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Speed up the inner loop of ansi_put() by a few percent.

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syscons' output is now only about 4-5 times slower than I want.
It loses a factor of 2 for scrolling output by unnecessarily copying
the screen buffer, a factor of 4/3 for dumb OPOST processing, and
a factor of 3/2 for clist processing.
This commit is contained in:
Bruce Evans 1995-07-11 17:59:22 +00:00
parent 7fbcd76bb5
commit f2fb20ef41
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=9483
3 changed files with 30 additions and 6 deletions
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12
sys/dev/syscons/syscons.c
View File

@ -25,7 +25,7 @@
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* $Id: syscons.c,v 1.117 1995/05/30 08:03:13 rgrimes Exp $
* $Id: syscons.c,v 1.118 1995/06/14 05:16:12 bde Exp $
*/
#include "sc.h"
@ -1860,7 +1860,15 @@ outloop:
u_short cur_attr = scp->term.cur_attr;
u_short *cursor_pos = scp->cursor_pos;
do {
*cursor_pos++ = (scr_map[*ptr++] | cur_attr);
/*
* gcc-2.6.3 generates poor (un)sign extension code. Casting the
* pointers in the following to volatile should have no effect,
* but in fact speeds up this inner loop from 26 to 18 cycles
* (+ cache misses) on i486's.
*/
#define UCVP(ucp) ((u_char volatile *)(ucp))
*cursor_pos++ = UCVP(scr_map)[*UCVP(ptr)] | cur_attr;
ptr++;
cnt--;
} while (cnt && PRINTABLE(*ptr));
len -= (cursor_pos - scp->cursor_pos);

12
sys/i386/isa/syscons.c
View File

@ -25,7 +25,7 @@
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* $Id: syscons.c,v 1.117 1995/05/30 08:03:13 rgrimes Exp $
* $Id: syscons.c,v 1.118 1995/06/14 05:16:12 bde Exp $
*/
#include "sc.h"
@ -1860,7 +1860,15 @@ outloop:
u_short cur_attr = scp->term.cur_attr;
u_short *cursor_pos = scp->cursor_pos;
do {
*cursor_pos++ = (scr_map[*ptr++] | cur_attr);
/*
* gcc-2.6.3 generates poor (un)sign extension code. Casting the
* pointers in the following to volatile should have no effect,
* but in fact speeds up this inner loop from 26 to 18 cycles
* (+ cache misses) on i486's.
*/
#define UCVP(ucp) ((u_char volatile *)(ucp))
*cursor_pos++ = UCVP(scr_map)[*UCVP(ptr)] | cur_attr;
ptr++;
cnt--;
} while (cnt && PRINTABLE(*ptr));
len -= (cursor_pos - scp->cursor_pos);

12
sys/isa/syscons.c
View File

@ -25,7 +25,7 @@
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* $Id: syscons.c,v 1.117 1995/05/30 08:03:13 rgrimes Exp $
* $Id: syscons.c,v 1.118 1995/06/14 05:16:12 bde Exp $
*/
#include "sc.h"
@ -1860,7 +1860,15 @@ outloop:
u_short cur_attr = scp->term.cur_attr;
u_short *cursor_pos = scp->cursor_pos;
do {
*cursor_pos++ = (scr_map[*ptr++] | cur_attr);
/*
* gcc-2.6.3 generates poor (un)sign extension code. Casting the
* pointers in the following to volatile should have no effect,
* but in fact speeds up this inner loop from 26 to 18 cycles
* (+ cache misses) on i486's.
*/
#define UCVP(ucp) ((u_char volatile *)(ucp))
*cursor_pos++ = UCVP(scr_map)[*UCVP(ptr)] | cur_attr;
ptr++;
cnt--;
} while (cnt && PRINTABLE(*ptr));
len -= (cursor_pos - scp->cursor_pos);