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Altera_Forum
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11 years ago

How to pad or extend the most significant bit (bit 23) into bits 24 through 31

Hi, As suggested by forumer kflynn (http://www.alteraforum.com/forum/member.php?u=86819) in this link (http://www.alteraforum.com/forum/showthread.php?t=48398), the below issue can be resolved ...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
11 years ago

since you are using Nios, this operation could be easily converted to simple custom instruction, something like: 


module ci_pad(
    input  dataa,
    output  result
);
assign result = { {8{dataa}}, dataa};
endmodule

alternatively, as PietervanderStar suggested (in C): 


value = (value & (0x1 << 24)) ?
    value | (0xFF << 24 ) :
    value;