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One might imagine that:<BR>
<BR>
VAR a,b:Target.Int;<BR>
<BR>
TInt.EQ(a, b) implies TWord.Extract(a, 10, 8) = TWord.Extract(b, 10, 8) (for various values of 10 and 8).<BR>
but it doesn't. a could be a one byte zero, b a two byte zero, they are EQ, but Extract offset 10 will fail on a.<BR>
<BR>
<BR>
I believe the right way to say this is "referential integrity is broken".<BR>
EQ should imply equivalent in all observable ways, but it doesn't.<BR>
Because two numbers with different size can be EQ, but different size leads to other varying behavior.<BR>
<BR>
<BR>
I'm not 100% certain of any of this, but at least 50%.<BR>
<BR>
<BR>
And then, I realize, given a Long.T and a Word.T, you can't directly compare them.<BR>
You have to go through VAL, which makes them the same size.<BR>
So there's a missing analog sort of. Target.Int is more loosely typed than its analogs Long.T and Word.T.<BR>
Target.Int allows mixing arithmetic on different sized operands, for better and worse.<BR>
<BR>
<BR>
In one hand TWord.Extract should just act like the value is infinitely zero extended.<BR>
On the other, as you point out, that's not what its callers really expect.<BR>
It's probably a useful semantic, but in some other context.<BR>
And in that imaginary context, TWord.Insert might grow the data to fit.<BR>
And likewise TInt.Add/Subtract would grow the value, not overflow..<BR>
I realize, this is not the context we care about, we just need something for the compiler.<BR>
(Though I'm not even sure what for, esp. why all the operations, other than for the constant folding in the NT386 backend, which makes good use of it all.)<BR>
<BR>
<BR>
- Jay<BR> <BR>
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From: hosking@cs.purdue.edu<BR>Date: Wed, 10 Feb 2010 12:47:13 -0500<BR>To: jay.krell@cornell.edu<BR>CC: m3commit@elegosoft.com<BR>Subject: Re: [M3commit] CVS Update: cm3<BR><BR><BASE>
<DIV>On 10 Feb 2010, at 11:35, Jay K wrote:</DIV>
<DIV><BR class=ecxApple-interchange-newline>
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<DIV style="FONT-FAMILY: Verdana; FONT-SIZE: 10pt" class=ecxhmmessage>I was just trying to get longint initialization to work.<BR>It seemed some of its problems might have been related to the fact that you Extract more high order zeros from TInt.Zero than Target.Int{Target.Integer.bytes}. But in the end (just now) I left TWord.Extract alone.<BR>It remains true that EQ(TInt.Zero) has multiple representations and they don't act alike.<BR></DIV></SPAN></BLOCKQUOTE>
<DIV><BR></DIV>
<DIV>I don't understand what you mean by this statement.</DIV><BR>
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<DIV style="FONT-FAMILY: Verdana; FONT-SIZE: 10pt" class=ecxhmmessage> Maybe that is desirable.<BR> <BR> - Jay<BR><BR> <BR>
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From:<SPAN class=ecxApple-converted-space> </SPAN><A href="mailto:hosking@cs.purdue.edu">hosking@cs.purdue.edu</A><BR>Date: Wed, 10 Feb 2010 10:13:31 -0500<BR>To:<SPAN class=ecxApple-converted-space> </SPAN><A href="mailto:jay.krell@cornell.edu">jay.krell@cornell.edu</A><BR>CC:<SPAN class=ecxApple-converted-space> </SPAN><A href="mailto:m3commit@elegosoft.com">m3commit@elegosoft.com</A><BR>Subject: Re: [M3commit] CVS Update: cm3<BR><BR>
