Auto format constants in decimal or hex

litex/gen/fhdl/verilog.py

@@ -29,6 +29,7 @@
 from litex.gen import LiteXContext
 from litex.gen.fhdl.namer import build_signal_namespace
 from litex.gen.fhdl.hierarchy import LiteXHierarchyExplorer
+from litex.gen.format import format_constant
 
 from litex.build.tools import get_litex_git_revision
 
@@ -165,10 +166,10 @@ def _generate_hierarchy(top):
 # Print Constant -----------------------------------------------------------------------------------
 
 def _generate_constant(node):
- return "{sign}{bits}'d{value}".format(
+ return "{sign}{bits}'{value}".format(
  sign = "" if node.value >= 0 else "-",
  bits = str(node.nbits),
- value = abs(node.value),
+ value = format_constant(abs(node.value), verilog=True),
  ), node.signed
 
 # Print Signal -------------------------------------------------------------------------------------

litex/gen/format.py

@@ -0,0 +1,34 @@
+
+def format_constant(c, verilog:bool = False):
+ """Automatically format constants based on type and value.
+
+ If the argument `verilog` isn't provided, a 'c' style constant is generated.
+
+ Integer constants are formatted as decimal or hexadecimal depending on which
+ value will give the clearest representation, as indicated by the least unique
+ numbers in the string representation.
+
+ NOTE: Integers below 100 are always formatted as decimal.
+
+ Parameters
+ ----------
+ c : any
+ constant to format. Only integer constants are formatted.
+
+ verilog : bool, optional
+ Format for verilog (default is False)
+
+ Raises
+ ------
+ None
+ """
+
+ if not isinstance(c, int):
+ return c
+
+ d, x = f"{c:d}", f"{c:x}"
+ decimal = abs(c) < 100 or len(set(d)) <= len(set(x))
+ if verilog:
+ return "d" + d if decimal else "h" + x
+ else:
+ return d if decimal else "0x" + x

litex/soc/integration/export.py

@@ -28,6 +28,7 @@
 
 from migen import *
 
+from litex.gen.format import format_constant
 from litex.soc.interconnect.csr import CSRStatus
 from litex.soc.integration.soc import SoCRegion
 
@@ -181,7 +182,7 @@ def get_soc_header(constants, with_access_functions=True):
  value = "\"" + value + "\""
  ctype = "const char *"
  else:
- value = str(value)
+ value = format_constant(value)
  ctype = "int"
  r += "#define "+name+" "+value+"\n"
  if with_access_functions: