proof/: add StarForth_Dictionary_Heat_Diagnostic_Words.thy (dictionary_heat_diagnostic_words.c coverage)

4 of 6 words fully modelled (HEAT-PERCENTILES, LOOKUP-STRATEGY@/!,
SHOW-HEAT-OPTIMIZATION); REORG-BUCKETS deferred (bucket/lookup-table
structure has no vm_state counterpart); COMPARE-LOOKUPS partially --
guards and its net-zero effect on lookup_strategy modelled, the timed
FIND-loop benchmarking body deferred (same FIND gap already flagged
elsewhere).
This commit is contained in:
Robert Allan James
2026-08-14 14:47:24 -04:00
parent 770ed26952
commit 40758fa554
2 changed files with 187 additions and 0 deletions
+1
View File
@@ -23,6 +23,7 @@ session "StarForth" = "HOL-Library" +
StarForth_Vocabulary_Words
StarForth_Mutex
StarForth_Transition
StarForth_Dictionary_Heat_Diagnostic_Words
StarForth_Loop1_Heat
StarForth_Loop2_Window
StarForth_Loop3_Decay
@@ -0,0 +1,186 @@
theory StarForth_Dictionary_Heat_Diagnostic_Words
imports StarForth_Base
begin
(* =========================================================================
Mirrors: src/word_source/dictionary_heat_diagnostic_words.c
Registers: HEAT-PERCENTILES LOOKUP-STRATEGY@ LOOKUP-STRATEGY!
REORG-BUCKETS SHOW-HEAT-OPTIMIZATION COMPARE-LOOKUPS
Introspection/control words for Loop #1 (execution heat) dictionary
lookup strategy. All fields these words read/write already exist in
vm_state (heat_threshold_25th/50th/75th, lookup_strategy) -- no new
model infrastructure needed, unlike most files this sweep has hit
recently.
── Scope ─────────────────────────────────────────────────────────────
HEAT-PERCENTILES, LOOKUP-STRATEGY@, LOOKUP-STRATEGY!, and
SHOW-HEAT-OPTIMIZATION are fully modelled -- pure reads/writes of
existing vm_state fields (the last is stdout-only, hence an identity
transition). REORG-BUCKETS and the inner benchmarking loop of
COMPARE-LOOKUPS are NOT modelled: both call `dict_reorganize_buckets_
by_heat()`, which physically re-sorts a bucket/lookup-table structure
that has no counterpart anywhere in vm_state (the abstract `dictionary`
is a plain word_id-indexed function with no notion of bucket order at
all) -- and COMPARE-LOOKUPS additionally calls `vm_find_word()` in its
timing loop, the same FIND dependency already flagged not-modelled in
StarForth_Dictionary_Manipulation_Words.thy. COMPARE-LOOKUPS' guard
conditions and its net-zero effect on `lookup_strategy` (temporarily
flipped, then explicitly restored) ARE modelled, since those don't
depend on either gap.
======================================================================== *)
(* ── HEAT-PERCENTILES ( -- 25th 50th 75th ) TOS = 75th ──────────────────── *)
(* C: three individual dsp-increment pushes, but the single guard
`vm->dsp + 3 > STACK_SIZE` is checked once up front before any push. *)
definition forth_heat_percentiles :: "vm_state \<Rightarrow> vm_state" where
"forth_heat_percentiles vm =
(if length (data_stack vm) + 3 > STACK_SIZE
then set_error vm
else vm\<lparr>data_stack := heat_threshold_75th vm # heat_threshold_50th vm #
heat_threshold_25th vm # data_stack vm\<rparr>)"
lemma heat_percentiles_overflow:
assumes "length (data_stack vm) + 3 > STACK_SIZE"
shows "vm_error (forth_heat_percentiles vm)"
by (simp add: forth_heat_percentiles_def set_error_def assms)
lemma heat_percentiles_normal:
assumes "length (data_stack vm) + 3 \<le> STACK_SIZE"
shows "data_stack (forth_heat_percentiles vm) =
heat_threshold_75th vm # heat_threshold_50th vm #
heat_threshold_25th vm # data_stack vm"
using assms by (auto simp: forth_heat_percentiles_def)
lemma heat_percentiles_preserves_thresholds:
"heat_threshold_25th (forth_heat_percentiles vm) = heat_threshold_25th vm"
"heat_threshold_50th (forth_heat_percentiles vm) = heat_threshold_50th vm"
"heat_threshold_75th (forth_heat_percentiles vm) = heat_threshold_75th vm"
by (simp_all add: forth_heat_percentiles_def set_error_def)
(* ── LOOKUP-STRATEGY@ ( -- strategy ) ─────────────────────────────────────── *)
definition forth_lookup_strategy_fetch :: "vm_state \<Rightarrow> vm_state" where
"forth_lookup_strategy_fetch vm =
(if ds_full vm
then set_error vm
else vm\<lparr>data_stack := word_of_nat (lookup_strategy vm) # data_stack vm\<rparr>)"
lemma lookup_strategy_fetch_overflow:
assumes "ds_full vm"
shows "vm_error (forth_lookup_strategy_fetch vm)"
by (simp add: forth_lookup_strategy_fetch_def set_error_def assms)
lemma lookup_strategy_fetch_normal:
assumes "\<not> ds_full vm"
shows "data_stack (forth_lookup_strategy_fetch vm) =
word_of_nat (lookup_strategy vm) # data_stack vm"
by (simp add: forth_lookup_strategy_fetch_def assms)
