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@ -7,7 +7,7 @@
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<h1>Stella Integrated Debugger (a work in progress)</h1>
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<h1>Stella Integrated Debugger (a work in progress)</h1>
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<p>The debugger in Stella may never be complete, as we're constantly
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<p>The debugger in Stella may never be complete, as we're constantly
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adding new features requested by homebrew developers. However, even in its
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adding new features requested by homebrew developers. However, even in its
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current form it's still quite powerful, and is able to boast at least one
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current form it's still quite powerful, and is able to boast at least one
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feature that no other 2600 debugger has; it's <b>completely</b> cross-platform.</p>
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feature that no other 2600 debugger has; it's <b>completely</b> cross-platform.</p>
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@ -42,17 +42,17 @@ feature that no other 2600 debugger has; it's <b>completely</b> cross-platform.<
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You can advance multiple frames with one command.</li>
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You can advance multiple frames with one command.</li>
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<li>Supports Distella 'configuration directives', which may be used to
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<li>Supports Distella 'configuration directives', which may be used to
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override automatic code/data determination in the disassembly. For now,
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override automatic code/data determination in the disassembly. For now,
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the following directives are supported: CODE, GFX, PGFX, DATA, ROW.
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the following directives are supported: CODE, GFX, PGFX, DATA, ROW.
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These directives can be entered at the debugger prompt, or (automatically)
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These directives can be entered at the debugger prompt, or (automatically)
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loaded and saved in configuration files.</li>
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loaded and saved in configuration files.</li>
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<li>Extensive disassembly support, both from the emulation core and with help
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<li>Extensive disassembly support, both from the emulation core and with help
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from Distella. Where possible, the disassembly differentiates between code,
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from Distella. Where possible, the disassembly differentiates between code,
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player graphics and playfield graphics (ie, addresses stored in GRPx and PFx)
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player graphics and playfield graphics (ie, addresses stored in GRPx and PFx)
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and data (addresses used as an operand of a command). Code sections are also
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and data (addresses used as an operand of a command). Code sections are also
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differentiated between actual code, and 'tentative' code (ie, areas that may
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differentiated between actual code, and 'tentative' code (ie, areas that may
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represent code sections, but haven't actually been executed yet). Such
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represent code sections, but haven't actually been executed yet). Such
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tentative code is marked with a '*' symbol.</li>
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tentative code is marked with a '*' symbol.</li>
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<li>Supports visual representation of the bitmap data of graphics areas,
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<li>Supports visual representation of the bitmap data of graphics areas,
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@ -142,9 +142,9 @@ present in the debugger):</p>
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<p>For space reasons, the Prompt, TIA, I/O and Audio displays are split into
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<p>For space reasons, the Prompt, TIA, I/O and Audio displays are split into
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4 tabs, only one of which is visible at a time. You can use the mouse or
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4 tabs, only one of which is visible at a time. You can use the mouse or
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keyboard to select which tab you want to view. Pressing Shift with the left
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keyboard to select which tab you want to view. Pressing Shift with the left
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or right arrow keys cycles between tabs from right-to-left and left-to-right,
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or right arrow keys cycles between tabs from right-to-left and left-to-right,
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respectively. Pressing Tab cycles between widgets in the current tab (except
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respectively. Pressing Tab cycles between widgets in the current tab (except
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for in the Prompt area, where 'tab' is used for something else).</p>
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for in the Prompt area, where 'tab' is used for something else).</p>
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<p>You can also enter the debugger at emulator startup by use the 'debug' command on the command line, or alternatively within the ROM launcher in 'Power-on options':
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<p>You can also enter the debugger at emulator startup by use the 'debug' command on the command line, or alternatively within the ROM launcher in 'Power-on options':
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@ -164,7 +164,7 @@ for in the Prompt area, where 'tab' is used for something else).</p>
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frame (scanline 262, for NTSC games). This is because Stella only checks
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frame (scanline 262, for NTSC games). This is because Stella only checks
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for keystrokes once per frame. Once in the debugger, you can control
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for keystrokes once per frame. Once in the debugger, you can control
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execution by stepping one instruction, scanline, or frame at a time
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execution by stepping one instruction, scanline, or frame at a time
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(or more than one at a time, using commands in the prompt). You can
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(or more than one at a time, using commands in the prompt). You can
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also set breakpoints or traps, which will cause the emulator to enter
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also set breakpoints or traps, which will cause the emulator to enter
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the debugger when they are triggered, even if it happens in mid-frame.</p>
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the debugger when they are triggered, even if it happens in mid-frame.</p>
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@ -209,11 +209,11 @@ Bash-style commands are also supported:</p>
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<tr><td>Shift-Home</td><td>Scroll to beginning of commands</td></tr>
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<tr><td>Shift-Home</td><td>Scroll to beginning of commands</td></tr>
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<tr><td>Shift-End</td><td>Scroll to end of commands</td></tr>
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<tr><td>Shift-End</td><td>Scroll to end of commands</td></tr>
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</table>
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</table>
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<p>You can also scroll with the mouse. Copy and paste is not yet supported.</p>
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<p>You can also scroll with the mouse. Copy and paste is not yet supported.</p>
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<p>To see the available commands, enter "help". For extended help, type "help cmd",
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<p>To see the available commands, enter "help". For extended help, type "help cmd",
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where 'cmd' is the command you wish to know about. The available commands are listed
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where 'cmd' is the command you wish to know about. The available commands are listed
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at the end of this section. Bash-style tab completion is supported for commands,
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at the end of this section. Bash-style tab completion is supported for commands,
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labels and functions (see below).</p>
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labels and functions (see below).</p>
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<p>For now, there are some functions that only exist in the prompt. We
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<p>For now, there are some functions that only exist in the prompt. We
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@ -427,7 +427,7 @@ end of a frame. This is different from how a real 2600 works, but most
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ROMs only check for input once per frame anyway.</p>
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ROMs only check for input once per frame anyway.</p>
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<p>Conditional breaks appear in "listbreaks", numbered starting from
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<p>Conditional breaks appear in "listbreaks", numbered starting from
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zero. You can remove a cond-break with "delbreakif number", where
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zero. You can remove a cond-break with "delbreakif number", where
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the number comes from "listbreaks" or by entering the same conditional break again.</p>
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the number comes from "listbreaks" or by entering the same conditional break again.</p>
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<p>Any time the debugger is entered due to a trap, breakpoint, or
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<p>Any time the debugger is entered due to a trap, breakpoint, or
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@ -460,7 +460,7 @@ presses both Select and Reset:</p>
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</pre>
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</pre>
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<p>User-defined functions appear in "listfunctions", which shows the label
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<p>User-defined functions appear in "listfunctions", which shows the label
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and expression for each function. Functions can be removed with
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and expression for each function. Functions can be removed with
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"delfunction label", where the labels come from "listfunctions".</p>
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"delfunction label", where the labels come from "listfunctions".</p>
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<p>If you've defined a lot of complex functions, you probably will
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<p>If you've defined a lot of complex functions, you probably will
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@ -494,14 +494,14 @@ of this file will depend on the version of Stella, as follows:</p>
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</tr>
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</tr>
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</table>
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</table>
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<p>Note that these '.stella' script files are only accessed if you enter
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<p>Note that these '.stella' script files are only accessed if you enter
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the debugger at least once during a program run. This means you can create
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the debugger at least once during a program run. This means you can create
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these files, and not worry about slowing down emulation unless you're
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these files, and not worry about slowing down emulation unless you're
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actively using the debugger.</p>
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actively using the debugger.</p>
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<h4>Built-in Functions</h4>
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<h4>Built-in Functions</h4>
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<p>Stella has some pre-defined functions for use with the "breakif"
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<p>Stella has some pre-defined functions for use with the "breakif"
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command. These allow you to break and enter the debugger on various
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command. These allow you to break and enter the debugger on various
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conditions without having to define the conditions yourself.</p>
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conditions without having to define the conditions yourself.</p>
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<p>Built-in functions and pseudo-registers always start with an _
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<p>Built-in functions and pseudo-registers always start with an _
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@ -538,7 +538,7 @@ will show you a list of them.</p>
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<p>These "registers" are provided for you to use in your conditional breaks.
