Makefile related syntax summary (openc910)

1. @   Indicates that the following instruction information will not be displayed during execution , example ：

2. $  Replace stay makefile Variables defined in or variables defined on the command line , example ：

3. (findstring FIND,IN) stay “IN” Find in “FIND” , Return if present “FIND”, Otherwise, it returns empty

4. -s Do not display content on the screen when executing commands （ Execution process ）

5. $(warning TEXT…) Non fatal error , Print tips only “ TEXT…”, make The execution process of continues

6. $(error TEXT…) Fatal error , Printing tips “ TEXT…” Information , And exit make Implementation

7. “ifeq” else”“endif” Can't use [Tab] Key as start （ Otherwise it's considered an order ）, example ：

8. stay makefile in ,tab And spaces are strictly separated

• With TAB The first is shell Script Syntax , Statements are passed directly to shell To analyze
• Such as ： echo The order is shell grammar , Can only tab start
• What starts with a space is makefile grammar
• Such as ：ifneq yes makefile grammar , Can only start with a space

9. make It's reading Makefile The value of the conditional expression is calculated , And select the execution statement according to the value of the conditional expression

10. When in shell In execution make On command ,make The working process is as follows ：

•         1）、make The name will be found in the current directory “Makefile” or “makefile” The file of
•         2）、 Find the first target file in the file , And take this document as the final target document
•         3）、 If the first target file does not exist , Or the following dependent files ( .o) The modification time is newer than the first object file , that , He will execute the commands defined later to generate the object file
•         4）、 If the dependent file does not exist , that make The entry that generates the dependent file will be found in the current file , First execute it to generate dependent files .o file , Then come back to generate the target file
• notes ： If the dependent file does not exist , First execute the commands in the dependency , Generate dependency file , Then execute the following command

11. usage 1：

  analysis ：

1.  SRC=$(wildcard *.S) # Get all in the current directory .S file name

2. $( SRC: %.S=%.o) or ${ SRC: %.S=%.o }  # Put variables SRC Every... In ⼀ End of values ⽤ %.o Replace %.S

12. usage 2：

analysis ：

1. find ./tests/lib/ -maxdepth 1 -type f -exec cp {} ./work/ \;

• ./tests/lib/ Find the path
• -maxdepth 1 In depth 1 The place of , That is, under the current path file
• -type f     The document type is general
• -exec cp {} ./work/ \   Carry out orders cp {} ./work/ \, Copy the found file to work Next

2.  cd ./work && make -s clean && make -s all CPU_ARCH_FLAG_0=c910

• Execute first cd ./work
• Re execution make -s clean
• Re execution make -s all
• Pass parameters CPU_ARCH_FLAG_0=c910