791617b3b0
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@41 42af7a65-404d-4744-a932-0658087f49c3
251 lines
8.5 KiB
Plaintext
251 lines
8.5 KiB
Plaintext
Architecture-Specific Code
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^^^^^^^^^^^^^^^^^^^^^^^^^^
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Table of Contents
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^^^^^^^^^^^^^^^^^
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o Architecture-Specific Code
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o Summary of Files
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o Supported Architectures
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o Configuring NuttX
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Architecture-Specific Code
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^^^^^^^^^^^^^^^^^^^^^^^^^^
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The file include/nuttx/arch.h identifies all of the APIs that must
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be provided by the architecture specific logic. (It also includes
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arch/<arch-name>/arch.h as described below).
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Directory Structure
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^^^^^^^^^^^^^^^^^^^
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Thie arch directory contains architecture specific logic. Each aructure
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provide a a subdirectory <arch-name>under arch/ with the folling characteristics:
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<arch-name>
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|-- Make.defs
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|-- defconfig
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|-- setenv.sh
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|-- include
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| |-- arch.h
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| |-- irq.h
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| `-- types.h
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`-- src
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|-- Makefile
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`-- (architecture-specific source files)
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Summary of Files
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^^^^^^^^^^^^^^^^
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Make.defs -- This makefile fragment provides architecture and
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tool-specific build options. It will be included by all other
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makefiles in the build (once it is installed). This make fragment
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should define:
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Tools: CC, LD, AR, NM, OBJCOPY, OBJDUMP
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Tool options: CFLAGS, LDFLAGS
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When this makefile fragment runs, it will be passed TOPDIR which
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is the path to the root directory of the build. This makefile
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fragment may include ${TOPDIR}/.config to perform configuration
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specific settings. For example, the CFLAGS will most likely be
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different if CONFIG_DEBUG=y.
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defconfig -- This is a configuration file similar to the Linux
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configuration file. In contains varialble/value pairs like:
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CONFIG_VARIABLE=value
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This configuration file will be used at build time:
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(1) as a makefile fragment included in other makefiles, and
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(2) to generate include/nuttx/config.h which is included by
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most C files in the system.
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The following variables are recognized by the build (you may
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also include architecture-specific settings).
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Architecture selection:
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CONFIG_ARCH - identifies the arch subdirectory
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CONFIG_ARCH_name - for use in C code
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General OS setup
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CONFIG_EXAMPLE - identifies the subdirectory in examples
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that will be used in the build
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CONFIG_DEBUG - enables built-in debug options
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CONFIG_DEBUG_VERBOSE - enables verbose debug output
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CONFIG_HAVE_LOWPUTC - architecture supports low-level, boot
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time console output
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CONFIG_MM_REGIONS - If the architecture includes multiple
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regions of memory to allocate from, this specifies the
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number of memory regions that the memory manager must
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handle and enables the API mm_addregion(start, end);
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CONFIG_RR_INTERVAL - The round robin timeslice will be set
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this number of milliseconds; Round robin scheduling can
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be disabled by setting this value to zero.
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CONFIG_SCHED_INSTRUMENTATION - enables instrumentation in
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scheduler to monitor system performance
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CONFIG_TASK_NAME_SIZE - Spcifies that maximum size of a
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task name to save in the TCB. Useful if scheduler
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instrumentation is selected. Set to zero to disable.
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CONFIG_START_YEAR, CONFIG_START_MONTH, CONFIG_START_DAY -
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Used to initialize the internal time logic.
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CONFIG_JULIAN_TIME - Enables Julian time conversions
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CONFIG_DEV_CONSOLE - Set if architecture-specific logic
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provides /dev/console. Enables stdout, stderr, stdin.
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The following can be used to disable categories of APIs supported
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by the OS. If the compiler supports weak functions, then it
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should not be necessary to disable functions unless you want to
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restrict usage of those APIs.
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There are certain dependency relationships in these features.
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o mq_notify logic depends on signals to awaken tasks
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waiting for queues to become full or empty.
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o pthread_condtimedwait() depends on signals to wake
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up waiting tasks.
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CONFIG_DISABLE_CLOCK, CONFIG_DISABLE_PTHREAD.