<DIV><SPAN style="TEXT-TRANSFORM: none; TEXT-INDENT: 0px; BORDER-COLLAPSE: separate; FONT: 12px Helvetica; WHITE-SPACE: normal; LETTER-SPACING: normal; COLOR: rgb(0,0,0); WORD-SPACING: 0px" class=ecxecxApple-style-span><SPAN style="TEXT-TRANSFORM: none; TEXT-INDENT: 0px; BORDER-COLLAPSE: separate; FONT: 12px Helvetica; WHITE-SPACE: normal; LETTER-SPACING: normal; COLOR: rgb(0,0,0); WORD-SPACING: 0px" class=ecxecxApple-style-span>
<DIV style="WORD-WRAP: break-word"><SPAN style="TEXT-TRANSFORM: none; TEXT-INDENT: 0px; BORDER-COLLAPSE: separate; FONT: 12px Helvetica; WHITE-SPACE: normal; LETTER-SPACING: normal; COLOR: rgb(0,0,0); WORD-SPACING: 0px" class=ecxecxApple-style-span><SPAN style="TEXT-TRANSFORM: none; TEXT-INDENT: 0px; BORDER-COLLAPSE: separate; FONT: 12px Helvetica; WHITE-SPACE: normal; LETTER-SPACING: normal; COLOR: rgb(0,0,0); WORD-SPACING: 0px" class=ecxecxApple-style-span><SPAN style="TEXT-TRANSFORM: none; TEXT-INDENT: 0px; BORDER-COLLAPSE: separate; FONT: 12px Helvetica; WHITE-SPACE: normal; LETTER-SPACING: normal; COLOR: rgb(0,0,0); WORD-SPACING: 0px" class=ecxecxApple-style-span><SPAN style="TEXT-TRANSFORM: none; TEXT-INDENT: 0px; BORDER-COLLAPSE: separate; FONT: 12px Helvetica; WHITE-SPACE: normal; LETTER-SPACING: normal; COLOR: rgb(0,0,0); WORD-SPACING: 0px" class=ecxecxApple-style-span><SPAN style="TEXT-TRANSFORM: none; TEXT-INDENT: 0px; BORDER-COLLAPSE: separate; FONT: 12px Helvetica; WHITE-SPACE: normal; LETTER-SPACING: normal; COLOR: rgb(0,0,0); WORD-SPACING: 0px" class=ecxecxApple-style-span><SPAN style="TEXT-TRANSFORM: none; TEXT-INDENT: 0px; BORDER-COLLAPSE: separate; FONT: 12px Helvetica; WHITE-SPACE: normal; LETTER-SPACING: normal; COLOR: rgb(0,0,0); WORD-SPACING: 0px" class=ecxecxApple-style-span><SPAN style="TEXT-TRANSFORM: none; TEXT-INDENT: 0px; BORDER-COLLAPSE: separate; FONT: 12px Helvetica; WHITE-SPACE: normal; LETTER-SPACING: normal; COLOR: rgb(0,0,0); WORD-SPACING: 0px" class=ecxecxApple-style-span><SPAN style="TEXT-TRANSFORM: none; TEXT-INDENT: 0px; BORDER-COLLAPSE: separate; FONT: 12px Helvetica; WHITE-SPACE: normal; LETTER-SPACING: normal; COLOR: rgb(0,0,0); WORD-SPACING: 0px" class=ecxecxApple-style-span>
<DIV><SPAN style="FONT-SIZE: medium" class=ecxecxApple-style-span><FONT class=ecxecxApple-style-span color=#0000ff face="'Gill Sans'">I'm not sure what you are trying to do or why. Can you provide further explanation?</FONT></SPAN></DIV></SPAN></SPAN></SPAN></SPAN></SPAN></SPAN></SPAN></SPAN></DIV></SPAN></SPAN></DIV><BR>
<DIV>
<DIV>On 10 Feb 2010, at 04:47, Jay K wrote:</DIV><BR class=ecxecxApple-interchange-newline>
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<DIV style="FONT-FAMILY: Verdana; FONT-SIZE: 10pt" class=ecxecxhmmessage>Shall I go ahead and let Extract act as if the data is infinitely zero extended?<BR>That seems easy to do. I don't know if it will fix the problems, or cause other problems.<BR>It is easy to try. The danger is if it causes subtle undetected-at-first-and-for-a-while problems.<BR> <BR> <BR> - Jay<BR><BR> <BR>
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From:<SPAN class=ecxecxApple-converted-space> </SPAN><A href="mailto:hosking@cs.purdue.edu">hosking@cs.purdue.edu</A><BR>Date: Mon, 8 Feb 2010 11:36:31 -0500<BR>To:<SPAN class=ecxecxApple-converted-space> </SPAN><A href="mailto:jay.krell@cornell.edu">jay.krell@cornell.edu</A><BR>CC:<SPAN class=ecxecxApple-converted-space> </SPAN><A href="mailto:m3commit@elegosoft.com">m3commit@elegosoft.com</A><BR>Subject: Re: [M3commit] CVS Update: cm3<BR><BR>
