Both blockers recorded at the previous resume point turned out to be
resolvable, not permanent:
- The "cell is unbounded int" blocker for D+/D-/DNEGATE/etc. was stale --
cell was already migrated to a 64-bit word type in commit fe6e705, before
this file was first touched. The note was never re-checked against
current StarForth_Base.thy before being carried forward. Same lesson the
control_words.c vm_ip finding taught one file earlier in this sweep:
re-verify carried-forward reasoning against the current file, don't just
trust a previous session's note.
- The missing vm->ecw_nesting field for 2>R/2R>/2R@ was a real, scoped gap
-- added ecw_nesting :: nat to vm_state in StarForth_Base.thy.
Adds S>D, D+, D-, DNEGATE, DABS, a d_compare helper, DMAX, DMIN, D<, D=,
D0=, D0<, D2*, D2/, 2>R, 2R>, 2R@. D2*/D2/ use push_bit/drop_bit/bit
(established idiom from StarForth_Q48_16.thy) for the 128-bit shifts; D2/
uses sint/div (floor division) rather than cell_sdiv (C99 truncating
division) since arithmetic right shift is floor division, not truncation,
for negative operands. DNEGATE's double-negation-is-identity property is
true but left unproved (needs the same carry/borrow-across-the-pair
algebra as D+/D-, not just simp) -- a nice-to-have, not core plumbing.
All 20 registered words in double_words.c are now covered. 28 theory
files verify with zero errors.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Adds VM_MEMORY_SIZE and DICTIONARY_MEMORY_SIZE constants to StarForth_Base.thy
(previously only STACK_SIZE existed). SP@/SP! left unmodelled (oops-flagged
with explanation) -- the list-based data_stack model has no independent dsp
register distinct from list length, which is exactly what SP! manipulates.
Genuine findings recorded in comments, not fixed:
- LATEST has an identical body to HERE (both just push vm->here) rather than
consulting vm->latest -- doesn't return what its own doc comment claims.
- ALIGN (via vm_align/vm_allot) bounds-checks here against
DICTIONARY_MEMORY_SIZE (2MB), while ALLOT/,/C,/2, bound-check directly
against VM_MEMORY_SIZE (5MB) instead -- two different ceilings for the
same dictionary pointer.
Full suite (26 theory files) verifies with zero errors.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
cell_t is a 64-bit signed C long; the formal model previously used
unbounded HOL int, hiding wraparound and signed/unsigned distinctions
entirely. Switches cell to "64 word" throughout and fixes every proof
site that assumed int semantics:
- StarForth_Base.thy: cell_safe/cell_abs/cell_sdiv/cell_smod plus the
sint-bridging lemmas used across the suite
- StarForth_Loop1_Heat.thy, StarForth_Loop3_Decay.thy: heat tracking
converted to signed word comparisons (<s/\<le>s)
- StarForth_Stack_Words.thy: PICK/ROLL against real C ground truth
- StarForth_Arithmetic_Words.thy: ABS/MIN/MAX/div/mod rebuilt on signed
word semantics (cell_sdiv/cell_smod match C99 truncating division;
2/ uses signed_drop_bit to match "n >> 1"); documents a genuine
ABS(INT64_MIN) wraparound hazard mirroring the real C behavior
- StarForth_Memory_Words.thy: @/!/C@/C! address checks converted to
the signed order
All 23 theory files verify with zero errors, including
StarForth_Concurrent and StarForth_Correctness.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Isabelle toolchain replaced (was genuinely 2011, 14+ years stale) and every
theory file fixed to actually compile -- most had apparently never been
checked under a working Isabelle at all. Fixed the vm_state self-reference
in StarForth_Base.thy properly (word_table is now a free-standing global
constant, not a circular record field), corrected the word_physics_transparent
axiom (was claiming full state equality from mere exec-equivalence, provably
too strong), and worked through 14 years of HOL-Library drift plus several
missing-hypothesis bugs across the physics-loop and ACL theories.
Two genuine (non-tactical) bugs found and left oops-flagged rather than
silently resolved: forth_roll's index arithmetic disagrees with both its own
test lemma and the real C ROLL implementation (three-way inconsistency), and
pm_wf isn't actually preserved by pm_record_hit/pm_record_miss. Both need a
decision, not a proof-script fix.
Full writeup in FABRIC-2.md item 5.2.
