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| <h4 class="subsection">3.17.29 picoChip Options</h4> |
| |
| <p><a name="index-picoChip-options-1730"></a> |
| These ‘<samp><span class="samp">-m</span></samp>’ options are defined for picoChip implementations: |
| |
| <dl> |
| <dt><code>-mae=</code><var>ae_type</var><dd><a name="index-mcpu-1731"></a>Set the instruction set, register set, and instruction scheduling |
| parameters for array element type <var>ae_type</var>. Supported values |
| for <var>ae_type</var> are ‘<samp><span class="samp">ANY</span></samp>’, ‘<samp><span class="samp">MUL</span></samp>’, and ‘<samp><span class="samp">MAC</span></samp>’. |
| |
| <p><samp><span class="option">-mae=ANY</span></samp> selects a completely generic AE type. Code |
| generated with this option will run on any of the other AE types. The |
| code will not be as efficient as it would be if compiled for a specific |
| AE type, and some types of operation (e.g., multiplication) will not |
| work properly on all types of AE. |
| |
| <p><samp><span class="option">-mae=MUL</span></samp> selects a MUL AE type. This is the most useful AE type |
| for compiled code, and is the default. |
| |
| <p><samp><span class="option">-mae=MAC</span></samp> selects a DSP-style MAC AE. Code compiled with this |
| option may suffer from poor performance of byte (char) manipulation, |
| since the DSP AE does not provide hardware support for byte load/stores. |
| |
| <br><dt><code>-msymbol-as-address</code><dd>Enable the compiler to directly use a symbol name as an address in a |
| load/store instruction, without first loading it into a |
| register. Typically, the use of this option will generate larger |
| programs, which run faster than when the option isn't used. However, the |
| results vary from program to program, so it is left as a user option, |
| rather than being permanently enabled. |
| |
| <br><dt><code>-mno-inefficient-warnings</code><dd>Disables warnings about the generation of inefficient code. These |
| warnings can be generated, for example, when compiling code which |
| performs byte-level memory operations on the MAC AE type. The MAC AE has |
| no hardware support for byte-level memory operations, so all byte |
| load/stores must be synthesized from word load/store operations. This is |
| inefficient and a warning will be generated indicating to the programmer |
| that they should rewrite the code to avoid byte operations, or to target |
| an AE type which has the necessary hardware support. This option enables |
| the warning to be turned off. |
| |
| </dl> |
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