theory StarForth_Defining_Words imports StarForth_Base StarForth_Memory_Words begin (* ========================================================================= Mirrors: src/word_source/defining_words.c Registers: : ; CREATE VARIABLE CONSTANT IMMEDIATE STATE [ ] FORGET COMPILE [COMPILE] LIT LITERAL does_rt DOES> DEFER IS DEFER@ ── Duplicate-registration finding (corrects a StarForth_Dictionary_ Manipulation_Words.thy note) ──────────────────────────────────────── `src/word_registry.c` registers dictionary_manipulation_words.c's `[`, `]`, `STATE` (Module 13, line 122) BEFORE defining_words.c's `[`, `]`, `STATE` (Module 17, line 126). FORTH dictionary lookup finds the MOST RECENT definition of a name first, so defining_words.c's versions are the only ones ever reachable -- dictionary_manipulation_words.c's `[`/ `]`/`STATE`/`INTERPRET` are permanently shadowed, dead code from the moment boot registration completes. This also CORRECTS that file's finding, not just supersedes it: its `[`/`]`/`STATE` write/read a dead file-scope `static cell_t state_variable`, cross-VM-shared and never the real per-VM STATE. The LIVE versions here (defining_word_left_bracket/right_bracket/state) use `vm->state_addr` (include/vm.h:452) -- a genuine per-VM VM-memory address, correctly written via `vm_store_cell`. The dead-static bug is real IN THE SHADOWED CODE, but does not reach runtime: no VM instance's `[`/`]`/`STATE` actually touches that static. Added `state_addr :: nat` to vm_state (StarForth_Base.thy) to model this correctly. ── Scope of this file ────────────────────────────────────────────────── Split three ways: 1. Mode/flag/address words ([, ], STATE, IMMEDIATE) -- fully modelled, provable against `vm_mode`/`state_addr`/`memory`/`dictionary`/ `latest_id`. 2. `:` / `;` -- guard conditions modelled; `:`'s STATE/mode-setting half of `vm_enter_compile_mode` is modelled (identical shape to `]`), but the dictionary-entry-creation half (`vm_create_word` -> a fresh DictEntry with `vm->compiling_word` tracking it) is NOT modelled -- see the finding below. `;`'s entire effect beyond the guard (`vm_exit_compile_mode`: find/compile EXIT, clear WORD_SMUDGED, set WORD_COMPILED, evict hot-words cache) is NOT modelled for the same reason plus dependence on the hot-words cache, itself never modelled in this suite. 3. Everything else (CREATE, VARIABLE, CONSTANT, FORGET, COMPILE, [COMPILE], LIT, LITERAL, does_rt, DOES>, DEFER, IS, DEFER@, and the three defining-runtime functions CREATE/VARIABLE/CONSTANT install) -- NOT modelled. Each hits one or more of the same three model gaps, named once here rather than repeated per word: (a) DICTIONARY-ENTRY CREATION is not modelled anywhere in this proof suite. `dictionary :: nat \ dict_entry option` (StarForth_ Base.thy:498) is treated as a fixed, pre-populated table by every theory so far -- FIND/TRAVERSE/etc. in StarForth_Dictionary_ Manipulation_Words.thy only READ it. This is the first file in the sweep whose primary job IS insertion (`:`, CREATE, VARIABLE, CONSTANT, DEFER all call `vm_create_word`). `vm_create_word` itself parses no input (name arrives pre-parsed) but allocates a new DictEntry, links it into `vm->latest`, and returns a raw `DictEntry*` the caller mutates directly (`entry->flags |= WORD_SMUDGED`, etc.) -- none of which has a counterpart in the word_id-indexed abstract model with no live pointer aliasing. This is a materially bigger gap than the raw-pointer-navigation gap already flagged in dictionary_manipulation_words.c (which only reads), and is the single largest finding of this file. (b) DATA-FIELD (DF) ADDRESSING: `dict_entry` (StarForth_Base.thy:293) has no field corresponding to a DictEntry's data-field cell (the storage `vm_dictionary_get_data_field` returns a pointer into). CREATE/VARIABLE/CONSTANT's runtimes, DODOES, and does_rt all read or write this cell -- the exact gap already named for `>BODY` in StarForth_Dictionary_Manipulation_Words.thy (`to_body_not_modelled`). Same root cause, different