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<p>These "registers" are provided for you to use in your conditional breaks.
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They're not registers in the conventional sense, since they don't exist in
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They're not registers in the conventional sense, since they don't exist in
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a real system. For example, while the debugger keeps track of the number
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a real system. For example, while the debugger keeps track of the number
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of scanlines in a frame, a real system would not (there is no register
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of scanlines in a frame, a real system would not (there is no register
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that holds 'number of scanlines' on an actual console).</p>
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that holds 'number of scanlines' on an actual console).</p>
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<table border="1" cellpadding="3">
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<table border="1" cellpadding="3">
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@ -603,8 +603,8 @@ or memory.</p>
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<p>Traps can also combined with a condition ("trapif"). If an access
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<p>Traps can also combined with a condition ("trapif"). If an access
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to a memory address is caught, the condition is evaluated additionally.
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to a memory address is caught, the condition is evaluated additionally.
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Only if the condition is true too, the emulations stops.
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Only if the condition is true too, the emulations stops. For details
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</p>
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about conditions see <b>Conditional Breaks</b> described above.</p>
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<p>An example: you are debugging a game, and you want to stop the
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<p>An example: you are debugging a game, and you want to stop the
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emulation and enter the debugger whenever RESP0 is strobed. You'd use
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emulation and enter the debugger whenever RESP0 is strobed. You'd use
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@ -619,17 +619,18 @@ that triggered the trap. The reason for this is simple: until the
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instruction is executed, the emulator can't know it's going to hit a
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instruction is executed, the emulator can't know it's going to hit a
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trap. After the trap is hit, the instruction is done executing, and
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trap. After the trap is hit, the instruction is done executing, and
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whatever effects it may have had on e.g. the TIA state have already
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whatever effects it may have had on e.g. the TIA state have already
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happened... but we don't have a way to run the emulated VCS in reverse,
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happened... but we don't have a way to run the emulated VCS in reverse,
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so the best we can do is stop before the next instruction runs.</p>
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so the best we can do is stop before the next instruction runs.</p>
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<p>Traps come in two varieties: read access traps and write access traps.
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<p>Traps come in two varieties: read access traps and write access traps.
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It is possible to set both types of trap on the same address (that's
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It is possible to set both types of trap on the same address (that's
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what the plain "trap" command does). To set a read or write only trap,
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what the plain "trap" command does). To set a read or write only trap,
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use "trapread(if)" or "trapwrite(if)". To remove a trap, you just attempt
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use "trapread(if)" or "trapwrite(if)".
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to set it again: the commands actually toggle the trap on & off. You
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can also get rid of all traps at once with the "cleartraps" command.</p>
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<p>Use "listtraps" to see all enabled traps.</p>
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<p>All traps appear in "listtraps", numbered starting from zero. You
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can remove a trap with "deltrap number", where the number comes from
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"listtraps" or by entering the identical trap again. You can get rid of
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all traps at once with the "cleartraps" command.</p></p>
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<h3>Prompt commands:</h3>
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<h3>Prompt commands:</h3>
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@ -658,6 +659,7 @@ clearsavestateifs - Clear all savestate points
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delbreakif - Delete conditional breakif <xx>
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delbreakif - Delete conditional breakif <xx>
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delfunction - Delete function with label xx
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delfunction - Delete function with label xx
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delsavestateif - Delete conditional savestate point <xx>
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delsavestateif - Delete conditional savestate point <xx>
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deltrap - Delete trap <xx>
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delwatch - Delete watch <xx>
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delwatch - Delete watch <xx>
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disasm - Disassemble address xx [yy lines] (default=PC)
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disasm - Disassemble address xx [yy lines] (default=PC)
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dump - Dump data at address <xx> [to yy] [0..7, dumps to file]
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dump - Dump data at address <xx> [to yy] [0..7, dumps to file]
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developer.<p>
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developer.<p>
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<p>Many of the variables inside the TIA can only be written to by the
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<p>Many of the variables inside the TIA can only be written to by the
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6502. The debugger lets you get inside the TIA and see the contents
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6502. The debugger lets you get inside the TIA and see the contents
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of these variables. These include the color registers, player/missile
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of these variables. These include the color registers, player/missile
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graphics and positions, and the playfield.</p>
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graphics and positions, and the playfield.</p>
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<p><img src="graphics/debugger_iotab.png"></p>
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<p><img src="graphics/debugger_iotab.png"></p>
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<p>As with the TIA tab, most of the values here will be self-explanatory to a 2600
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<p>As with the TIA tab, most of the values here will be self-explanatory to a 2600
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developer, and almost all can be modified. However, the SWCHx registers need
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developer, and almost all can be modified. However, the SWCHx registers need
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further explanation:<p>
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further explanation:<p>
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<p>SWCHx(W) can be modified; here, the (W) stands for write. Similarly,
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<p>SWCHx(W) can be modified; here, the (W) stands for write. Similarly,
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SWACNT/SWBCNT can be directly modified. However, the results of reading back from
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SWACNT/SWBCNT can be directly modified. However, the results of reading back from
