nuttx/boards/risc-v/fe310/hifive1-revb
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
scripts make/expression: improving up asm/C/C++ compile times 2020-11-02 07:53:53 -08:00
src
Kconfig
README-qemu.txt
README.txt

1. Download and install toolchain

  $ curl https://static.dev.sifive.com/dev-tools/riscv64-unknown-elf-gcc-8.3.0-2019.08.0-x86_64-linux-ubuntu14.tar.gz

2. Download and install J-Link Software Documentation Pack

  https://www.segger.com/downloads/jlink/

  $ sudo apt install JLink_Linux_V656b_x86_64.deb

3. Configure and build NuttX

  $ mkdir ./nuttx; cd ./nuttx
  $ git clone https://bitbucket.org/nuttx/nuttx.git
  $ git clone https://bitbucket.org/nuttx/apps.git
  $ cd nuttx
  $ make distclean
  $ ./tools/configure.sh hifive1-revb:nsh
  $ make V=1

4. Flash the nuttx with J-Link and run

  $ picocom -b 115200 /dev/ttyACM0

  $ /opt/SEGGER/JLink_V656b/JLinkGDBServer -device FE310

  $ riscv64-unknown-elf-gdb ./nuttx
  (gdb) target extended-remote:2331
  (gdb) load nuttx
  (gdb) c

5. TODO

  Support GPIO/SPI/I2C/RTC/WDT/PWM
  Support RISC-V User mode