1/* 2 * Copyright (c) 1992, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Ralph Campbell. 7 * 8 * %sccs.include.redist.c% 9 * 10 * @(#)start.s 8.2 (Berkeley) 01/21/94 11 */ 12 13/* 14 * start.s - 15 * 16 * Contains code that is the first executed at boot time. 17 * 18 * Copyright (C) 1989 Digital Equipment Corporation. 19 * Permission to use, copy, modify, and distribute this software and 20 * its documentation for any purpose and without fee is hereby granted, 21 * provided that the above copyright notice appears in all copies. 22 * Digital Equipment Corporation makes no representations about the 23 * suitability of this software for any purpose. It is provided "as is" 24 * without express or implied warranty. 25 * 26 * from: $Header: /sprite/src/boot/decprom/ds3100.md/RCS/start.s, 27 * v 1.1 90/02/16 16:19:39 shirriff Exp $ SPRITE (DECWRL) 28 */ 29 30#include <machine/regdef.h> 31#include <machine/machConst.h> 32#include <machine/machAsmDefs.h> 33#include <pmax/stand/dec_prom.h> 34 35/* 36 * Amount to take off of the stack for the benefit of the debugger. 37 */ 38#define START_FRAME ((4 * 4) + 4 + 4) 39 40 .globl start 41start: 42 .set noreorder 43 la sp, start - START_FRAME 44 sw zero, START_FRAME - 4(sp) # Zero out old ra for debugger 45 sw zero, START_FRAME - 8(sp) # Zero out old fp for debugger 46 move s0, a0 # save argc 47 move s1, a1 # save argv 48 beq a3, 0x30464354, 1f # jump if boot from DS5000 49 move s3, a3 # save call vector 50 la s3, callvec # init call vector 511: 52 la a0, edata # clear BSS 53 la a1, end 54 jal bzero # bzero(edata, end - edata) 55 subu a1, a1, a0 56 sw s3, callv # save call vector 57 move a0, s0 # restore argc 58 jal main # main(argc, argv) 59 move a1, s1 # restore argv 60 li v0, DEC_PROM_RESTART # done, so call prom 61 j v0 62 nop 63 64/* dummy routine for gcc2 */ 65 .globl __main 66__main: 67 j ra 68 nop 69 70LEAF(prom_restart) 71 li v0, DEC_PROM_RESTART 72 j v0 73 nop 74END(prom_restart) 75 76LEAF(prom_open) 77 li v0, DEC_PROM_OPEN 78 j v0 79 nop 80END(prom_open) 81 82LEAF(prom_lseek) 83 li v0, DEC_PROM_LSEEK 84 j v0 85 nop 86END(prom_lseek) 87 88LEAF(prom_read) 89 li v0, DEC_PROM_READ 90 j v0 91 nop 92END(prom_read) 93 94LEAF(printf) 95 lw v0, callv # get pointer to call back vectors 96 sw a1, 4(sp) # store args on stack for printf 97 lw v0, 48(v0) # offset for callv->printf 98 sw a2, 8(sp) 99 j v0 # call PROM printf 100 sw a3, 12(sp) 101END(printf) 102