Program no longer compiling

[j64c]

Hi Guys,

I have been playing around with Assembly on the Arduino and al was going great yesterday. Now today when I open my project compilation fails early declaring the function in the '.S' file.

Summary

one.S:5:1: error: expected unqualified-id before '.' token
.global start

My '.ino' file

extern "C" 
{
  void start();
  void forever();
}

void setup()
{
  noInterrupts();
  start();
}

void loop() 
{
  forever();
}

And the '.S' file

#define __SFR_OFFSET 0

#include "avr/io.h"

.global start
.global forever

start:
    SBI DDRB, 2
    RET

forever:
L1:
    LDI R16, 0x00
    SBI PORTB, 2

LOOP1:    
    INC R16
    CPI R16, 0x0A
    BRNE LOOP1
    JMP L2

L2:    
    CBI PORTB, 2
    JMP L1

And the error log

Arduino: 1.8.16 (Windows 10), Board: "Arduino Uno"

P:\Arduino\One\one.S:1:0: warning: "__SFR_OFFSET" redefined

 #define __SFR_OFFSET 0

 

In file included from c:\program files (x86)\arduino\hardware\tools\avr\avr\include\avr\io.h:99:0,

                 from c:\program files (x86)\arduino\hardware\tools\avr\avr\include\avr\pgmspace.h:90,

                 from C:\Program Files (x86)\Arduino\hardware\arduino\avr\cores\arduino/Arduino.h:28,

                 from sketch\one.S.cpp:1:

c:\program files (x86)\arduino\hardware\tools\avr\avr\include\avr\sfr_defs.h:172:0: note: this is the location of the previous definition

 #    define __SFR_OFFSET 0x20

 

one.S:5:1: error: expected unqualified-id before '.' token

 .global start

 ^

P:\Arduino\One\one.ino: In function 'void setup()':

one:10:3: error: 'start' was not declared in this scope

   start();

   ^~~~~

P:\Arduino\One\one.ino:10:3: note: suggested alternative: 'sqrt'

   start();

   ^~~~~

   sqrt

P:\Arduino\One\one.ino: In function 'void loop()':

one:15:3: error: 'forever' was not declared in this scope

   forever();

   ^~~~~~~

P:\Arduino\One\one.ino:15:3: note: suggested alternative: 'free'

   forever();

   ^~~~~~~

   free

exit status 1

expected unqualified-id before '.' token



This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.

It's got me stumped as it was compiling all day yesterday without a hitch.

Any advice would be greatly appreciated.

Many thanks in advance!

[MarkT]

@j64c

from sketch\one.S.cpp:1:

That's suspicious, something's adding a .cpp suffix.

[j64c]

Hi Mark,

A weird thing I just found (that makes it work), is if I make a backup of the '.S' file, delete the original file so it doesn't appear in the editor, then rename the backup to the original filename again, it compiles happily. Any changes I make in the '.S' file (via notepad) take affect also.

So if the file appears in the editor, it won't compile. If it's not in the editor, it will compile.

I can't see any way of closing the '.S' file from the editor without deleting it, using the method mentioned above.

Very strange. I have a sort of workaround, but not really ideal.

[j64c]

This is what the log file looks like using the above method.

I'm not sure how it's building the '.S' file as it says "Using previously compiled file:", but it certainly is making the changes that I'm doing on the assembly file in an external editor.

