loader/eckd.s

   1 # During the system IPL, 24 bytes are read from the device.
   2 #
   3 # NOTE: zArch IPLs in ESA/390 mode.
   4 #
   5
   6 .org 0
   7 .globl START
   8 START:
   9
  10 #
  11 # Bytes 0-7 contain PSW to be loaded after IO operation completes
  12 #
  13         .byte   0x00
  14                 #   bits  value   name                        desc
  15                 #      0      0   <zero>
  16                 #      1      0   PER Mask (R)                disabled
  17                 #    2-4      0   <zero>
  18                 #      5      0   DAT Mode (T)                disabled
  19                 #      6      0   I/O Mask (IO)               disabled
  20                 #      7      0   External Mask (EX)          disabled
  21
  22         .byte   0x08
  23                 #   bits  value   name                        desc
  24                 #   8-11      0   Key
  25                 #     12      1   <one>
  26                 #     13      0   Machine-Check Mask (M)      disabled
  27                 #     14      0   Wait State (W)              executing
  28                 #     15      0   Problem State (P)           supervisor state
  29
  30         .byte   0x00
  31                 #   bits  value   name                        desc
  32                 #  16-17      0   Address-Space Control (AS)  disabled
  33                 #  18-19      0   Condition Code (CC)
  34                 #  20-23      0   Program Mask                exceptions disabled
  35
  36         .byte   0x00
  37                 #   bits  value   name                        desc
  38                 #  24-30      0   <zero>
  39                 #     31      0   Extended Addressing (EA)    ! 64 mode
  40
  41         .byte   0x80    # bits 32-39
  42         .byte   0x80    # bits 40-47
  43         .byte   0x00    # bits 48-55
  44         .byte   0x00    # bits 56-63
  45                 #   bits  value   name                        desc
  46                 #     32      1   Basic Addressing (BA)       BA = 31, !BA = 24
  47                 #  33-63   addr   Instruction Address         Address to exec
  48
  49 #
  50 # The remaining 16 bytes should contain CCW to read data from device
  51 #
  52
  53 # CCW format-0:
  54 #   bits  name
  55 #    0-7  Cmd Code
  56 #   8-31  Data Address
  57 #     32  Chain-Data (CD)
  58 #     33  Chain-Command (CC)
  59 #     34  Sup.-Len.-Inditcation (SLI)
  60 #     35  Skip (SKP)
  61 #     36  Prog.-Contr.-Inter. (PCI)
  62 #     37  Indir.-Data-Addr. (IDA)
  63 #     38  Suspend (S)
  64 #     39  Modified I.D.A. (MIDA)
  65 #  40-47  <ignored>
  66 #  48-63  number of bytes to read
  67
  68 #
  69 # CCW 1 (bytes 8-15): format-0
  70 #
  71         # READ DATA 4 kB to 0x800000
  72         .byte   0x86, 0x80, 0x00, 0x00
  73         .byte   0x00, 0x00, 0x10, 0x00
  74
  75 #
  76 # CCW 2 (bytes 16-23): format-0
  77 #
  78         # invalid (unused)
  79         .byte   0x00, 0x00, 0x00, 0x00
  80         .byte   0x00, 0x00, 0x00, 0x00