[M3devel] bit field operations for insert/extract

[Jay K]

None yet. But notice the endian checks around the insert_mn or extract_mn uses in cg.m3.
The change would be to remove those.

 - Jay


Subject: Re: [M3devel] bit field operations for insert/extract
From: hosking at cs.purdue.edu
Date: Tue, 23 Nov 2010 09:37:00 -0500
CC: m3devel at elegosoft.com
To: jay.krell at cornell.edu



Refresh my memory.  What m3front change did you make?


On Nov 23, 2010, at 3:33 AM, Jay K wrote:Tony, I'm going to try again to use bitfield operations for extract_mn.
And insert_mn.
I think I know what went wrong before for extract_mn: just remove the endian check in m3front.
But I'm going to be sure test p240 covers it well.

The easy part, duh, your original extract_mn was correct I think, just, again, missing the m3front change.

Insert_mn is less obvious.
I started writing it... bitfield_ref..modify_expr...uh, seems suspicious, to be modifying an existing value.

I guess it's more like, that, but with a temp that starts with the full value of x:
 create temp
 modify(temp, x)
 modify(bitfield_ref(temp, count, offset), y);
 m3_load(temp) 

?

I'll try something like that.
It seems unfortunate.
Maybe we can know if x is already a value and not a variable?


 - Jay

 		 	   		  
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