STM32上移植Lua解析器

基于arm-gcc和Makefile，将lua解析器移植到stm32f407

代码移植

下载

从GitHub下载最新lua代码，笔者下载的是5.4.8版本

git clone https://github.com/lua/lua.git

修改代码

笔者的单片机工程是基于Makefile、Kconfig、arm-gcc编译的，和linux内核的编译环境类似。修改步骤如下：

1、删除lua.c和luac.c文件，lua.c是pc上使用的lua入口程序。luac.c是将lua脚本编译成字节码的程序，这个也删掉。

2、增加Makefile文件

C_INC-y += \
-I$(BASE_LUA_DIR)/ \C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/lapi.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/lcode.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/lctype.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/ldebug.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/ldo.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/ldump.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/lfunc.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/lgc.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/llex.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/lmem.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/lobject.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/lopcodes.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/lparser.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/lstate.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/lstring.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/ltable.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/ltm.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/lundump.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/lvm.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/lzio.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/lauxlib.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/lbaselib.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/lcorolib.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/ldblib.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/liolib.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/lmathlib.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/loadlib.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/loslib.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/lstrlib.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/ltablib.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/lutf8lib.c
C_SRC-$(CONFIG_BASE_LUA)                    += $(BASE_LUA_DIR)/linit.c

3、增加Kconfig文件

config BASE_LUAtristate "add lua support"default nhelpadd lua support.

4、修改链接脚本，加大c代码栈空间

_system_stack_size = 0x1000;

5、修改lauxlib.c中的堆内存分配函数，使用freertos的heap_4实现堆内存分配，给lua解析器预留约32KByte

static void *l_alloc (void *ud, void *ptr, size_t osize, size_t nsize) {(void)ud; (void)osize;  /* not used */if (nsize == 0) {kfree(ptr);return NULL;}elsereturn krealloc(ptr, nsize);
}

6、修改linit.c裁剪部分功能，节省flash空间

static const luaL_Reg loadedlibs[] = {{LUA_GNAME, luaopen_base},{LUA_LOADLIBNAME, luaopen_package},{LUA_COLIBNAME, luaopen_coroutine},{LUA_TABLIBNAME, luaopen_table},// {LUA_IOLIBNAME, luaopen_io},// {LUA_OSLIBNAME, luaopen_os},{LUA_STRLIBNAME, luaopen_string},{LUA_MATHLIBNAME, luaopen_math},{LUA_UTF8LIBNAME, luaopen_utf8},// {LUA_DBLIBNAME, luaopen_debug},{NULL, NULL}
};

7、创建单片机版的lua.c作为运行lua程序的入口，笔者使用fal库管理flash分区，将lua脚本存放在了flash的一个分区中，lua.c实现如下:

#include "shell.h"
#include "string.h"
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include "board.h"
#include "heap_4.h"
#include "clib.h"
#include "lua.h"
#include "lualib.h"
#include "lauxlib.h"
#include "boot.h"#define LUA_SCRIPT_SIZE     (8 * 1024)extern int check_part(const char *part_name, const char *sys_id, uint32_t *size, uint32_t *crc);static void lua_exec(int argc, char *argv[])
{int ret = 0;const struct fal_partition *part;uint32_t size, crc;lua_State *L = NULL;char *lp = kmalloc(LUA_SCRIPT_SIZE);if (lp == NULL) {printf("kmalloc fail!\n");return;}/* 校验data分区 */ret = check_part(BOOT_DATA_PART_NAME, LUA_ID, &size, &crc);printf("size=0x%x, crc=0x%x\n", size, crc);if (size > LUA_SCRIPT_SIZE) {printf("Lua script cannot be larger than %d!\n", LUA_SCRIPT_SIZE);}if (ret == 0) {part = fal_partition_find(BOOT_DATA_PART_NAME);if (part == NULL) {printf("%s part not found.\n", BOOT_DATA_PART_NAME);goto fail;}if (fal_partition_read(part, F_BOOT_CRC_START, (uint8_t *)lp, size) < 0) {printf("%s part read error!", BOOT_DATA_PART_NAME);goto fail;}lp[size] = '\0';                                // 设置结束符L = luaL_newstate();luaL_openlibs(L);printf("running...\n\n");if (luaL_dostring(L, lp) == LUA_OK) {const char *result = lua_tostring(L, -1);   // 获取返回值printf("Result: %s\n", result);             // 打印结果} else {printf("Error in executing code: %s\n", lua_tostring(L, -1));}lua_close(L);}
fail:kfree(lp);return 0;
}SHELL_EXPORT_CMD(SHELL_CMD_PERMISSION(0) | SHELL_CMD_TYPE(SHELL_TYPE_CMD_MAIN) | SHELL_CMD_DISABLE_RETURN, \lua, lua_exec, lua exec);

以上就完成了lua代码的移植，编译后lua解析器约占200Kbyte

验证执行

编写lua脚本如下：

print("Hello World!");
print(_VERSION);

下载到data分区，使用lua命令运行，结果如下：

*stm32:/$ lua
size=0x27, crc=0x41d32920
running...Hello World1
Lua 5.4
Result: (null)