Annotation of 43BSDTahoe/sys/mdec/rdboot.c, revision 1.1.1.1

1.1       root        1: /*
                      2: **     @(#)rdboot.c    7.1 (Berkeley) 1/22/88
                      3: */
                      4: 
                      5: /*
                      6: ** This is a VMB boot block for microvax.  For more info, see
                      7: ** the KA-630 User's manual.
                      8: */
                      9: 
                     10: /*
                     11: **          ---------------------------------------------------
                     12: ** BB + 0: |      1     |      N     |      any value          |
                     13: **          ---------------------------------------------------
                     14: */
                     15: xxx:   .long   0x001040000
                     16: /*
                     17: **          ---------------------------------------------------
                     18: **      4: |        low  lbn         |      high lbn           |
                     19: **          ---------------------------------------------------
                     20: */
                     21:        .long   0x000010000
                     22: /*
                     23: ** BB + 2*N
                     24: **          ---------------------------------------------------
                     25: **    + 0: | check byte |      K     |     0     |   18 (HEX)  |
                     26: **          ---------------------------------------------------
                     27: */
                     28:        .long   0x0e7000018
                     29: /*
                     30: **          ---------------------------------------------------
                     31: **    + 4: |     any  value          |  1 or 81  |      0      |
                     32: **          ---------------------------------------------------
                     33: */
                     34:        .long   0x000008100
                     35: /*
                     36: **          ---------------------------------------------------
                     37: **    + 8: |     size in blocks of the image                   |
                     38: **          ---------------------------------------------------
                     39: */
                     40:        .long   0x00000000f
                     41: /*
                     42: **          ---------------------------------------------------
                     43: **    +12: |     load offset from default load address         |
                     44: **          ---------------------------------------------------
                     45: */
                     46:        .long   0x000000000
                     47: /*
                     48: **          ---------------------------------------------------
                     49: **    +16: |     offset into image to start execution          |
                     50: **          ---------------------------------------------------
                     51: */
                     52:        .long   0x000000002
                     53: /*
                     54: **          ---------------------------------------------------
                     55: **    +20: |     sum of previous three longwords               |
                     56: **          ---------------------------------------------------
                     57: */
                     58:        .long   0x000000011
                     59: /*
                     60: **
                     61: ** BB +0:      These two bytes can have any value
                     62: **
                     63: ** BB+2:       This value is the word offset from the start of the
                     64: **             bootblock to the identification area described below.
                     65: **
                     66: ** BB+3:       This byte must be one.
                     67: **
                     68: ** BB+4:       This longword contains the logical block number
                     69: **             (word swapped) of the secondary image.
                     70: **
                     71: ** BB+(2*n)+0: This byte defines the expected instruction set.
                     72: **             18(hex) means VAX.
                     73: **
                     74: ** BB+(2*n)+1: This byte defines the expected controller type, 0
                     75: **             means unknown.
                     76: **
                     77: ** BB+(2*n)+2: This byte defines the file structure on the volume,
                     78: **             it may be any value.
                     79: **
                     80: ** BB+(2*n)+3: This byte must be the ones complement of the sum of
                     81: **             the previous three bytes.
                     82: **
                     83: ** BB+(2*n)+4: This byte must be zero.
                     84: **
                     85: ** BB+(2*n)+5: This byte must be 1 or 81 (hex).  This byte defines
                     86: **             the version number of the format standard and the
                     87: **             type of disk.  The version is one, the high bit is 0
                     88: **             for single sided, 1 for double sided.
                     89: **
                     90: ** BB+(2*n)+6: These two bytes may be any value, but generally they
                     91: **             are zero.
                     92: **
                     93: ** BB+(2*n)+8: This entry is a longword containing the size in
                     94: **             blocks of the secondary bootstrap image.
                     95: **
                     96: ** BB+(2*n)+12:        This entry is a longword containing a load offset
                     97: **             (usually zero) from the default load address of the
                     98: **             secondary bootstrap.
                     99: **
                    100: ** BB+(2*n)+16:        This entry is a longword containing the byte offset
                    101: **             into the secondary bootstrap where execution is to
                    102: **             begin.
                    103: **
                    104: ** BB+(2*n)+20:        This entry is a longword containing the sum of the
                    105: **             previous three longwords.
                    106: */

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