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bcopy_page.S revision 1.5 
      1 /*	$NetBSD: bcopy_page.S,v 1.5 2002/08/17 16:36:33 thorpej Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1995 Scott Stevens
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by Scott Stevens.
     18  * 4. The name of the author may not be used to endorse or promote products
     19  *    derived from this software without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     22  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     23  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     24  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     26  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     30  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     31  *
     32  * RiscBSD kernel project
     33  *
     34  * bcopy_page.S
     35  *
     36  * page optimised bcopy and bzero routines
     37  *
     38  * Created      : 08/04/95
     39  */
     40 
     41 #include <machine/param.h>
     42 #include <machine/asm.h>
     43 
     44 /* #define BIG_LOOPS */
     45 
     46 /*
     47  * bcopy_page(src, dest)
     48  *
     49  * Optimised copy page routine.
     50  *
     51  * On entry:
     52  *   r0 - src address
     53  *   r1 - dest address
     54  *
     55  * Requires:
     56  *   number of bytes per page (NBPG) is a multiple of 512 (BIG_LOOPS), 128
     57  *   otherwise.
     58  */
     59 
     60 #define	CHUNK_SIZE	32
     61 
     62 #ifdef __XSCALE__
     63 	/* Conveniently, the chunk size is the XScale cache line size. */
     64 #define	PREFETCH_FIRST_CHUNK	pld	[r0]
     65 #define	PREFETCH_NEXT_CHUNK	pld	[r0, #(CHUNK_SIZE)]
     66 #else
     67 #define	PREFETCH_FIRST_CHUNK	/* nothing */
     68 #define	PREFETCH_NEXT_CHUNK	/* nothing */
     69 #endif
     70 
     71 #ifndef COPY_CHUNK
     72 #define	COPY_CHUNK \
     73 	PREFETCH_NEXT_CHUNK ; \
     74 	ldmia	r0!, {r3-r8,ip,lr} ; \
     75 	stmia	r1!, {r3-r8,ip,lr}
     76 #endif /* ! COPY_CHUNK */
     77 
     78 #ifndef SAVE_REGS
     79 #define	SAVE_REGS	stmfd	sp!, {r4-r8, lr}
     80 #define	RESTORE_REGS	ldmfd	sp!, {r4-r8, pc}
     81 #endif
     82 
     83 ENTRY(bcopy_page)
     84 	PREFETCH_FIRST_CHUNK
     85 	SAVE_REGS
     86 #ifdef BIG_LOOPS
     87 	mov	r2, #(NBPG >> 9)
     88 #else
     89 	mov	r2, #(NBPG >> 7)
     90 #endif
     91 
     92 1:
     93 	COPY_CHUNK
     94 	COPY_CHUNK
     95 	COPY_CHUNK
     96 	COPY_CHUNK
     97 
     98 #ifdef BIG_LOOPS
     99 	/* There is little point making the loop any larger; unless we are
    100 	   running with the cache off, the load/store overheads will
    101 	   completely dominate this loop.  */
    102 	COPY_CHUNK
    103 	COPY_CHUNK
    104 	COPY_CHUNK
    105 	COPY_CHUNK
    106 
    107 	COPY_CHUNK
    108 	COPY_CHUNK
    109 	COPY_CHUNK
    110 	COPY_CHUNK
    111 
    112 	COPY_CHUNK
    113 	COPY_CHUNK
    114 	COPY_CHUNK
    115 	COPY_CHUNK
    116 #endif
    117 	subs	r2, r2, #1
    118 	bne	1b
    119 
    120 	RESTORE_REGS		/* ...and return. */
    121 
    122 /*
    123  * bzero_page(dest)
    124  *
    125  * Optimised zero page routine.
    126  *
    127  * On entry:
    128  *   r0 - dest address
    129  *
    130  * Requires:
    131  *   number of bytes per page (NBPG) is a multiple of 512 (BIG_LOOPS), 128
    132  *   otherwise
    133  */
    134 
    135 ENTRY(bzero_page)
    136 	stmfd	sp!, {r4-r8, lr}
    137 #ifdef BIG_LOOPS
    138 	mov	r2, #(NBPG >> 9)
    139 #else
    140 	mov	r2, #(NBPG >> 7)
    141 #endif
    142 	mov	r3, #0
    143 	mov	r4, #0
    144 	mov	r5, #0
    145 	mov	r6, #0
    146 	mov	r7, #0
    147 	mov	r8, #0
    148 	mov	ip, #0
    149 	mov	lr, #0
    150 
    151 1:
    152 	stmia	r0!, {r3-r8,ip,lr}
    153 	stmia	r0!, {r3-r8,ip,lr}
    154 	stmia	r0!, {r3-r8,ip,lr}
    155 	stmia	r0!, {r3-r8,ip,lr}
    156 
    157 #ifdef BIG_LOOPS
    158 	/* There is little point making the loop any larger; unless we are
    159 	   running with the cache off, the load/store overheads will
    160 	   completely dominate this loop.  */
    161 	stmia	r0!, {r3-r8,ip,lr}
    162 	stmia	r0!, {r3-r8,ip,lr}
    163 	stmia	r0!, {r3-r8,ip,lr}
    164 	stmia	r0!, {r3-r8,ip,lr}
    165 
    166 	stmia	r0!, {r3-r8,ip,lr}
    167 	stmia	r0!, {r3-r8,ip,lr}
    168 	stmia	r0!, {r3-r8,ip,lr}
    169 	stmia	r0!, {r3-r8,ip,lr}
    170 
    171 	stmia	r0!, {r3-r8,ip,lr}
    172 	stmia	r0!, {r3-r8,ip,lr}
    173 	stmia	r0!, {r3-r8,ip,lr}
    174 	stmia	r0!, {r3-r8,ip,lr}
    175 
    176 #endif
    177 
    178 	subs	r2, r2, #1
    179 	bne	1b
    180 
    181 	ldmfd	sp!, {r4-r8, pc}
    182