rajamesandJunie
a8b70e88d3
Source tree reorganization: - Move StarForth v3 engine to v3/ (src/, include/, Makefile) - Move kernel to kernel/ (src/, include/, linker/, Makefile) - Create v4/ skeleton for F18-ISA golden model (DECOMPOSITION.md, JUSTIFICATION.md) - Move FABRIC-0..4.md to docs/fabric/ - Move ONTOLOGY.md and ROADMAP.md to docs/ Board infrastructure: - Add boards/ser5/, boards/raspi/, boards/milkv/, boards/zynq7020/ - Each board has board.mk (ISA, CPU flags, boot recipe) and README.md - Root Makefile becomes thin dispatcher: boot_image, all, clean, docs take TARGET - make boot_image TARGET=SER5|RASPI|MILKV builds one GPT/MBR image per board - ZYNQ7020 target exists but stops with clear error (ARMv7 port not built yet) - scripts/mkdiskimage.sh builds disk images for all boards Docs pipeline: - docs/book/ with LaTeX master (main.tex) and Makefile - pandoc converts Markdown to LaTeX at build time - Two Lua filters: table-widths.lua (wide tables wrap), code-breaks.lua (inline code breaks) - make docs builds single PDF (754 pages, 0 missing characters) - make docs TARGET=<board> adds board appendix - build/docs/<book|board>/meta.tex stamps git commit into PDF Bug fixes: - 42 include paths that only worked by accident now use correct relative paths - clang-18 hardcode replaced with configurable CC variable (fixed aarch64 build) - Pi 5: kernel_2712.img linked at 0x80000, .bss zeroed, memory reserved - Doxyfile, .clang-tidy, README.md, Kconfig paths updated Verified: - Hosted v3 build passes 1012 tests, 0 failures - SER5 image boots in QEMU (OVMF), POST passes, K exact (65536 = Q48_ONE) - Milk-V image boots in QEMU (OpenSBI + U-Boot + bootefi), POST passes - make clean TARGET=<board> removes only that board and its ISA objects - make all builds all boards, hosted v3, and docs in one run Co-authored-by: Junie <junie@jetbrains.com>
61 lines
3.0 KiB
C
61 lines
3.0 KiB
C
/* fe25519.h -- arithmetic mod p = 2^255-19, for Ed25519.
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*
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* Five-limb representation, uniform radix 2^51 (value =
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* sum(limb[i] * 2^(51*i)), limb i in roughly [0, 2^51)) -- the standard
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* Ed25519 reference layout (matches the widely-reviewed "amd64-51"-style
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* implementations), not something invented for this codebase. 51*5=255
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* exactly, so unlike a mismatched limb-count/width choice, the reduction
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* constant is the clean 2^255 mod p = 19 with no extra scaling.
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*
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* Uses __int128 for multiply-accumulate (product of two ~51-bit limbs is
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* up to ~102 bits, summed across up to 5 terms per bucket -- needs a
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* wide type). Confirmed safe in this kernel's freestanding -nostdlib
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* build by direct toolchain testing (gcc/aarch64-linux-gnu-gcc/
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* riscv64-linux-gnu-gcc, matching Makefile.starkernel's exact flags):
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* __int128 multiply, add, and shift-by-constant all compile with zero
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* undefined symbols on all three target architectures. This is DIFFERENT
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* from __int128 DIVISION, which src/starkernel/arch/amd64/timer.c
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* documents as broken (needs libgcc's __udivti3, undefined in this
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* -nostdlib build) -- this file never divides __int128 values, so that
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* restriction doesn't apply here. An earlier draft of this file avoided
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* __int128 entirely (10 limbs, radix 2^26, int64_t only) out of
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* over-caution before this was checked directly; abandoned after running
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* into real bugs from that scheme's own complexity, not from __int128
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* unavailability -- __int128 was never actually the constraint once
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* verified.
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*/
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#ifndef FE25519_H
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#define FE25519_H
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#include <stdint.h>
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/* int64_t, not uint64_t: fe25519_sub produces negative intermediate
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* limbs (a[i] - b[i] can be < 0 for a specific limb even when the total
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* value a-b, mod p, is what's wanted), and fe25519_carry() relies on
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* arithmetic right shift to propagate negative "borrows" the same way
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* it propagates positive carries -- proven correct by the property-based
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* host test, not just assumed. */
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typedef struct { int64_t v[5]; } fe25519;
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void fe25519_0(fe25519 *r);
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void fe25519_1(fe25519 *r);
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void fe25519_copy(fe25519 *r, const fe25519 *a);
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void fe25519_add(fe25519 *r, const fe25519 *a, const fe25519 *b);
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void fe25519_sub(fe25519 *r, const fe25519 *a, const fe25519 *b);
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void fe25519_neg(fe25519 *r, const fe25519 *a);
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void fe25519_mul(fe25519 *r, const fe25519 *a, const fe25519 *b);
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void fe25519_sq(fe25519 *r, const fe25519 *a);
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void fe25519_invert(fe25519 *r, const fe25519 *a);
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void fe25519_mul_small(fe25519 *r, const fe25519 *a, uint32_t c);
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/* Pack to 32 little-endian bytes (fully reduced mod p) / unpack from same. */
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void fe25519_pack(uint8_t out[32], const fe25519 *a);
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void fe25519_unpack(fe25519 *r, const uint8_t in[32]);
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/* 1 if a == b (as field elements, after full reduction), else 0. */
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int fe25519_eq(const fe25519 *a, const fe25519 *b);
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/* Parity of the fully-reduced value's low bit (used for point decompression's sign bit). */
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int fe25519_parity(const fe25519 *a);
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#endif /* FE25519_H */
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