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
74 lines
2.7 KiB
C
74 lines
2.7 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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/* test_umul.c -- the reference unsigned multiply.
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*
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* v4_umul is what the capsule-level UM* is checked against, so it is checked
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* here against things that do not depend on it: algebraic identities that hold
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* at any width, and at 32-bit cells the host's own 64-bit product.
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*/
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#include "v4/umul.h"
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#include <stdio.h>
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static int failures = 0, checks = 0;
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#define CHECK(c,...) do{checks++; if(!(c)){failures++; printf("FAIL %s:%d: ",__FILE__,__LINE__); printf(__VA_ARGS__); printf("\n");}}while(0)
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#define MAXU ((v4_ucell)~(v4_ucell)0)
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static const v4_ucell vec[] = {
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0u, 1u, 2u, 3u, 7u, 255u, 256u, 65535u, 65536u, 0x12345678u,
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(v4_ucell)0x9E3779B97F4A7C15ULL, (v4_ucell)0xDEADBEEFCAFEF00DULL,
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V4_MSB - 1u, V4_MSB, V4_MSB + 1u, MAXU - 1u, MAXU
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};
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#define NVEC (sizeof vec / sizeof vec[0])
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int main(void)
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{
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v4_ucell lo, hi, lo2, hi2;
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printf("v4 umul tests: V4_CELL_BITS=%d\n", V4_CELL_BITS);
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v4_umul(3, 7, &lo, &hi); CHECK(lo == 21 && hi == 0, "3*7");
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/* (2^n - 1)^2 = 2^2n - 2^(n+1) + 1 */
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v4_umul(MAXU, MAXU, &lo, &hi); CHECK(lo == 1 && hi == MAXU - 1u, "max*max");
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/* 2^(n-1) * 2^(n-1) = 2^(2n-2) */
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v4_umul(V4_MSB, V4_MSB, &lo, &hi);
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CHECK(lo == 0 && hi == (V4_MSB >> 1), "msb*msb");
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for (unsigned i = 0; i < NVEC; i++) {
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v4_ucell x = vec[i];
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v4_umul(x, 0, &lo, &hi); CHECK(lo == 0 && hi == 0, "x*0 [%u]", i);
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v4_umul(x, 1, &lo, &hi); CHECK(lo == x && hi == 0, "x*1 [%u]", i);
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/* x * (2^n - 1) = x*2^n - x */
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v4_umul(x, MAXU, &lo, &hi);
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CHECK(lo == (v4_ucell)(0u - x) && hi == (x ? x - 1u : 0u), "x*max [%u]", i);
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for (unsigned k = 0; k < V4_CELL_BITS; k++) {
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/* x * 2^k is x shifted across the double cell */
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v4_umul(x, ((v4_ucell)1) << k, &lo, &hi);
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CHECK(lo == (v4_ucell)(x << k), "x<<%u lo [%u]", k, i);
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CHECK(hi == (k ? x >> (V4_CELL_BITS - k) : 0u), "x<<%u hi [%u]", k, i);
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}
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for (unsigned j = 0; j < NVEC; j++) {
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v4_ucell y = vec[j];
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v4_umul(x, y, &lo, &hi);
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v4_umul(y, x, &lo2, &hi2);
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CHECK(lo == lo2 && hi == hi2, "commutes [%u,%u]", i, j);
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CHECK(lo == (v4_ucell)(x * y), "low cell [%u,%u]", i, j);
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#if V4_CELL_BITS == 32
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{
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uint64_t p = (uint64_t)x * (uint64_t)y;
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CHECK(lo == (uint32_t)p && hi == (uint32_t)(p >> 32),
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"host product [%u,%u]", i, j);
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}
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#endif
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}
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}
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printf(" %d checks, %d failures\n", checks, failures);
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return failures ? 1 : 0;
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}
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