C:\Program Files (x86)\Arduino\arduino-builder -dump-prefs -logger=machine -hardware C:\Program Files (x86)\Arduino\hardware -tools C:\Program Files (x86)\Arduino\tools-builder -tools C:\Program Files (x86)\Arduino\hardware\tools\avr -built-in-libraries C:\Program Files (x86)\Arduino\libraries -libraries C:\Users\User\Documents\Arduino\libraries -fqbn=arduino:avr:uno -vid-pid=2341_0043 -ide-version=10816 -build-path C:\Users\User\AppData\Local\Temp\arduino_build_386948 -warnings=none -build-cache C:\Users\User\AppData\Local\Temp\arduino_cache_442155 -prefs=build.warn_data_percentage=75 -prefs=runtime.tools.arduinoOTA.path=C:\Program Files (x86)\Arduino\hardware\tools\avr -prefs=runtime.tools.arduinoOTA-1.3.0.path=C:\Program Files (x86)\Arduino\hardware\tools\avr -prefs=runtime.tools.avrdude.path=C:\Program Files (x86)\Arduino\hardware\tools\avr -prefs=runtime.tools.avrdude-6.3.0-arduino17.path=C:\Program Files (x86)\Arduino\hardware\tools\avr -prefs=runtime.tools.avr-gcc.path=C:\Program Files (x86)\Arduino\hardware\tools\avr -prefs=runtime.tools.avr-gcc-7.3.0-atmel3.6.1-arduino7.path=C:\Program Files (x86)\Arduino\hardware\tools\avr -verbose P:\Arduino\VGA\vga.ino
C:\Program Files (x86)\Arduino\arduino-builder -compile -logger=machine -hardware C:\Program Files (x86)\Arduino\hardware -tools C:\Program Files (x86)\Arduino\tools-builder -tools C:\Program Files (x86)\Arduino\hardware\tools\avr -built-in-libraries C:\Program Files (x86)\Arduino\libraries -libraries C:\Users\User\Documents\Arduino\libraries -fqbn=arduino:avr:uno -vid-pid=2341_0043 -ide-version=10816 -build-path C:\Users\User\AppData\Local\Temp\arduino_build_386948 -warnings=none -build-cache C:\Users\User\AppData\Local\Temp\arduino_cache_442155 -prefs=build.warn_data_percentage=75 -prefs=runtime.tools.arduinoOTA.path=C:\Program Files (x86)\Arduino\hardware\tools\avr -prefs=runtime.tools.arduinoOTA-1.3.0.path=C:\Program Files (x86)\Arduino\hardware\tools\avr -prefs=runtime.tools.avrdude.path=C:\Program Files (x86)\Arduino\hardware\tools\avr -prefs=runtime.tools.avrdude-6.3.0-arduino17.path=C:\Program Files (x86)\Arduino\hardware\tools\avr -prefs=runtime.tools.avr-gcc.path=C:\Program Files (x86)\Arduino\hardware\tools\avr -prefs=runtime.tools.avr-gcc-7.3.0-atmel3.6.1-arduino7.path=C:\Program Files (x86)\Arduino\hardware\tools\avr -verbose P:\Arduino\VGA\vga.ino
Using board 'uno' from platform in folder: C:\Program Files (x86)\Arduino\hardware\arduino\avr
Using core 'arduino' from platform in folder: C:\Program Files (x86)\Arduino\hardware\arduino\avr
Detecting libraries used...
"C:\\Program Files (x86)\\Arduino\\hardware\\tools\\avr/bin/avr-g++" -c -g -Os -w -std=gnu++11 -fpermissive -fno-exceptions -ffunction-sections -fdata-sections -fno-threadsafe-statics -Wno-error=narrowing -flto -w -x c++ -E -CC -mmcu=atmega328p -DF_CPU=16000000L -DARDUINO=10816 -DARDUINO_AVR_UNO -DARDUINO_ARCH_AVR "-IC:\\Program Files (x86)\\Arduino\\hardware\\arduino\\avr\\cores\\arduino" "-IC:\\Program Files (x86)\\Arduino\\hardware\\arduino\\avr\\variants\\standard" "C:\\Users\\User\\AppData\\Local\\Temp\\arduino_build_386948\\sketch\\vga.ino.cpp" -o nul
Generating function prototypes...
