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Minor modifications, adding comments

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elvis
2025-01-15 00:10:44 +01:00
parent 11adaa5103
commit cf0bc41a23
15 changed files with 124 additions and 54 deletions
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38
lib/miniImp/reduceRegisters.ml
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@ -18,7 +18,8 @@ module RISCCfg = CfgRISC.RISCCfg
module VariableMap = Map.Make(Variable)
let variables_frequency (instr : RISCCfg.elt) : (Variable.t * int) list =
let add_one = (fun x -> match x with None -> Some 1 | Some x -> Some (x + 1)) in
let add_one = (fun x -> match x with None -> Some 1 | Some x -> Some (x + 1))
in
let helper (acc: int VariableMap.t) (instr: RISCCfg.elt) : int VariableMap.t =
match instr with
@ -40,7 +41,9 @@ let variables_frequency (instr : RISCCfg.elt) : (Variable.t * int) list =
helper VariableMap.empty instr |> VariableMap.to_list
let variables_all_frequency (instructions : RISCCfg.elt list) : (Variable.t * int) list =
(* computes syntactic frequency of all variables in the code *)
let variables_all_frequency (instructions : RISCCfg.elt list)
: (Variable.t * int) list =
List.fold_left
( fun (acc: int VariableMap.t) (instr: RISCCfg.elt) ->
VariableMap.union
@ -50,16 +53,20 @@ let variables_all_frequency (instructions : RISCCfg.elt list) : (Variable.t * in
let reduceregisters (n: int) (cfg: RISCCfg.t) : RISCCfg.t =
(if n < 4 then (failwith "ReduceRegisters: number of registers too small") else ());
(if n < 4 then (
failwith "ReduceRegisters: number of registers too small"
) else ());
(* we get all the variables with associated frequency (only syntactic use) *)
let all_variables = List.fold_left
(fun acc (_, code) ->
Utility.unique_union_assoc (fun _n x y -> x + y) acc (variables_all_frequency code))
Utility.unique_union_assoc
(fun _n x y -> x + y) acc (variables_all_frequency code))
[]
(Cfg.NodeMap.to_list cfg.content)
in
(* add one to in and out variables *)
let all_variables =
match cfg.inputOutputVar with
| None -> all_variables
@ -80,6 +87,8 @@ let reduceregisters (n: int) (cfg: RISCCfg.t) : RISCCfg.t =
)
in
(* replace each operation with a list of operations that have the new
registers or load from memory *)
let replaceregisters
(remappedregisters: Variable.t VariableMap.t)
(memorymap: int VariableMap.t)
@ -143,7 +152,10 @@ let reduceregisters (n: int) (cfg: RISCCfg.t) : RISCCfg.t =
BRegOp (brop, tmpreg1, tmpreg2, tmpreg2);
LoadI (m3, tmpreg1);
Store (tmpreg2, tmpreg1)]
| _ -> [BRegOp (brop, {index = r1.index}, {index = r2.index}, {index = r3.index})]
| _ -> [BRegOp (brop,
{index = r1.index},
{index = r2.index},
{index = r3.index})]
)
| BImmOp (biop, r1, i, r3) -> (
match ( VariableMap.find_opt r1.index remappedregisters,
@ -237,8 +249,8 @@ let reduceregisters (n: int) (cfg: RISCCfg.t) : RISCCfg.t =
" registers have no binding.")
)
| Store (r1, r3) -> (
(* we want to maybe store an address in memory (very confusing, don't
think can happen) *)
(* we want to maybe store an address in memory (very confusing,
but maybe possible) *)
match ( VariableMap.find_opt r1.index remappedregisters,
VariableMap.find_opt r3.index remappedregisters,
VariableMap.find_opt r1.index memorymap,
@ -269,6 +281,8 @@ let reduceregisters (n: int) (cfg: RISCCfg.t) : RISCCfg.t =
in
(* partition the variables into two sets, most frequent and least frequent
then apply the transformation *)
let aux (cfg: RISCCfg.t) (all_variables: (string * int) list) =
(* we keep the first two variables free for immediate use *)
let most_frequent, least_frequent =
@ -298,8 +312,13 @@ let reduceregisters (n: int) (cfg: RISCCfg.t) : RISCCfg.t =
let newcfg = {
cfg with
content = Cfg.NodeMap.map
(fun x -> replaceregisters most_frequent_mapping least_frequent_mapping ["1"; "2"] x)
cfg.content}
( fun x ->
replaceregisters
most_frequent_mapping
least_frequent_mapping
["1"; "2"]
x
) cfg.content}
in
match newcfg.inputOutputVar with
@ -417,7 +436,6 @@ let reduceregisters (n: int) (cfg: RISCCfg.t) : RISCCfg.t =
)
in
( if List.length all_variables <= n
then cfg
else aux cfg all_variables )