The code you've posted does not seem to match what you're asking for. According to your code, it appears that you're trying to compare values across columns in the same row, not a different row. So which is it?
Anyway, assuming that your code is indicative of what you want, be sure to look at the docs for the the renderer: http://docs.sencha.com/extjs/4.2.1/#!/api/Ext.grid.column.Column-cfg-renderer
One of the arguments passed to the renderer method is the "record", which will contain all the values for the record which is filling the values for the entire row. If you wanted to compare values across columns, you could do something like:
if( value==record.get( 'csv ') ) {
...do something here...
}
If you really need to compare values across rows, then the "store" also gets passed as one of the arguments to renderer, so you could compare values against specific row values that way.
Alternatively, you could do most of this in Model itself. If you are just comparing columns in the same row, you could create an additional field in your Model that stores the result of the comparison. If you did that, all that your renderer would need to do is switch on the value of that new field, rather than doing the entire comparison AND rendering.