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freebsd/sys/boot/alpha/libalpha/start.S
Doug Rabson d2041924cd Move the call to extend_heap() from main to start so that if our BSS
expands beyond the limit we will extend the address space before trying
to zero the BSS. This should give us plenty of headroom for modest
expansion of the loader.
2000-10-25 23:36:01 +00:00

94 lines
2.1 KiB
ArmAsm

/*
* $FreeBSD$
* From: $NetBSD: start.S,v 1.4 1998/03/28 00:54:15 cgd Exp $
*/
/*
* Mach Operating System
* Copyright (c) 1992 Carnegie Mellon University
* All Rights Reserved.
*
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie Mellon
* the rights to redistribute these changes.
*/
#include <machine/asm.h>
/*
* start --
* Entry point for boot/standalone programs.
*
* Arguments:
* a0 long (first free physical page)
*
* This is where the prom comes to. Leaves all exception and interrupts
* to prom, runs off prom's stack too. No return values.
*/
.text
.set noreorder /* don't reorder instructions */
#define ENTRY_FRAME 32
#define STACK_SIZE 12288
NESTED(start, 1, ENTRY_FRAME, ra, 0, 0)
br pv,Lstartgp
Lstartgp:
LDGP(pv)
#ifndef BOOT1
CALL(extend_heap)
#endif
lda a0,_edata
lda a1,_end
subq a1,a0,a1
CALL(bzero)
#ifndef BOOT1
lda sp,stackbase + STACK_SIZE - ENTRY_FRAME
#endif
CALL(main) /* transfer to C */
XLEAF(_rtt, 0)
XLEAF(halt, 0)
call_pal PAL_halt /* halt if we ever return */
END(start)
/*
* Dummy routine for GCC2.
*/
LEAF(__main,0)
RET
END(__main)
/*
* cpu_number
* Return the cpu number, using the whami instruction.
*/
LEAF(cpu_number, 0)
call_pal PAL_VMS_mfpr_whami
RET
END(cpu_number)
#ifndef BOOT1
BSS(stackbase, STACK_SIZE)
#endif