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the SWCHx register are influenced by SWACNT/SWBCNT, and SWCHx(R) is a read-only display
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the SWCHx register are influenced by SWACNT/SWBCNT, and SWCHx(R) is a read-only display
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reflecting this result.</p>
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reflecting this result.</p>
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video as generated by the TIA. If a complete frame hasn't been drawn,
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video as generated by the TIA. If a complete frame hasn't been drawn,
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the partial contents of the current frame will be displayed up to the
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the partial contents of the current frame will be displayed up to the
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current scanline, with the contents of the old frame (in black &
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current scanline, with the contents of the old frame (in black &
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white) filling the rest of the display. Note that if 'phosphor mode'
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white) filling the rest of the display. Note that if 'phosphor mode'
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or TV effects are enabled, you won't see the effects here; this shows the
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or TV effects are enabled, you won't see the effects here; this shows the
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raw TIA image only.</p>
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raw TIA image only.</p>
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<li><b>Fill to scanline</b>: If you've already started a partial frame
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<li><b>Fill to scanline</b>: If you've already started a partial frame
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draw (ie, the frame is already partially 'greyed' out), selecting this
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draw (ie, the frame is already partially 'greyed' out), selecting this
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option will draw all scanlines up to the vertical position where the
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option will draw all scanlines up to the vertical position where the
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mouse was clicked. Note that if you weren't in partial-frame mode,
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mouse was clicked. Note that if you weren't in partial-frame mode,
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this option will have no effect.</li>
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this option will have no effect.</li>
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<li><b>Toggle breakpoint</b>: Will toggle a conditional breakpoint at the
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<li><b>Toggle breakpoint</b>: Will toggle a conditional breakpoint at the
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scanline where the mouse was clicked. You can to use
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scanline where the mouse was clicked. You can to use
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the Prompt Tab to turn the breakpoint off again.</li>
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the Prompt Tab to turn the breakpoint off again.</li>
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<li><b>Set zoom position</b>: Influences what is shown in the TIA
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<li><b>Set zoom position</b>: Influences what is shown in the TIA
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zoom area (further described in part (G). The zoom area will
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zoom area (further described in part (G). The zoom area will
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contain the area centered at the position where the mouse was
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contain the area centered at the position where the mouse was
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clicked.</li>
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clicked.</li>
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<li><b>Save snapshot</b>: Saves the TIA image currently shown,
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<li><b>Save snapshot</b>: Saves the TIA image currently shown,
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<br>
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<br>
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<h2><u>(G)</u> TIA Zoom</h2>
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<h2><u>(G)</u> TIA Zoom</h2>
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<p>Below the TIA Info (F) is the TIA Zoom area. This allows you to enlarge
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<p>Below the TIA Info (F) is the TIA Zoom area. This allows you to enlarge
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part of the TIA display, so you can see fine details. Note that unlike
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part of the TIA display, so you can see fine details. Note that unlike
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the TIA display area, this one <b>does</b> generate frames as the real
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the TIA display area, this one <b>does</b> generate frames as the real
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system would. So, if you've enabled 'phosphor mode' for a ROM, it
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system would. So, if you've enabled 'phosphor mode' for a ROM, it
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won't be honoured here (ie, you'll see alternating frames at 30Hz display,
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won't be honoured here (ie, you'll see alternating frames at 30Hz display,
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just like on a real system).</p>
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just like on a real system).</p>
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<p>You can also right-click anywhere in this window to show a context menu,
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<p>You can also right-click anywhere in this window to show a context menu,
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<p><img src="graphics/debugger_tiazoomcmenu.png"></p>
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<p><img src="graphics/debugger_tiazoomcmenu.png"></p>
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<p>These options allow you to zoom in on the image for even greater detail.
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<p>These options allow you to zoom in on the image for even greater detail.
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If you click on the output window, you can scroll around using the cursor,
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If you click on the output window, you can scroll around using the cursor,
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PageUp/Dn and Home/End keys. You can also select the zoom position from
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PageUp/Dn and Home/End keys. You can also select the zoom position from
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a context menu in the TIA Display.</p>
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a context menu in the TIA Display.</p>
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<p>Below the TIA Zoom (G), there is a status line that shows the reason the
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<p>Below the TIA Zoom (G), there is a status line that shows the reason the
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debugger was entered (if a breakpoint/trap was hit), as shown:</p>
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debugger was entered (if a breakpoint/trap was hit), as shown:</p>
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<p><img src="graphics/debugger_bpstatus.png"></p>
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<p><img src="graphics/debugger_bpstatus.png"></p>
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<p>The output here will generally be self-explanatory. Due to space concerns,
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<p>The output here will generally be self-explanatory. Due to space concerns,
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conditional breakpoints will be shown as "CBP: ...", normal breakpoints
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conditional breakpoints will be shown as "CBP: ...", normal breakpoints
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as "BP: ...", read traps as "RTrap: ..." and write traps as "WTrap: ...".
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as "BP: ...", read traps as "RTrap: ..." and write traps as "WTrap: ...".
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See the "Breakpoints" section for details.</p>
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See the "Breakpoints" section for details.</p>
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<p>All the registers and flags are displayed, and can be changed by
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<p>All the registers and flags are displayed, and can be changed by
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double-clicking on them (to the left). Flags are toggled on double-click.
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double-clicking on them (to the left). Flags are toggled on double-click.
