support for display drivers as console

[unix-history] / usr / src / sys / vax / stand / srt0.c

/*
* Copyright (c) 1982, 1986 Regents of the University of California.
* All rights reserved.  The Berkeley software License Agreement
* specifies the terms and conditions for redistribution.
*
*      @(#)srt0.c      7.4 (Berkeley) %G%
*/

#include "../vax/mtpr.h"
#define LOCORE
#include "../vax/cpu.h"

/*
* Startup code for standalone system
* Non-relocating version -- for programs which are loaded by boot
* Relocating version for boot*
*/

       .globl  _end
       .globl  _edata
       .globl  _main
       .globl  __rtt
       .globl  _configure
       .globl  _cpu
       .globl  _openfirst
       .globl  _boothowto
       .globl  _bootdev

       .set    HIGH,31         # mask for total disable

entry:  .globl  entry
       nop; nop                        # .word 0x0101
       mtpr    $HIGH,$IPL              # just in case

#ifdef REL
       # we need to do special stuff on microvax II
       mfpr    $SID,r0
       cmpzv   $24,$8,r0,$VAX_630
       bneq    1f

       /*
        * Were we booted by VMB?  If so, r11 is not boothowto,
        * but rather the address of the `Extended RPB' (see KA630
        * User's Manual, pp 3-21).  These tests were devised by
        * richl@tektronix, 11/10/87.
        */
       cmpl    (r11),r11               # if boothowto, r11 will be small
       bneq    1f                      # and these will not fault
       cmpl    4(r11),$0
       bneq    1f
       cmpl    8(r11),$-1
       bneq    1f
       tstl    0xc(r11)
       bneq    1f

       /*
        * Booted by VMB: get flags from extended rpb.
        * We can only guess at the boot device (here ra(0,0)).
        */
       movl    0x30(r11),r11
       movl    $9,r10                  # device = ra(0,0)
1:
       movl    $RELOC,sp
#else
       movl    $RELOC-0x2400,sp
#endif
start:
#ifndef REL
       /*
        * Clear bss segment
        */
       movl    aedata,r0
clr:
       clrl    (r0)+
       cmpl    r0,sp
       jlss    clr
#else
       /*
        * `entry' below generates a pc-relative reference to the
        * code, so this works no matter where we are now.
        * Clear bss segment *after* moving text and data.
        */
       movc3   aedata,entry,(sp)
dclr:
       clrl    (r3)+
       cmpl    r3,$_end
       jlss    dclr
/* this loop shouldn't be necessary, but is when booting from an ra81 */
xclr:   
       clrl    (r3)+
       cmpl    r3,$0x100000
       jlss    xclr
       jmp     *abegin
begin:
#endif
       movl    r11,_boothowto
       movl    r10,_bootdev
again:
       mtpr    $0,$SCBB
       calls   $0,_configure
       movl    $1,_openfirst
       calls   $0,_main
#ifdef REL
       jmp     again
#else
       ret
#endif

       .data
#ifdef REL
abegin: .long   begin
aedata: .long   _edata-RELOC
#else
aedata: .long   _edata
#endif
_bootdev:       .long   0
_boothowto:     .long   0
       .text

__rtt:
       .word   0x0
#ifdef  REL
       halt
#else
       jmp     start
#endif

       .globl  _badaddr
_badaddr:
       .word   0
       movl    $1,r0
       movl    4(ap),r3
       movl    8(ap),r4
       movl    $4,r2
       movab   9f,(r2)
       bbc     $0,r4,1f; tstb  (r3)
1:      bbc     $1,r4,1f; tstw  (r3)
1:      bbc     $2,r4,1f; tstl  (r3)
1:      clrl    r0                      # made it w/o machine checks
2:      movl    $4,r2
       clrl    (r2)
       ret
       .align  2
9:
       casel   _cpu,$1,$VAX_MAX
0:
       .word   8f-0b           # 1 is 780
       .word   5f-0b           # 2 is 750
       .word   5f-0b           # 3 is 730
       .word   6f-0b           # 4 is 8600
       .word   5f-0b           # 5 is 8200
       .word   1f-0b           # 6 is 8800
       .word   1f-0b           # 7 is 610
       .word   5f-0b           # 8 is 630
5:
       mtpr    $0xf,$MCESR
       brb     1f
6:
       mtpr    $0,$EHSR
       brb     1f
8:
       mtpr    $0,$SBIFS
1:
       addl2   (sp)+,sp                # discard mchchk trash
       movab   2b,(sp)
       rei

/*
* Short assembly versions of strcmp, strcpy, and strlen
* that do not use special instructions.
*/
       .globl  _strcmp
_strcmp:
       .word   0
       movq    4(ap),r0
0:      cmpb    (r0),(r1)+
       bneq    1f
       tstb    (r0)+
       bneq    0b
       clrl    r0
       ret
1:      cvtbl   (r0),r0
       cvtbl   -(r1),r1
       subl2   r1,r0
       ret

       .globl  _strcpy
_strcpy:
       .word   0
       movq    4(ap),r0
0:      movb    (r1)+,(r0)+
       bneq    0b
       movl    4(ap),r0
       ret

       .globl  _strlen
_strlen:
       .word   0
       movl    4(ap),r0
0:      tstb    (r0)+
       bneq    0b
       decl    r0
       subl2   4(ap),r0
       ret