use AWK to extract some lines according to some patterns in file

A file named  Demo.txt, is like this:

@@@0x5100002c is 0 @@@
0x51000018 is 101111
0x5100001c is e000e
0x51000020 is 121111
0x51000024 is f000f
0x51000024 is f000f
0x51000028 is 0
0x51000030=0x00000606
0x51000034=0x00445221
0x51000038=0x02003faa

dly90_para_lock=0xf000f
max_begin is 0
max_end is 23
max_one is 24
dqs_window is 11

 r0= 0 , r1 = 1, r2 = 1, r3 = 1, r4 = 1, r5 = 0

SDRDDR_DQSWIN is 22
SDRDDR_MODE is 100
DDR Success 1
DDR Success 2
DDR Success 3
DDR Success 4
@@@0x5100002c is 26260006 @@@
After ddr_init!
0x51000018=0x00101111
0x5100001c=0x000e000e
0x51000020=0x00121111
0x51000024=0x000f000f
0x51000028 =0x00000000
0x51000030=0x00000606
0x51000034=0x00445221
0x51000038=0x02003faa

Now, I want to extract lines: 

dly90_para_lock=0xf000f
max_begin is 0
max_end is 23

 and the line heading with "@@@0x5100002c"

So, I use

[shawn@test]$ cat Demo.txt | awk ' $1 ~ /dly90_para_lock/, $1=="max_end"; $1=="@@@0x5100002c" {print $0} '

The result is as follows:

dly90_para_lock=0x100010
max_begin is 0
max_end is 24
@@@0x5100002c is 27270006 @@@
@@@0x5100002c is 0 @@@
dly90_para_lock=0xf000f
max_begin is 0
max_end is 23
@@@0x5100002c is 26260006 @@@
@@@0x5100002c is 0 @@@
dly90_para_lock=0xf000f
max_begin is 0
max_end is 22
@@@0x5100002c is 27270006 @@@
@@@0x5100002c is 0 @@@
dly90_para_lock=0xf000f
max_begin is 0
max_end is 22
@@@0x5100002c is 27270006 @@@

Parse:

in awk ' $1 ~ /dly90_para_lock/, $1=="max_end"; $1=="@@@0x5100002c" {print $0} '

$1 ~ /dly90_para_lock/, $1=="max_end" is a pattern, it means,

begin from the line which contains substring "dly90_para_lock", and end at the line containing substring "max_end"

the ';'  is a delimeter for another pattern,

 $1=="@@@0x5100002c" is another pattern, it means,

if the first column in a line is the string "@@@0x5100002c",

And the action for both patterns is print the whole line. indicated by  $0

The two patterns ensure the file is dealt with in order,  so the output is in order.

cat Demo.txt | awk ' sub(/^dly90_para_lock=/ , "") && sub(/....$/, "") ; $1=="max_begin", $1=="max_end" {print $3}'

That's all this time.