This is library for programming under the BipOS (Amazfit Bip MOD). From version BipOS 0.5 the startup code of the applications is completely redisigned. Each application now is a separate file stored in resources. The executable file format is Arm-elf (or simply"elf"). The mod got a new name BipOS. When the MOD starts, resources are scanned for applications. Each firmware has a different amount of resources, and applications are always placed at the end. Therefore, the loader looks for resources by Elf signature starting with resource 930. Found applications are placed in the menu "Applications". In order to improve overall convenience and reduce the number of incompatibilities designed firmware independent applications. So one and the same application will work both on Latin 1.1.5.12 and not latin 1.1.2.05 with no changes (you only need to place it in the RES file of the corresponding version). Independence from the firmware managed through using of a universal library libbip.a which contains the addresses of the firmware functions. After loading the elf into RAM, the internal addresses of functions and variables are relocated, and library addresses of functions are changed to real addresses of functions in firmware.
Starting with libbip 1.5 (BipOS 0.5.5), the addresses of the firmware functions are stored in the reloc_* files. They must be in the RES or FONT sections of the watch's flash memory.