feat: remove redundant codes under virt64, c906

Changes:

- create new folder name `common64` and save all common codes of rv64
  inside

Signed-off-by: Shell <[email protected]>

Author: polarvid

libcpu/risc-v/SConscript

@@ -5,17 +5,16 @@ from building import *
 
 Import('rtconfig')
 
+common64_arch = ['virt64', 'c906']
 cwd   = GetCurrentDir()
 group = []
 list  = os.listdir(cwd)
 
 # add common code files
-if   rtconfig.CPU == "virt64" :
-    group = group
-elif rtconfig.CPU == "c906" :
-    group = group
+if rtconfig.CPU in common64_arch :
+    group += SConscript(os.path.join('common64', 'SConscript'))
 else :
-    group = group + SConscript(os.path.join('common', 'SConscript'))
+    group += SConscript(os.path.join('common', 'SConscript'))
 
 # cpu porting code files
 if  rtconfig.CPU == "c906":

libcpu/risc-v/common64/SConscript

@@ -0,0 +1,12 @@
+from building import *
+
+cwd     = GetCurrentDir()
+src     = Glob('*.c') + Glob('*.cpp') + Glob('*_gcc.S')
+CPPPATH = [cwd]
+
+if not GetDepend('ARCH_USING_ASID'):
+    SrcRemove(src, ['asid.c'])
+
+group = DefineGroup('libcpu', src, depend = [''], CPPPATH = CPPPATH)
+
+Return('group')