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From: bob@dhw68k.cts.com (Bob Best)
Newsgroups: comp.os.minix
Subject: Evans Kernel - Interrupt speedup
Summary: superfluous instruction in p2_s_call (mpx286.x)
Message-ID: <23327@dhw68k.cts.com>
Date: 30 May 89 19:27:05 GMT
Reply-To: bob@dhw68k.cts.com (Bob Best)
Organization: Wolfskill & Dowling residence; Anaheim, CA (USA)
Lines: 13

The following instruction in procedure p2_s_call in file mpx286.x
is superfluous.  It can safely be commented out of the code, thus
reducing the execution time of this frequently called function.

	defsldt	(_tss+TSS2_S_LDT)

It is possible that Bruce had intended to implement the hardware task
switching capabilities of the 286+ processors, in which case this
instruction would have been essential.  Since task switching is done
in software, this instruction is of no consequence.
-- 
Bob Best
uucp: {spsd, zardoz, felix}!dhw68k!bob	InterNet: bob@dhw68k.cts.com