl  1(%rsi),%r8d
        cmpb    %r8b,%al
        jne     2f

        movzbl  2(%rdi),%eax
        movzbl  2(%rsi),%r8d
        cmpb    %r8b,%al
        jne     2f

        movzbl  3(%rdi),%eax
        movzbl  3(%rsi),%r8d
2:
        subl    %r8d,%eax
        \end
.endm

/*
 * memmove(dst, src, cnt)
 *         rdi, rsi, rdx
 */

/*
 * Register state at entry is supposed to be as follows:
 * rdi - destination
 * rsi - source
 * rcx - count
 *
 * The macro possibly clobbers the above and: rcx, r8, r9, r10
 * It does not clobber rax nor r11.
 */
.macro MEMMOVE erms overlap end
        /*
         * For sizes 0..32 all data is read before it is written, so there
         * is no correctness issue with direction of copying.
         */
        movq    %rdx,%rcx
        cmpq    $32,%rdx
        jbe     101632f

.if \overlap == 1
        movq    %rdi,%r8
        subq    %rsi,%r8
        cmpq    %rcx,%r8        /* overlapping && src < dst? */
        jb      2f
.endif

        /*
         * AMD's movsq gets better at around 1024 bytes, Intel's gets
         * better at around 256 bytes (Zen 2, 9900K era)
         */
        cmpq    $1024,%rcx
        ja      1256f

103200:
        movq    (%rsi),%rdx
        movq    %rdx,(%rdi)
        movq    8(%rsi),%rdx
        movq    %rdx,8(%rdi)
        movq    16(%rsi),%rdx
        movq    %rdx,16(%rdi)
        movq    24(%rsi),%rdx
        movq    %rdx,24(%rdi)
        leaq    32(%rsi),%rsi
        leaq    32(%rdi),%rdi
        subq    $32,%rcx
        cmpq    $32,%rcx
        jae     103200b
        cmpb    $0,%cl
        jne     101632f
        \end
        ALIGN_TEXT
101632:
        cmpb    $16,%cl
        jl      100816f
        movq    (%rsi),%rdx
        movq    8(%rsi),%r8
        movq    -16(%rsi,%rcx),%r9
        movq    -8(%rsi,%rcx),%r10
        movq    %rdx,(%rdi)
        movq    %r8,8(%rdi)
        movq    %r9,-16(%rdi,%rcx)
        movq    %r10,-8(%rdi,%rcx)
        \end
        ALIGN_TEXT
100816:
        cmpb    $8,%cl
        jl      100408f
        movq    (%rsi),%rdx
        movq    -8(%rsi,%rcx),%r8
        movq    %rdx,(%rdi)
        movq    %r8,-8(%rdi,%rcx,)
        \end
        ALIGN_TEXT
100408:
        cmpb    $4,%cl
        jl      100204f
        movl    (%rsi),%edx
        movl    -4(%rsi,%rcx),%r8d
        movl    %edx,(%rdi)
        movl    %r8d,-4(%rdi,%rcx)
        \end
        ALIGN_TEXT
100204:
        cmpb    $2,%cl
        jl      100001f
        movzwl  (%rsi),%edx
        movzwl  -2(%rsi,%rcx),%r8d
        movw    %dx,(%rdi)
        movw    %r8w,-2(%rdi,%rcx)
        \end
        ALIGN_TEXT
100001:
        cmpb    $1,%cl
        jl      100000f
        movb    (%rsi),%dl
        movb    %dl,(%rdi)
100000:
        \end

        /*
         * 256 or more bytes
         */
        ALIGN_TEXT
1256:
        testb   $15,%dil
        jnz     100f
.if \erms == 1
        rep
        movsb
.else
        shrq    $3,%rcx                         /* copy by 64-bit words */
        rep
        movsq
        movq    %rdx,%rcx
        andl    $7,%ecx                         /* any bytes left? */
        jne     100408b
.endif
        \end
100:
        movq    (%rsi),%r8
        movq    8(%rsi),%r9
        movq    %rdi,%r10
        movq    %rdi,%rcx
        andq    $15,%rcx
        leaq    -16(%rdx,%rcx),%rdx
        neg     %rcx
        leaq    16(%rdi,%rcx),%rdi
        leaq    16(%rsi,%rcx),%rsi
        movq    %rdx,%rcx
.if \erms == 1
        rep
        movsb
        movq    %r8,(%r10)
        movq    %r9,8(%r10)
.else
        shrq    $3,%rcx                         /* copy by 64-bit words */
        rep
        movsq
        movq    %r8,(%r10)
        movq    %r9,8(%r10)
        movq    %rdx,%rcx
        andl    $7,%ecx                         /* any bytes left? */
        jne     100408b
.endif
        \end

