/* $NetBSD: srt0.S,v 1.4 2005/12/11 12:16:08 christos Exp $ */ /*- * Copyright (c) 2001 Ben Harris * 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. * * 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. * * Modified by Reinoud Zandijk to get the program high water mark into the * HIMEM variable as normally seen in RISC OS. This is the max address+1 of * the current `WIMPSlot'. It used to be a #define. The HIMEM var needs to be * initialised though so it doesn't get zero'd when the BSS is later cleared. * (see srt1.c) */ /* Minimum desired free memory */ #ifndef BOOT_MIN_AVAIL_MEMORY #define BOOT_MIN_AVAIL_MEMORY 10 * 1024 * 1024 #endif /* If enough above BOOT_MIN_AVAIL_MEMORY, leave BOOT_LEAVE_MEMORY unused */ /* Avoids sparkfs failing on memory if we try to read a kernel from it */ #ifndef BOOT_LEAVE_MEMORY #define BOOT_LEAVE_MEMORY 5 * 1024 * 1024 #endif /* * Both BOOT_LEAVE_MEMORY and BOOT_MIN_AVAIL_MEMORY + BOOT_LEAVE_MEMORY * must fit into an immediate ATM constant - 8 bits with arbitrary rotation */ #include #include ENTRY(_start) #ifdef BOOT_MAXIMISE_MEMORY mvn r0, #0 mvn r1, #0 swi Wimp_SlotSize add r0, r0, r2 #if (BOOT_LEAVE_MEMORY > 0) cmp r0, #BOOT_MIN_AVAIL_MEMORY + BOOT_LEAVE_MEMORY subhi r0, r0, #BOOT_LEAVE_MEMORY #endif mvn r1, #0 swi Wimp_SlotSize #endif swi OS_GetEnv ldr r6, Lhimem str r1, [r6] mov sp, r1 mov fp, #0 b __start Lhimem: .word HIMEM