BSD 4_1_snap development

Work on file sys/mdec/tmtoggle.s

Synthesized-from: CSRG/cd1/4.1.snap

diff --git a/sys/mdec/tmtoggle.s b/sys/mdec/tmtoggle.s
new file mode 100644 (file)
index 0000000..0341b55
--- /dev/null
+++ b/sys/mdec/tmtoggle.s
@@ -0,0 +1,18 @@
+/*
+ * Prototype toggle in bootstrap code for tm type tapes.
+ * If on anything but a 780 with the drive on uba0
+ * this will have to be repaired by patching uba and umem.
+ */
+begin:
+       movl    uba,r1
+       movl    $0x80200000,0x800(r1)
+       clrl    0x804(r1)
+       movl    umem,r2
+       bisl2   $0172520,r2
+       mnegw   $512,4(r2)
+       clrw    6(r2)
+       movw    $03,2(r2)
+       halt
+       .align  2
+uba:   .long   0x20006000
+umem:  .long   0x2013e000