nuttx/boards/arm/lpc2378/olimex-lpc2378
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/nsh libc/stdio: Allocate file_struct dynamically 2020-09-11 17:58:17 +08:00
include Refine the preprocessor conditional guard style (#190) 2020-01-31 19:07:39 +01:00
scripts make/expression: improving up asm/C/C++ compile times 2020-11-02 07:53:53 -08:00
src build: Remove the empty variable assignment 2020-05-24 08:24:13 -06:00
Kconfig Merged in alinjerpelea/nuttx (pull request #967) 2019-08-07 20:49:39 +00:00
README.txt Change all 'Nuttx' to 'NuttX' 2020-10-20 01:45:06 -07:00

There's not much here:

EXT1 - P3 0:7 are used for LEDs.

UEXT pin 3/4 -TXD2/RXD2- is UART2.

The board I have has the revision '-' of LPC2378 even though I got the board
more than 2 years after the chip revision was released :-( .
I can't get NuttX to work if I fully enabled the MAM.

I used FTDI ft232 usb-serial with nsh piping as seen on the screenshot.