6502bench SourceGen: Editors

Edit Address

This adds a target address directive (".ORG") to the current offset. If you leave the field blank, the directive will be removed.

Addresses are always interpreted as hexadecimal. You can prefix it with a '$', but that's not necessary.

24-bit addresses may be written with a bank separator, e.g. "12/3456" would resolve to address $123456.

There will always be an address directive at the start of the list. Attempts to remove it will be ignored.

The state of the processor status flags are tracked for every instruction. Each individual flag is recorded as zero, one, or "indeterminate", meaning it could hold either value at the start of that instruction. You can override the value of individual flags.

The 65816 emulation bit, which is not part of the processor status register, may also be set in the editor.

The M, X, and E flags will not be editable unless your CPU configuration is set to a 16-bit CPU.

Edit Label

Sets or clears a label at the selected offset. The label must have the proper form, and not have the same name as another symbol.

The label may be marked as local, global, or global and exported. Local labels may be generated in the assembler output in a convenient form, such as a local loop identifier. Global labels are always output as-is. Exported labels are added to a table that may be imported by other projects.

Edit Operand

Operands can be displayed in a variety of numeric formats, or as a symbol. The ASCII character format is only available for operands whose value falls into the range of low- or high-ASCII characters.

Symbols may be used in their entirety, or offset by a byte or two. The low / high / bank selector determines which byte is used as the low byte. For 16-bit operands, this acts as a shift rather than a byte select.

A few shortcuts are provided when specifying a symbol. As noted in the introductory sections, operand symbols are weak references. If the symbol hasn't been defined as a label yet, the operand will be formatted as hex, which is probably not what you want.

The default behavior is to just set the operand's symbol.

For operands that target an offset inside the file, if the target address does not yet have a label, and the symbol doesn't exist, you may set the symbol as the label on the target address as well. You can do this in addition to setting the operand symbol, or in lieu of setting the operand symbol. (You will often want to only create the label, and let SourceGen convert the numeric reference to a symbolic reference automatically.) If you select the "set label instead" option, and the operand already had a symbol reference defined, the operand's format will be set to default.

For operands that target an external address, if the symbol doesn't exist, you can ask the editor to create a project symbol with the appropriate label and address value. The operand symbol will also be set.

The MVN and MVP instructions on the 65816 are a bit peculiar, because they have two operands rather than one. SourceGen currently only allows you to set one format, which will be applied to both operands. If you specify a symbol, the symbol will be used twice, adjusted if necessary. (This may be addressed in a future release.)

Edit Data Format

This dialog offers a variety of choices, and can be used to apply a format to a range of offsets. If the range crosses a visual boundary, such as a change in address, a user-specified label, or a long comment or note, the region will be split. The top of the dialog indicates how many bytes have been selected, and how many regions they have been divided into.

(End-of-line comments do not split a region, and will disappear if they end up inside a multi-byte data item.)

The "Simple Data" items behave the same as their equivalents in the Edit Operand dialog. However, because the width is not determined by an instruction opcode, you will need to specify how wide each item is, and the byte order.

Suppose you find a table of 16-bit addresses in the code. Click on the first byte, shift-click the last byte, then select the Edit Data menu item. The number of bytes selected should be even. Select "16-bit words, little-endian", then to the right "Address". When you click OK, the selected data will be formatted as a series of 16-bit address values.

The "Bulk Data" items can represent large chunks of data compactly. The "fill" option is only available if all selected bytes have the same value.

The "String" items are enabled or disabled depending on whether the data you have selected is in the appropriate format. For example, "Null-terminated strings" is only enabled if the data is exclusively ASCII characters followed by $00. Zero-length strings are allowed, but only if some non-zero-length strings are present.

Standard ASCII and "high ASCII" are both supported, but strings must be composed exclusively of one or the other.

To avoid burying a label in the middle of a data item, contiguous areas are split at labels. This can sometimes have unexpected effects. For example, this can be formatted as two 16-bit words or one 32-bit word:

         .DD1    $01
         .DD1    $ef
         .DD1    $01
         .DD1    $f0

With a label in the middle, it be formatted as two 16-bit words, but not as a 32-bit word:

         .DD1    $01
         .DD1    $ef
LABEL    .DD1    $01
         .DD1    $f0
CODE     LDA     LABEL

If this is inconvenient, you can add a label at a 32-bit boundary, and reference that instead:

LABEL    .DD1    $01
         .DD1    $ef
         .DD1    $01
         .DD1    $f0
CODE     LDA     LABEL+2

With the label out of the way, the data can be formatted as desired.

Edit Comment

Enter an end-of-line (EOL) comment, or leave the text field blank to delete it. EOL comments may be placed on instruction and data lines, but not on assembler directives.

It's wise to restrict comments to the ASCII character set, because not all assemblers can accept UTF-8 input. Code generators for such assemblers will convert non-ASCII characters to '?' or something similar. If this isn't a concern, you can enter any characters you like.

There is no fixed limit on the number of characters, but you may want to limit the overall length if you're hoping to create 80-column output. Some retro assemblers may have hard line length limitations, which could result in the comment being truncated in generated sources.

A semicolon (';') is placed at the start of the line. If an assembler has different conventions, a different character may be used. You don't need to include a delimiter in the comment field.

Comments on platform symbols are read from the platform symbol file, and cannot be edited from within SourceGen. Comments on project symbols are stored in the project file, and can be edited with the project symbol editor.

Edit Long Comment

Long comments can be arbitrarily long and span multiple lines. They will be word-wrapped at a line width of your choosing. They're always drawn with a fixed-width font, so you can create ASCII-art diagrams. Comment delimiters are added automatically at the start of each line.

For a true retro look you can "box" the comment with asterisks. You can create a fill-width row of asterisks by putting a '*' on a line by itself. (Assembly source generators are allowed to use a character other than '*' for the output, e.g. they might use a full set of box outline characters, though that's somewhat against the spirit of the thing.)

The bottom window will update automatically as you type, showing what the output is expected to look like. The actual assembler source output will depend on features of the target assembler, such as comment delimiter choices and maximum line length limitations. For example, Merlin allows a leading '*' to indicate a comment, while cc65 does not, so cc65 code uses ";*' instead. Because the length limitation affects the length of the line, not just the comment text, an asterisk-boxed comment will have one fewer character per line in cc65 output.

Clear the text field to delete the comment.

You can use Ctrl+Enter as a keyboard shortcut for "OK".

The long comment at the very top of the project is special, as it's not associated with a file offset. If you delete it, you can get it back by using Edit > Edit Header Comment.

Edit Note

Notes are similar to long comments, in that they can be arbitrarily long and span multiple lines. However, because they're never included in generated output, options like line width formatting and boxing aren't relevant.

Instead, you can select a highlight color for the note to make it stand out. You may want to assign certain colors to specific things, e.g. blue for "I don't know what this is" or green for "this is a bookmark for the really interesting stuff". The color will be applied to the note in the code list and in the "Notes" window.

Clear the text field to delete the note.

You can use Ctrl+Enter as a keyboard shortcut for "OK".

Edit Project Symbol

This is used to edit the properties of a project symbol.

The label must meet the criteria for symbols (see All About Symbols), and must not have the same name as another project symbol. It can overlap with platform symbols and user labels.

The value may be entered in decimal, hexadecimal, or binary. The base you choose will be remembered, so that the value will be displayed the same way when used in a .EQ directive.

If you enter a comment, it will be placed at the end of the line of the .EQ directive.

Symbols marked as "address" will be applied automatically when an operand references an address outside the scope of the data file. Symbols marked as "constant" will not, though you can still specify it manually.