arm 汇编

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Difference between .equ and .word in ARM Assembly?

.word is a directive that allocates a word-sized amount of storage space (memory) in that location. It can additionally have that location initialized with a given value.

.equ is more like a C preprocessor #define statement - it gets substituted in any subsequent code.

https://sourceware.org/binutils/docs-2.24/as/Equ.html#Equ

https://sourceware.org/binutils/docs-2.24/as/Word.html#Word

This is not actually ARM-specific, but applies to all gas targets.

.word 即是一个相当于内存中固定位置分配一个 word大小（4字节）的变量，它可以在初始化时就赋值一个给定的值。

.equ 更像是c语言中的 #define 语句，后面的任何位置的代码都可以用到它。

.equUSR_MODE,0x10/* normal user mode */.equ FIQ_MODE,0x11/* fiq fast interrupts mode */.equ IRQ_MODE,0x12/* irq standard interrupts mode */.equ SVC_MODE,0x13/* supervisor interrupts mode */.equ ABT_MODE,0x17/* abort processing memory faults mode */.equ UDF_MODE,0x1b/* undefined instructions mode */.equ MODE_MASK,0x1f/* system running in priviledged operating mode */.equ NO_INT,0xc0.equ    CPSR_IRQ_EN,0x80.equ    CPSR_IRQ_MASK,0x40/* disable interrupt mode (irq) */.equ    CPSR_FIQ_MASK,0x80/* disable fast interrupt mode (fiq) */

.word 0x2000/* 自拷贝文件大小 */.word 0x0.word 0x0.word 0x0

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