网上查到的各个文件的解释是：

startup_stm32f10x_cl.s 互联型的器件，STM32F105xx，STM32F107xx
startup_stm32f10x_hd.s 大容量的STM32F101xx，STM32F102xx，STM32F103xx
startup_stm32f10x_hd_vl.s 大容量的STM32F100xx
startup_stm32f10x_ld.s 小容量的STM32F101xx，STM32F102xx，STM32F103xx
startup_stm32f10x_ld_vl.s 小容量的STM32F100xx
startup_stm32f10x_md.s 中容量的STM32F101xx，STM32F102xx，STM32F103xx
startup_stm32f10x_md_vl.s 中容量的STM32F100xx
startup_stm32f10x_xl.s FLASH在512K到1024K字节的STM32F101xx，STM32F102xx，STM32F103xx

固件库中的Release_Notes_for_STM32F10x_CMSIS.html写到：

STM32F10x CMSIS Startup files: startup_stm32f10x_xx.s

• Add new startup files for STM32 Low-density Value line devices: startup_stm32f10x_ld_vl.s
• Add new startup files for STM32 Medium-density Value line devices: startup_stm32f10x_md_vl.s
• SystemInit() function is called from startup file (startup_stm32f10x_xx.s) before to branch to application main.
  To reconfigure the default setting of SystemInit() function, refer to system_stm32f10x.c file
• GNU startup file for Low density devices (startup_stm32f10x_ld.s) is updated to fix compilation errors.

  那到底啥是大容量，小容量啊？又查user manual才知道

  

  也就是说，例如我用STM32F103RB，那么选启动文件为startup_stm32f10x_md.s