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CONFIG_DISABLE_SIGNALS, CONFIG_DISABLE_MQUEUE
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Misc libc settings
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CONFIG_NOPRINTF_FIELDWIDTH - sprintf-related logic is a
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little smaller if we do not support fieldwidthes
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Allow for architecture optimized implementations
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The architecture can provide optimized versions of the
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following to improve sysem performance
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CONFIG_ARCH_MEMCPY, CONFIG_ARCH_MEMCMP, CONFIG_ARCH_MEMMOVE
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CONFIG_ARCH_MEMSET, CONFIG_ARCH_STRCMP, CONFIG_ARCH_STRCPY
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CONFIG_ARCH_STRNCPY, CONFIG_ARCH_STRLEN, CONFIG_ARCH_BZERO
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CONFIG_ARCH_KMALLOC, CONFIG_ARCH_KZMALLOC, CONFIG_ARCH_KFREE
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Sizes of configurable things (0 disables)
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CONFIG_MAX_TASKS - The maximum number of simultaneously
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active tasks. This value must be a power of two.
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CONFIG_NPTHREAD_KEYS - The number of items of thread-
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specific data that can be retained
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CONFIG_NFILE_DESCRIPTORS - The maximum number of file
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descriptors (one for each open)
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CONFIG_NFILE_STREAMS - The maximum number of streams that
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can be fopen'ed
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CONFIG_STDIO_BUFFER_SIZE - Size of the buffer to allocate
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on fopen. (Only if CONFIG_NFILE_STREAMS > 0)
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CONFIG_NUNGET_CHARS - Number of characters that can be
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buffered by ungetc() (Only if CONFIG_NFILE_STREAMS > 0)
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CONFIG_PREALLOC_MQ_MSGS - The number of pre-allocated message
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structures. The system manages a pool of preallocated
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message structures to minimize dynamic allocations
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CONFIG_MQ_MAXMSGSIZE - Message structures are allocated with
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a fixed payload size given by this settin (does not include
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other message structure overhead.
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CONFIG_PREALLOC_WDOGS - The number of pre-allocated watchdog
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structures. The system manages a pool of preallocated
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watchdog structures to minimize dynamic allocations
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Stack and heap information
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CONFIG_BOOT_FROM_FLASH - Some configurations support XIP
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operation from FLASH.
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CONFIG_STACK_POINTER - The initial stack pointer
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CONFIG_PROC_STACK_SIZE - The size of the initial stack
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CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
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CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
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CONFIG_HEAP_BASE - The beginning of the heap
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CONFIG_HEAP_SIZE - The size of the heap
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setenv.sh -- This is a script that you can include that will be installed at
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the toplevel of the directory structure and can be sourced to set any
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necessary environment variables.
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include/arch.h
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This is a hook for any architecture specific definitions that may
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be needed by the system. It is included by include/nuttx/arch.h
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include/types.h
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This provides architecture/toolchain-specific definitions for
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standard types. This file should typedef:
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sbyte, ubyte, uint8, boolean, sint16, uint16, sint32, uint32
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and
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sint64, uint64
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if the architecture supports 64-bit integers.
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irqstate_t
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Must be defined to the be the size required to hold the interrupt
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enable/disable state.
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This file will be included by include/sys/types.h and be made
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available to all files.
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include/irq.h
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This file needs to define some architecture specific functions (usually
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inline if the compiler supports inlining) and structure. These include:
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- struct xcptcontext. This structures represents the saved context
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of a thread.
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- irqstate_t irqsave(void) -- Used to disable all interrupts.
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- void irqrestore(irqstate_t flags) -- Used to restore interrupt
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enables to the same state as before irqsave was called.
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This file must also define NR_IRQS, the total number of IRQs supported
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by the board.
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src/Makefile
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This makefile will be executed to build the targets src/libup.a and
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src/up_head.o. The up_head.o file holds the entry point into the system
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(power-on reset entry point, for example). It will be used in
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the final link with libup.a and other system archives to generate the
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final executable.
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Supported Architectures
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^^^^^^^^^^^^^^^^^^^^^^^
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arch/c5471
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TI TMS320C5471 (also called TMS320DM180).
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NuttX operates on the ARM7 of this dual core processor. This port
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uses the Spectrum Digital evaluation board with a GNU arm-elf toolchain*.
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This port is in progress and partially functional (However, my board
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is dead at the moment so it will be awhile before I fix it).
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arch/pjrc-8051
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8051 Microcontroller. This port uses the PJRC 87C52 development system
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and the SDCC toolchain. This port is not quite ready for prime time.
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arch/sim
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x86 Linux Simulation</b>. Fully functional.
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Other ports for the for the TI TMS320DM270 and for MIPS are in various states
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of progress
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Configuring NuttX
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^^^^^^^^^^^^^^^^^
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Configuring NuttX requires only copying
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arch/<arch-name>/Make.def to ${TOPDIR}/Make.defs
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arch/<arch-name>/setenv.sh to ${TOPDIR}/setenv.sh
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arch/<arch-name>/defconfig to ${TOPDIR}/.config
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There is a script that automates these steps. The following steps will
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accomplish the same configuration:
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cd tools
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./configure.sh <arch-name>
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