"C:\\Program Files (x86)\\Arduino\\hardware\\tools\\avr/bin/avr-g++" -c -g -Os -w -std=gnu++11 -fpermissive -fno-exceptions -ffunction-sections -fdata-sections -fno-threadsafe-statics -Wno-error=narrowing -flto -w -x c++ -E -CC -mmcu=atmega328p -DF_CPU=16000000L -DARDUINO=10816 -DARDUINO_AVR_UNO -DARDUINO_ARCH_AVR "-IC:\\Program Files (x86)\\Arduino\\hardware\\arduino\\avr\\cores\\arduino" "-IC:\\Program Files (x86)\\Arduino\\hardware\\arduino\\avr\\variants\\standard" "C:\\Users\\User\\AppData\\Local\\Temp\\arduino_build_386948\\sketch\\vga.ino.cpp" -o "C:\\Users\\User\\AppData\\Local\\Temp\\arduino_build_386948\\preproc\\ctags_target_for_gcc_minus_e.cpp"
"C:\\Program Files (x86)\\Arduino\\tools-builder\\ctags\\5.8-arduino11/ctags" -u --language-force=c++ -f - --c++-kinds=svpf --fields=KSTtzns --line-directives "C:\\Users\\User\\AppData\\Local\\Temp\\arduino_build_386948\\preproc\\ctags_target_for_gcc_minus_e.cpp"
Compiling sketch...
Using previously compiled file: C:\Users\User\AppData\Local\Temp\arduino_build_386948\sketch\vga.S.o
"C:\\Program Files (x86)\\Arduino\\hardware\\tools\\avr/bin/avr-g++" -c -g -Os -w -std=gnu++11 -fpermissive -fno-exceptions -ffunction-sections -fdata-sections -fno-threadsafe-statics -Wno-error=narrowing -MMD -flto -mmcu=atmega328p -DF_CPU=16000000L -DARDUINO=10816 -DARDUINO_AVR_UNO -DARDUINO_ARCH_AVR "-IC:\\Program Files (x86)\\Arduino\\hardware\\arduino\\avr\\cores\\arduino" "-IC:\\Program Files (x86)\\Arduino\\hardware\\arduino\\avr\\variants\\standard" "C:\\Users\\User\\AppData\\Local\\Temp\\arduino_build_386948\\sketch\\vga.ino.cpp" -o "C:\\Users\\User\\AppData\\Local\\Temp\\arduino_build_386948\\sketch\\vga.ino.cpp.o"
Compiling libraries...
Compiling core...
Using precompiled core: C:\Users\User\AppData\Local\Temp\arduino_cache_442155\core\core_arduino_avr_uno_0c812875ac70eb4a9b385d8fb077f54c.a
Linking everything together...
"C:\\Program Files (x86)\\Arduino\\hardware\\tools\\avr/bin/avr-gcc" -w -Os -g -flto -fuse-linker-plugin -Wl,--gc-sections -mmcu=atmega328p -o "C:\\Users\\User\\AppData\\Local\\Temp\\arduino_build_386948/vga.ino.elf" "C:\\Users\\User\\AppData\\Local\\Temp\\arduino_build_386948\\sketch\\vga.S.o" "C:\\Users\\User\\AppData\\Local\\Temp\\arduino_build_386948\\sketch\\vga.ino.cpp.o" "C:\\Users\\User\\AppData\\Local\\Temp\\arduino_build_386948/..\\arduino_cache_442155\\core\\core_arduino_avr_uno_0c812875ac70eb4a9b385d8fb077f54c.a" "-LC:\\Users\\User\\AppData\\Local\\Temp\\arduino_build_386948" -lm
"C:\\Program Files (x86)\\Arduino\\hardware\\tools\\avr/bin/avr-objcopy" -O ihex -j .eeprom --set-section-flags=.eeprom=alloc,load --no-change-warnings --change-section-lma .eeprom=0 "C:\\Users\\User\\AppData\\Local\\Temp\\arduino_build_386948/vga.ino.elf" "C:\\Users\\User\\AppData\\Local\\Temp\\arduino_build_386948/vga.ino.eep"
"C:\\Program Files (x86)\\Arduino\\hardware\\tools\\avr/bin/avr-objcopy" -O ihex -R .eeprom "C:\\Users\\User\\AppData\\Local\\Temp\\arduino_build_386948/vga.ino.elf" "C:\\Users\\User\\AppData\\Local\\Temp\\arduino_build_386948/vga.ino.hex"
"C:\\Program Files (x86)\\Arduino\\hardware\\tools\\avr/bin/avr-size" -A "C:\\Users\\User\\AppData\\Local\\Temp\\arduino_build_386948/vga.ino.elf"
Sketch uses 478 bytes (1%) of program storage space. Maximum is 32256 bytes.
Global variables use 9 bytes (0%) of dynamic memory, leaving 2039 bytes for local variables. Maximum is 2048 bytes.