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  • Rev 26 2015-08-22 01:21:38 GMT
  • Author: dgisselq
  • Log message:
    Added signed and unsigned multiply opcodes to the assembler.

    An opcode was added for a 'negate' instruction. This is a derived instruction
    that turns into two instructions. Neg RX becomes an XOR -1,Rx followed by an
    Add 1,Rx command. (Move 1+Rx,Rx would've stalled the bus by one cycle.)

    Instructions now keep track of the source linenumber (but not yet filename)
    where they were issued. That way, upon an error in linking at the end, the
    instruction can be referenced by the proper line number. (Filenames are still
    not implemented, hence include files may reference the line number of the
    include file with no proper indication of that ... yet).

    The OBJFILE intrface now supports a clos() function. This allows the
    assembler to close and delete the object file for those cases where the
    preprocessor encounters an error.

    The master test file, sw/test.S, was adjuted as follows: many of the tests
    within it can be separated by #ifdef lines. Hence, if you only wish to test
    whether or not CARRY works, undefine all of the other ifdefs but leave the
    CARRY_TEST defined. (PUSH_TEST, a test of the PUSH(RX,SP) macro, still doesn't
    work because the assembler still doesn't implement macros. This is still a
    coming feature.)

    The master test file now has tests for the break function, as well as for the
    new trap CC bit and the new multiply signed and unsigned instructions in the
    ALU.

    Many error conditions were added to the assembler preprocessor. Now, if an
    EOF is encountered in anything but the INITIAL state (not within a macro),
    an error will be created. Likewise, any unrecognized preprocessor directive
    will create an error.

    The lexical analyzer now supports character values, such as 'a' or '\n' using
    a C-type syntax. (Tri-graphs are not supported.) It also supports such
    extended syntax as '$GPG'. (Hmm ... wonder why I needed that?)

    The lexical analyzer now recognizes and properly supports #line preprocessor
    output statements. Theselines are then used to track what source line errors
    occurr at.

    Operand precedence has been adjusted, so the assembler should be able to
    properly handle things like 5+3*8 and get the same number answer as 3*8+5.
    (This has been implemented, although not thoroughly tested.)

    Upon completion of any preprocessing file, the assembler now checks the status
    of the preprocessor as returned by its exit code. Anything other than a zero
    status will cause the assembler to delete the resulting object code file it is
    building and exit with an error.

    The assembler also supports the '-d' command line flag to turn on debugging in
    the yacc processor (setting yydebug). It'll produce a lot of debugging output,
    but it just might help to figure out what 'syntax error' is actually taking
    place.
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