Robert Allan James
e23900d115
5 of 12 words fully modelled: ENTROPY@/ENTROPY! (XT-pop gap sidestepped same as ACL words, but note this file's is_valid_dict_entry is a real membership-check safety improvement over acl_words.c's null-only check), RESET-ENTROPY (dictionary-wide bulk reset, same technique as ACL-INIT-PRIMITIVES), ZUSE-AUTHENTICATE (single-field set), VERSION (identity, no stack effect at all). TOP-WORDS/SEED/RANDOM/WAIT get guard/shape only -- SEED and RANDOM both depend on g_prng_state, a file-scope C static shared across the whole Tripod fleet (yet another instance of the recurring file-scope-static-instead-of-per-VM pattern, here meaning every VM draws from the same RNG stream). WORD-ENTROPY/(-/ INIT not modelled (pure printf / TIB dependency / real filesystem I/O plus a custom text parser). Finding: register_starforth_words registers its 10 words, bootstraps the STARFORTH vocabulary, then re-registers 12 words (same 10 plus ENTROPY@/ENTROPY!) into that vocabulary context -- noted as the second file where registration order matters for which body actually runs, judgment on intentionality deferred to the largely-unmodelled vocabulary chain mechanics. Suite now 44 theories, green.
299 lines
14 KiB
Plaintext
299 lines
14 KiB
Plaintext
theory StarForth_StarForth_Words
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imports StarForth_Base
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begin
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(* =========================================================================
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Mirrors: src/word_source/starforth_words.c
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Registers: ENTROPY@ ENTROPY! WORD-ENTROPY RESET-ENTROPY TOP-WORDS (-
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INIT VERSION SEED RANDOM WAIT ZUSE-AUTHENTICATE
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── Registration finding: words are registered TWICE ─────────────────────
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`register_starforth_words` (line 802) registers 10 words, calls
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`vm_bootstrap_root_vocabulary(vm, "STARFORTH")`, then re-registers 12
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words (the same 10 plus ENTROPY@/ENTROPY!) "in the STARFORTH vocabulary
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context" per its own comment. Whether this is intentional vocabulary-
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system plumbing or a real double-registration bug is outside this
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theory's scope to judge (it would need the vocabulary-chain mechanics
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StarForth_Vocabulary_Words.thy already flagged as file-scope-static and
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largely unmodelled) -- noted here since it's the second file in the
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sweep (after defining_words.c/dictionary_manipulation_words.c) where
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registration ORDER matters for which word body actually runs.
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── XT-pop gap, same convention as ACL words ─────────────────────────────
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ENTROPY@/ENTROPY! pop a raw address, cast it to `DictEntry*`, and
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ADDITIONALLY validate it via `is_valid_dict_entry` (a dictionary
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membership walk) before use -- a real safety improvement over
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acl_words.c's `pop_xt` (null check only). Modelled the same way
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ACL_Pin_Monotone/StarForth_ACL_Words.thy do: operating on an
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already-resolved `dict_entry`, not the pop/cast/validate mechanism
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(still the same underlying "cast cell_t <-> DictEntry*" gap).
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── Scope ─────────────────────────────────────────────────────────────
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Fully modelled: ENTROPY@, ENTROPY!, RESET-ENTROPY (dictionary-wide bulk
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reset, same technique as ACL-INIT-PRIMITIVES), ZUSE-AUTHENTICATE
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(single-field set), VERSION (stdout-only identity, no stack effect at
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all -- doesn't even touch data_stack).
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Guard/shape only, body deferred: TOP-WORDS (printf display), SEED
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(mutates `g_prng_state`, a file-scope C static with no vm_state
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counterpart), RANDOM (result depends on the same unmodelled PRNG state
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via `prng_next()`), WAIT (loops calling `vm_tick(vm)`, which does far
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more than the heartbeat sub-transitions StarForth_Loop7_Heartrate.thy
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models -- composing it accurately is its own project).
