Use 64 bits, as it is nowadays the standard.

jmgc · jmgc · commit 32fcbed1f4cf · 2024-05-12T12:43:12.000+02:00
diff --git a/cosimulation/modelsim/Makefile b/cosimulation/modelsim/Makefile
@@ -1,6 +1,6 @@
 # This makefile assumes that 32bit Modelsim is installed.
 # If you have a 64 bit version, run 'ARCH=64 make'
-ARCH?=32
+ARCH?=64
 CFLAGS_32= -m32
 CFLAGS_64= -m64
 