words. (c) MUTABLE PER-ENTRY DISPATCH: `word_table` (StarForth_Base.thy:626) is a fixed, uninterpreted global constant -- by design (see that section's comment), not a per-VM-instance mutable field. DEFER's `IS` reassigns an entry's *effective* dispatch target at runtime (stored in the DF cell and read by `defining_runtime_defer`); a fixed `word_table` cannot express this at all, independent of gap (b). LIT additionally treats the top return-stack cell as a raw C `cell_t*` threaded-code instruction pointer, advanced with C pointer arithmetic (`rip++`) and dereferenced directly -- NOT as a VM address resolved through `vm_ptr`/`vm_addr_ok` the way control_words.c's return-stack-held IP values were (see StarForth_Control_Words.thy's resume note: that gap turned out to already be covered by `mem_read` on VM-address-valued return-stack entries). LIT's IP is a genuinely different, raw-host-pointer usage of the same field; the list-based `return_stack :: cell list` model has no way to hold or advance a host pointer. ======================================================================== *) definition WORD_IMMEDIATE :: nat where "WORD_IMMEDIATE = 0x80" (* ── [ ( -- ) : interpret mode, LIVE version (see file header) ──────────── *) (* C: vm_store_cell(vm, vm->state_addr, 0); vm->mode = MODE_INTERPRET. *) definition forth_d_left_bracket :: "vm_state \ vm_state" where "forth_d_left_bracket vm = vm\memory := mem_write (memory vm) (state_addr vm) 0, vm_mode := ModeInterpret\" lemma d_left_bracket_sets_interpret: "vm_mode (forth_d_left_bracket vm) = ModeInterpret" by (simp add: forth_d_left_bracket_def) lemma d_left_bracket_writes_state_cell: "mem_read (memory (forth_d_left_bracket vm)) (state_addr vm) = 0" by (simp add: forth_d_left_bracket_def mem_read_def mem_write_def) lemma d_left_bracket_data_stack_unchanged: "data_stack (forth_d_left_bracket vm) = data_stack vm" by (simp add: forth_d_left_bracket_def) lemma d_left_bracket_never_errors: "vm_error (forth_d_left_bracket vm) = vm_error vm" by (simp add: forth_d_left_bracket_def) (* ── ] ( -- ) : compile mode, LIVE version ───────────────────────────────── *) (* C: vm_store_cell(vm, vm->state_addr, (cell_t)-1); vm->mode = MODE_COMPILE. *) definition forth_d_right_bracket :: "vm_state \ vm_state" where "forth_d_right_bracket vm = vm\memory := mem_write (memory vm) (state_addr vm) (-1), vm_mode := ModeCompile\" lemma d_right_bracket_sets_compile: "vm_mode (forth_d_right_bracket vm) = ModeCompile" by (simp add: forth_d_right_bracket_def) lemma d_right_bracket_writes_state_cell: "mem_read (memory (forth_d_right_bracket vm)) (state_addr vm) = -1" by (simp add: forth_d_right_bracket_def mem_read_def mem_write_def) lemma d_right_bracket_data_stack_unchanged: "data_stack (forth_d_right_bracket vm) = data_stack vm" by (simp add: forth_d_right_bracket_def) lemma d_right_bracket_never_errors: "vm_error (forth_d_right_bracket vm) = vm_error vm" by (simp add: forth_d_right_bracket_def) lemma d_bracket_right_then_left: "vm_mode (forth_d_left_bracket (forth_d_right_bracket vm)) = ModeInterpret" by (simp add: forth_d_left_bracket_def) lemma d_bracket_left_then_right: "vm_mode (forth_d_right_bracket (forth_d_left_bracket vm)) = ModeCompile" by (simp add: forth_d_right_bracket_def) (* ── STATE ( -- addr ) : LIVE version, pushes a real VM address ─────────── *) (* C: vm_push(vm, (cell_t)vm->state_addr). Unlike the shadowed dictionary_ manipulation_words.c version (which pushed the address of a dead host static, and was left unmodelled), this pushes `state_addr` -- a genuine per-VM field, so this word IS modellable. *) definition forth_d_state :: "vm_state \ vm_state" where "forth_d_state vm = (if ds_full vm then set_error vm else vm\data_stack := word_of_nat (state_addr vm) # data_stack vm\)" lemma d_state_normal: assumes "\ ds_full vm" shows "data_stack (forth_d_state vm) = word_of_nat (state_addr vm) # data_stack vm" by (simp add: forth_d_state_def assms) lemma d_state_overflow: assumes "ds_full vm" shows "vm_error (forth_d_state