17 of 23 words fully modelled (Q.+/-/*//, Q.ABS/NEG, Q.FROM-INT/TO-INT,
Q.1/0/SCALE, Q.=/</>/0=, Q.MAX/MIN), reusing q48_add/q48_mul/q48_div/
q48_from_u64/q48_to_u64 already in StarForth_Q48_16.thy and cell_abs
(Q.ABS's raw sign-bit test is bit-for-bit cell_abs's `n <s 0`). Added
q48_sub there alongside, the one missing arithmetic primitive.
Q.LOG/EXP/SQRT/SIN/COS deferred (same transcendental-approximation class
already excluded from the sweep at q48_16_words.c). Q.PRINT deferred
(stdout only).
Finding: every word in this file pops/pushes via the VM_POP/VM_PUSH
macros, which resolve to completely unchecked vm_pop_fast/vm_push_fast
when STARFORTH_PERFORMANCE is defined -- a build-flag-gated stack-safety
hazard distinct from (and broader than) the individual missing-guard
instances found elsewhere in the sweep, since it silently disables every
guard in the entire file at once. Modelled assuming the safe path.
Suite now 52 theories, green.
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.
Robert Allan James