keil

startup

EQU

name EQU expr{, type}

Usage

• equal
• Use EQU to define constants. This is similar to the use of #define to define a constant in C.

Examples

abc EQU 2 ; Assigns the value 2 to the symbol abc.
xyz EQU label+8 ; Assigns the address (label+8) to the symbol xyz.
fiq EQU 0x1C, CODE32 ; Assigns the absolute address 0x1C to the symbol fiq, and marks it as code.

SPACE

{label} SPACE expr
{label} FILL expr{,value{,valuesize}}

Usage

Use the ALIGN directive to align any code following a SPACE or FILL directive.

Examples

AREA MyData, DATA, READWRITE
data1 SPACE 255 ; defines 255 bytes of zeroed store
data2 FILL 50,0xAB,1 ; defines 50 bytes containing 0xAB

AREA

AREA sectionname{,attr}{,attr}...
The AREA directive instructs the assembler to assemble a new code or data section.

THUMB

THUMB指令指示汇编程序使用UAL语法将后续指令解释为Thumb指令

PRESERVE8

REQUIRE8和PRESERVE8指令指定当前文件需要或保留堆栈的八字节对齐

EXPORT

EXPORT指令声明了一个符号，链接器可以使用该符号来解析单独的对象和库文件中的符号引用。 GLOBAL是EXPORT的同义词

DCD

{label} DCD{U} expr{,expr}
DCD指令分配一个或多个内存字，在四字节边界上对齐，并定义内存的初始运行时内容。 DCDU是相同的，除了存储器对齐是任意的

IF

LNOT

逻辑非
IF :LNOT::DEF:__MICROLIB ;如果没有定义__MICROLIB

ARM

LDR

LDR register, =[expr | label-exp]
The LDR pseudo-instruction loads a low register with either:

• a 32-bit constant value
• an address.

Examples

LDR r1, =0xfff ; loads 0xfff into r1
LDR r2, =labelname ; loads the address of labelname into r2

BLX

BLX{cond}{.W} label
BLX{cond} Rm
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BX

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