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Selected registers here can also be changed by using the "Data Operations" buttons,
|
Selected registers here can also be changed by using the "Data Operations" buttons,
|
||||||
further described in (J). All items are shown in hex. Any label defined for the
|
further described in (J). All items are shown in hex. Any label defined for the
|
||||||
current PC value is shown to the right. Decimal and binary equivalents
|
current PC value is shown to the right. Decimal and binary equivalents
|
||||||
are shown for SP/A/X/Y to the right (first decimal, then binary).</p>
|
are shown for SP/A/X/Y to the right (first decimal, then binary).</p>
|
||||||
<p>The column to the far right shows the 'source' of contents of the respective
|
<p>The column to the far right shows the 'source' of contents of the respective
|
||||||
registers. For example, consider the command 'LDA ($80),Y'. The operand of
|
registers. For example, consider the command 'LDA ($80),Y'. The operand of
|
||||||
the command resolves to some address, which isn't always easy to determine at
|
the command resolves to some address, which isn't always easy to determine at
|
||||||
first glance. The 'Src Addr' area shows the actual resulting operand/address
|
first glance. The 'Src Addr' area shows the actual resulting operand/address
|
||||||
being used with the given opcode.</p>
|
being used with the given opcode.</p>
|
||||||
<p>There's not much else to say about the CPU widget: if you know 6502
|
<p>There's not much else to say about the CPU widget: if you know 6502
|
||||||
assembly, it's pretty self-explanatory. If you don't, well, you should
|
assembly, it's pretty self-explanatory. If you don't, well, you should
|
||||||
|
@ -938,8 +940,8 @@ learn :)</p>
|
||||||
the RIOT RAM (K), depending on which of these widgets is currently active.
|
the RIOT RAM (K), depending on which of these widgets is currently active.
|
||||||
<p><img src="graphics/debugger_dataops.png"></p>
|
<p><img src="graphics/debugger_dataops.png"></p>
|
||||||
<p>Each of these buttons also have a keyboard shortcut (indicated in square
|
<p>Each of these buttons also have a keyboard shortcut (indicated in square
|
||||||
brackets). In fact, many of the inputboxes in various parts of the debugger
|
brackets). In fact, many of the inputboxes in various parts of the debugger
|
||||||
respond to these same keyboard shortcuts. If in doubt, give them a try.</p>
|
respond to these same keyboard shortcuts. If in doubt, give them a try.</p>
|
||||||
<pre>
|
<pre>
|
||||||
0 [z] - Set the current location/register to zero.
|
0 [z] - Set the current location/register to zero.
|
||||||
Inv [i !] - Invert the current location/register [toggle all its bits].
|
Inv [i !] - Invert the current location/register [toggle all its bits].
|
||||||
|
@ -963,13 +965,13 @@ of the 2600's zero-page RAM.</p>
|
||||||
To change a RAM location, either double-click on it or press Enter while
|
To change a RAM location, either double-click on it or press Enter while
|
||||||
it's highlighted. Enter the new value (hex only for now, sorry), then
|
it's highlighted. Enter the new value (hex only for now, sorry), then
|
||||||
press Enter to make the change. If you change your mind, press Escape
|
press Enter to make the change. If you change your mind, press Escape
|
||||||
and the original value will be restored. The currently selected RAM cell
|
and the original value will be restored. The currently selected RAM cell
|
||||||
can also be changed by using the Data operations buttons/associated
|
can also be changed by using the Data operations buttons/associated
|
||||||
shortcut keys (J).</p>
|
shortcut keys (J).</p>
|
||||||
<p><img src="graphics/debugger_ram.png"></p>
|
<p><img src="graphics/debugger_ram.png"></p>
|
||||||
<p>The 'Undo' button in the upper right should be self-explanatory; it will
|
<p>The 'Undo' button in the upper right should be self-explanatory; it will
|
||||||
undo the most previous operation to one cell only. The 'Revert' button is
|
undo the most previous operation to one cell only. The 'Revert' button is
|
||||||
more comprehensive. It will undo <i>all</i> operations on <i>all</i> cells
|
more comprehensive. It will undo <i>all</i> operations on <i>all</i> cells
|
||||||
since you first made a change.</p>
|
since you first made a change.</p>
|
||||||
<p>The UI objects at the bottom refer to the currently selected RAM cell.
|
<p>The UI objects at the bottom refer to the currently selected RAM cell.
|
||||||
The 'label' textbox shows the label attached to this RAM location (if any),
|
The 'label' textbox shows the label attached to this RAM location (if any),
|
||||||
|
@ -985,19 +987,19 @@ energy, but it's also very useful when debugging to determine which
|
||||||
memory location holds which quantity.</p>
|
memory location holds which quantity.</p>
|
||||||
<p><img src="graphics/debugger_ramsearch.png"></p>
|
<p><img src="graphics/debugger_ramsearch.png"></p>
|
||||||
<p>To search RAM, click 'Search' and enter a byte value into the search editbox (0-255).
|
<p>To search RAM, click 'Search' and enter a byte value into the search editbox (0-255).
|
||||||
All matching values will be highlighted in the RAM widget. If 'Search' is clicked
|
All matching values will be highlighted in the RAM widget. If 'Search' is clicked
|
||||||
and the input is empty, all RAM locations are highlighted.</p>
|
and the input is empty, all RAM locations are highlighted.</p>
|
||||||
|
|
||||||
<p>The 'Compare' button is used to compare the given value using all
|
<p>The 'Compare' button is used to compare the given value using all
|
||||||
addresses currently highlighted. This may be an absolute number (such as 2),
|
addresses currently highlighted. This may be an absolute number (such as 2),
|
||||||
or a comparative number (such as -1). Using a '+' or '-' operator
|
or a comparative number (such as -1). Using a '+' or '-' operator
|
||||||
means 'search addresses for values that have changed by that amount'.</p>
|
means 'search addresses for values that have changed by that amount'.</p>
|
||||||
<p>The 'Reset' button resets the entire operation; it clears the highlighted
|
<p>The 'Reset' button resets the entire operation; it clears the highlighted
|
||||||
addresses and allows another search.</p>
|
addresses and allows another search.</p>
|
||||||
<p>The following is an example of inspecting all addresses that have
|
<p>The following is an example of inspecting all addresses that have
|
||||||
decreased by 1:</p>
|
decreased by 1:</p>
|
||||||
<ul>
|
<ul>
|
||||||
<li>Click 'Search' with empty input. All address/values are highlighted</li>
|
<li>Click 'Search' with empty input. All address/values are highlighted</li>
|
||||||
<li>Exit debugger mode and lose a life, let your energy decrease, or
|
<li>Exit debugger mode and lose a life, let your energy decrease, or
|
||||||
do whatever it is you're trying to debug</li>
|
do whatever it is you're trying to debug</li>
|
||||||
<li>Enter debugger mode again, click 'Compare' and and enter a '-1' for input.
|
<li>Enter debugger mode again, click 'Compare' and and enter a '-1' for input.
