标签：try 设置 bin short hit mkdir rdd output text
1. 设置obj与src
ifneq ($(OBJTREE),$(SRCTREE)) ifeq ($(CURDIR),$(SRCTREE)) dir := else dir := $(subst $(SRCTREE)/,,$(CURDIR)) endif obj := $(if $(dir),$(OBJTREE)/$(dir)/,$(OBJTREE)/) src := $(if $(dir),$(SRCTREE)/$(dir)/,$(SRCTREE)/) $(shell mkdir -p $(obj)) else obj := src := endif
一般目标输出到源代码目录下，因此执行完上面的代码后，src和obj都为空。
2.设置编译选项
主要是设置以下三个编译选项
# clean the slate ... PLATFORM_RELFLAGS = PLATFORM_CPPFLAGS = PLATFORM_LDFLAGS =
2.1 $(ARCH)=arm，所以包含的文件是arm_config.mk，架构相关的编译选项。
ifdef ARCH sinclude $(TOPDIR)/$(ARCH)_config.mk # include architecture dependend rules endif
arm_config.mk只有一行，内容如下
PLATFORM_CPPFLAGS += -DCONFIG_ARM -D__ARM__
2.2 $(CPU)=s3c64xx，所以包含的文件是cpu/s3c64xx/config.mk，处理器相关的编译选项。
ifdef CPU sinclude $(TOPDIR)/cpu/$(CPU)/config.mk # include CPU specific rules endif
cpu/s3c64xx/config.mk内容如下：
PLATFORM_RELFLAGS += -fno-strict-aliasing -fno-common -ffixed-r8 -msoft-float # Make ARMv5 to allow more compilers to work, even though its v6. PLATFORM_CPPFLAGS += -march=armv5t # ========================================================================= # # Supply options according to compiler version # # ========================================================================= #PLATFORM_CPPFLAGS +=$(call cc-option,-mapcs-32,-mabi=apcs-gnu) PLATFORM_RELFLAGS +=$(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,))
2.3 $(SOC)=s3c6410，所以包含的文件是cpu/s3c64xx/s3c6410/config.mk。但这个文件不存在，因为用sinclude包含，所以不会报错
ifdef SOC sinclude $(TOPDIR)/cpu/$(CPU)/$(SOC)/config.mk # include SoC specific rules endif
以上代码执行完成后，
1 PLATFORM_RELFLAGS : -fno-strict-aliasing -fno-common -ffixed-r8 -msoft-float 2 PLATFORM_CPPFLAGS : -DCONFIG_ARM -D__ARM__ -march=armv5t
3 指定交叉编译工具，$(CROSS_COMPILE) = /usr/local/arm/4.3.2/bin/arm-linux-
AS = $(CROSS_COMPILE)as LD = $(CROSS_COMPILE)ld CC = $(CROSS_COMPILE)gcc CPP = $(CC) -E AR = $(CROSS_COMPILE)ar NM = $(CROSS_COMPILE)nm STRIP = $(CROSS_COMPILE)strip OBJCOPY = $(CROSS_COMPILE)objcopy OBJDUMP = $(CROSS_COMPILE)objdump RANLIB = $(CROSS_COMPILE)RANLIB
4 连接器选项的设置
LDFLAGS += -Bstatic -T $(LDSCRIPT) -Ttext $(TEXT_BASE) $(PLATFORM_LDFLAGS)
4.1 $(BOARD)=smdk6410，$(BOARDDIR)=samsung/smdk6410，所以包含的文件是board/samsung/smdk6410/config.mk。
ifdef VENDOR BOARDDIR = $(VENDOR)/$(BOARD) else BOARDDIR = $(BOARD) endif ifdef BOARD sinclude $(TOPDIR)/board/$(BOARDDIR)/config.mk # include board specific rules endif
board/samsung/smdk6410/config.mk文件中定义了TEXT_BASE。u-boot编译时使用TEXT_BASE作为代码段链接的起始地址。
ifndef TEXT_BASE TEXT_BASE = 0xCFE00000 endif
4.2 指定board/samsung/smdk6410/u-boot.lds位u-boot的链接脚本
LDSCRIPT := $(TOPDIR)/board/$(BOARDDIR)/u-boot.lds
OUTPUT_FORMAT("elf32-littlearm", "elf32-littlearm", "elf32-littlearm") /*OUTPUT_FORMAT("elf32-arm", "elf32-arm", "elf32-arm")*/ OUTPUT_ARCH(arm) ENTRY(_start) SECTIONS { . = 0x00000000; . = ALIGN(4); .text : { cpu/s3c64xx/start.o (.text) cpu/s3c64xx/s3c6410/cpu_init.o (.text) cpu/s3c64xx/onenand_cp.o (.text) cpu/s3c64xx/nand_cp.o (.text) cpu/s3c64xx/movi.o (.text) *(.text) lib_arm/div0.o } . = ALIGN(4); .rodata : { *(.rodata) } . = ALIGN(4); .data : { *(.data) } . = ALIGN(4); .got : { *(.got) } __u_boot_cmd_start = .; .u_boot_cmd : { *(.u_boot_cmd) } __u_boot_cmd_end = .; . = ALIGN(4); .mmudata : { *(.mmudata) } . = ALIGN(4); __bss_start = .; .bss : { *(.bss) } _end = .; }
5 指定隐含的编译规则
AFLAGS为汇编代码编译选项，CFLAGS为C代码编译选项
4 CFLAGS : -g -Os -fno-strict-aliasing -fno-common -ffixed-r8 -msoft-float -D__KERNEL__ -DTEXT_BASE=0xCFE00000 -I/home/yjg/arm6410/qudong/01-uboot/uboot_ok6410/include -fno-builtin -ffreestanding -nostdinc -isystem /usr/local/arm/4.3.2/bin/../lib/gcc/arm-none-linux-gnueabi/4.3.2/include -pipe -DCONFIG_ARM -D__ARM__ -march=armv5t -Wall -Wstrict-prototypes
5 AFLAGS : -D__ASSEMBLY__ -g -Os -fno-strict-aliasing -fno-common -ffixed-r8 -msoft-float -D__KERNEL__ -DTEXT_BASE=0xCFE00000 -I/home/yjg/arm6410/qudong/01-uboot/uboot_ok6410/include -fno-builtin -ffreestanding -nostdinc -isystem /usr/local/arm/4.3.2/bin/../lib/gcc/arm-none-linux-gnueabi/4.3.2/include -pipe -DCONFIG_ARM -D__ARM__ -march=armv5t
%.s: %.S $(CPP) $(AFLAGS) -o $@ $< %.o: %.S $(CC) $(AFLAGS) -c -o $@ $< %.o: %.c $(CC) $(CFLAGS) -c -o $@ $<
CPP: /usr/local/arm/4.3.2/bin/arm-linux-gcc -E，只激活预处理,不生成文件。
6 ARFLAGS，ARFLAGS声明如下，暂时不知道在哪里使用。
ARFLAGS = crv
标签：try 设置 bin short hit mkdir rdd output text
原文地址：http://www.cnblogs.com/yangjiguang/p/7820328.html
