Date: Sun, 4 Jul 1999 10:55:41 -0500 (CDT) From: Jonathan Lemon <jlemon@americantv.com> To: hackers@freebsd.org Subject: Re: support for i386 hardware debug watch points Message-ID: <199907041555.KAA22371@free.pcs> In-Reply-To: <local.mail.freebsd-hackers/199907041453.KAA03044@dean.pc.sas.com> References: <local.mail.freebsd-hackers/19990703142624.ED06C64@overcee.netplex.com.au>
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In article <local.mail.freebsd-hackers/199907041453.KAA03044@dean.pc.sas.com> yo u write: >This is not as efficent as it could be implemented with a separate >flag to indicate whether saving the debug registers is necessary since >loading/storing the debug registers is fairly expensive (11 clocks on >an i486). Yes; you may want to just use another bit in pcb_flags that indicates if the debug registers are in use. >Should 'struct reg' be extended to directly include the debug >registers or should we go the route of having another data structure >for the debug registers, not unlike how the floating point registers >are handled? I'd be inclined to create another data structure, unless the debug registers are architecturally defined to be identical on all x86 chips. >Otherwise, I think I will need to set up a 'struct dbregs', provide >the appropriate 'fill_dbregs()' and 'set_dbregs()', and then provide a >PT_SETDBREGS, PT_GETDBREGS interface to 'ptrace()'. Either that, or create a routine like i386_set_breakpoint() in sys_machdep that would handle setting breakpoints for different types of cpu architectures. -- Jonathan To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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