|
||||||
|
@ -1014,28 +1016,28 @@ decreased by 1:</p>
|
||||||
<br>
|
<br>
|
||||||
<h2><u>(M)</u> ROM Disassembly</h2>
|
<h2><u>(M)</u> ROM Disassembly</h2>
|
||||||
<p>This area contains a disassembly of the current bank of ROM. If a symbol
|
<p>This area contains a disassembly of the current bank of ROM. If a symbol
|
||||||
file is loaded, the disassembly will have labels. Even without a symbol file, the standard TIA/RIOT labels will still be present.</p>
|
file is loaded, the disassembly will have labels. Even without a symbol file, the standard TIA/RIOT labels will still be present.</p>
|
||||||
<p>The disassembly is often quite extensive, and whenever possible tries to automatically
|
<p>The disassembly is often quite extensive, and whenever possible tries to automatically
|
||||||
differentiate between code, graphics, data and unused bytes. There are actually two
|
differentiate between code, graphics, data and unused bytes. There are actually two
|
||||||
levels of disassembly in Stella. First, the emulation core tracks accesses as a game
|
levels of disassembly in Stella. First, the emulation core tracks accesses as a game
|
||||||
is running, making for very accurate results. This is known as a <b>dynamic</b> analysis.
|
is running, making for very accurate results. This is known as a <b>dynamic</b> analysis.
|
||||||
Second, the built-in Distella code does a <b>static</b> analysis, which tentatively fills
|
Second, the built-in Distella code does a <b>static</b> analysis, which tentatively fills
|
||||||
in sections that the dynamic disassembler missed (usually because the addresses haven't
|
in sections that the dynamic disassembler missed (usually because the addresses haven't
|
||||||
been accessed at runtime yet).</p>
|
been accessed at runtime yet).</p>
|
||||||
<p>As such, code can be marked in two ways (absolute, when done by the emulation core),
|
<p>As such, code can be marked in two ways (absolute, when done by the emulation core),
|
||||||
and tentative (when done by Distella, and the emulation core hasn't accessed it yet).
|
and tentative (when done by Distella, and the emulation core hasn't accessed it yet).
|
||||||
Such 'tentative' code is marked with the '*' symbol, indicating that it has the potential
|
Such 'tentative' code is marked with the '*' symbol, indicating that it has the potential
|
||||||
to be accessed as code sometime during the program run. This gives very useful information,
|
to be accessed as code sometime during the program run. This gives very useful information,
|
||||||
since it can indicate areas toggled by an option in the game (ie, when a player dies,
|
since it can indicate areas toggled by an option in the game (ie, when a player dies,
|
||||||
when difficulty level changes, etc). It can also indicate whether blocks of code after
|
when difficulty level changes, etc). It can also indicate whether blocks of code after
|
||||||
a relative jump are in fact code, or simply data.</p>
|
a relative jump are in fact code, or simply data.</p>
|
||||||
|
|
||||||
|
|
||||||
<p><img src="graphics/debugger_rom.png"></p>
|
<p><img src="graphics/debugger_rom.png"></p>
|
||||||
|
|
||||||
<p>The <B>"Bank state"</B> is self-explanatory, and shows a summary of the current
|
<p>The <B>"Bank state"</B> is self-explanatory, and shows a summary of the current
|
||||||
bank information. For normal bankswitched ROMs, this will be the current bank number,
|
bank information. For normal bankswitched ROMs, this will be the current bank number,
|
||||||
however more advanced schemes will show other types of information here. More detailed
|
however more advanced schemes will show other types of information here. More detailed
|
||||||
information is available in Detailed Bankswitch Information (N).</p>
|
information is available in Detailed Bankswitch Information (N).</p>
|
||||||
|
|
||||||
<p>Each line of disassembly has four fields:</p>
|
<p>Each line of disassembly has four fields:</p>
|
||||||
|
@ -1050,32 +1052,32 @@ by the "break" command, <b>not</b> the conditional "breakif" breakpoints
|
||||||
Counter isn't necessarily involved).</li>
|
Counter isn't necessarily involved).</li>
|
||||||
<li><b>Labels</b>: Any labels assigned to the given address, either generated
|
<li><b>Labels</b>: Any labels assigned to the given address, either generated
|
||||||
automatically by Distella, read from a DASM symbol file or custom
|
automatically by Distella, read from a DASM symbol file or custom
|
||||||
labels created by the user. If 'PC addresses' is enabled, the address will
|
labels created by the user. If 'PC addresses' is enabled, the address will
|
||||||
be shown in grey.</li>
|
be shown in grey.</li>
|
||||||
<li><b>Disassembled bytes</b>: This is either a standard 6502 mnemonic (possibly with operand),
|
<li><b>Disassembled bytes</b>: This is either a standard 6502 mnemonic (possibly with operand),
|
||||||
or information about graphics and/or data. For instructions, the cycle count will be
|
or information about graphics and/or data. For instructions, the cycle count will be
|
||||||
included, separated by a semicolon. For graphics, a bitmap of the data, and the address
|
included, separated by a semicolon. For graphics, a bitmap of the data, and the address
|
||||||
of the data is included. For actual data, only the address is included.</li>
|
of the data is included. For actual data, only the address is included.</li>
|
||||||
<li><b>Hex bytes</b>: These are the raw machine bytes for the code/graphics/data.
|
<li><b>Hex bytes</b>: These are the raw machine bytes for the code/graphics/data.
