rajamesandClaude Opus 5.5
0da7e32a0b
Ruled 2026-10-04, revising D-2: stack overflow and underflow are errors that are shown and return to the prompt, not silent wrap-around. - Each stack counts what it holds. Before every opcode the executor checks that the stacks hold what it takes and have room for what it leaves; otherwise the opcode does nothing and the node faults, as for a bad address, to that kind's handler. Every fault empties both stacks. - The fault handler is now a table of five jumps: address, data overflow, data underflow, return overflow, return underflow. The host node says "Stack overflow", "Stack underflow", "Return stack overflow", "Return stack underflow", then ERROR and the prompt. - Two registers, DSTACK-DEPTH and RSTACK-DEPTH: a fetch reads the depth, a store empties the stack. QUIT, ABORT and the error exits empty the return stack before they call anything; ABORT empties the data stack. - capsule/forth.v4: DEPTH, PICK and ROLL, to FORTH-79 (counting from one). PICK and ROLL set the values above the one wanted aside in memory, and work with the stack full. - Division by zero now takes its operands off the stack, as v3 does. - A colon with no room for its entry abandons the line. - tests: every opcode at every depth of both stacks; the faults, the registers and the three words from the prompt. The sizes are unchanged: ten values, nine return entries. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
v4/
StarForth v4: the 32-instruction F18-derived core. The design lives in
docs/v4.0.0/JUSTIFICATION.md (why) and docs/v4.0.0/DECOMPOSITION.md
(every v3 word mapped to a v4 fate).
The first deliverable is the hosted C99 golden model (JUSTIFICATION.md §10,
step 1). It must pass POST and hold K≡1.0 with 32- and 64-bit cells on all
three host ISAs.
Acceptance (JUSTIFICATION.md §16): v4 must be equivalent to v3 at any point
in time, with the same vocabularies and behaviour, on the F18-derived engine;
and every ISA, hosted and bare metal, must still reach its ok prompt.
make -C v4 test passing is a development check, not acceptance.
What exists so far is the single node: registers, circular stacks, memory, all
32 opcodes, per-opcode and per-call-target heat, and three console
registers (CONSOLE-TX, which captures output, and CONSOLE-RX and CONSOLE-STATUS, which hand out
input a test feeds) standing in for the console node until the mesh exists. The tests load definitions
onto a node either opcode by opcode (v4/include/v4/asm.h) or as text in the notation DECOMPOSITION.md
uses (v4/include/v4/text.h). make -C v4 test builds
and runs the tests at both cell widths; make -C v4 sanitize repeats them
under ASan and UBSan. There is no compiler capsule, no POST and no K
measurement yet.