usr/src/sys/mdec/hpboot.s.rom

/*
 * Copyright (c) 1980 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 */

/* "%W% (Berkeley) %G%" */

#define PARTITION               /* Partition is in bits 12 to 15 of R5

/*
 * RP??/RM?? 1st level boot program: loads next 7.5Kbytes from
 * boot sector of file system and sets it up to run.
 * Reads from the controller and drive passed in from the boot
 * rom.
 *   R1:  address of the boot devices's adapter
 *   R2:  controller number of the boot device
 *   R3:  unit number of the boot device
 *   R5:  software boot control flags
 *   R6:  address of driver subroutine from ROM
 *   SP:  base address of usable memory + 0x200
 */
        .set    BOOTLAST,15             /* last boot sector */
        .set    RPBPSECT,512            /* bytes per sector */
        .set    RELOC,0x70000

init:
        .word   0                       /* entry mask for DEC monitor */
        nop;nop;nop;nop;nop;nop;nop;nop /* some no-ops for 750 boot to skip */
        nop;nop;
start:
        clrl    r10                     /* major("/dev/hp0a") */
        extzv   $13,$2,r1,r4            /* get MBA number from R1 */
        insv    r4,$24,$8,r10           /* set MBA number */
        insv    r3,$16,$8,r10           /* drive number */
#ifdef PARTITION
        extzv   $12,$4,r5,r4            /* get partition from r5 */
        bicw2   $0xf000,r5              /* remove from r5 */
        insv    r4,$8,$4,r10            /* set partition */
#endif
        movl    r5,r11                  /* Save software boot control flags */
        movl    $RELOC,sp
                                        /* Save register during move */
        movl    r1,r7                   /* MBA adapter address */
        movl    r2,r8                   /* controller number */
        movl    r3,r9                   /* unit number */
        moval   init,r4
        movc3   $end,(r4),(sp)
                                        /* Restore registers */
        movl    r7,r1                   /* MBA adapter address */
        movl    r8,r2                   /* controller number */
        movl    r9,r3                   /* unit number */
        jmp     *$RELOC+start2
/* now running relocated */
/* bring in the boot program */
start2:                                 /* running relocated */
        pushr   $0xffff                 /* BEGIN FIREWALL */
        movl    $1,r4                   /* first boot sector */
        clrl    r5                      /* transfer address */
        clrl    -(sp)                   /* transfer address */
1:
        movl    r4,r8                   /* requested sector # */
        jsb     (r6)                    /* call ROM-based driver */
        blbs    r0,2f
        halt                            /* read error */
2:
        addl2   $RPBPSECT,r5            /* bump address */
        movl    r5,(sp)
        aobleq  $BOOTLAST,r4,1b

        .set    PROGSIZE,(BOOTLAST*RPBPSECT)
done:
        tstl    (sp)+                   /* pop address */
        popr    $0xffff                 /* END FIREWALL */

/* clear core and execute program */
        movl    $PROGSIZE,r4
clrcor:
        clrq    (r4)
        acbl    $RELOC,$8,r4,clrcor
/* run loaded program */
        calls   $0,*$0
        brw     start2

end: