arm shared code contains not shared code?

[printk]

Hello,
I am learning the rtems source, and when i look into this folder:
----------------------------
rtems at book64:~/rtems-lite/rtems/c/src/lib/libcpu/arm/shared$ tree
.
├── arm920
│   └── mmu.c
└── include
    ├── am335x.h
    ├── arm-cp15.h
    ├── cache_.h
    ├── mmu.h
    ├── omap3.h
    └── omap_timer.h

2 directories, 7 files
rtems at book64:~/rtems-lite/rtems/c/src/lib/libcpu/arm/shared$ 
----------------------------
this folder i guess it means stuff shared by arm arch? or something
else?
why these files here to, it seems can not 'share' with other
arm 'SoC'
  am335x.h
  omap3.h
  omap_timer.h
How about move these file to some place machine depended folders?
I guess the arm just means the arm cpu in the SoC, not a arm SoC.

thanks,
duhuanpeng