Date: Tue, 22 May 2001 02:59:13 -0700 From: Terry Lambert <tlambert2@mindspring.com> To: Chuck Youse <chuck@newsscope.com> Cc: Terry Lambert <tlambert@primenet.com>, Peter Pentchev <roam@orbitel.bg>, Ruslan Ermilov <ru@FreeBSD.ORG>, Nik Clayton <nik@FreeBSD.ORG>, arch@FreeBSD.ORG Subject: Re: [PATCH] syscons ioctl() to grab text mode buffer Message-ID: <3B0A3871.1BA0C0DB@mindspring.com> References: <Pine.BSF.4.21.0105191306460.38086-100000@warsaw.newsscope.com>
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Chuck Youse wrote: > > On a practical note, the code generated merely inverts the sense > > of the same cmpl at default optimization, and at -O2 ends up being > > either: > > > > testl %eax,%eax > > jge .L3 > > > > or: > > > > cmpl $-1,%eax > > jne .L3 > > > > So the number of instruction cycles is identical. Off the top of > > Well, the second sequence is longer by a byte. I don't have the data > sheets handy, it probably also takes another cycle as it involves an > immediate operand sign-extended to 32-bits instead of just a > register-register compare. > > Just nitpicking If we want to nitpick, we should probably generate the same test cases for the Alpha... -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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