vm)" by (simp add: forth_d_state_def set_error_def assms) lemma d_state_preserves_state_addr: "state_addr (forth_d_state vm) = state_addr vm" by (simp add: forth_d_state_def set_error_def) (* ── IMMEDIATE ( -- ) : mark latest word immediate, no mode guard ───────── *) (* C: error if vm->latest is NULL; else vm->latest->flags |= WORD_IMMEDIATE. Unlike HIDDEN (dictionary_manipulation_words.c), there is no compile-mode guard at all. *) definition forth_immediate :: "vm_state \ vm_state" where "forth_immediate vm = (case latest_id vm of None \ set_error vm | Some wid \ (case dictionary vm wid of None \ set_error vm | Some e \ vm\dictionary := (dictionary vm) (wid := Some (e\de_flags := de_flags e OR WORD_IMMEDIATE\))\))" lemma immediate_requires_latest: assumes "latest_id vm = None" shows "vm_error (forth_immediate vm)" by (simp add: forth_immediate_def set_error_def assms) lemma immediate_requires_latest_present_in_dict: assumes "latest_id vm = Some wid" assumes "dictionary vm wid = None" shows "vm_error (forth_immediate vm)" by (simp add: forth_immediate_def set_error_def assms) lemma immediate_sets_flag: assumes "latest_id vm = Some wid" assumes "dictionary vm wid = Some e" shows "\e'. dictionary (forth_immediate vm) wid = Some e' \ de_flags e' = de_flags e OR WORD_IMMEDIATE" using assms by (simp add: forth_immediate_def) lemma immediate_data_stack_unchanged: "data_stack (forth_immediate vm) = data_stack vm" by (auto simp: forth_immediate_def set_error_def split: option.split) lemma immediate_no_mode_guard: \ \Unlike HIDDEN, IMMEDIATE has no `vm_mode vm \ ModeCompile` check at all -- when the latest-word guards above are satisfied, its error status is exactly whatever it was on entry (no NEW error is raised by a compile-mode check, since there is none). Stated explicitly since every other flag-setting word in this sweep (SMUDGE, HIDDEN) DOES gate on compile mode.\ assumes "latest_id vm = Some wid" "dictionary vm wid = Some e" shows "vm_error (forth_immediate vm) = vm_error vm" using assms by (simp add: forth_immediate_def) (* ── : ( "name" -- ) : nested-guard + mode/STATE half only ──────────────── *) (* C (defining_word_colon + vm_enter_compile_mode): error if already in MODE_COMPILE (nested ':' is illegal per FORTH-79); else vm->mode = MODE_COMPILE, vm->state_var = -1, vm_store_cell(vm, vm->state_addr, -1), THEN vm_create_word(...) -- the entry-creation half, see file header finding (a), is NOT modelled. Modelled here: guard + the mode/state_var/ state_addr-cell effect, which is state-only and has the identical shape to `]` plus the extra `state_var` write `]` itself does not do. *) definition forth_colon_guard :: "vm_state \ vm_state" where "forth_colon_guard vm = (if vm_mode vm = ModeCompile then set_error vm else vm\vm_mode := ModeCompile, state_var := -1, memory := mem_write (memory vm) (state_addr vm) (-1)\)" lemma colon_nested_errors: assumes "vm_mode vm = ModeCompile" shows "vm_error (forth_colon_guard vm)" by (simp add: forth_colon_guard_def set_error_def assms) lemma colon_sets_compile_mode: assumes "vm_mode vm \ ModeCompile" shows "vm_mode (forth_colon_guard vm) = ModeCompile" by (simp add: forth_colon_guard_def assms) lemma colon_sets_state_var: assumes "vm_mode vm \ ModeCompile" shows "state_var (forth_colon_guard vm) = -1" by (simp add: forth_colon_guard_def assms) lemma colon_writes_state_cell: assumes "vm_mode vm \ ModeCompile" shows "mem_read (memory (forth_colon_guard vm)) (state_addr vm) = -1" by (simp add: forth_colon_guard_def mem_read_def mem_write_def assms) lemma colon_guard_not_full_colon: True \ \forth_colon_guard is NOT a full model of `:` -- it omits the dictionary-entry-creation half (`vm_create_word`, `vm->compiling_word`, WORD_SMUDGED, the DF write of the threaded-body start address). See file header finding (a)/(b). Named so the omission is greppable.