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Not modelled at all: WORD-ENTROPY (pure printf, but included as an
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identity for completeness), `(-` (TIB/input-buffer dependency, the
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documented cluster from StarForth_String_Words.thy/StarForth_System_
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Words.thy), INIT (real filesystem I/O + a substantial custom text
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parser rewriting `NNNN LOAD` references -- a whole subsystem, not a
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word-level property).
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======================================================================== *)
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(* ── ENTROPY@ ( addr -- n ) ────────────────────────────────────────────── *)
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definition forth_entropy_fetch :: "vm_state \<Rightarrow> dict_entry \<Rightarrow> vm_state" where
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"forth_entropy_fetch vm e =
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(if ds_full vm then set_error vm
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else vm\<lparr>data_stack := de_heat e # data_stack vm\<rparr>)"
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lemma entropy_fetch_underflow_note: True
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\<comment> \<open>The C underflow guard (`vm->dsp < 0` before the pop) and the
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null/validity checks on the popped address are all part of the
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unmodelled XT-pop/cast/validate mechanism (see file header) -- once
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an already-resolved `dict_entry` is in hand, as modelled here, only
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the destination stack-overflow guard remains a real vm_state
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condition.\<close>
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by simp
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lemma entropy_fetch_normal:
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assumes "\<not> ds_full vm"
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shows "data_stack (forth_entropy_fetch vm e) = de_heat e # data_stack vm"
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by (simp add: forth_entropy_fetch_def assms)
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(* ── ENTROPY! ( n addr -- ) ────────────────────────────────────────────── *)
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(* C pops addr first (TOS), then value -- matches the ( n addr -- ) stack
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comment: addr is on top, n below it. *)
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definition forth_entropy_store :: "nat \<Rightarrow> vm_state \<Rightarrow> vm_state" where
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"forth_entropy_store wid vm =
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(case data_stack vm of
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addr # value # xs \<Rightarrow>
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vm\<lparr>data_stack := xs,
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dictionary := (case dictionary vm wid of
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None \<Rightarrow> dictionary vm
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| Some e \<Rightarrow> (dictionary vm)(wid := Some (e\<lparr>de_heat := value\<rparr>)))\<rparr>
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| _ \<Rightarrow> set_error vm)"
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lemma entropy_store_underflow_nil:
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assumes "data_stack vm = []"
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shows "vm_error (forth_entropy_store wid vm)"
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by (simp add: forth_entropy_store_def set_error_def assms)
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lemma entropy_store_underflow_one:
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assumes "data_stack vm = [x]"
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shows "vm_error (forth_entropy_store wid vm)"
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by (simp add: forth_entropy_store_def set_error_def assms)
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lemma entropy_store_found:
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assumes "data_stack vm = addr # value # xs"
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assumes "dictionary vm wid = Some e"
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shows "data_stack (forth_entropy_store wid vm) = xs"
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and "dictionary (forth_entropy_store wid vm) wid = Some (e\<lparr>de_heat := value\<rparr>)"
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using assms by (simp_all add: forth_entropy_store_def)
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(* ── RESET-ENTROPY ( -- ) : dictionary-wide bulk reset ───────────────────── *)
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(* C: for every entry with execution_heat > 0, zero de_heat AND the three
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physics fields temperature_q8/avg_latency_ns/last_active_ns. Entries
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with execution_heat = 0 already are left untouched (redundant given
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they're already all-zero in practice, but modelled faithfully -- the
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guard is on de_heat only, not on the physics fields independently). *)
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definition reset_entropy_entry :: "dict_entry \<Rightarrow> dict_entry" where
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"reset_entropy_entry e =
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(if 0 <s de_heat e
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then e\<lparr>de_heat := 0,
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de_physics := (de_physics e)
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\<lparr>dp_temperature_q8 := 0, dp_avg_latency_ns := 0, dp_last_active_ns := 0\<rparr>\<rparr>
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else e)"
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definition forth_reset_entropy :: "vm_state \<Rightarrow> vm_state" where
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"forth_reset_entropy vm =
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vm\<lparr>dictionary := (\<lambda>wid. map_option reset_entropy_entry (dictionary vm wid))\<rparr>"
