How to Use altivec?

[varunkjayan]

hi

i am using the T4240rdb board i want to know how to enable altivec feature is it built in

in the t4240rdb fsl-image-core and how can we exploit the altivec feature is there any code or command for that

[bpe]

Altivec is a feature of e6500 core accessed by special command subset.

In kernel, it is enabled by CONFIG_ALTIVEC option which is enabled in the SDK default configuration

for all supported e6500-based processors/boards.

For user space,  '-maltivec' GCC option allows the compiler to utilize Altivec instructions. Again,

the SDK sets this flag when it builds rootfs by default.

Have a great day,
Platon

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[varunkjayan]

thank you for replying i have one more question 

for example if we are going to add some 4000 matrices and then use this altivec feature will it help in reducing the computation time significantly than the normal compiling and executing

[bpe]

Read the materials at the links below for more information on  Altivec support in GCC:

PowerPC AltiVec Built-in Functions - Using the GNU Compiler Collection (GCC)

An Introduction to GCC Compiler Intrinsics in Vector Processing | Linux Journal

How to activate ALTIVEC2 in gcc ?