sys/mdec/tstoggle.s

/*
 * Prototype toggle in bootstrap code for ts type tapes.
 * If on anything but a 780 with the drive on uba0
 * this will have to be repaired by patching uba and umem.
 */
        .set    UBA0,0x20006000
        .set    UMEM0,0x2013e000
        .set    UBA_MAP,0x800
        .set    TSADDR,0772520-0760000

start:
        movl    uba,r10
        movl    mrv,UBA_MAP(r10)
        addl3   mrv,$1,UBA_MAP+4(r10)
        addl3   umem,$TSADDR,r11
        clrw    2(r11)
1:      tstb    2(r11)
        bgeq    1b
        movw    $0x200+setchr,(r11)
1:      tstb    2(r11)
        bgeq    1b
        movw    $0x200+read,(r11)
        halt
        .align  2
uba:    .long   UBA0
umem:   .long   UMEM0
mrv:    .long   0x80000000
setchr: .word   0xc004,0x200+char,0,0x8 # set characteristics command
char:   .word   0x200+status,0,0xe,0    # characteristics
read:   .word   0xc001,0,0,0x200        # read command
status: