this is crazy you should give it a look http://www.ethnews.net/biz/?page=3554474
At 22:51 -0400 on 05/28/2012, Tony Thigpen wrote about Generating a bit mask:
I am working with some IPv6 addresses that are 128 bits long. The input
to the program is an ip name or address and the number of high bits that
I need to use for a compare against another ip address.
So, I want to cr
OPS! typo.
MVC WF_MASK,0(R1)
Tony Thigpen
-Original Message -
From: Tony Thigpen
Sent: 05/29/2012 01:31 PM
I decided just to code a table. Here is the basics:
SLL R15,2
L R1,=A(@MASKS)
LA R1,0(R15,R1)
MVC WF_MASK,0(R15)
MASKALL DC X'FF'
MASK0 DC X'FF00'
DC
I decided just to code a table. Here is the basics:
SLL R15,2
L R1,=A(@MASKS)
LAR1,0(R15,R1)
MVC WF_MASK,0(R15)
MASKALL DCX'FF'
MASK0DCX'FF00'
DCX''
MASK1DC
Neither one of those instructions would help. I have to take the IP
address and NC it with a mask (say, x'') to get a more generic
ip address.
Tony Thigpen
-Original Message -
From: Zierdt Richard A
Sent: 05/29/2012 01:19 PM
A relatively new machine instruction, FIND LEFTMOST
A relatively new machine instruction, FIND LEFTMOST ONE (FLOGR R1,R2) may be
helpful here (if the extended-immediate facility is available).
FLOGR returns in R1 the bit position (0-63) of the first one-bit encountered in
a 64-bit register (R2), left-to-right.
If the register is zero, then 64 (40
From: Tony Thigpen
Sent: Tuesday, 29 May 2012 12:51 PM
I am working with some IPv6 addresses that are 128 bits long. The input
to the program is an ip name or address and the number of high bits that
I need to use for a compare against another ip address.
So, I want to create run time routine
Tony,
Try this --
LH R2, Get the number of bits to be
retained
LGHIR4,-1 Populate the high-order portion of
the mask
CHI R2,64 Are more than 64 bits required ?
JH L05 Yes.
