This thread has been locked.
If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.
请问CodeStartBranch.asm，能看做是bootloader 的一部分吗？
DSP281X的CodeStartBranch.asm
是Boot的一部分 引导作用
;//###########################################################################
02
;//
03
;// FILE: DSP281x_CodeStartBranch.asm
04
05
;// TITLE: Branch for redirecting code execution after boot.
06
07
08
09
;// Ver | dd mmm yyyy | Who | Description of changes
10
;// =====|=============|======|===============================================
11
;// 1.00| 11 Sep 03 | L.H. | Updated based on D.A source to allow
12
;// | | | disabling the watchdog before branching to
13
;// | | | the C init routine. This is useful if the
14
;// | | | watchdog is timing out before main() is reached.
15
16
17
18
***********************************************************************
19
20
WD_DISABLE .set 1 ;set to 1 to disable WD, else set to 0
21
22
.ref _c_int00
23
24
25
* Function: codestart section
26
*
27
* Description: Branch to code starting point
28
29
30
.sect "codestart"
31
32
code_start:
33
.if WD_DISABLE == 1
34
LB wd_disable ;Branch to watchdog disable code
35
.else
36
LB _c_int00 ;Branch to start of boot.asm in RTS library
37
.endif
38
39
;end codestart section
40
41
42
43
* Function: wd_disable
44
45
* Description: Disables the watchdog timer
46
47
48
49
.text
50
wd_disable:
51
SETC OBJMODE ;Set OBJMODE for 28x object code
52
EALLOW ;Enable EALLOW protected register access
53
MOVZ DP, #7029h>>6 ;Set data page for WDCR register
54
MOV @7029h, #0068h ;Set WDDIS bit in WDCR to disable WD
55
EDIS ;Disable EALLOW protected register access
56
57
58
59
60
;end wd_disable
61
62
63
64
.end
65
66
; end of file CodeStartBranch.asm
bootloader 与CodeStartBranch有点类似物流系统与收货方的关系，bootloader 会根据不同的引导模式进行相应的操作。如果是flash与ram模式就会比较简单，bootloader会比较直接地引导到CodeStartBranch，而其他模式则会比较曲折，类似经过一些“中转站”。所以，CodeStartBranch应该只是bootloader 的最终入口，与bootloader机制并不具有严格的包含关系。当然，如果把概念放大一些，也是可以作为一部分的。看你的个人理解了。