|
||||||
Note that only code, graphics or data will show bytes and can be edited.</li>
|
Note that only code, graphics or data will show bytes and can be edited.</li>
|
||||||
</ul>
|
</ul>
|
||||||
|
|
||||||
<p>At this point, we should explain the various 'types' that the disassembler
|
<p>At this point, we should explain the various 'types' that the disassembler
|
||||||
can use. These are known as 'directives', and partly correspond to configuration
|
can use. These are known as 'directives', and partly correspond to configuration
|
||||||
options from the standalone Distella program. They are listed in order of
|
options from the standalone Distella program. They are listed in order of
|
||||||
decreasing hierarchy:</p>
|
decreasing hierarchy:</p>
|
||||||
<table border="1" cellpadding="3">
|
<table border="1" cellpadding="3">
|
||||||
<tr><td><b>CODE</b></td><td>Addresses which have appeared in the program counter, or
|
<tr><td><b>CODE</b></td><td>Addresses which have appeared in the program counter, or
|
||||||
which tentatively can appear in the program counter. These can be edited in hex.</td></tr>
|
which tentatively can appear in the program counter. These can be edited in hex.</td></tr>
|
||||||
<tr><td><b>GFX</b></td><td>Addresses which contain data stored in the player graphics registers
|
<tr><td><b>GFX</b></td><td>Addresses which contain data stored in the player graphics registers
|
||||||
(GRP0/GRP1). These addresses are shown with a bitmap of the graphics, which
|
(GRP0/GRP1). These addresses are shown with a bitmap of the graphics, which
|
||||||
can be edited in either hex or binary. The bitmap is shown as large blocks.</td></tr>
|
can be edited in either hex or binary. The bitmap is shown as large blocks.</td></tr>
|
||||||
<tr><td><b>PGFX</b></td><td>Addresses which contain data stored in the playfield graphics registers
|
<tr><td><b>PGFX</b></td><td>Addresses which contain data stored in the playfield graphics registers
|
||||||
(PF0/PF1/PF2). These addresses are shown with a bitmap of the graphics, which
|
(PF0/PF1/PF2). These addresses are shown with a bitmap of the graphics, which
|
||||||
can be edited in either hex or binary. The bitmap is shown as small dashes.</td></tr>
|
can be edited in either hex or binary. The bitmap is shown as small dashes.</td></tr>
|
||||||
<tr><td><b>DATA</b></td><td>Addresses used as an operand for some opcode. These can be edited
|
<tr><td><b>DATA</b></td><td>Addresses used as an operand for some opcode. These can be edited
|
||||||
in hex.</td></tr>
|
in hex.</td></tr>
|
||||||
<tr><td><b>ROW</b></td><td>Addresses not used as any of the above. These are shown up
|
<tr><td><b>ROW</b></td><td>Addresses not used as any of the above. These are shown up
|
||||||
to 8 per line, and cannot be edited.</td></tr>
|
to 8 per line, and cannot be edited.</td></tr>
|
||||||
</table>
|
</table>
|
||||||
|
|
||||||
|
@ -1083,7 +1085,7 @@ to 8 per line, and cannot be edited.</td></tr>
|
||||||
<p>For code sections, the 6502 mnemonic will be UPPERCASE for all standard instructions,
|
<p>For code sections, the 6502 mnemonic will be UPPERCASE for all standard instructions,
|
||||||
or lowercase for "illegal" 6502 instructions (like "dcp"). If automatic resolving
|
or lowercase for "illegal" 6502 instructions (like "dcp"). If automatic resolving
|
||||||
of code sections has been disabled for any reason, you'll likely see a lot
|
of code sections has been disabled for any reason, you'll likely see a lot
|
||||||
of illegal opcodes if you scroll to a data table in ROM. This can also
|
of illegal opcodes if you scroll to a data table in ROM. This can also
|
||||||
occur if the disassembler hasn't yet encountered addresses in the PC.
|
occur if the disassembler hasn't yet encountered addresses in the PC.
|
||||||
If you step/trace/scanline/frame advance into such an area, the disassembler
|
If you step/trace/scanline/frame advance into such an area, the disassembler
|
||||||
will make note of it, and disassemble it correctly from that point on.</p>
|
will make note of it, and disassemble it correctly from that point on.</p>
|
||||||
|
@ -1103,17 +1105,17 @@ or Scanline advance, or manually setting the PC), the disassembly will
|
||||||
scroll to the current PC location.</p>
|
scroll to the current PC location.</p>
|
||||||
|
|
||||||
<p>Even though ROM is supposed to be Read Only Memory, this is an
|
<p>Even though ROM is supposed to be Read Only Memory, this is an
|
||||||
emulator: you can change ROM all you want within the debugger. The hex
|
emulator: you can change ROM all you want within the debugger. The hex
|
||||||
bytes in the ROM Widget are editable. Double-click on them to edit
|
bytes in the ROM Widget are editable. Double-click on them to edit
|
||||||
them. When you're done, press Enter to accept the changes (in which case
|
them. When you're done, press Enter to accept the changes (in which case
|
||||||
the cart will be re-disasembled) or Escape to cancel them.
|
the cart will be re-disasembled) or Escape to cancel them.
|
||||||
Note that only instructions that have been fully disassembled
|
Note that only instructions that have been fully disassembled
|
||||||
can be edited. In particular, blank lines or 'ROW' directives
|
can be edited. In particular, blank lines or 'ROW' directives
|
||||||
cannot be edited. Also note that certain ROMs can have
|
cannot be edited. Also note that certain ROMs can have
|
||||||
sections of address space swapped in and out dynamically. As such, changing
|
sections of address space swapped in and out dynamically. As such, changing
|
||||||
the contents of a certain address will change the area pointed to <b>at
|
the contents of a certain address will change the area pointed to <b>at
|
||||||
that time</b>. In particular, modifying an address that points to internal
|
that time</b>. In particular, modifying an address that points to internal
|
||||||
RAM will change the RAM, not the underlying ROM. A future release may
|
RAM will change the RAM, not the underlying ROM. A future release may
|
||||||
graphically differentiate between RAM and ROM areas.</p>
|
graphically differentiate between RAM and ROM areas.</p>
|
||||||
|
|
||||||
<p>The ROM Disassembly also contains a Settings dialog, accessible by right-clicking
|
<p>The ROM Disassembly also contains a Settings dialog, accessible by right-clicking
|
||||||
|
@ -1149,14 +1151,14 @@ in either binary or hexidecimal.</li>
|
||||||
|
|
||||||
<li>The ROM Widget only works on ROM or zero-page RAM separately. If your game runs
|
<li>The ROM Widget only works on ROM or zero-page RAM separately. If your game runs
|
||||||
code from zero-page RAM, the disassembly will show addresses $80 to $FF (zero-page
|
code from zero-page RAM, the disassembly will show addresses $80 to $FF (zero-page
|
||||||
RAM address space) only. Once your RAM routine returns, the ROM Widget will switch
|
RAM address space) only. Once your RAM routine returns, the ROM Widget will switch
|
||||||
back to ROM space ($1000 - $1FFF and mirrors). The same is true of the "disasm"
|
back to ROM space ($1000 - $1FFF and mirrors). The same is true of the "disasm"
|
||||||
command; it will show either ROM or RAM space, not both at the same time.</li>
|
command; it will show either ROM or RAM space, not both at the same time.</li>
|
||||||
|
|
||||||
<li>The standard VCS memory map has the cartridge port at locations
|
<li>The standard VCS memory map has the cartridge port at locations
|
||||||
$F000-$FFFF. However, not all the address lines exist on a 6507, so
|
$F000-$FFFF. However, not all the address lines exist on a 6507, so
|
||||||
the cartridge port is "mirrored" at every other 4K chunk of address
|
the cartridge port is "mirrored" at every other 4K chunk of address
|
||||||
space ($1000, $3000, up to $D000). Some developers find it easier
|
space ($1000, $3000, up to $D000). Some developers find it easier
|
||||||
to think of the different banks of ROM as being at different addresses
|
to think of the different banks of ROM as being at different addresses
|
||||||
(such as: Bank 0 at $D000 and bank 1 at $F000). When such a ROM runs,
|
(such as: Bank 0 at $D000 and bank 1 at $F000). When such a ROM runs,
|
||||||
the Program Counter can point to one of the mirrors instead of the main
|
the Program Counter can point to one of the mirrors instead of the main
|
||||||
|
@ -1175,7 +1177,7 @@ the same address.</li>
|
||||||
<br>
|
<br>
|
||||||
<h2><u>(N)</u> Detailed Bankswitch Information</h2>
|
<h2><u>(N)</u> Detailed Bankswitch Information</h2>
|
||||||
|
|
||||||
<p>This area shows a detailed breakdown of the bankswitching scheme. Since
|
<p>This area shows a detailed breakdown of the bankswitching scheme. Since
|
||||||
the bankswitch schemes can greatly vary in operation, this tab will be
|
the bankswitch schemes can greatly vary in operation, this tab will be
|
||||||
different for each scheme, but its specific functionality should be self-explanatory.
