i960 Command-line Options
-------------------------

`-ACA | -ACA_A | -ACB | -ACC | -AKA | -AKB | -AKC | -AMC'
     Select the 80960 architecture.  Instructions or features not
     supported by the selected architecture cause fatal errors.

     `-ACA' is equivalent to `-ACA_A'; `-AKC' is equivalent to `-AMC'.
     Synonyms are provided for compatibility with other tools.

     If none of these options is specified, `as' will generate code for
     any instruction or feature that is supported by *some* version of
     the 960 (even if this means mixing architectures!).  In principle,
     `as' will attempt to deduce the minimal sufficient processor type
     if none is specified; depending on the object code format, the
     processor type may be recorded in the object file.  If it is
     critical that the `as' output match a specific architecture,
     specify that architecture explicitly.

`-b'
     Add code to collect information about conditional branches taken,
     for later optimization using branch prediction bits.  (The
     conditional branch instructions have branch prediction bits in the
     CA, CB, and CC architectures.)  If BR represents a conditional
     branch instruction, the following represents the code generated by
     the assembler when `-b' is specified:

                  call    INCREMENT ROUTINE
                  .word   0       # pre-counter
          Label:  BR
                  call    INCREMENT ROUTINE
                  .word   0       # post-counter

     The counter following a branch records the number of times that
     branch was *not* taken; the differenc between the two counters is
     the number of times the branch *was* taken.

     A table of every such `Label' is also generated, so that the
     external postprocessor `gbr960' (supplied by Intel) can locate all
     the counters.  This table is always labelled `__BRANCH_TABLE__';
     this is a local symbol to permit collecting statistics for many
     separate object files.  The table is word aligned, and begins with
     a two-word header.  The first word, initialized to 0, is used in
     maintaining linked lists of branch tables.  The second word is a
     count of the number of entries in the table, which follow
     immediately: each is a word, pointing to one of the labels
     illustrated above.

           +------------+------------+------------+ ... +------------+
           |            |            |            |     |            |
           |  *NEXT     |  COUNT: N  | *BRLAB 1   |     | *BRLAB N   |
           |            |            |            |     |            |
           +------------+------------+------------+ ... +------------+
          
                         __BRANCH_TABLE__ layout

     The first word of the header is used to locate multiple branch
     tables, since each object file may contain one. Normally the links
     are maintained with a call to an initialization routine, placed at
     the beginning of each function in the file.  The GNU C compiler
     will generate these calls automatically when you give it a `-b'
     option.  For further details, see the documentation of `gbr960'.

`-norelax'
     Normally, Compare-and-Branch instructions with targets that require
     displacements greater than 13 bits (or that have external targets)
     are replaced with the corresponding compare (or `chkbit') and
     branch instructions.  You can use the `-norelax' option to specify
     that `as' should generate errors instead, if the target
     displacement is larger than 13 bits.

     This option does not affect the Compare-and-Jump instructions; the
     code emitted for them is *always* adjusted when necessary
     (depending on displacement size), regardless of whether you use
     `-norelax'.