Reorganize source tree: kernel/, v3/, v4/ split and board infrastructure

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>
2026-10-01 15:40:09 -04:00
parent 3c709c115b
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+/*
+  StarForth — Steady-State Virtual Machine Runtime
+
+  Copyright (c) 2023–2025 Robert A. James
+  All rights reserved.
+
+  This file is part of the StarForth project.
+
+  Licensed under the StarForth License, Version 1.0 (the "License");
+  you may not use this file except in compliance with the License.
+
+  You may obtain a copy of the License at:
+      https://github.com/star.4th@proton.me/StarForth/LICENSE.txt
+
+  This software is provided "AS IS", WITHOUT WARRANTY OF ANY KIND,
+  express or implied, including but not limited to the warranties of
+  merchantability, fitness for a particular purpose, and noninfringement.
+
+ See the License for the specific language governing permissions and
+ limitations under the License.
+
+ StarForth — Steady-State Virtual Machine Runtime
+  Copyright (c) 2023–2025 Robert A. James
+  All rights reserved.
+
+  This file is part of the StarForth project.
+
+  Licensed under the StarForth License, Version 1.0 (the "License");
+  you may not use this file except in compliance with the License.
+
+  You may obtain a copy of the License at:
+       https://github.com/star.4th@proton.me/StarForth/LICENSE.txt
+
+  This software is provided "AS IS", WITHOUT WARRANTY OF ANY KIND,
+  express or implied, including but not limited to the warranties of
+  merchantability, fitness for a particular purpose, and noninfringement.
+
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+ */
+
+#ifndef Q48_16_H
+#define Q48_16_H
+
+#include <stdint.h>
+
+/* ============================================================================
+ * Q48.16 Fixed-Point Arithmetic
+ * ============================================================================
+ *
+ * Format: uint64_t with fixed decimal point after bit 15
+ *   - Bits 0-15: Fractional part (1/65536 resolution)
+ *   - Bits 16-63: Integer part (up to 2^48-1)
+ *
+ * Example: 0x00010000 = 1.0, 0x00018000 = 1.5, 0x00010001 = 1 + 1/65536
+ *
+ * All operations are integer-only: no floating-point, no transcendental functions.
+ * Used for inference engine calculations (variance, regression, diagnostics).
+ *
+ * Why Q48.16?
+ * - 48-bit integer range: 0 to 281,474,976,710,655 (enough for VM metrics)
+ * - 16-bit fractional: ~0.0000152 resolution (precise enough for statistical calculations)
+ * - Perfect fit for 64-bit uint64_t: efficient on modern CPUs
+ */
+
+typedef uint64_t q48_16_t;
+
+/* ============================================================================
+ * Core Arithmetic Operations (All Q48.16 ↔ Q48.16)
+ * ============================================================================
+ */
+
+/*
+ * @brief Multiply two Q48.16 values, keeping result in Q48.16
+ *
+ * Math: (a / 2^16) * (b / 2^16) * 2^16 = (a * b) / 2^16
+ * Returns: (a * b) >> 16
+ *
+ * @param a First Q48.16 operand
+ * @param b Second Q48.16 operand
+ * @return (a * b) >> 16 in Q48.16 format
+ */
+q48_16_t q48_mul(q48_16_t a, q48_16_t b);
+
+/*
+ * @brief Divide two Q48.16 values, keeping result in Q48.16
+ *
+ * Math: (a / 2^16) / (b / 2^16) * 2^16 = (a << 16) / b
+ * Returns: (a << 16) / b
+ *
+ * @param a Dividend in Q48.16
+ * @param b Divisor in Q48.16 (non-zero)
+ * @return (a << 16) / b in Q48.16 format
+ */
+q48_16_t q48_div(q48_16_t a, q48_16_t b);
+
+/* Guard: skip static inlines already provided by include/starkernel/q48_16.h
