阅读ram.bin 机制，添加一些注释

build/build_flash_kl3.sh

@@ -714,6 +714,7 @@ build_obj_func() {
             plc_make_starttime=$(date +%s)
             export build_amp_type=2
         else
+            # CUS?
             cus_make_starttime=$(date +%s)
             export build_amp_type=1
         fi
@@ -929,6 +930,7 @@ build_obj_func() {
 echo "start building: $0 $@ , $(date +%Y-%m-%d\ %H:%M:%S)"
 if [ "${DEF_CORE_TYPE}" == "ampplc" ]; then
     build_obj_func ${DEF_IMAGE_TYPE} ${DEF_CUS_APP} CUS
+    # 这里生成ld文件是为了plc程序可以调用
     echo "build_flash_kl3.sh call make_ld.sh."
     ../tools/rom_img/make_ld.sh --addrs ../ap/.output/cus/lib/ht_${DEF_IMAGE_TYPE}.out \
     ../startup/ldscripts/riscv3/amp_cus_symbol > ../startup/ldscripts/riscv3/cus.addrs.ld