|
different for each scheme, but its specific functionality should be self-explanatory.
|
||||||
An example of both 4K (non-bankswitched) and DPC (Pitfall II) is as follows:</p>
|
An example of both 4K (non-bankswitched) and DPC (Pitfall II) is as follows:</p>
|
||||||
|
@ -1192,22 +1194,22 @@ Go ahead and try to change something!</p>
|
||||||
<h2><u>(O)</u> Detailed Cartridge extended RAM Information</h2>
|
<h2><u>(O)</u> Detailed Cartridge extended RAM Information</h2>
|
||||||
|
|
||||||
<p>If applicable, this area shows a detailed breakdown of any extra RAM supported by
|
<p>If applicable, this area shows a detailed breakdown of any extra RAM supported by
|
||||||
the bankswitching scheme. Since the bankswitch schemes can greatly vary in operation,
|
the bankswitching scheme. Since the bankswitch schemes can greatly vary in operation,
|
||||||
this tab will be different for each scheme, but its specific functionality should be
|
this tab will be different for each scheme, but its specific functionality should be
|
||||||
self-explanatory. An example of both F8SC (8K Atari + ram) and DPC (Pitfall II) is
|
self-explanatory. An example of both F8SC (8K Atari + ram) and DPC (Pitfall II) is
|
||||||
as follows:</p>
|
as follows:</p>
|
||||||
|
|
||||||
<p><img src="graphics/debugger_ram-f8sc.png"></p>
|
<p><img src="graphics/debugger_ram-f8sc.png"></p>
|
||||||
<p><img src="graphics/debugger_ram-dpc.png"></p>
|
<p><img src="graphics/debugger_ram-dpc.png"></p>
|
||||||
|
|
||||||
<p>The RAM is shown in a grid similar to how zero-page RAM is shown in M6532/RIOT RAM
|
<p>The RAM is shown in a grid similar to how zero-page RAM is shown in M6532/RIOT RAM
|
||||||
(K) and (L). See those sections for a description of usage.
|
(K) and (L). See those sections for a description of usage.
|
||||||
|
|
||||||
<p>In the cases where RAM is always mapped into the same place in the cartridge
|
<p>In the cases where RAM is always mapped into the same place in the cartridge
|
||||||
address space (such as Sara-chip), the RAM addresses are labeled as such. In other
|
address space (such as Sara-chip), the RAM addresses are labeled as such. In other
|
||||||
cases, such as when the RAM is either quiescent (and mapped in at different places),
|
cases, such as when the RAM is either quiescent (and mapped in at different places),
|
||||||
or not viewable by the 6507 at all, the RAM addresses are labeled as the cart sees them.
|
or not viewable by the 6507 at all, the RAM addresses are labeled as the cart sees them.
|
||||||
In the examples above, F8SC RAM is labeled starting at its read port, or $F080. However,
|
In the examples above, F8SC RAM is labeled starting at its read port, or $F080. However,
|
||||||
the RAM in the DPC scheme is not viewable by the 6507, so its addresses start from $0.
|
the RAM in the DPC scheme is not viewable by the 6507, so its addresses start from $0.
