Robert Allan JamesandClaude Sonnet 5
66c2f3e539
All 13 silent vm->error=1 sites in vm_core.c now log a diagnostic
first: vm_enter_compile_mode, vm_compile_word, vm_compile_literal,
vm_compile_call, vm_exit_compile_mode, execute_colon_word (2 sites
each/combined), and the four fundamental memory primitives
vm_load_u8/vm_store_u8/vm_load_cell/vm_store_cell.
Found and fixed two real NULL-pointer-dereference risks while adding
the diagnostics: vm_compile_call() and vm_exit_compile_mode() each had
a combined `if (!vm || <cond>) { vm->error = 1; ... }` guard that
dereferenced vm->error even on the !vm branch of its own condition.
Split both, and applied the same defensive split to the four memory
primitives since vm_ptr()/vm_addr_ok() both tolerate vm==NULL
internally.
Live-verified, amd64: 999999999 @ . recovers correctly at Zuse's own
console (Stage A's mechanism holds), but the new vm_load_cell
diagnostic itself didn't print -- traced to memory_words.c's own
redundant, still-silent vm_addr_ok() pre-check in memory_word_fetch()
(and the same shape in memory_word_store()), which intercepts before
ever reaching vm_load_cell(). memory_words.c is vendored, out of this
initiative's scope, spun off to FABRIC-4.md -- recorded as a concrete
cross-reference for that future work rather than left to be
rediscovered.
Three-arch clean qemu acceptance passed, full POST suite included.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BWpNjdwPtFLuVLaAq44L9K