/*      $NetBSD: memcmp.S,v 1.2 2024/01/07 07:58:34 isaki Exp $ */

/*
* Copyright (C) 2020 Tetsuya Isaki. All rights reserved.
* Copyright (C) 2020 Y.Sugahara (moveccr). All rights reserved.
*
* 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 ``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 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.
*/

/*
* Size optimized (but slow) version for primary bootloader.
*/

#include <machine/asm.h>

|
| int memcmp(const void *b1, const void *b2, size_t len)
|
ASENTRY_NOPROFILE(memcmp)
               moveml  %sp@,%d0-%d1/%a0-%a1    | %d0: (return address)
                                               | %d1: b1
                                               | %a0: b2
                                               | %a1: len

               exg     %d1,%a1                 | %d1: len
                                               | %a0: b2
                                               | %a1: b1
               moveql  #0,%d0
loop:
               subql   #1,%d1                  | if (--len < 0)
               jcs     exit                    |  goto exit
compare:
               cmpmb   %a0@+,%a1@+
               jeq     loop
               | To comply with standards, recalc exact return value.
               | Although everyone expects only 0 or not...
               moveq   #0,%d1
               moveb   %a1@-,%d0
               moveb   %a0@-,%d1
               subl    %d1,%d0                 | (uint)*b1 - (uint)*b2
exit:
               rts


#if defined(SELFTEST)
#include "iocscall.h"
               .macro  PRINT   msg
               leal    \msg,%a1
               IOCS(__B_PRINT)
               .endm

               .macro  TEST    name
               leal    \name,%a2
               jbsr    test
               .endm

ASENTRY_NOPROFILE(selftest_memcmp)
               moveml  %d2-%d7/%a2-%a6,%sp@-
               PRINT   %pc@(msg_testname)

               TEST    test1
               TEST    test2
               TEST    test3
               TEST    test4
               TEST    test5

               PRINT   %pc@(msg_crlf)
               moveml  %sp@+,%d2-%d7/%a2-%a6
               rts

test:
               movel   %a2@+,buf:W             | contents of b1
               movel   %a2@+,(buf+4):W         | contents of b2
               movel   %a2@+,%sp@-             | push len
               peal    (buf+4):W               | push b2
               peal    (buf):W                 | push b1
               jbsr    memcmp
               leal    %sp@(12),%sp

               cmpl    %a2@,%d0                | compare return value
               jne     fail
               PRINT   %pc@(msg_ok)
               rts
fail:
               PRINT   %pc@(msg_fail)
               rts

test1:
               | b1 == b2 within length
               .long   0x11223344              | b1
               .long   0x11223355              | b2
               .long   3                       | len
               .long   0                       | expected

test2:
               | b1 > b2 before the last
               .long   0x11813344              | b1
               .long   0x11013344              | b2
               .long   3                       | len
               .long   0x00000080              | expected

test3:
               | b1 < b2 in the last byte
               .long   0x11220044              | b1
               .long   0x11220144              | b2
               .long   3                       | len
               .long   -1                      | expected

test4:          | len == 0
               .long   0x11223344              | b1
               .long   0x11223344              | b2
               .long   0                       | len
               .long   0                       | expected

test5:          | *b1 - *b2 = 0 - 255 = -255
               .long   0x00000000              | b1
               .long   0xff000000              | b2
               .long   1                       | len
               .long   -255                    | expected

msg_testname:
               .asciz  "memcmp"
msg_ok:
               .asciz  " ok"
msg_fail:
               .asciz  " fail"
msg_crlf:
               .asciz  "\r\n"

               BSS(buf, 8)
#endif

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