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From: fpm@crash.cts.com (Frank Maclachlan)
Subject: Speedup for 386BSD 0.1 pccons display (w/ patch)
Organization: CTS Network Services (crash, ctsnet), El Cajon, CA
Date: 11 Nov 92 14:44:34 PST
Message-ID: <1992Nov11.144434.19076@crash>
Summary: Roughly doubles scrolling speed
Keywords: 386BSD pccons patch
Lines: 33
The 386bsd 0.1 console display driver, '/sys/i386/isa/pccons.c',
uses bcopyb() to block move screen memory when scrolling up. This
is inefficient on machines w/ a 16 bit or greater data path to the
screen memory. I changed the bcopyb() call to bcopy() and realized
a 2x speedup when displaying scrolling text w/ a 16 bit VGA card.
The following diff is against the original (virgin) 386bsd 0.1
/sys/i386/isa/pccons.c file:
*** pccons.c.ORIG Tue Aug 11 17:08:53 1992
--- pccons.c Wed Nov 11 15:06:34 1992
***************
*** 791,797 ****
}
if (sc && crtat >= Crtat+vs.ncol*vs.nrow) { /* scroll check */
if (openf) do (void)sgetc(1); while (scroll);
! bcopyb(Crtat+vs.ncol, Crtat, vs.ncol*(vs.nrow-1)*CHR);
fillw ((at << 8) + ' ', Crtat + vs.ncol*(vs.nrow-1),
vs.ncol);
crtat -= vs.ncol;
--- 791,797 ----
}
if (sc && crtat >= Crtat+vs.ncol*vs.nrow) { /* scroll check */
if (openf) do (void)sgetc(1); while (scroll);
! bcopy(Crtat+vs.ncol, Crtat, vs.ncol*(vs.nrow-1)*CHR);
fillw ((at << 8) + ' ', Crtat + vs.ncol*(vs.nrow-1),
vs.ncol);
crtat -= vs.ncol;
--
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