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lemma reset_entropy_hot_entry_zeroed:
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assumes "dictionary vm wid = Some e"
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assumes "0 <s de_heat e"
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shows "dictionary (forth_reset_entropy vm) wid =
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Some (e\<lparr>de_heat := 0,
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de_physics := (de_physics e)
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\<lparr>dp_temperature_q8 := 0, dp_avg_latency_ns := 0, dp_last_active_ns := 0\<rparr>\<rparr>)"
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using assms by (simp add: forth_reset_entropy_def reset_entropy_entry_def)
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lemma reset_entropy_cold_entry_untouched:
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assumes "dictionary vm wid = Some e"
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assumes "\<not> 0 <s de_heat e"
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shows "dictionary (forth_reset_entropy vm) wid = Some e"
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using assms by (simp add: forth_reset_entropy_def reset_entropy_entry_def)
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lemma reset_entropy_preserves_absence:
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assumes "dictionary vm wid = None"
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shows "dictionary (forth_reset_entropy vm) wid = None"
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using assms by (simp add: forth_reset_entropy_def)
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lemma reset_entropy_data_stack_unchanged:
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"data_stack (forth_reset_entropy vm) = data_stack vm"
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by (simp add: forth_reset_entropy_def)
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lemma reset_entropy_never_errors:
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"vm_error (forth_reset_entropy vm) = vm_error vm"
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by (simp add: forth_reset_entropy_def)
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(* ── ZUSE-AUTHENTICATE ( -- ) : single-field set ──────────────────────────── *)
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definition forth_zuse_authenticate :: "vm_state \<Rightarrow> vm_state" where
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"forth_zuse_authenticate vm = vm\<lparr>zuse_session := True\<rparr>"
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lemma zuse_authenticate_sets_session:
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"zuse_session (forth_zuse_authenticate vm) = True"
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by (simp add: forth_zuse_authenticate_def)
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lemma zuse_authenticate_data_stack_unchanged:
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"data_stack (forth_zuse_authenticate vm) = data_stack vm"
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by (simp add: forth_zuse_authenticate_def)
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lemma zuse_authenticate_never_errors:
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"vm_error (forth_zuse_authenticate vm) = vm_error vm"
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by (simp add: forth_zuse_authenticate_def)
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(* ── VERSION ( -- ) : stdout-only, no stack effect at all ────────────────── *)
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definition forth_version :: "vm_state \<Rightarrow> vm_state" where
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"forth_version vm = vm"
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lemma version_identity: "forth_version vm = vm"
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by (simp add: forth_version_def)
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(* ── WORD-ENTROPY ( -- ) : stdout-only display, identity ──────────────────── *)
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definition forth_word_entropy :: "vm_state \<Rightarrow> vm_state" where
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"forth_word_entropy vm = vm"
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lemma word_entropy_identity: "forth_word_entropy vm = vm"
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by (simp add: forth_word_entropy_def)
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(* ── TOP-WORDS ( n -- ) : guard/pop only, display body not modelled ──────── *)
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definition forth_top_words_guard :: "vm_state \<Rightarrow> vm_state" where
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"forth_top_words_guard vm =
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(case data_stack vm of
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[] \<Rightarrow> set_error vm
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| n # xs \<Rightarrow> vm\<lparr>data_stack := xs\<rparr>)"
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lemma top_words_underflow:
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assumes "data_stack vm = []"
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shows "vm_error (forth_top_words_guard vm)"
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by (simp add: forth_top_words_guard_def set_error_def assms)
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lemma top_words_pops_one:
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assumes "data_stack vm = n # xs"
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shows "data_stack (forth_top_words_guard vm) = xs"
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by (simp add: forth_top_words_guard_def assms)
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(* ── SEED ( n -- ) : guard/pop only, PRNG state not modelled ─────────────── *)
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definition forth_seed_guard :: "vm_state \<Rightarrow> vm_state" where
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"forth_seed_guard vm =
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(case data_stack vm of
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[] \<Rightarrow> set_error vm
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| n # xs \<Rightarrow> vm\<lparr>data_stack := xs\<rparr>)"
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lemma seed_underflow:
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assumes "data_stack vm = []"
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shows "vm_error (forth_seed_guard vm)"
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by (simp add: forth_seed_guard_def set_error_def assms)
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lemma seed_pops_one:
