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Altera_Forum
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21 years ago

IORD_XDIRECT AND IOWR_XDIRECT?

Hello: Now I have some problems about the I/O Marco IORD_XDIRECT AND IOWR_XDIRECT.For example: I have a 16 bits slave periphery and the BEn0 ,BEn1 are both always low(means that th...
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Altera_Forum
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21 years ago

Hi mountain8848,

The stb and stbio are used to store a byte (from memory). The stbio instruction

bypasses the data cache, the stb does not.

The ldbu and ldbuio are used to load a byte (from memory). The lduio instruction

bypassess the data cache, the ldbu does not. The "u" just means that the

high-order bits in the target register are set to zero (unsigned) rather than

being sign-extended.

Regards,

--Scott