79 lines
2.9 KiB
ArmAsm
79 lines
2.9 KiB
ArmAsm
| $NetBSD: SRT0.S,v 1.3 2000/11/30 22:26:27 scw Exp $
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| Copyright (c) 1995 Gordon W. Ross
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| All rights reserved.
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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. The name of the author may not be used to endorse or promote products
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| derived from this software without specific prior written permission.
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| 4. 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 Gordon Ross
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| THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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| IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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| OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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| IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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| INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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| NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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| DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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| THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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| (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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| THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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| this is a pre-startup wrapper for bugcrt which relocates the
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| code to the correct place before exec()ing.
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| SRT0.S - Stand-alone Run-Time startup code, part 0
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#include <m68k/asm.h>
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.file "SRT0.S"
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.text
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GLOBAL(_estack)
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xstart:
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| first, relocate code to correct place without touching critical regs
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| (args are in: d0, d1, d4, a0, a1, a2, a3, a4, a5, a6)
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| [a3 and a4 only when netbooting]
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movl %a3, %d3 | SAVE a3 in d3
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movl %a4, %d5 | SAVE a4 in d5
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lea %pc@(xstart:w), %a3 | a3 = current addr (could be anywhere)
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lea xstart:l, %a4 | a4 = desired location (LINKADDR)
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cmpl %a3, %a4 | already there?
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beqs restart | short-circuit out
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| Relocate the code and data
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movl #_C_LABEL(edata),%d2 | Desired end of program
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subl %a4,%d2 | Calculate length, round up.
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lsrl #2,%d2
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Lcp:
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movl %a3@+, %a4@+
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dbra %d2, Lcp
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| Force a long jump to the relocated code (not pc-relative)
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lea restart:l, %a3
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jmp %a3@
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restart:
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| now in the relocated code
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| Set up stack (just before relocated text)
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lea _C_LABEL(_estack):l, %a3
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movl %a3, %sp
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| now that we have relocated, call the bugcrt (note we skip over the special
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| bug header which has a PC and SP in it)
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movl %d3, %a3 | RESTORE a3
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movl %d5, %a4 | RESTORE a4
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jmp _start
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| The end.
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