nuttx/boards/arm/nrf52/nrf52840-dk
chao.an b88561299b make/expression: improving up asm/C/C++ compile times
In the current compilation environment, the recursive assignment(=) for compile
flags will be delayed until every file is actually need to be compile.

For example:
--------------------------------------------------------------------------------
arch/arm/src/Makefile:

INCLUDES += ${shell $(INCDIR) "$(CC)" $(ARCH_SRCDIR)$(DELIM)chip}
INCLUDES += ${shell $(INCDIR) "$(CC)" $(ARCH_SRCDIR)$(DELIM)common}
INCLUDES += ${shell $(INCDIR) "$(CC)" $(ARCH_SRCDIR)$(DELIM)$(ARCH_SUBDIR)}
INCLUDES += ${shell $(INCDIR) "$(CC)" $(TOPDIR)$(DELIM)sched}

CPPFLAGS += $(INCLUDES) $(EXTRAFLAGS)
CFLAGS += $(INCLUDES) $(EXTRAFLAGS)
CXXFLAGS += $(INCLUDES) $(EXTRAFLAGS)
AFLAGS += $(INCLUDES) $(EXTRAFLAGS)
--------------------------------------------------------------------------------

All compilation options will be included recursively,
which will be delayed until the compilation options are actually used:

tools/Config.mk:

--------------------------------------------------------------------------------
define COMPILE
  @echo "CC: $1"
  $(Q) $(CC) -c $(CFLAGS) $($(strip $1)_CFLAGS) $1 -o $2
endef
--------------------------------------------------------------------------------

All compile flags to be reexecuted $(INCDIR) as long as one file needs to be compiled,
but in fact, the compilation options have not changed in the current directory.

So the we recommand to change the syntax of assignment
From
    Recursive (=)
To
    Simple    (:=)

In this way, we can ensure that all compilation options are expanded only once and reducing repeated works.

Signed-off-by: chao.an <anchao@xiaomi.com>
2020-11-02 07:53:53 -08:00
..
configs boards/nrf52840-dk: normalize adc and pwm configs 2020-09-13 10:57:11 -03:00
include nrf52: Changed headers for apache 2.0 license 2020-10-10 12:24:28 -06:00
scripts make/expression: improving up asm/C/C++ compile times 2020-11-02 07:53:53 -08:00
src nrf52: Changed headers for apache 2.0 license 2020-10-10 12:24:28 -06:00
Kconfig boards/arm/nrf52/nrf52840-dk: add highpri example configuration 2020-07-18 20:00:52 +01:00
README.txt

nRF52840-DK
===========

README for NuttX port to NRF52840-DK (PCA10056) boards.

Status
======
  Only the basic NSH configuration is supported for now.