.if \overlap == 1
        /*
         * Copy backwards.
         */
        ALIGN_TEXT
2:
        cmpq    $256,%rcx
        ja      2256f

        leaq    -8(%rdi,%rcx),%rdi
        leaq    -8(%rsi,%rcx),%rsi

        cmpq    $32,%rcx
        jb      2016f

2032:
        movq    (%rsi),%rdx
        movq    %rdx,(%rdi)
        movq    -8(%rsi),%rdx
        movq    %rdx,-8(%rdi)
        movq    -16(%rsi),%rdx
        movq    %rdx,-16(%rdi)
        movq    -24(%rsi),%rdx
        movq    %rdx,-24(%rdi)
        leaq    -32(%rsi),%rsi
        leaq    -32(%rdi),%rdi
        subq    $32,%rcx
        cmpq    $32,%rcx
        jae     2032b
        cmpb    $0,%cl
        jne     2016f
        \end
        ALIGN_TEXT
2016:
        cmpb    $16,%cl
        jl      2008f
        movq    (%rsi),%rdx
        movq    %rdx,(%rdi)
        movq    -8(%rsi),%rdx
        movq    %rdx,-8(%rdi)
        subb    $16,%cl
        jz      2000f
        leaq    -16(%rsi),%rsi
        leaq    -16(%rdi),%rdi
2008:
        cmpb    $8,%cl
        jl      2004f
        movq    (%rsi),%rdx
        movq    %rdx,(%rdi)
        subb    $8,%cl
        jz      2000f
        leaq    -8(%rsi),%rsi
        leaq    -8(%rdi),%rdi
2004:
        cmpb    $4,%cl
        jl      2002f
        movl    4(%rsi),%edx
        movl    %edx,4(%rdi)
        subb    $4,%cl
        jz      2000f
        leaq    -4(%rsi),%rsi
        leaq    -4(%rdi),%rdi
2002:
        cmpb    $2,%cl
        jl      2001f
        movw    6(%rsi),%dx
        movw    %dx,6(%rdi)
        subb    $2,%cl
        jz      2000f
        leaq    -2(%rsi),%rsi
        leaq    -2(%rdi),%rdi
2001:
        cmpb    $1,%cl
        jl      2000f
        movb    7(%rsi),%dl
        movb    %dl,7(%rdi)
2000:
        \end
        ALIGN_TEXT
2256:
        std
.if \erms == 1
        leaq    -1(%rdi,%rcx),%rdi
        leaq    -1(%rsi,%rcx),%rsi
        rep
        movsb
        cld
.else
        leaq    -8(%rdi,%rcx),%rdi
        leaq    -8(%rsi,%rcx),%rsi
        shrq    $3,%rcx
        rep
        movsq
        cld
        movq    %rdx,%rcx
        andb    $7,%cl
        jne     2004b
.endif
        \end
.endif
.endm

/*
 * memset(dst, c,   len)
 *        rdi, r10, rdx
 */
.macro MEMSET erms end
        movq    %rdi,%rax
        movq    %rdx,%rcx

        cmpq    $32,%rcx
        jbe     101632f

        cmpq    $256,%rcx
        ja      1256f

103200:
        movq    %r10,(%rdi)
        movq    %r10,8(%rdi)
        movq    %r10,16(%rdi)
        movq    %r10,24(%rdi)
        leaq    32(%rdi),%rdi
        subq    $32,%rcx
        cmpq    $32,%rcx
        ja      103200b
        cmpb    $16,%cl
        ja      201632f
        movq    %r10,-16(%rdi,%rcx)
        movq    %r10,-8(%rdi,%rcx)
        \end
        ALIGN_TEXT
101632:
        cmpb    $16,%cl
        jl      100816f
201632:
        movq    %r10,(%rdi)
        movq    %r10,8(%rdi)
        movq    %r10,-16(%rdi,%rcx)
        movq    %r10,-8(%rdi,%rcx)
        \end
        ALIGN_TEXT
100816:
        cmpb    $8,%cl
        jl      100408f
        movq    %r10,(%rdi)
        movq    %r10,-8(%rdi,%rcx)
        \end
        ALIGN_TEXT
100408:
        cmpb    $4,%cl
        jl      100204f
        movl    %r10d,(%rdi)
        movl    %r10d,-4(%rdi,%rcx)
        \end
        ALIGN_TEXT
100204:
        cmpb    $2,%cl
        jl      100001f
        movw    %r10w,(%rdi)
        movw    %r10w,-2(%rdi,%rcx)
        \end
        ALIGN_TEXT
100001:
        cmpb    $0,%cl
        je      100000f
        movb    %r10b,(%rdi)
100000:
        \end
        ALIGN_TEXT
1256:
        movq    %rdi,%r9
        movq    %r10,%rax
        testl   $15,%edi
        jnz     3f
1:
.if \erms == 1
        rep
        stosb
        movq    %r9,%rax
.else
        movq    %rcx,%rdx
        shrq    $3,%rcx
        rep
        stosq
        movq    %r9,%rax
        andl    $7,%edx
        jnz     2f
        \end
2:
        movq    %r10,-8(%rdi,%rdx)
.endif
        \end
        ALIGN_TEXT
3:
        movq    %r10,(%rdi)
        movq    %r10,8(%rdi)
        movq    %rdi,%r8
        andq    $15,%r8
        leaq    -16(%rcx,%r8),%rcx
        neg     %r8
        leaq    16(%rdi,%r8),%rdi
        jmp     1b
.endm

.macro DUMMYARG
.endm