|
||||||
|
|
||||||
|
|
||||||
|
@ -1239,21 +1241,21 @@ Control-R and Control-Shift-R.</p>
|
||||||
<br>
|
<br>
|
||||||
<h2>Distella Configuration Files</h2>
|
<h2>Distella Configuration Files</h2>
|
||||||
<p>As mentioned in ROM Disassembly (M), Stella supports the following directives:
|
<p>As mentioned in ROM Disassembly (M), Stella supports the following directives:
|
||||||
CODE/GFX/PGFX/DATA/ROW. While the debugger will try to automatically mark address
|
CODE/GFX/PGFX/DATA/ROW. While the debugger will try to automatically mark address
|
||||||
space with the appropriate directive, there are times when it will fail. There are
|
space with the appropriate directive, there are times when it will fail. There are
|
||||||
several options in this case:</p>
|
several options in this case:</p>
|
||||||
<ol>
|
<ol>
|
||||||
<li><b>Manually set the directives</b>: Directives can be set in the debugger
|
<li><b>Manually set the directives</b>: Directives can be set in the debugger
|
||||||
prompt with the code/gfx/pgfx/data/row commands. These accept an address range
|
prompt with the code/gfx/pgfx/data/row commands. These accept an address range
|
||||||
for the given directive type. Setting a range with the same type a second time
|
for the given directive type. Setting a range with the same type a second time
|
||||||
will remove that directive from the range.</li>
|
will remove that directive from the range.</li>
|
||||||
<li><b>Use configuration files</b>: Configuration files can be used to automatically
|
<li><b>Use configuration files</b>: Configuration files can be used to automatically
|
||||||
load a list of directives when a ROM is loaded. These files can be generated with the
|
load a list of directives when a ROM is loaded. These files can be generated with the
|
||||||
'saveconfig' command, and loaded with the 'loadconfig' command. There are also
|
'saveconfig' command, and loaded with the 'loadconfig' command. There are also
|
||||||
'listconfig' and 'clearconfig' commands to show and erase (respectively) the current
|
'listconfig' and 'clearconfig' commands to show and erase (respectively) the current
|
||||||
directive listing. Upon opening the debugger for the first time, Stella attempts
|
directive listing. Upon opening the debugger for the first time, Stella attempts
|
||||||
to load a configuration file from several places. For this example, assume a ROM
|
to load a configuration file from several places. For this example, assume a ROM
|
||||||
named "rr.a26", with properties entry "River Raid". Attempts will be made as follows:
|
named "rr.a26", with properties entry "River Raid". Attempts will be made as follows:
|
||||||
<ul>
|
<ul>
|
||||||
<li>ROM dir based on properties entry name: <i>River Raid.cfg</i></li>
|
<li>ROM dir based on properties entry name: <i>River Raid.cfg</i></li>
|
||||||
<li>ROM dir based on actual ROM name: <i>rr.cfg</i></li>
|
<li>ROM dir based on actual ROM name: <i>rr.cfg</i></li>
|
||||||
|
@ -1307,15 +1309,15 @@ but it helps to know at least a little about 6502 programming.</p>
|
||||||
symbols at the bottom of the screen).</li>
|
symbols at the bottom of the screen).</li>
|
||||||
|
|
||||||
<li>Enter the debugger by pressing the ` (backquote) key. Don't get
|
<li>Enter the debugger by pressing the ` (backquote) key. Don't get
|
||||||
killed before you do this, though. You should still have all 5 lives.</li>
|
killed before you do this, though. You should still have all 5 lives.</li>
|
||||||
|
|
||||||
<li>In the RAM display, click the "Search" button and enter "5" for input.
|
<li>In the RAM display, click the "Search" button and enter "5" for input.
|
||||||
This searches RAM for your value and highlights all addresses that match
|
This searches RAM for your value and highlights all addresses that match
|
||||||
the input. You should see two addresses highlighted: "00a5" and "00ba".
|
the input. You should see two addresses highlighted: "00a5" and "00ba".
|
||||||
These are the only two addresses that currently have the value 5, so they're
|
These are the only two addresses that currently have the value 5, so they're
|
||||||
the most likely candidates for "number of lives" counter. (However, some
|
the most likely candidates for "number of lives" counter. (However, some
|
||||||
games might actually store one less than the real number of lives, or
|
games might actually store one less than the real number of lives, or
|
||||||
one more, so you might have to experiment a bit. Since this is a "rigged
|
one more, so you might have to experiment a bit. Since this is a "rigged
|
||||||
demo", I already know Battlezone stores the actual number of lives.
|
demo", I already know Battlezone stores the actual number of lives.
|
||||||
Most games do, actually).</li>
|
Most games do, actually).</li>
|
||||||
|
|
||||||
|
@ -1325,9 +1327,9 @@ but it helps to know at least a little about 6502 programming.</p>
|
||||||
<li>Get killed! Ram an enemy tank, or let him shoot you. Wait for
|
<li>Get killed! Ram an enemy tank, or let him shoot you. Wait for
|
||||||
the explosion to finish. You will now have 4 lives.</li>
|
the explosion to finish. You will now have 4 lives.</li>
|
||||||
|
|
||||||
<li>Enter the debugger again. Click the "Compare" button in RAM widget and enter
|
<li>Enter the debugger again. Click the "Compare" button in RAM widget and enter
|
||||||
a value of 4. Now the RAM widget should only show one highlighted address:
|
a value of 4. Now the RAM widget should only show one highlighted address:
|
||||||
"00ba". What we did was search within our previous results (the ones that
|
"00ba". What we did was search within our previous results (the ones that
|
||||||
were 5 before) for the new value 4. Address $00ba used to have the value 5,
|
were 5 before) for the new value 4. Address $00ba used to have the value 5,
|
||||||
but now it has 4. This means that Battlezone (almost certainly) stores the
|
but now it has 4. This means that Battlezone (almost certainly) stores the
|
||||||
current number of lives at address $00ba.</li>
|
current number of lives at address $00ba.</li>
|
||||||
|
@ -1355,9 +1357,9 @@ but it helps to know at least a little about 6502 programming.</p>
|
||||||
Program Counter pointing to the instruction *after* the one that wrote
|
Program Counter pointing to the instruction *after* the one that wrote
|
||||||
to location $ba.</li>
|
to location $ba.</li>
|
||||||
|
|
||||||
<li>Once in the debugger, look at the ROM display. The PC should be at address
|
<li>Once in the debugger, look at the ROM display. The PC should be at address
|
||||||
$f238, instruction "LDA $e1". You want to examine a few instructions before
|
$f238, instruction "LDA $e1". You want to examine a few instructions before
|
||||||
the PC, so scroll up using the mouse or arrow keys. Do you see
|
the PC, so scroll up using the mouse or arrow keys. Do you see
|
||||||
the one that affects the lives counter? That's right, it's the "DEC $ba"
|
the one that affects the lives counter? That's right, it's the "DEC $ba"
|
||||||
at location $f236.</li>
|
at location $f236.</li>
|
||||||
|
|
||||||
|
@ -1382,9 +1384,9 @@ but it helps to know at least a little about 6502 programming.</p>
|
||||||
|
|
||||||
<pre> $ea $ea</pre>
|
<pre> $ea $ea</pre>
|
||||||
|
|
||||||
<p>Select the line at address $f236 and enter 'ROM patch' mode. This is done
|
<p>Select the line at address $f236 and enter 'ROM patch' mode. This is done
|
||||||
by either double-clicking the line, or pressing enter. Then delete the bytes
|
by either double-clicking the line, or pressing enter. Then delete the bytes
|
||||||
with backspace key and enter "ea ea". Another way to do this would have been
|
with backspace key and enter "ea ea". Another way to do this would have been
|
||||||
to enter "rom $f236 $ea $ea" in the Prompt widget.
|
to enter "rom $f236 $ea $ea" in the Prompt widget.
|
||||||
</li>
|
</li>
|
||||||
|
|
||||||
|
|
390
docs/index.html
390
docs/index.html
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Reference in New Issue