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DOC: Cleaned up symbols keyboard example and provided a walk through

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michaelangel007 2014-11-29 07:50:56 -08:00
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help/dbg-symbols.html
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@ -6,25 +6,48 @@
</head>
<body style="DIRECTION: ltr" lang="en-US">
<h2><a name="Symbols"></a>Symbols</h2>
<p>
<p>
When a programmer writes an assembly language program instead of directly referring to a memory address over and over again they use a <b>symbolic name</b> instead.
For example, instead of always directly hard-coding $C000 everywhere to read the keyboard they would instead write:
<p><font color="#00b8ff"><font face="courier"><b><pre style="background: rgb(0,0,0) 0% 50%;">
KEYBOARD EQU $C000
1 LDA KEYBOARD
BPL 1
</p>
<p><font color="#00b8ff"><font face="courier"><b><pre style="background: rgb(0,0,0) 0% 50%;">
ORG $300
KEYBOARD EQU $C000
300:AD 00 C0 .1 LDA KEYBOARD
303:10 FB BPL .1
305:8D 00 04 STA $0400
306:60 RTS
</pre></b></font></font></p>
</p>When debugging assembly programs since you typically don't have the source file availabe you can tell the debugger how to interpret a memory address as a variable name or symbol.
A <b>symbol</b> is the symbolic name and the address assigned to it.</P>
<p>
Let's try this out in the debugger. Make sure AppleWin is running. Press F2 (to reboot), then Ctrl-F2 (to break), and F7 (to enter the debugger.)
&nbsp; If you don't want to type in the following hex code, you can select it, copy it (Ctrl-C), and paste it into the Debugger console (Ctrl-V).
</p>
<p><font color="#00b8ff"><font face="Courier"><b><pre style="BACKGROUND: rgb(0,0,0) 0% 50%;">
300:AD 00 C0 10 FB 8D 00 04 60
300L
</pre></b></font></font></p>
<p>
Press F7 to exit the debugger, then type:
</p>
<p><font color="#00b8ff"><font face="Courier"><b><pre style="BACKGROUND: rgb(0,0,0) 0% 50%;">
HOME:CALL 768
</pre></b></font></font></p>
<p>
Press Enter.&nbsp; The emulated computer will wait for your to press a key and then echo it in the top left.
</p>
<p>
When debugging assembly programs since you typically don't have the source file availabe you can tell the debugger how to interpret a memory address as a variable name or symbol.
A <b>symbol</b> is the symbolic name and the address assigned to it.
</p>
<p>AppleWin supports loading of the assemblers ACME, and Merlin's symbol tables -- a collection of symbols, one per line, organized and collectively called a symbol table.
The semi-colon is a comment-till-end-of-line. The file format per line is: <b>ADDRESS SYMBOL</b></p>
<p>e.g.
<p><font color="#00b8ff"><font face="courier"><b><pre style="background: rgb(0,0,0) 0% 50%;">
<p>e.g.</p>
<p><font color="#00b8ff"><font face="courier"><b><pre style="background: rgb(0,0,0) 0% 50%;">
; IO Map
C000 KEYBOARD
</pre></b></font></font></p>
<p>There are 9 symbol tables to help organize "modules"; each symbol table individually can be turned off/on independently.
<p>
There are <b>9</b> symbol tables to help organize "modules"; each symbol table individually can be turned off/on independently.
<pre>
MAIN APPLE2E.SYM
BASIC A2_BASIC.SYM
@ -37,11 +60,11 @@ C000 KEYBOARD
PRODOS A2_PRODOS.SYM
</pre></p>
<p>On startup the debugger reads 3 symbol tables by default: Main, Basic, User1.</p>
</p>
</p>
<p>Looking up symbols is easy.&nbsp; If you can't remember an address of a symbol,
or the reversse -- can't remember the symbol for an address -- you can use the following symbol commands:
(#### referes to either a hex address or a symbolic name)
</p>
(#### referes to either a hex address or a symbolic name)
</p>
<p><br>
<br>
</p>
@ -60,10 +83,10 @@ C000 KEYBOARD
</tr>
<tr bgcolor="#cccccc">
<td width="25%">
<p><font color="#000000"><font face="Courier"><b><span style="BACKGROUND: 0% 50%; moz-background-clip: initial; moz-background-origin: initial; moz-background-inline-policy: initial">SYM</span></b></font></font></p>
<p><font color="#000000"><font face="Courier"><b><span style="BACKGROUND: 0% 50%; ">SYM</span></b></font></font></p>
</td>
<td width="75%">
<p><i><span style="BACKGROUND: 0% 50%; moz-background-clip: initial; moz-background-origin: initial; moz-background-inline-policy: initial">Display
<p><i><span style="BACKGROUND: 0% 50%; ">Display
the number of symbols in the Main, User, and Source symbol tables.</span></i></p>
</td>
</tr>
@ -251,7 +274,7 @@ HOME</span></b></font></font></p>
</tr>
<tr bgcolor="#000000">
<td bgcolor="#000000" width="276">
<p><font color="#00b8ff"><font face="Courier"><b><span style="BACKGROUND: rgb(0,0,0) 0% 50%; moz-background-clip: initial; moz-background-origin: initial; moz-background-inline-policy: initial">SYM
<p><font color="#00b8ff"><font face="Courier"><b><span style="BACKGROUND: rgb(0,0,0) 0% 50%;">SYM
LIFE = 300</span></b></font></font></p>
</td>
<td bgcolor="#000000" width="515">
@ -260,7 +283,7 @@ LIFE = 300</span></b></font></font></p>
</tr>
<tr bgcolor="#000000">
<td bgcolor="#000000" width="276">
<p><font color="#00b8ff"><font face="Courier"><b><span style="BACKGROUND: rgb(0,0,0) 0% 50%; moz-background-clip: initial; moz-background-origin: initial; moz-background-inline-policy: initial">E
<p><font color="#00b8ff"><font face="Courier"><b><span style="BACKGROUND: rgb(0,0,0) 0% 50%;">E
LIFE 64</span></b></font></font></p>
</td>
<td bgcolor="#000000" width="515">