Directives, or the set_directive_* commands,
can be specified as Tcl commands that are associated with a specific solution, or set of
solutions. Allowing you to customize the synthesis results for the same source code
across different solutions. This lets you preserve the original code while engaging in
what-if analysis of the design.
Directives must be run in the interactive mode, vitis_hls -i, or can be run as a script using the -f option as described in vitis, v++, and vitis-run Commands.
Pragmas are directives that you can apply in the source code, rather than as a
Tcl script, and so change the synthesis results for all implementations of your code.
There are HLS pragmas for every set_directive command,
so you can choose how you want to work with your AMD Vitis™ HLS project. Refer to HLS Pragmas for information on the different pragmas.
Directives and pragmas are also available through the Vitis HLS IDE for assignment to specific elements of your source code, as described in Adding Pragmas and Directives.