6502/6502bench
1
0
Fork 0
mirror of https://github.com/fadden/6502bench.git synced 2024-11-26 06:49:19 +00:00
Code Issues Projects Releases Wiki Activity

Add advanced tutorial

Browse Source 
Also, fixed a bug where the operand highlight would get out of sync
after an edit.
This commit is contained in:
Andy McFadden 2018-10-09 14:55:16 -07:00
parent fd6d8273a9
commit acf19870c2
7 changed files with 258 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
SourceGen/AppForms/EditProjectProperties.Designer.cs generated
View File

@ -141,9 +141,9 @@ namespace SourceGen.AppForms {
this.seekAltTargetCheckBox.AutoSize = true;
this.seekAltTargetCheckBox.Location = new System.Drawing.Point(7, 45);
this.seekAltTargetCheckBox.Name = "seekAltTargetCheckBox";
this.seekAltTargetCheckBox.Size = new System.Drawing.Size(130, 17);
this.seekAltTargetCheckBox.Size = new System.Drawing.Size(121, 17);
this.seekAltTargetCheckBox.TabIndex = 3;
this.seekAltTargetCheckBox.Text = "Seek alternate targets";
this.seekAltTargetCheckBox.Text = "Seek nearby targets";
this.seekAltTargetCheckBox.UseVisualStyleBackColor = true;
this.seekAltTargetCheckBox.CheckedChanged += new System.EventHandler(this.seekAltTargetCheckBox_CheckedChanged);
//

1
SourceGen/AppForms/ProjectView.cs
View File

@ -1021,6 +1021,7 @@ namespace SourceGen.AppForms {
mReanalysisTimer.StartTask("Generate DisplayList");
mDisplayList.GenerateAll();
mReanalysisTimer.EndTask("Generate DisplayList");
UpdateSelectionHighlight();
}
#endregion Project management

BIN
SourceGen/Examples/Tutorial/Tutorial2 Normal file
View File

Binary file not shown.

87
SourceGen/Examples/Tutorial/Tutorial2.S Normal file
View File

@ -0,0 +1,87 @@
; Copyright 2018 faddenSoft. All Rights Reserved.
; See the LICENSE.txt file for distribution terms (Apache 2.0).
;
; Assembler: Merlin 32
INPUT equ $3000
OUTPUT equ $0400
PTR1 equ $02
PTR2 equ $04
START equ $2000
org START-2
dw START
sec
ror A
bmi skipstr
string0 asc 'first string',00
string1 asc 'another string',00
string2 asc 'string the third',00
string3 asc 'last string',00
skipstr
lda #<stringtab
sta PTR1
lda #>stringtab
sta PTR1+1
jsr thing
and #$03
asl A
tay
lda (PTR1),y
sta PTR2
iny
lda (PTR1),y
sta PTR2+1
ldy #$ff
]loop iny
lda (PTR2),y
beq copydone
ora #$80
sta OUTPUT,y
bne ]loop ;always taken
stringtab
dw string0
dw string1
dw string2
dw string3
copydone
lda #$ff
sta _mod+1
_mod lda #$00
bne skipbrk
middat ds 4
outdat ds 1
skipbrk
lda middat
ora middat+1
and middat+2
eor middat+3
ldx #$00
dfb $2c
rebr ldx #$01
sta outdat
lda INPUT
lsr A
lsr A
lsr A
lsr A
sta INPUT
bne rebr
rts
thing
lda INPUT
rts

2
SourceGen/RuntimeData/Help/intro.html
View File

@ -636,7 +636,7 @@ L1005 EOR #$00
</pre>
<p>If you really don't like the way this works, you can disable the
search for alternate targets entirely from the
search for nearby targets entirely from the
<a href="settings.html#project-properties">project properties</a>.
Self-modifying code will always be adjusted because of the limitation
on mid-instruction labels.</p>

