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git-svn-id: https://svn.code.sf.net/p/acme-crossass/code-0/trunk@3 4df02467-bbd4-4a76-a152-e7ce94205b78
120 lines
3.8 KiB
Plaintext
120 lines
3.8 KiB
Plaintext
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ACME
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...the ACME Crossassembler for Multiple Environments
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--- compatibility problems ---
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If you haven't used ACME before, you don't need to read this text.
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It is only of use to people who upgraded from ACME 0.05 (or earlier)
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to ACME 0.07 (or later).
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You might encounter some slight incompatibilities: I have done a few
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changes to ACME's workings.
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Because backwards compatibility is the root of all evil (*g*), I did
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not include any possibility to enforce the old behaviour. If one of
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the following changes applies to your source files, assemble them with
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this new release of ACME and then compare new and old output files.
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Sorry for this inconvenience, but at least I think that there won't be
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any further changes in the future.
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----------------------------------------------------------------------
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Section: Offset assembly / segment assembly
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----------------------------------------------------------------------
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Offset assembly is now done using a new pseudo opcode called
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"!pseudopc". Have a look at "AllPOs.txt" for further information on
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its syntax and usage.
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The old way of just redefining the program counter by using more than
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one "*= EXPRESSION" statements does something totally different now:
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Whenever the program counter is redefined, ACME will actually change
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its pointer into the output buffer, so you can write your code in
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distinct segments. These segments can be given in any order. After
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assembly, ACME stores everything from the lowest address used to the
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highest address used. Have a look at "AllPOs.txt" for an example on
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how to use this facility.
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----------------------------------------------------------------------
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Section: Argument order of MVP/MVN
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----------------------------------------------------------------------
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The syntax of the 65816 opcodes MVN and MVP is usually given as
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MVN source_bank, destination_bank
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All previous versions of ACME did it the other way round: First the
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destination bank, then the source bank. This has been fixed, ACME now
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uses the syntax given above.
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----------------------------------------------------------------------
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Section: Typecast
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----------------------------------------------------------------------
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You can use leading zeros to make ACME use a bigger addressing mode
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than needed. Until now, this did not work when using labels. The
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source code
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label1 = $fa
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label2 = $00fa
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lda $fa
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lda $00fa
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lda label1
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lda label2
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was assembled to:
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lda $fa
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lda $00fa
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lda $fa
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lda $fa
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Release 0.07 of ACME now correctly assembles the given source code to:
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lda $fa
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lda $00fa
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lda $fa
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lda $00fa
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----------------------------------------------------------------------
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Section: !endoffile
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----------------------------------------------------------------------
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Previous versions of ACME knew a pseudo opcode called "!end" that
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marks the end of a source code file. Because the word "end" doesn't
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actually specify *what* is about to end, I changed this to
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"!endoffile". You can also use a short version, called "!eof". The old
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PO "!end" no longer works.
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----------------------------------------------------------------------
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Section: Using the BIT command without parameters
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----------------------------------------------------------------------
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Release 0.07 of ACME will complain if you try to assemble BIT without
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any parameter. Previous versions did just output the byte $2c - a
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commonly known trick to mask the following 2-byte command on the 6502
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processor. If you still want to do this, use
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!src <6502/std.a> ; parse library file
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to include some standard macros. Then you can use
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+bit8 ; output $24 to mask following 1-byte command
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and
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+bit16 ; output $2c to mask following 2-byte command
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respectively.
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That's all. Again, sorry for the inconvenience...
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