Uboot Learning Two----The second----The main makefile environment variables: Host operating system and host architecture (Hostos, Hostarch) (31-43 rows)

Hostarch: = $ (Shell uname-m | \
Sed-e s/i.86/i386/\
-E s/sun4u/sparc64/\
-E s/arm.*/arm/\
-E s/sa110/arm/\
-E s/powerpc/ppc/\
-E s/ppc64/ppc/\
-e s/macppc/ppc/)

Hostos: = $ (Shell uname-s | tr ' [: Upper:] ' [: Lower:] ' | \
Sed-e ' s/\ (cygwin\). */cygwin/')

Exporthostarch Hostos//Export the CPU's architecture and CPU operating system to these two environment variables, below standby.

The use of Shell functions in makefile ("Learn Makefile_ Chenhao with me" on page 53rd):
Contents: = $ (Shell cat foo)
Files: = $ (shell echo *.c)
(1) The Shell function and the inverse quotation mark "'" are the same functions. Execute uname-m in Shell to print out the hardware schema name of the host
(2) in the Shell | Called Pipe, Pipe: The output of the expression in front of the pipeline is then processed as the input of the following one. The final output is the output of our entire equation.
(3) Hostarch

CPU Architecture Arch is architecture, the meaning of architecture.

Uboot Learning Two----The second----The main makefile environment variables: Host operating system and host architecture (Hostos, Hostarch) (31-43 rows)