2
SourceGen/RuntimeData/Help/settings.html
View File

@ -176,7 +176,7 @@ entry point hint) will use this value. This is chiefly of use for
identify strings and regions filled with a single byte value. If it's
not checked, anything that isn't detected as code or explicitly formatted
will simply be shown as a byte value.</p>
<p>If "seek alternate targets" is checked, the analyzer will try to use
<p>If "seek nearby targets" is checked, the analyzer will try to use
nearby labels for data loads and stores.</p>
<p>The "minimum characters for string" setting determines how many
ASCII characters need to appear consecutively for the data analyzer to

179
SourceGen/RuntimeData/Help/tutorials.html
View File

@ -195,7 +195,7 @@ it and check the References window.)</p>
comment, and hit Enter. Your comment appears in the "comment" column.</p>
<h3>Editing Operands</h3>
<h3>Editing Instruction Operands</h3>
<p>The operand in the LDA instruction at line $2000 refers to an address
($3000) that isn't part of the file. We want to create an equate directive to
@ -239,7 +239,7 @@ symbolic reference, there's another option in the Edit Operand dialog that
does it.)</p>
<h3>Editing Data Formats</h3>
<h3>Editing Data Operands</h3>
<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. Notice that
@ -247,8 +247,10 @@ the opcode for the very last line is '+', which means it's 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>
<p>Select the last line, then Edit &gt; Edit Data Format. At the top of the
dialog that appears, it will say "65 bytes selected". You can format this
<p>Select the last line, then Actions &gt; Edit Operand. 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 "65 bytes selected". You
can format this
as a single 65-byte string, as 65 individual items, or various things
in between. For now, select "Single bytes", and then on the right,
select "ASCII". Click "OK".</p>
@ -256,8 +258,8 @@ select "ASCII". Click "OK".</p>
same set of addresses.</p>
<p>Select address $203D on its own, then Actions &gt; Edit Label. Set the
label to "STR1". Move up a bit and select address $2030, then scroll to
the bottom and shift-click address $2070. Select Actions &gt; Edit Data
Format. At the top it should now say, "65 bytes selected in 2 groups".
the bottom and shift-click address $2070. Select Actions &gt; Edit Operand.
At the top it should now say, "65 bytes selected in 2 groups".
There are two groups because the presence of a label split the data into
two separate regions. Select "mixed ASCII and non-ASCII", then click
"OK".</p>
@ -274,7 +276,7 @@ Format (or hit Ctrl+B).</p>
<p>The data starting at $2025 appears to be 16-bit addresses that point
into the table of strings, so let's format them appropriately.</p>
<p>Select the line at $2025, then shift-click the line at $202E. Select
Actions &gt; Edit Data Format. If you selected the correct set of bytes,
Actions &gt; Edit Operand. If you selected the correct set of bytes,
the top should say, "10 bytes selected". Click the
"16-bit words, little-endian" radio button, then over to the right, click
the "Address" radio button. Click "OK".</p>
@ -307,12 +309,10 @@ it should always match exactly.)</p>
<p>Click "Close" to close the window.</p>
<h3>Go Forth</h3>
<h3>End of Part One</h3>
<p>That's it for the basic tutorial. Play with the program some more to see
what it can do, or do something wild like read the manual.</p>
<p>While you can do some fancy things, nothing you do will alter the
data file. The assembled output will always match the original.</p>
<p>At this point you know enough to work with a SourceGen project. Continue
on to the next tutorial to learn more.</p>
<h2><a name="advanced-features">Advanced Features</a></h2>
@ -390,8 +390,161 @@ code entry point hint -- but did several of them at once.</p>
SourceGen asks if you want to continue, click OK.</p>
<h3>[to be continued]</h3>
<h3>Going Deeper</h3>
<p>Start a new project. Select "Generic 6502". For the data file, navigate
to the Examples directory, then from the Tutorials directory
select "Tutorial2".</p>
<p>The first thing you'll notice is that we immediately ran into a BRK,
which is a pretty reliable sign that we're not in a code section. The
generic profile puts a code entry point hint on the first byte, but that's
