arm汇编看不懂

mulagi

MACRO
$HandlerLabel HANDLER $HandleLabel                       ---------------------------什么意思
$HandlerLabel
sub sp,sp,#4        ;decrement sp(to store jump address)
stmfd sp!,{r0}        USH the work register to stack(lr does't push because it return to original address)
ldr     r0,=$HandleLabel;load the address of HandleXXX to r0
ldr     r0,[r0]         ;load the contents(service routine start address) of HandleXXX
str     r0,[sp,#4]      ;store the contents(ISR) of HandleXXX to stack
ldmfd   sp!,{r0,pc}     OP the work register and pc(jump to ISR)
     MEND
[ ENDIAN_CHANGE
     ASSERT  EF:ENTRY_BUS_WIDTH                          -------------看不懂
     [ ENTRY_BUS_WIDTH=32
        b ChangeBigEndian     ;DCD 0xea000007 ----------------------------------------看不懂
     ]
     
     [ ENTRY_BUS_WIDTH=16
       andeq r14,r7,r0,lsl #20   ;DCD 0x0007ea00
     ]
     
     [ ENTRY_BUS_WIDTH=8
       streq r0,[r0,-r10,ror #1] ;DCD 0x070000ea
      ]
|
     b ResetHandler              ----------------------------------------看不懂
]

sunxq

仔细读一下ARM的汇编语言就懂了。前面一段是宏的语法，用来自定中断向量;
后面一段是汇编指示的连续应用，[代表IF，]代表ENDIF，|是ELSE
以下摘自ADS_assemberGuide_B.pdf文档7.6.1节，在ADS安装时有。
ASSERT
The ASSERT directive generates an error message during the second pass of the assembly
if a given assertion is false.
Syntax
ASSERT logical-expression
where:
logical-expression
is an assertion that can evaluate to either {TRUE} or {FALSE}.
Usage
Use ASSERT to ensure that any necessary condition is met during assembly.
If the assertion is false an error message is generated and assembly fails.
See also INFO on page 7-45.
Example
ASSERT label1 <= label2

mencius

arm的汇编就是难懂啊 谢了