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| <h5 class="subsubsection">9.4.2.3 Relocatable Expression Modifiers</h5> |
| |
| <p><a name="index-AVR-modifiers-675"></a><a name="index-syntax_002c-AVR-676"></a> |
| The assembler supports several modifiers when using relocatable addresses |
| in AVR instruction operands. The general syntax is the following: |
| |
| <pre class="smallexample"> modifier(relocatable-expression) |
| </pre> |
| |
| <a name="index-symbol-modifiers-677"></a> |
| <dl> |
| <dt><code>lo8</code><dd> |
| This modifier allows you to use bits 0 through 7 of |
| an address expression as 8 bit relocatable expression. |
| |
| <br><dt><code>hi8</code><dd> |
| This modifier allows you to use bits 7 through 15 of an address expression |
| as 8 bit relocatable expression. This is useful with, for example, the |
| AVR ‘<samp><span class="samp">ldi</span></samp>’ instruction and ‘<samp><span class="samp">lo8</span></samp>’ modifier. |
| |
| <p>For example |
| |
| <pre class="smallexample"> ldi r26, lo8(sym+10) |
| ldi r27, hi8(sym+10) |
| </pre> |
| <br><dt><code>hh8</code><dd> |
| This modifier allows you to use bits 16 through 23 of |
| an address expression as 8 bit relocatable expression. |
| Also, can be useful for loading 32 bit constants. |
| |
| <br><dt><code>hlo8</code><dd> |
| Synonym of ‘<samp><span class="samp">hh8</span></samp>’. |
| |
| <br><dt><code>hhi8</code><dd> |
| This modifier allows you to use bits 24 through 31 of |
| an expression as 8 bit expression. This is useful with, for example, the |
| AVR ‘<samp><span class="samp">ldi</span></samp>’ instruction and ‘<samp><span class="samp">lo8</span></samp>’, ‘<samp><span class="samp">hi8</span></samp>’, ‘<samp><span class="samp">hlo8</span></samp>’, |
| ‘<samp><span class="samp">hhi8</span></samp>’, modifier. |
| |
| <p>For example |
| |
| <pre class="smallexample"> ldi r26, lo8(285774925) |
| ldi r27, hi8(285774925) |
| ldi r28, hlo8(285774925) |
| ldi r29, hhi8(285774925) |
| ; r29,r28,r27,r26 = 285774925 |
| </pre> |
| <br><dt><code>pm_lo8</code><dd> |
| This modifier allows you to use bits 0 through 7 of |
| an address expression as 8 bit relocatable expression. |
| This modifier useful for addressing data or code from |
| Flash/Program memory. The using of ‘<samp><span class="samp">pm_lo8</span></samp>’ similar |
| to ‘<samp><span class="samp">lo8</span></samp>’. |
| |
| <br><dt><code>pm_hi8</code><dd> |
| This modifier allows you to use bits 8 through 15 of |
| an address expression as 8 bit relocatable expression. |
| This modifier useful for addressing data or code from |
| Flash/Program memory. |
| |
| <br><dt><code>pm_hh8</code><dd> |
| This modifier allows you to use bits 15 through 23 of |
| an address expression as 8 bit relocatable expression. |
| This modifier useful for addressing data or code from |
| Flash/Program memory. |
| |
| </dl> |
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