wrong here. This particular file begins with <code>00 20</code>, which
could be a load address (C64 binaries look like this). So let's start
with that assumption.</p>
<p>Click on the first line of code at address $1000, and select
Actions &gt; Remove Hints. The $20 got absorbed into a string. The string
is making it hard to manipulate the next few bytes, so let's fix that by
selecting Edit &gt; Toggle Data Scan. This turns off the feature that
looks for strings and .FILL regions, so now each uncategorized byte is
on its own line.</p>
<p>Select the first two lines, use Actions &gt; Edit Operand, and format
it as a 16-bit little-endian word. We're assuming this is the load
address for the data that follows, so click on the line with address
$1002, select Actions &gt; Set Address, and enter "2000". With that
line still selected, use Actions &gt; Hint As Code Entry Point to identify
it as code.</p>
<p>That looks better, but it's branching off the bottom of the screen
(unless you have a really tall screen or small fonts) because of all the
intervening data. Use Edit &gt; Toggle Data Scan to turn the string
finder back on.</p>
<p>There are four strings starting at address $2004, each of which is
followed by $00. These look like null-terminated strings, so let's make
it official. But first, let's do it wrong. Click on the line with
address $2004 to select it. Hold the shift key down, then double-click
on the operand field of the line with address $2031 (i.e. click on
"last string").</p>
<p>The Edit Data Format dialog opens, but the null-terminated strings
option is not available. This is because we didn't include the null byte
on the last string. To be recognized as one of the "special" string types,
every selected string must match the expected pattern.</p>
<p>Cancel out of the dialog. Hold the control key down, and double-click
on the operand on line $203c ($00). Control-clicking adds the line to
the selection, and double-clicking the operand reopens the dialog. You
should see "Null-terminated strings (4)" as an available option now. Click
on that, then click OK. The strings are now shown as .ZSTR.</p>
<p>It's wise to save your work periodically. Use File &gt; Save to create
a project file for Tutorial2.</p>
<h4>Pointers and Parts</h4>
<p>Let's move on to the code at $203d. It starts by storing a couple of
values into direct page address $02/03. This appears to be setting up a
pointer to $2063, which is a data area inside the file. So let's make it
official.</p>
<p>Select line $2063, and use Actions &gt; Edit Label to give it the
label "XDATA". Now edit the operand on line $203d, and set it to the
symbol "XDATA", with the part "low". Edit the operand on line $2043,
and set it to "XDATA" with the part "high". (Note the symbol text box
gets focus immediately, so you can start typing the symbol name as soon
as the dialog opens; you don't need to click around first.) If all
went well, the operands should now read <code>LDA #&lt;XDATA</code>
and <code>LDA #&gt;XDATA</code>.</p>
<p>Let's name the pointer. Edit the operand on line $203f, enter the
symbol "PTR1", and in the Symbol Shorcuts section, click "Set operand
AND create project symbol". Click OK. Note that operand on line $2043
has changed to "PTR1+1".</p>
<p>Double-click on the JSR on line $2045 to jump to L209A. This just
loads a value from $3000 into the accumulator and returns, so not much
to see here. Hit the back-arrow in the toolbar to jump back to the JSR.</p>
<p>The next bit of code masks the accumulator so it holds a value between
0 and 3, then doubles it and uses it as an index into PTR1. We know PTR1
points to XDATA, which looks like it has some 16-bit addresses. The
values loaded are stored in two more zero-page locations, $04-05.</p>
<p>$04 is being displayed as "PTR1+2", which isn't quite right, so let's
fix that. Double-click on the operand of address $204e, set the symbol
to "PTR2", and again click "Set operand AND create project symbol".
Click OK. That looks better.</p>
<p>The next bit of code copies bytes from PTR2 to $0400, stopping when it
hits a zero byte. Looks like this is copying null-terminated strings.
This confirms our idea that XDATA holds 16-bit addresses, so let's
format it. Select lines $2063 to $2066, and Actions &gt; Edit Operand.
