Copyright 2002, 2005 Free Software Foundation, Inc.
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This directory contains assembly code for nails-enabled 21264. The code is not
very well optimized.
For addmul_N, as N grows larger, we could make multiple loads together, then do
about 3.3 i/c. 10 cycles after the last load, we can increase to 4 i/c. This
would surely allow addmul_4 to run at 2 c/l, but the same should be possible
also for addmul_3 and perhaps even addmul_2.
current fair best
Routine c/l unroll c/l unroll c/l i/c
mul_1 3.25 2.75 2.75 3.273
addmul_1 4.0 4 3.5 4 14 3.25 3.385
addmul_2 4.0 1 2.5 2 10 2.25 3.333
addmul_3 3.0 1 2.33 2 14 2 3.333
addmul_4 2.5 1 2.125 2 17 2 3.135
addmul_5 2 1 10
addmul_6 2 1 12
addmul_7 2 1 14
(The "best" column doesn't account for bookkeeping instructions and
thereby assumes infinite unrolling.)
Basecase usages:
1 addmul_1
2 addmul_2
3 addmul_3
4 addmul_4
5 addmul_3 + addmul_2 2.3998
6 addmul_4 + addmul_2
7 addmul_4 + addmul_3
