%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%% http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%
%% ULTRASPARC MACHINE MODEL
%%
%% This module is used by the scheduler.
%% The following interface is used:
%% ...
%%
%% NOTES:
%% - the machine model is simple (on the verge of simplistic)
%% * all FUs are pipelined => model only one cycle at a time
%% * instruction latencies are mostly 1
%% * floating point is left for later (I _think_ it works, but ...)
%% - conservative: instructions that require multiple resources are
%% modelled as 'single'; instead, they could reserve IEU+BR or whatever
%% - possibly inefficient: I think machine state model could be turned into
%% a bitvector.
-module(hipe_ultra_mod2).
-export([init_resources/1,
init_instr_resources/2,
resources_available/4,
advance_cycle/1
]).
-export([raw_latency/2,
war_latency/2,
waw_latency/2,
%% m_raw_latency/2,
%% m_war_latency/2,
%% m_waw_latency/2,
m_raw_latency/0,
m_war_latency/0,
m_waw_latency/0,
br_to_unsafe_latency/2,
unsafe_to_br_latency/2,
br_br_latency/2
]).
-include("../sparc/hipe_sparc.hrl").
-define(debug(Str,Args),ok).
%-define(debug(Str,Args),io:format(Str,Args)).
-define(debug_ultra(Str,Args),ok).
%-define(debug_ultra(Str,Args),io:format(Str,Args)).
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%
%% Straightforward and somewhat simplistic model for UltraSparc:
%% - only one cycle at a time is modelled
%% - resources are simplified:
%% * ieu0, ieu1, ieu, mem, br, single
%% * per-cycle state = done | { I0, I1, NumI, X, Mem, Br }
%% * unoptimized representation (could be bit vector)
init_resources(_Size) ->
?debug_ultra('init res ~p~n',[_Size]),
empty_state().
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
init_instr_resources(N,Nodes) ->
ultra_instr_rsrcs(Nodes,hipe_vectors:new(N, '')).
ultra_instr_rsrcs([],I_res) -> I_res;
ultra_instr_rsrcs([N|Ns],I_res) ->
ultra_instr_rsrcs(Ns,ultra_instr_type(N,I_res)).
ultra_instr_type({N,I},I_res) ->
hipe_vectors:set(I_res,N-1,instr_type(I)).
instr_type(I) ->
case I of
#move{} ->
ieu;
#multimove{} -> %% TODO: expand multimoves before scheduling
ieu;
#alu{} ->
case hipe_sparc:alu_operator(I) of
'>>' -> ieu0;
'<<' -> ieu0;
_ -> ieu
end;
#alu_cc{} ->
ieu1;
#sethi{} ->
ieu;
#load{} ->
mem;
#store{} ->
mem;
#b{} ->
br;
#br{} ->
br;
#goto{} ->
br;
#jmp_link{} -> % imprecise; should be mem+br?
single;
#jmp{} -> % imprecise
br;
#call_link{} -> % imprecise; should be mem+br?
single;
#cmov_cc{} -> % imprecise
single;
#cmov_r{} -> % imprecise
single;
#load_atom{} -> % should be resolved to sethi/or
single;
#load_address{} -> % should be resolved to sethi/or
single;
#load_word_index{} -> % should be resolved to sethi/or
single;
%% uncommon types:
#label{} ->
none;
#nop{} ->
none;
#comment{} ->
none;
_ ->
exit({ultrasparc_instr_type,{cant_schedule,I}})
end.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
resources_available(_Cycle, I, Rsrc, I_res) ->
res_avail(instruction_resource(I_res, I), Rsrc).
instruction_resource(I_res, I) ->
hipe_vectors:get(I_res, I-1).
%% The following function checks resource availability.
%% * all function units are assumed to be fully pipelined, so only
%% one cycle at a time is modelled.
%% * for IEU0 and IEU1, these must precede all generic IEU instructions
%% (handled by X bit)
%% * at most 2 integer instructions can issue in a cycle
%% * mem is straightforward
%% * br closes the cycle (= returns done).
%% * single requires an entirely empty state and closes the cycle
res_avail(ieu0, { free, I1, NumI, free, Mem, Br })
when is_integer(NumI), NumI < 2 ->
{ yes, { occ, I1, NumI+1, free, Mem, Br }};
res_avail(ieu1, { _I0, free, NumI, free, Mem, Br })
when is_integer(NumI), NumI < 2 ->
{ yes, { free, occ, NumI+1, free, Mem, Br }};
res_avail(ieu, { I0, I1, NumI, _X, Mem, Br })
when is_integer(NumI), NumI < 2 ->
{ yes, { I0, I1, NumI+1, occ, Mem, Br }};
res_avail(mem, { I0, I1, NumI, X, free, Br }) ->
{ yes, { I0, I1, NumI, X, occ, Br }};
res_avail(br, { _I0, _I1, _NumI, _X, _Mem, free }) ->
{ yes, done };
res_avail(single, { free, free, 0, free, free, free }) ->
{ yes, done };
res_avail(_, _) ->
no.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
advance_cycle(_Rsrc) ->
empty_state().
empty_state() -> { free, free, 0, free, free, free }.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Latencies are taken from UltraSparc hardware manual
%%
%% *** UNFINISHED ***
%% more precisely, they are taken from my memory of the US-manual
%% at the moment.
%%
%% Note: all ld/st are assumed to hit in the L1 cache (D-cache),
%% which is sort of imprecise.
raw_latency(alu, store) -> 0;
raw_latency(load, _) -> 2; % only if load is L1 hit
raw_latency(alu_cc, b) -> 0;
raw_latency(_I0, _I1) ->
1.
war_latency(_I0, _I1) ->
0.
waw_latency(_I0, _I1) ->
1.
%% *** UNFINISHED ***
%% At present, all load/stores are assumed to hit in the L1 cache,
%% which isn't really satisfying.
%% m_raw_latency(_St, _Ld) ->
%% 1.
%%
%% m_war_latency(_Ld, _St) ->
%% 1.
%%
%% m_waw_latency(_St1, _St2) ->
%% 1.
%% Use these for 'default latencies' = do not permit reordering.
m_raw_latency() ->
1.
m_war_latency() ->
1.
m_waw_latency() ->
1.
br_to_unsafe_latency(_BrTy, _UTy) ->
0.
unsafe_to_br_latency(_UTy, _BrTy) ->
0.
br_br_latency(_BrTy1, _BrTy2) ->
0.
