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- <a name="S12Z-Addressing-Modes"></a>
- <div class="header">
- <p>
- Next: <a href="S12Z-Register-Notation.html#S12Z-Register-Notation" accesskey="n" rel="next">S12Z Register Notation</a>, Previous: <a href="S12Z-Syntax-Overview.html#S12Z-Syntax-Overview" accesskey="p" rel="prev">S12Z Syntax Overview</a>, Up: <a href="S12Z-Syntax.html#S12Z-Syntax" accesskey="u" rel="up">S12Z Syntax</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="AS-Index.html#AS-Index" title="Index" rel="index">Index</a>]</p>
- </div>
- <hr>
- <a name="Addressing-Modes-3"></a>
- <h4 class="subsubsection">9.24.2.2 Addressing Modes</h4>
- <a name="index-S12Z-addressing-modes"></a>
- <a name="index-addressing-modes_002c-S12Z"></a>
-
- <p>The following addressing modes are understood for the S12Z.
- </p><dl compact="compact">
- <dt><em>Immediate</em></dt>
- <dd><p>‘<samp>#<var>number</var></samp>’
- </p>
- </dd>
- <dt><em>Immediate Bit Field</em></dt>
- <dd><p>‘<samp>#<var>width</var>:<var>offset</var></samp>’
- </p>
- <p>Bit field instructions in the immediate mode require the width and offset to
- be specified.
- The <var>width</var> parameter specifies the number of bits in the field.
- It should be a number in the range [1,32].
- <var>Offset</var> determines the position within the field where the operation
- should start.
- It should be a number in the range [0,31].
- </p>
- </dd>
- <dt><em>Relative</em></dt>
- <dd><p>‘<samp>*<var>symbol</var></samp>’, or ‘<samp>*[+-]<var>digits</var></samp>’
- </p>
- <p>Program counter relative addresses have a width of 15 bits.
- Thus, they must be within the range [-32768, 32767].
- </p>
- </dd>
- <dt><em>Register</em></dt>
- <dd><p>‘<samp><var>reg</var></samp>’
- </p>
- <a name="index-register-names_002c-S12Z"></a>
- <p>Some instructions accept a register as an operand.
- In general, <var>reg</var> may be a
- data register (‘<samp>D0</samp>’, ‘<samp>D1</samp>’ … ‘<samp>D7</samp>’),
- the ‘<samp>X</samp>’ register or the ‘<samp>Y</samp>’ register.
- </p>
- <p>A few instructions accept as an argument the stack pointer
- register (‘<samp>S</samp>’), and/or the program counter (‘<samp>P</samp>’).
- </p>
- <p>Some very special instructions accept arguments which refer to the
- condition code register. For these arguments the syntax is
- ‘<samp>CCR</samp>’, ‘<samp>CCH</samp>’ or ‘<samp>CCL</samp>’ which refer to the complete
- condition code register, the condition code register high byte
- and the condition code register low byte respectively.
- </p>
-
- </dd>
- <dt><em>Absolute Direct</em></dt>
- <dd><p>‘<samp><var>symbol</var></samp>’, or ‘<samp><var>digits</var></samp>’
- </p>
- </dd>
- <dt><em>Absolute Indirect</em></dt>
- <dd><p>‘<samp>[<var>symbol</var></samp>’, or ‘<samp><var>digits</var>]</samp>’
- </p>
-
- </dd>
- <dt><em>Constant Offset Indexed</em></dt>
- <dd><p>‘<samp>(<var>number</var>,<var>reg</var>)</samp>’
- </p>
- <p><var>Reg</var> may be either ‘<samp>X</samp>’, ‘<samp>Y</samp>’, ‘<samp>S</samp>’ or
- ‘<samp>P</samp>’ or one of the data registers ‘<samp>D0</samp>’, ‘<samp>D1</samp>’ …
- ‘<samp>D7</samp>’.
- If any of the registers ‘<samp>D2</samp>’ … ‘<samp>D5</samp>’ are specified, then the
- register value is treated as a signed value.
- Otherwise it is treated as unsigned.
