140 lines
4.1 KiB
ArmAsm
140 lines
4.1 KiB
ArmAsm
/*-
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* Copyright (c) 1991, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Ralph Campbell.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <machine/machAsmDefs.h>
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#if defined(LIBC_SCCS) && !defined(lint)
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ASMSTR("from: @(#)bcopy.s 8.1 (Berkeley) 6/4/93")
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ASMSTR("$Id: bcopy.S,v 1.1 1994/05/24 07:12:48 glass Exp $")
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#endif /* LIBC_SCCS and not lint */
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/* bcopy(s1, s2, n) */
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#ifdef MIPSEL
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# define LWHI lwr
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# define LWLO lwl
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# define SWHI swr
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# define SWLO swl
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#endif
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#ifdef MIPSEB
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# define LWHI lwl
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# define LWLO lwr
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# define SWHI swl
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# define SWLO swr
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#endif
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LEAF(bcopy)
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.set noreorder
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addu t0, a0, a2 # t0 = end of s1 region
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sltu t1, a1, t0
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sltu t2, a0, a1
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and t1, t1, t2 # t1 = true if from < to < (from+len)
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beq t1, zero, forward # non overlapping, do forward copy
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slt t2, a2, 12 # check for small copy
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ble a2, zero, 2f
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addu t1, a1, a2 # t1 = end of to region
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1:
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lb v0, -1(t0) # copy bytes backwards,
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subu t0, t0, 1 # doesnt happen often so do slow way
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subu t1, t1, 1
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bne t0, a0, 1b
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sb v0, 0(t1)
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2:
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j ra
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nop
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forward:
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bne t2, zero, smallcpy # do a small bcopy
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xor v0, a0, a1 # compare low two bits of addresses
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and v0, v0, 3
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subu a3, zero, a1 # compute # bytes to word align address
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beq v0, zero, aligned # addresses can be word aligned
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and a3, a3, 3
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beq a3, zero, 1f
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subu a2, a2, a3 # subtract from remaining count
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LWHI v0, 0(a0) # get next 4 bytes (unaligned)
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LWLO v0, 3(a0)
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addu a0, a0, a3
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SWHI v0, 0(a1) # store 1, 2, or 3 bytes to align a1
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addu a1, a1, a3
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1:
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and v0, a2, 3 # compute number of words left
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subu a3, a2, v0
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move a2, v0
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addu a3, a3, a0 # compute ending address
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2:
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LWHI v0, 0(a0) # copy words a0 unaligned, a1 aligned
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LWLO v0, 3(a0)
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addu a0, a0, 4
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addu a1, a1, 4
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bne a0, a3, 2b
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sw v0, -4(a1)
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b smallcpy
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nop
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aligned:
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beq a3, zero, 1f
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subu a2, a2, a3 # subtract from remaining count
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LWHI v0, 0(a0) # copy 1, 2, or 3 bytes to align
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addu a0, a0, a3
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SWHI v0, 0(a1)
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addu a1, a1, a3
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1:
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and v0, a2, 3 # compute number of whole words left
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subu a3, a2, v0
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move a2, v0
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addu a3, a3, a0 # compute ending address
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2:
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lw v0, 0(a0) # copy words
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addu a0, a0, 4
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addu a1, a1, 4
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bne a0, a3, 2b
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sw v0, -4(a1)
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smallcpy:
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ble a2, zero, 2f
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addu a3, a2, a0 # compute ending address
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1:
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lbu v0, 0(a0) # copy bytes
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addu a0, a0, 1
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addu a1, a1, 1
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bne a0, a3, 1b
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sb v0, -1(a1)
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2:
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j ra
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nop
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.set reorder
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END(bcopy)
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