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>
21 lines
868 B
C
21 lines
868 B
C
/* testcode.h -- run a word on a node, for tests. */
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#ifndef V4_TESTCODE_H
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#define V4_TESTCODE_H
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#include "v4/exec.h"
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/* Where a word called by v4_test_call returns to. Nothing is executed there:
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* arriving is the stop condition. */
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#define V4_TEST_HALT ((v4_cell)(V4_NODE_WORDS - 1u))
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/* Call the word at `entry` as a caller would: push a return address, set P,
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* and step instruction words until the word returns. The stacks and A, B are
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* left as the caller set them, so arguments go on the data stack first.
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* Returns the number of instruction words stepped, or -1 if the word had not
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* returned after `max_words` or the node stopped on a fault (D-14, D-16). A
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* stop left by an earlier call is cleared first. */
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long v4_test_call(v4_node *n, v4_exec_state *es, v4_heat *h,
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v4_cell entry, long max_words);
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#endif /* V4_TESTCODE_H */
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