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assumes "data_stack vm = n # xs"
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shows "data_stack (forth_seed_guard vm) = xs"
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by (simp add: forth_seed_guard_def assms)
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lemma seed_global_not_modelled: True
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\<comment> \<open>g_prng_state is a file-scope C static (line 71), not a vm_state
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field -- ANOTHER instance of the file-scope-static-instead-of-per-VM
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pattern this sweep has now found many times (see StarForth_System_
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Words.thy/StarForth_Vocabulary_Words.thy for the aggregated write-up
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candidates), but here the effect is arguably WORSE: it means SEED
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re-seeds a single process-wide RNG shared by every VM in the Tripod
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fleet, and RANDOM below draws from that same shared stream.\<close>
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by simp
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(* ── RANDOM ( lo hi -- n ) : guard/shape only, result not modelled ───────── *)
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definition forth_random_guard :: "vm_state \<Rightarrow> vm_state" where
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"forth_random_guard vm =
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(case data_stack vm of
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hi # lo # xs \<Rightarrow> vm\<lparr>data_stack := xs\<rparr>
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| _ \<Rightarrow> set_error vm)"
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lemma random_underflow_nil:
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assumes "data_stack vm = []"
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shows "vm_error (forth_random_guard vm)"
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by (simp add: forth_random_guard_def set_error_def assms)
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lemma random_underflow_one:
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assumes "data_stack vm = [x]"
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shows "vm_error (forth_random_guard vm)"
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by (simp add: forth_random_guard_def set_error_def assms)
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lemma random_pops_two:
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assumes "data_stack vm = hi # lo # xs"
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shows "data_stack (forth_random_guard vm) = xs"
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by (simp add: forth_random_guard_def assms)
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lemma random_result_not_modelled: True
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\<comment> \<open>Result depends on prng_next(), which draws from the same unmodelled
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g_prng_state global as SEED -- see seed_global_not_modelled.\<close>
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by simp
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(* ── WAIT ( n -- ) : guard + non-positive-n no-op modelled, loop deferred ── *)
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definition forth_wait_guard :: "vm_state \<Rightarrow> vm_state" where
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"forth_wait_guard vm =
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(case data_stack vm of
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[] \<Rightarrow> set_error vm
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| n # xs \<Rightarrow> vm\<lparr>data_stack := xs\<rparr>)"
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lemma wait_underflow:
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assumes "data_stack vm = []"
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shows "vm_error (forth_wait_guard vm)"
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by (simp add: forth_wait_guard_def set_error_def assms)
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lemma wait_nonpositive_ticks_is_pop_only: True
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\<comment> \<open>C: `if (ticks <= 0) return;` -- once the underflow guard passes and
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ticks \<le>s 0, the word's entire remaining effect is the pop already
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captured by forth_wait_guard.\<close>
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by simp
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lemma wait_loop_not_modelled: True
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\<comment> \<open>ticks > 0: calls vm_tick(vm) that many times. vm_tick does far more
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than the heartbeat_state sub-transitions StarForth_Loop7_Heartrate.thy
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models (hb_fire_tick etc. operate on heartbeat_state alone) --
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composing an accurate n-times vm_tick transition is its own project,
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not attempted here.\<close>
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by simp
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(* ── (- , INIT -- NOT MODELLED ────────────────────────────────────────── *)
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lemma paren_dash_not_modelled: True
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\<comment> \<open>(- : consumes vm->input_buffer/input_pos -- the TIB/input-subsystem
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dependency already documented as a deferred cluster in StarForth_
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String_Words.thy/StarForth_System_Words.thy.\<close>
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by simp
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lemma init_not_modelled: True
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\<comment> \<open>INIT: real filesystem I/O (fopen/fread on ./capsules/core/init.4th)
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plus a substantial custom text parser that rewrites `NNNN LOAD`
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block references while copying into the block subsystem -- a whole
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subsystem-level operation, not a word-level property.\<close>
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by simp
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end
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