installer/setmode.s

   1 #
   2 # Copyright (c) 2007-2011 Josef 'Jeff' Sipek
   3 #
   4
   5 .globl MAIN
   6         .type   MAIN, @function
   7 MAIN:
   8 #
   9 # At this point, the machine is running in ESA390 mode. Let's load a new
  10 # PSW, making it switch to 64-bit mode
  11 #
  12
  13         # switch to 64-bit mode
  14         #
  15         # Signal Processor
  16         #   Order 0x12: Set Architecture
  17         #   R1 bits 56-63 = 0x01 (switch all CPUs to z/Arch)
  18         SR      %r1, %r1
  19         LHI     %r1, 0x1        # switch all to z/Arch
  20         SR      %r3, %r3        # CPU Address (CPU0000)
  21         SIGP    %r1, %r3, 0x12  # Signal, order 0x12
  22         SAM64
  23         # On error:
  24         #   Bit 55 = 1, cc1 (inval param)
  25         #   Bit 54 = 1, cc1 (incorrect state)
  26
  27         # FIXME: check for errors?
  28
  29 #
  30 # At this point, we should be in 64-bit mode
  31 #
  32
  33         #
  34         # It is unfortunate that the below code is required.
  35         #
  36         # Let's set the stack pointer to make gcc happy
  37         #
  38         # A standard stack frame is 160 bytes.
  39         #
  40
  41         # r15 = 0x100000
  42         #     = (1 << 20)
  43         #
  44         SGR     %r15, %r15
  45         LGHI    %r15, 0x1
  46         SLLG    %r15, %r15, 20
  47         AGHI    %r15, -160
  48
  49         BRC     15,load_nucleus