- <var>Number</var> may be any integer in the range [-8388608,8388607].
- </p>
- </dd>
- <dt><em>Offset Indexed Indirect</em></dt>
- <dd><p>‘<samp>[<var>number</var>,<var>reg</var>]</samp>’
- </p>
- <p><var>Reg</var> may be either ‘<samp>X</samp>’, ‘<samp>Y</samp>’, ‘<samp>S</samp>’ or
- ‘<samp>P</samp>’.
- <var>Number</var> may be any integer in the range [-8388608,8388607].
- </p>
- </dd>
- <dt><em>Auto Pre-Increment/Pre-Decrement/Post-Increment/Post-Decrement</em></dt>
- <dd><p>‘<samp>-<var>reg</var></samp>’,
- ‘<samp>+<var>reg</var></samp>’,
- ‘<samp><var>reg</var>-</samp>’ or
- ‘<samp><var>reg</var>+</samp>’
- </p>
- <p>This addressing mode is typically used to access a value at an address,
- and simultaneously to increment/decrement the register pointing to that
- address.
- Thus <var>reg</var> may be any of the 24 bit registers ‘<samp>X</samp>’, ‘<samp>Y</samp>’, or
- ‘<samp>S</samp>’.
- Pre-increment and post-decrement are not available for
- register ‘<samp>S</samp>’ (only post-increment and pre-decrement are available).
- </p>
- </dd>
- <dt><em>Register Offset Direct</em></dt>
- <dd><p>‘<samp>(<var>data-reg</var>,<var>reg</var>)</samp>’
- </p>
- <p><var>Reg</var> can be either ‘<samp>X</samp>’, ‘<samp>Y</samp>’, or ‘<samp>S</samp>’.
- <var>Data-reg</var>
- must be one of the data registers ‘<samp>D0</samp>’, ‘<samp>D1</samp>’ … ‘<samp>D7</samp>’.
- If any of the registers ‘<samp>D2</samp>’ … ‘<samp>D5</samp>’ are specified, then
- the register value is treated as a signed value.
- Otherwise it is treated as unsigned.
- </p>
- </dd>
- <dt><em>Register Offset Indirect</em></dt>
- <dd><p>‘<samp>[<var>data-reg</var>,<var>reg</var>]</samp>’
- </p>
- <p><var>Reg</var> can be either ‘<samp>X</samp>’ or ‘<samp>Y</samp>’.
- <var>Data-reg</var>
- must be one of the data registers ‘<samp>D0</samp>’, ‘<samp>D1</samp>’ … ‘<samp>D7</samp>’.
- If any of the registers ‘<samp>D2</samp>’ … ‘<samp>D5</samp>’ are specified, then
- the register value is treated as a signed value.
- Otherwise it is treated as unsigned.
- </p></dd>
- </dl>
-
- <p>For example:
- </p>
- <div class="smallexample">
- <pre class="smallexample"> trap #197 ;; Immediate mode
- bra *+49 ;; Relative mode
- bra .L0 ;; ditto
- jmp 0xFE0034 ;; Absolute direct mode
- jmp [0xFD0012] ;; Absolute indirect mode
- inc.b (4,x) ;; Constant offset indexed mode
- jsr (45, d0) ;; ditto
- dec.w [4,y] ;; Constant offset indexed indirect mode
- clr.p (-s) ;; Pre-decrement mode
- neg.l (d0, s) ;; Register offset direct mode
- com.b [d1, x] ;; Register offset indirect mode
- psh cch ;; Register mode
- </pre></div>
-
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- Next: <a href="S12Z-Register-Notation.html#S12Z-Register-Notation" accesskey="n" rel="next">S12Z Register Notation</a>, Previous: <a href="S12Z-Syntax-Overview.html#S12Z-Syntax-Overview" accesskey="p" rel="prev">S12Z Syntax Overview</a>, Up: <a href="S12Z-Syntax.html#S12Z-Syntax" accesskey="u" rel="up">S12Z Syntax</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="AS-Index.html#AS-Index" title="Index" rel="index">Index</a>]</p>
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