It should say "8 bytes selected" at the top. Select "16-bit words,
little-endian", and then from the Display As box, select "Address".
Click OK. If you scroll up, you'll see that your .ZSTR strings now have
labels that match the labels in XDATA.</p>
<p>Now that we know what XDATA holds, let's rename it. Change the label
to STRADDR. The symbol parts in the operands at $203d and $2041 update
automatically.</p>
<p>Let's pause briefly to look at the cycle-count feature. Use
Edit &gt; Settings to open the app settings panel, then select the
Asm Config tab. Click the "Show cycle counts" checkbox, then click OK.</p>
<p>Every line with an instruction now has a cycle count on it. The cycle
counts are adjusted for everything SourceGen can figure out. For example,
the BEQ on line $205a shows "2+" cycles, meaning that it takes at least two
cycles but might take more. That's because conditional branches take an
extra cycles if the branch is taken. The BNE on line $2061" shows 3 cycles,
because we know that the branch is always taken.</p>
<p>The cycle-count comments are included in assembled output as well. If
you add an end-of-line comment, it appears after the cycle count.</p>
<p>Hit Ctrl+S to save your project. Make that a habit.</p>
<h4>Odds &amp; Ends</h4>
<p>The rest of the code isn't really intended to do anything useful. It
just exists to illustrate some odd situations.</p>
<p>Look at the code starting at $206b. It ends with a BRK at $2074, which
as noted earlier is a bad sign. If you look up two lines, you'll see that
it's loading the accumulator with zero, then doing a BNE, which should never
be taken (note the cycle count for the BNE is 2). The trick is in the
two lines before that, which use self-modifying code to change the LDA
immediate operand from $00 to $ff. The BNE is actually a branch-always.</p>
<p>We can fix this by correcting the status flags. Select line $2072,
and then Actions &gt; Override Status Flags. This lets us specify what
the flags should be before the instruction is executed. For each flag,
we can override the default behavior and specify that the flag is
clear (0), set (1), or indeterminate (could be 0 or 1). In this case,
we know that the self-modified code will be loading a non-zero value, so
in the "Z" column click on the button in the "Zero" row. Click OK. The
BNE is now an always-taken branch, and the code list rearranges itself
appropriately (and the cycle count is now 3).</p>
<p>Continuing on, the code at $2079 touches a few consecutive locations. Edit
the label on line $2074, setting it to "VAR". Notice how the references
to $2074 through $2077 have changed from auto-generated labels to
references to VAR. For some projects this may be undesirable. Use
Edit &gt; Project Properties, then in the Analysis Parameters box
un-check "Seek nearby targets", and click OK. You'll notice that the
references to $2075 on have switched back to auto labels. Furthermore, if
you scroll up, you'll see that the stores to PTR1+1 and PTR2+1 are now
just stores to $03 and $05.</p>
<p>The nearby-target behavior is generally desirable, because it lets you
avoid explicitly labeling every part of a multi-byte data item. For now,
use Edit &gt; Undo to turn it back on.</p>
<p>The code at $2085 looks a bit strange. LDX, then a BIT with a weird
symbol, then another LDX. If you look at the "bytes" column, you'll notice
that the three-byte BIT instruction has only one byte on its line. The
trick here is that the <code>LDX #$01</code> is embedded inside the BIT
instruction. When the code runs through here, X is set to $00, then
the BIT instruction sets some flags, then the STA runs. Several lines
down there's a BNE to $2088, which is in the middle of the BIT instruction.
It loads X with $01, then also continues to the STA.</p>
<p>Embedded instructions are unusual but not unheard-of. When you see the
extra symbol in the opcode field, you need to look closely at what's going
on.</p>
<h3>Go Forth</h3>
<p>That's it for the tutorials. There's significantly more detail on
all aspects of SourceGen in the manual.</p>
<p>While you can do some fancy things, nothing you do will alter the
data file. The assembled output will always match the original. So
don't be afraid to play around.</p>
</div>