Claude
3bd81097e1
The header scan (Captain Bob, 2026-11-10): 788 source files -- 351 with the
SL-1.0 header, 12 with the old name (docs/working/experiments, kept by
ruling), 31 under someone else's licence (tools/kconfig, Linux's, GPL-2.0:
kept), and 394 with none. Ruled: the SPDX form; capsules (.4th, .f18) and
proofs (.thy) left for a ruling of their own (mkcapsule's 64x16 block format,
content-addressed capsules).
253 files now begin
SPDX-License-Identifier: LicenseRef-Starship-1.0
Copyright (c) 2023-2026 Robert A. James
as a /* */ block (C, headers, assembly, linker scripts) or # lines (scripts,
Makefiles, Kconfig; below a shebang or a coding line); tools/mkcapsule.c,
which had the copyright line, gets the SPDX line only.
Not touched: docs/working/ (archive and old campaign material, as the
ruling kept the experiments); v4/system/post_cases.c (generated by
v4/tools/mkpost.py, "do not edit" -- the generator has the header).
Comments only: the kernel builds on amd64, aarch64, riscv64; make -C v4
test-32: 39 programs, 0 failures; every changed script parses.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GE3SDvQn5EoxdGufk84zz2
64 lines
2.5 KiB
C
64 lines
2.5 KiB
C
/* SPDX-License-Identifier: LicenseRef-Starship-1.0
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* Copyright (c) 2023-2026 Robert A. James
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*/
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/* cell.h -- v4 cell width as a build parameter.
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*
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* DECOMPOSITION.md D-5: the host node's cell width matches the host CPU
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* (32 on a Zynq-7000 Cortex-A9, 64 on an aarch64 host). JUSTIFICATION.md
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* section 5 makes this the second invariance axis: if K==1.0 holds across
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* cell widths as well as across ISAs, the conservation law is shown not to
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* depend on word size.
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*
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* The compiler capsule is written width-independent against these types.
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* Nothing in v4 may assume a particular V4_CELL_BITS; if you find yourself
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* wanting to, the code belongs in the host node, not the mesh.
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*
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* JUSTIFICATION.md section 5 also fixes the split that matters for the
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* physics: heat and K arithmetic stay 64-bit on every host regardless of
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* cell width, because they must not lose precision when the cell shrinks.
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* That is why this header defines a separate v4_heat_t rather than reusing
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* v4_cell.
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*/
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#ifndef V4_CELL_H
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#define V4_CELL_H
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#include <stdint.h>
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#ifndef V4_CELL_BITS
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#error "V4_CELL_BITS must be defined to 32 or 64 (e.g. -DV4_CELL_BITS=32)."
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#endif
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#if V4_CELL_BITS == 32
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typedef int32_t v4_cell;
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typedef uint32_t v4_ucell;
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#elif V4_CELL_BITS == 64
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typedef int64_t v4_cell;
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typedef uint64_t v4_ucell;
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#else
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#error "V4_CELL_BITS must be 32 or 64."
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#endif
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/* Physics/heat arithmetic width. Fixed at 64 by JUSTIFICATION.md section 5:
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* "Heat and K arithmetic remain 64-bit (int64_t in C99 on every host; double
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* cells on a 32-bit node). Changing only the payload width keeps the
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* experiment clean: any difference in K can be attributed to cell width and
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* not to lost precision." The C side is therefore always 64-bit; the
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* double-cell framing is the 32-bit node's problem, not this type's. */
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typedef int64_t v4_heat_t;
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typedef uint64_t v4_uheat_t;
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/* MSB -- the cell-width top-bit constant.
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*
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* DECOMPOSITION.md section 5.5 (RSHIFT) and section 5.7 (D2/) both call for
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* "MSB, the cell-width top-bit constant" but never define it, which leaves a
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* bit-width-dependent constant to be invented mid-arithmetic. It is defined
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* here once, as a value with exactly the cell's sign bit set and nothing
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* else, so that the sign-test idioms in those two words are width-correct by
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* construction at 32 and at 64. */
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#define V4_MSB (((v4_ucell)1) << (V4_CELL_BITS - 1))
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/* All-ones, the width-correct "true". FORTH-79 uses -1 for TRUE. */
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#define V4_ALL_ONES ((v4_cell)-1)
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#endif /* V4_CELL_H */
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