| $NetBSD: SRT0.S,v 1.1.1.1 1995/02/14 22:56:37 gwr Exp $ | Copyright (c) 1995 Gordon W. Ross | 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. | 3. The name of the author may not be used to endorse or promote products | derived from this software without specific prior written permission. | 4. All advertising materials mentioning features or use of this software | must display the following acknowledgement: | This product includes software developed by Gordon Ross | | 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. | SRT0.S - Stand-alone Run-Time startup code, part 0 .file "SRT0.S" .text .globl start start: | Check to see if the code is located correctly. | This SHOULD do a PC-relative load into a0, but... | lea start, a0 | current location (0x4000) | XXX - GAS version 1.93 gets the above lea wrong! .word 0x41fa .word 0xfffe | Now force a long (not PC-relative) load to a1 and compare. lea start:l, a1 | desired location (LINKADDR) cmpl a0, a1 beqs restart | Relocate the code and data to where they belong. movl #_edata,d0 | Desired end of program subl a1,d0 | Calculate length, round up. lsrl #2,d0 Lcp: movl a0@+, a1@+ dbra d0, Lcp | Force a long jump to the relocated code (not pc-relative) lea restart:l, a0 jmp a0@ restart: | now in the relocated code | Set up stack (just before relocated text) lea start:l, a0 movl a0, sp | Call the run-time startup C code, which will: | initialize, call main, call exit jsr __start:l | If _start returns, fall into abort. .globl _abort _abort: trap #0 | If abort returns, fall into reset. .globl _reset _reset: reset jmp _reset | function to get the vector base register .globl _getvbr _getvbr: movc vbr, d0 rts | The end.