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6502bench/docs/sgtutorial/editing-data.html
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<h2>Editing Data</h2>
<div class="grid-container">
<div class="grid-item-image">
<img src="images/t1-data-stringblob.png" alt="t1-data-stringblob"/>
</div>
<div class="grid-item-text">
<p>There's some string and numeric data down at the bottom of the file. The
final string appears to be multiple strings stuck together. (You may need
to increase the width of the Operand column to see the whole thing.) Notice
that the opcode for the very last line is '+', which means the operand
is a continuation of the previous line. Long data items can span multiple
lines, split every 64 characters (including delimiters), but they are
still single items: selecting any part selects the whole.</p>
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<img src="images/t1-data-editdlg-1.png" alt="t1-data-editdlg-1"/>
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<div class="grid-item-text">
<p>Select the last line in the file, then <samp>Actions &gt; Edit Operand</samp>.
You'll notice that this dialog is much different from the one you got when editing
the operand of an instruction. At the top it will say "<samp>65 bytes
selected</samp>". You can format this as a single 65-byte string, as 65 individual
items, or various things in between. For now, select <samp>Single bytes</samp>,
and then on the right, select <samp>ASCII (low or high) character</samp>.
Click <samp>OK</samp>.</p>
</div>
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<div class="grid-item-image">
<img src="images/t1-data-edited-1.png" alt="t1-data-edited-1"/>
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<p>Each character is now on its own line. The selection still spans the
same set of addresses.</p>
</div>
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<div class="grid-item-image">
<img src="images/t1-data-editdlg-2.png" alt="t1-data-editdlg-2"/>
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<div class="grid-item-text">
<p>Select address $203D on its own, then Actions &gt; Edit Label. Set the
label to "<kbd>STR1</kbd>". Move up a bit and select address $2030, then scroll to
the bottom and shift-click address $2070. Select
<samp>Actions &gt; Edit Operand</samp>.
At the top it should now say, "<samp>65 bytes selected in 2 groups</samp>".
There are two groups because the presence of a label split the data into
two separate regions. From the <samp>Character encoding</samp> pop-up down
in the "String" section, make sure <samp>Low or High ASCII</samp> encoding
is selected, then select the <samp>Mixed character and non-character</samp>
string type and click <samp>OK</samp>.</p>
</div>
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<img src="images/t1-data-edited-2.png" alt="t1-data-edited-2"/>
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<p>We now have two <code>.STR</code> lines, one for <samp>"string zero "</samp>,
and one with the "<samp>STR1</samp>" label and the rest of the string data.
This is okay,
but it's not really what we want. The code at $200B appears to be loading
a 16-bit address from data at $2025, so we want to use that if we can.</p>
<p>Select <samp>Edit &gt; Undo</samp> three times. You should be back to the
state where there's a single <code>.STR</code> line at the bottom of
the file, split across two lines with a '+'.</p>
</div>
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<img src="images/t1-data-string-bytes.png" alt="t1-data-string-bytes"/>
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<p>Select the line at $2026. This is currently formatted as a string,
but that appears to be incorrect, so let's format it as individual bytes
instead. There's an easy way to do that: use
<samp>Actions &gt; Toggle Single-Byte Format</samp>
(or hit <kbd class="key">Ctrl+B</kbd>).</p>
</div>
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<div class="grid-item-text">
<p>The data starting at $2025 appears to be 16-bit little-endian
addresses that point into the table of strings, so let's format
them appropriately.</p>
<!--
<p>Double-click the operand column on line $2025 ("$30") to open
the operand data format editor. Because you only have one byte selected,
most of the options are disabled. This won't do what we want, so
click <samp>Cancel</samp>.</p>
-->
</div>
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<img src="images/t1-data-editdlg-3.png" alt="t1-data-editdlg-3"/>
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<p>Select the line at $2025, then shift-click the line at $202E. Right-click
and select <samp>Edit Operand</samp>. If you selected the correct set of bytes,
the top line in the dialog should now say, "<samp>10 bytes selected</samp>".
Because 10 is a multiple of two, the 16-bit formats are enabled. It's not a multiple
of 3 or 4, so the 24-bit and 32-bit options are not enabled. Click the
<samp>16-bit words, little-endian</samp> radio button, then over to the right,
click the <samp>Address</samp> radio button. Click <samp>OK</samp>.</p>
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<img src="images/t1-data-edited-3.png" alt="t1-data-edited-3"/>
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<p>We just told SourceGen that those 10 bytes are actually five 16-bit numeric
references. SourceGen determined that the addresses are contained in the
file, and generated labels for each of them. Labels only work if they're
on their own line, so the long string was automatically split into five
separate <code>.STR</code> statements.</p>
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<p>Note we didn't explicitly format the string data. We formatted
the addresses at $2025, which placed labels at the start of the strings,
but the strings themselves were automatically detected and formatted
by SourceGen. By default, SourceGen looks for ASCII strings, but this
can be changed in the project properties. You can even disable the
string auto-detection entirely if you want.</p>
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