<DIV>Yes, that is what I am now trying to clean up.</DIV>
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<DIV>On 8 Feb 2010, at 11:18, Jay K wrote:</DIV><BR class=ecxecxecxApple-interchange-newline>
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<DIV style="FONT-FAMILY: Verdana; FONT-SIZE: 10pt" class=ecxecxecxhmmessage>Rodney I *think* generally mixed sizes are supported in TWord, TInt.<BR> Though I don't necessarily understand all of the code.<BR>There was a problem recently fixed, granted.<BR>One problem here though is that you can't TWord.Extract beyond the size.<BR>So the varying sizes of "zero" behave differently.<BR>You might imagine it's zeros as far out as needed, but it doesn't work that way currently.<BR> <BR> - Jay<BR> <BR>> Date: Mon, 8 Feb 2010 10:02:58 -0600<BR>> From:<SPAN class=ecxecxecxApple-converted-space> </SPAN><A href="mailto:rodney_bates@lcwb.coop">rodney_bates@lcwb.coop</A><BR>> To:<SPAN class=ecxecxecxApple-converted-space> </SPAN><A href="mailto:m3commit@elegosoft.com">m3commit@elegosoft.com</A><BR>> Subject: Re: [M3commit] CVS Update: cm3<BR>><SPAN class=ecxecxecxApple-converted-space> </SPAN><BR>><SPAN class=ecxecxecxApple-converted-space> </SPAN><BR>><SPAN class=ecxecxecxApple-converted-space> </SPAN><BR>> Jay K wrote:<BR>> > I wonder if we need<BR>> > TInt8, TInt16, TInt32, TInt64, TInt, TLong<BR>> > TWord8, TWord16, TWord32, TWord64, TWord, TLongWord<BR>> ><SPAN class=ecxecxecxApple-converted-space> </SPAN><BR>> > that accurately implement ints/words of the exact specified size,<BR>> > with TInt/TWord/TLong/TLongWord depending on the target.<BR>> > I wouldn't mind trying to remove this word "Word".<BR>> > And replace it with UInt or such.<BR>> > TInt, TUInt, TLong, TULong?<BR>> > TSignedInt, TUnsignedInt, TSignedLong, TUnsignedLong?<BR>> > TInt, TUnsignedInt, TLong, TUnsignedLong?<BR>> ><SPAN class=ecxecxecxApple-converted-space> </SPAN><BR>> > TInt.Zero is just always 8 bytes.<BR>> > The size is I believe meant to be fairly opaque to the user.<BR>> > This is the first I've noticed it being visible, such that TInt.EQ is<SPAN class=ecxecxecxApple-converted-space> </SPAN><BR>> > true for values with "quite different" behavior. I would have "thunk"<SPAN class=ecxecxecxApple-converted-space> </SPAN><BR>> > (thought without much thought) that anything TInt.EQ is more equivalent<SPAN class=ecxecxecxApple-converted-space> </SPAN><BR>> > than they actually are.<BR>> ><SPAN class=ecxecxecxApple-converted-space> </SPAN><BR>><SPAN class=ecxecxecxApple-converted-space> </SPAN><BR>> Hmm. I recall in a discussion a while back that the arithmetic on<BR>> target ints was not coded to handle operands with mixed values of<BR>> n. Could this have something to do with this?<BR>><SPAN class=ecxecxecxApple-converted-space> </SPAN><BR>> ><SPAN class=ecxecxecxApple-converted-space> </SPAN><BR>> > - Jay<BR>> ><SPAN class=ecxecxecxApple-converted-space> </SPAN><BR>> ><SPAN class=ecxecxecxApple-converted-space> </SPAN><BR>> ><BR></DIV></SPAN></BLOCKQUOTE></DIV><BR></DIV></SPAN><BR class=ecxecxApple-interchange-newline></BLOCKQUOTE></DIV><BR></DIV></SPAN><BR class=ecxApple-interchange-newline></BLOCKQUOTE></DIV><BR> </body>
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