text: import os
  
  # toolchains options
  ARCH='arm'
  CPU='cortex-m4'
  CROSS_TOOL='keil'
  
  if os.getenv('RTT_CC'):
  	CROSS_TOOL = os.getenv('RTT_CC')
  
  # cross_tool provides the cross compiler
  # EXEC_PATH is the compiler execute path, for example, CodeSourcery, Keil MDK, IAR
  
  if  CROSS_TOOL == 'gcc':
  	PLATFORM 	= 'gcc'
  	EXEC_PATH 	= 'D:/SourceryGCC/bin'
  elif CROSS_TOOL == 'keil':
  	PLATFORM 	= 'armcc'
  	EXEC_PATH 	= 'C:/Keil_v5'
  elif CROSS_TOOL == 'iar':
      print('================ERROR============================')
      print('Not support iar yet!')
      print('=================================================')
      exit(0)
  
  if os.getenv('RTT_EXEC_PATH'):
  	EXEC_PATH = os.getenv('RTT_EXEC_PATH')
  
  BUILD = 'debug'
  
  if PLATFORM == 'gcc':
      # toolchains
      PREFIX = 'arm-none-eabi-'
      CC = PREFIX + 'gcc'
      AS = PREFIX + 'gcc'
      AR = PREFIX + 'ar'
      LINK = PREFIX + 'gcc'
      TARGET_EXT = 'elf'
      SIZE = PREFIX + 'size'
      OBJDUMP = PREFIX + 'objdump'
      OBJCPY = PREFIX + 'objcopy'
  
      DEVICE = ' -mcpu=cortex-m4 -mthumb -ffunction-sections -fdata-sections'
      CFLAGS = DEVICE
      AFLAGS = ' -c' + DEVICE + ' -x assembler-with-cpp'
      LFLAGS = DEVICE + ' -Wl,--gc-sections,-Map=rtthread-nrf52832.map,-cref,-u,Reset_Handler -T nrf52_xxaa.ld'
  
      CPATH = ''
      LPATH = ''
  
      if BUILD == 'debug':
          CFLAGS += ' -O0 -gdwarf-2'
          AFLAGS += ' -gdwarf-2'
      else:
          CFLAGS += ' -O2'
  
      POST_ACTION = OBJCPY + ' -O binary $TARGET rtthread.bin\n' + SIZE + ' $TARGET \n'
  
  elif PLATFORM == 'armcc':
      # toolchains
      CC = 'armcc'
      AS = 'armasm'
      AR = 'armar'
      LINK = 'armlink'
      TARGET_EXT = 'axf'
  
      DEVICE = ' --device DARMSTM'
      CFLAGS = DEVICE + ' --apcs=interwork'
      AFLAGS = DEVICE
      LFLAGS = DEVICE + ' --info sizes --info totals --info unused --info veneers --list rtthread-nrf52832.map --scatter rtthread-nrf52832.sct'
  
      CFLAGS += ' --c99'
      CFLAGS += ' -I' + EXEC_PATH + '/ARM/RV31/INC'
      LFLAGS += ' --libpath ' + EXEC_PATH + '/ARM/RV31/LIB'
  
      EXEC_PATH += '/arm/bin40/'
  
      if BUILD == 'debug':
          CFLAGS += ' -g -O0'
          AFLAGS += ' -g'
      else:
          CFLAGS += ' -O2'
  
      POST_ACTION = 'fromelf --bin $TARGET --output rtthread.bin \nfromelf -z $TARGET'
  