\ by simp (* ── ; ( -- ) : compile-mode guard only ──────────────────────────────────── *) (* C: error unless vm->mode == MODE_COMPILE; else calls vm_exit_compile_mode, entirely unmodelled (finds/compiles EXIT, flips WORD_SMUDGED/WORD_COMPILED, evicts hot-words cache -- none modelled in this suite). *) definition forth_semicolon_guard :: "vm_state \ vm_state" where "forth_semicolon_guard vm = (if vm_mode vm \ ModeCompile then set_error vm else vm)" lemma semicolon_requires_compile_mode: assumes "vm_mode vm \ ModeCompile" shows "vm_error (forth_semicolon_guard vm)" by (simp add: forth_semicolon_guard_def set_error_def assms) lemma semicolon_guard_not_full_semicolon: True \ \forth_semicolon_guard covers only the guard raised directly in defining_word_semicolon. vm_exit_compile_mode's own effects (EXIT lookup+compile, WORD_SMUDGED/WORD_COMPILED flag flip, hot-words cache eviction) are entirely unmodelled -- none of EXIT-lookup, per-entry mutable flags via a live pointer, or the hot-words cache have any counterpart in this suite's abstract model.\ by simp (* ── Everything else in this file -- NOT MODELLED ───────────────────────── See file header findings (a) dictionary-entry creation, (b) data-field addressing, (c) mutable per-entry dispatch. One sentinel lemma per word/ helper, matching the StarForth_Dictionary_Manipulation_Words.thy convention. *) lemma create_not_modelled: True \ \CREATE: vm_create_word (gap a) + DF write of captured DFA (gap b).\ by simp lemma variable_not_modelled: True \ \VARIABLE: vm_allot + vm_create_word (gap a) + DF write of the cell's address (gap b).\ by simp lemma constant_not_modelled: True \ \CONSTANT: vm_create_word (gap a) + DF write of the popped value (gap b).\ by simp lemma create_runtime_not_modelled: True \ \defining_runtime_create: reads current_executing_entry's DF cell (gap b).\ by simp lemma variable_runtime_not_modelled: True \ \defining_runtime_variable: reads current_executing_entry's DF cell (gap b).\ by simp lemma constant_runtime_not_modelled: True \ \defining_runtime_constant: reads current_executing_entry's DF cell (gap b).\ by simp lemma lit_not_modelled: True \ \LIT: reads/advances the return-stack top as a raw C cell_t* threaded-code IP -- see file header, distinct from control_words.c's already-resolved IP-as-vaddr usage.\ by simp lemma literal_not_modelled: True \ \LITERAL: compiles a literal into threaded code via vm_compile_literal -- depends on the same unmodelled compile-target machinery as `:`/COMPILE.\ by simp lemma dodoes_not_modelled: True \ \defining_runtime_dodoes: DF/PFA layout (gap b) + runs a raw threaded-code interpreter loop over cell_t* IPs (gap c-adjacent, distinct mechanism from vm_ip).\ by simp lemma does_rt_not_modelled: True \ \defining_runtime_does_rt: patches vm->latest's DF (gap b) and reassigns its func pointer to defining_runtime_dodoes (gap c).\ by simp lemma does_greater_not_modelled: True \ \DOES>: compiles does_rt + EXIT into the defining word's body -- same unmodelled compile-target machinery as `:`.\ by simp lemma compile_not_modelled: True \ \COMPILE: vm_find_word (parse+lookup, same class as FIND, already flagged not-modelled) + vm_compile_word.\ by simp lemma bracket_compile_not_modelled: True \ \[COMPILE]: identical body to COMPILE (defining_word_bracket_compile IS defining_word_compile).\ by simp lemma forget_not_modelled: True \ \FORGET: walks vm->latest's raw linked chain by name, frees C structs, and rewinds `here` from a DF read (gap a/b combined) -- categorically the same class of gap as `block_words.c`'s cache-subsystem deferrals: a whole-subsystem project, not a one-word extension.\ by simp lemma defer_not_modelled: True \ \DEFER: vm_create_word (gap a) with a zeroed DF slot (gap b).\ by simp lemma defer_runtime_not_modelled: True \ \defining_runtime_defer: reads a DictEntry* out of the DF cell (gap b) and calls through it (gap c).\ by simp lemma is_not_modelled: True \ \IS: vm_find_word (parse+lookup) + writes an XT into the target's DF cell (gap b) -- the mutable-dispatch mechanism of gap (c).\ by simp lemma defer_fetch_not_modelled: True \ \DEFER@: vm_find_word + reads the DF cell (gap b).\ by simp end