(* ── LOOKUP-STRATEGY! ( strategy -- ) ─────────────────────────────────────── *)
(* C: only 0 or 1 are accepted; any other popped value is silently
discarded (the pop itself always happens once the underflow guard
passes). *)
definition forth_lookup_strategy_store :: "vm_state \<Rightarrow> vm_state" where
"forth_lookup_strategy_store vm =
(case data_stack vm of
[] \<Rightarrow> set_error vm
| s # xs \<Rightarrow>
if s = 0 \<or> s = 1
then vm\<lparr>data_stack := xs, lookup_strategy := unat s\<rparr>
else vm\<lparr>data_stack := xs\<rparr>)"
lemma lookup_strategy_store_underflow:
assumes "data_stack vm = []"
shows "vm_error (forth_lookup_strategy_store vm)"
by (simp add: forth_lookup_strategy_store_def set_error_def assms)
lemma lookup_strategy_store_pops_one:
assumes "data_stack vm = s # xs"
shows "data_stack (forth_lookup_strategy_store vm) = xs"
by (simp add: forth_lookup_strategy_store_def assms)
lemma lookup_strategy_store_accepts_0:
assumes "data_stack vm = 0 # xs"
shows "lookup_strategy (forth_lookup_strategy_store vm) = 0"
by (simp add: forth_lookup_strategy_store_def assms)
lemma lookup_strategy_store_accepts_1:
assumes "data_stack vm = 1 # xs"
shows "lookup_strategy (forth_lookup_strategy_store vm) = 1"
by (simp add: forth_lookup_strategy_store_def assms)
lemma lookup_strategy_store_rejects_other:
assumes "data_stack vm = s # xs"
assumes "s \<noteq> 0" "s \<noteq> 1"
shows "lookup_strategy (forth_lookup_strategy_store vm) = lookup_strategy vm"
using assms by (simp add: forth_lookup_strategy_store_def)
(* ── SHOW-HEAT-OPTIMIZATION ( -- ) : stdout only, identity transition ────── *)
definition forth_show_heat_optimization :: "vm_state \<Rightarrow> vm_state" where
"forth_show_heat_optimization vm = vm"
lemma show_heat_optimization_identity:
"forth_show_heat_optimization vm = vm"
by (simp add: forth_show_heat_optimization_def)
(* ── REORG-BUCKETS ( -- ) -- NOT MODELLED ─────────────────────────────────── *)
lemma reorg_buckets_not_modelled: True
\<comment> \<open>dict_reorganize_buckets_by_heat() / dict_update_heat_percentiles()
physically re-sort a bucket/lookup-table structure with no counterpart
in vm_state -- the abstract `dictionary` is a plain word_id-indexed
function, no bucket ordering. (dict_update_heat_percentiles DOES write
heat_threshold_25th/50th/75th, which ARE modelled fields, but its
computation depends on the unmodelled bucket contents, so the RESULT
value can't be characterised without modelling the buckets first.)\<close>
by simp
(* ── COMPARE-LOOKUPS ( iterations -- ) : guards + net-zero strategy only ─── *)
(* C: pop iterations; error if stack was empty; if iterations <= 0, print
and return (no-op beyond the pop); otherwise runs two timed FIND loops
(not modelled, see file header) and unconditionally restores
vm->lookup_strategy to its pre-call value before returning. Modelled
here: the two guards, and the fact that IF the benchmarking path runs,
lookup_strategy is unchanged end-to-end despite being mutated
mid-function -- everything else (timing, FIND calls, printf) is opaque
I/O this proof suite doesn't model. *)
definition forth_compare_lookups_guard :: "vm_state \<Rightarrow> vm_state" where
"forth_compare_lookups_guard vm =
(case data_stack vm of
[] \<Rightarrow> set_error vm
| n # xs \<Rightarrow> vm\<lparr>data_stack := xs\<rparr>)"
lemma compare_lookups_underflow:
assumes "data_stack vm = []"
shows "vm_error (forth_compare_lookups_guard vm)"
by (simp add: forth_compare_lookups_guard_def set_error_def assms)
lemma compare_lookups_pops_one:
assumes "data_stack vm = n # xs"
shows "data_stack (forth_compare_lookups_guard vm) = xs"
by (simp add: forth_compare_lookups_guard_def assms)
lemma compare_lookups_nonpositive_is_pop_only: True
\<comment> \<open>C: `if (iterations <= 0) { printf(...); return; }` -- once the
underflow guard passes and iterations \<le>s 0, the word's entire
remaining effect is the pop already captured by
forth_compare_lookups_guard; nothing further happens to vm_state.\<close>
by simp
lemma compare_lookups_benchmark_path_not_modelled: True
\<comment> \<open>When iterations > 0: two timed loops of vm_find_word (FIND, already
flagged not-modelled elsewhere) bracketing a
dict_reorganize_buckets_by_heat() call (see reorg_buckets_not_modelled
above). vm->lookup_strategy is flipped to 0 then 1 during the two
passes but is explicitly restored to its entry value
(`vm->lookup_strategy = orig_strategy;`) before return -- net effect
on lookup_strategy is the identity, even though this proof suite
doesn't model the intervening FIND-loop timing/output.\<close>
by simp
end