Converting RPMs to XDC Macros - Converting RPMs to XDC Macros - 2026.1 English - UG903

Automated Conversion Process

Follow these steps to automate the conversion:

1. In all HDL sources, replace each RPM attribute with a similarly named string. For example:
   • Replace hu_set with m_hu_set
   • Replace u_set with m_u_set
   • Replace rloc with m_rloc

   This prevents the RPMs from being processed, while still passing the inactive attributes to the synthesized netlist as cell properties.

2. Open the synthesized design or run link_design, and create XDC macros based on the inactive properties. For example, each HU_SET produces a cell property called m_hu_set that you can use to create the equivalent XDC macro. Each cell within the original HU_SET has a property m_rloc that you can convert into an RLOC.
3. Save the constraints, which now include the XDC macro definitions.

The best way to handle large-scale conversions is to use Tcl to build XDC macro cell lists based on their unique m_hu_set or m_uset values.

VHCL Conversion Example

The original VHDL source includes a HU_SET RPM called set0 with two cells, one with RLOC X0Y0 and the other with RLOC X0Y1.

signal r0 : std_logic; 
signal r1 : std_logic;

attribute hu_set : string; 
attribute rloc : string;

attribute hu_set of r0 : signal is "set0"; 
attribute hu_set of r1 : signal is "set0";

attribute rloc of r0 : signal is "X0Y0"; 
attribute rloc of r1 : signal is "X0Y1";

Next the VHDL source is modified to replace hu_set and RLOC with similarly named but inactive attributes:

signal r0 : std_logic; 
signal r1 : std_logic;

attribute m_hu_set : string; 
attribute m_rloc : string;

attribute m_hu_set of r0 : signal is "set0"; 
attribute m_hu_set of r1 : signal is "set0";

attribute m_rloc of r0 : signal is "X0Y0"; 
attribute m_rloc of r1 : signal is "X0Y1";

After synthesis, filter the cells by properties:

Vivado% get_cells -filter {m_hu_set == "set0"} 
r0_reg r1_reg

Vivado% get_property m_rloc [get_cells {r0_reg r1_reg}] 
X0Y0 X0Y1

This provides the necessary information to create an XDC macro to replace the RPM:

Vivado% create_macro set0
Vivado% update_macro set0 {r0_reg X0Y0 r1_reg X0Y1}

Save these XDC constraints as part of the design constraints.

Tcl Script Example for HU_SET Coversion

# create a sorted list of all unique RPMs according to m_hu_set values 
set RPMs [lsort -uniq [get_property m_hu_set [get_cells -hier -filter
{primitive_level != INTERNAL}]]]

# remove the first element which is empty (no m_hu_set property) 
set RPMs [lrange $RPMs 1 end]

# iterate over list of RPMs, convert each to an XDC macro
# get each RPM cell of the RPM with its RLOC
# build a list for the update_macro command
foreach rpm $RPMs {
  create_macro $rpm
  set cells [get_cells -hier -filter "m_hu_set == $rpm"]
  set rlocs [list]
  foreach cell $cells { lappend rlocs $cell
    lappend rlocs [get_property m_rloc $cell]
  }
  update_macro $rpm $rlocs
  puts "created XDC macro $rpm, cell list: rlocs"
}

This script finds all HU_SET-based RPMs, gathers their properties, and creates equivalent XDC macros automatically.