diff --git a/cmake/emu/nsim.cmake b/cmake/emu/nsim.cmake
index a187cdad03e..323593fc1d8 100644
--- a/cmake/emu/nsim.cmake
+++ b/cmake/emu/nsim.cmake
@@ -13,14 +13,13 @@ if(CONFIG_MP_MAX_NUM_CPUS GREATER 1)
   set(MULTIFILES ${MDB} -multifiles=)
   foreach(val RANGE ${CONFIG_MP_MAX_NUM_CPUS})
     if(val LESS CONFIG_MP_MAX_NUM_CPUS)
-      MATH(EXPR PSET_NUM "${CONFIG_MP_MAX_NUM_CPUS}-${val}")
-      MATH(EXPR CORE_NUM "${CONFIG_MP_MAX_NUM_CPUS}-${val}-1")
-      if(PSET_NUM GREATER 0)
-        list(APPEND MDB_OPTIONS &&)
-      endif()
-      list(APPEND MDB_OPTIONS ${MDB} -pset=${PSET_NUM} -psetname=core${CORE_NUM})
+      MATH(EXPR PSET_NUM "${val}+1")
+      set(CORE_NUM ${val})
+      list(APPEND MDB_OPTIONS && ${MDB} -pset=${PSET_NUM} -psetname=core${CORE_NUM})
       if(PSET_NUM GREATER 1)
         list(APPEND MDB_OPTIONS -prop=download=2)
+      endif()
+      if(PSET_NUM LESS ${CONFIG_MP_MAX_NUM_CPUS})
         set(MULTIFILES ${MULTIFILES}core${CORE_NUM},)
       else()
         set(MULTIFILES ${MULTIFILES}core${CORE_NUM})