+ * (both headers share the same definitions; STARKERNEL_Q48_16_H is defined
+ * by the kernel version so we avoid -Werror redefinition in mixed builds). */
+#ifndef STARKERNEL_Q48_16_H
+
+/**
+ * @brief Add two Q48.16 values
+ *
+ * Math: (a / 2^16) + (b / 2^16) = (a + b) / 2^16
+ * Returns: a + b (no shift needed, both have same scaling)
+ *
+ * @param a First Q48.16 operand
+ * @param b Second Q48.16 operand
+ * @return a + b in Q48.16 format
+ */
+static inline q48_16_t q48_add(q48_16_t a, q48_16_t b) {
+    return a + b;
+}
+
+/**
+ * @brief Subtract two Q48.16 values
+ *
+ * Math: (a / 2^16) - (b / 2^16) = (a - b) / 2^16
+ * Returns: a - b (no shift needed)
+ *
+ * @param a Minuend in Q48.16
+ * @param b Subtrahend in Q48.16
+ * @return a - b in Q48.16 format
+ */
+static inline q48_16_t q48_sub(q48_16_t a, q48_16_t b) {
+    return a - b;
+}
+
+/**
+ * @brief Absolute value of Q48.16
+ *
+ * @param a Q48.16 value
+ * @return |a| in Q48.16 format
+ */
+static inline q48_16_t q48_abs(q48_16_t a) {
+    return (a < 0x8000000000000000ULL) ? a : (0ULL - a);
+}
+
+/* ============================================================================
+ * Conversion Operations (u64 ↔ Q48.16)
+ * ============================================================================
+ */
+
+/**
+ * @brief Convert unsigned 64-bit integer to Q48.16
+ *
+ * Math: u * 2^16 (shift left by 16 bits)
+ * Example: q48_from_u64(1) = 0x10000 (1.0 in Q48.16)
+ *
+ * @param u Unsigned 64-bit integer (max 2^48-1 to avoid overflow)
+ * @return u << 16 in Q48.16 format
+ */
+static inline q48_16_t q48_from_u64(uint64_t u) {
+    return u << 16;
+}
+
+/**
+ * @brief Convert Q48.16 to a 64-bit integer (truncate fractional)
+ *
+ * Math: q / 2^16 (arithmetic shift right by 16 bits)
+ * Example: q48_to_u64(0x10000) = 1, q48_to_u64(-0x10000) = -1
+ *
+ * q48_16_t values are two's-complement signed under the hood (q48_neg/
+ * q48_abs already treat them that way); a plain unsigned (logical) shift
+ * would corrupt negative inputs instead of sign-extending them, so this
+ * shifts via a signed intermediate. Bit-identical to the old behavior for
+ * non-negative q (the only case this function's other caller, the
+ * inference engine's sum-of-squares accumulation, ever produces).
+ *
+ * @param q Q48.16 value
+ * @return q >> 16, sign-extended, reinterpreted as uint64_t
+ */
+static inline uint64_t q48_to_u64(q48_16_t q) {
+    return (uint64_t)(((int64_t)q) >> 16);
+}
+
+#endif /* STARKERNEL_Q48_16_H */
+
+/*
+ * @brief Convert double to Q48.16 (for testing/initialization only)
+ *
+ * NOT used in inference engine (inference is integer-only).
+ * Provided for testing and diagnostic tools only.
+ *
+ * @param d Double-precision float
+ * @return d * 2^16 as Q48.16
+ */
+q48_16_t q48_from_double(double d);
+
+/*
+ * @brief Convert Q48.16 to double (for testing/diagnostics only)
+ *
+ * NOT used in inference engine (inference is integer-only).
+ * Provided for logging and RStudio dashboard output.
+ *
+ * @param q Q48.16 value
+ * @return q / 2^16 as double
+ */
+double q48_to_double(q48_16_t q);
+
+/* ============================================================================
+ * Approximation Operations (Integer-Only)
+ * ============================================================================
+ */
+
+/*
+ * @brief Approximate natural logarithm in Q48.16 (integer-only)
+ *
+ * Purpose: Required for decay slope inference via exponential fitting
+ * Model: ln(heat[t]) = ln(h0) - slope*t
+ *
+ * Method: Piecewise linear approximation or Newton-Raphson iteration
+ * - Input x must be > 0 (assertion check)
+ * - Output is ln(x) in Q48.16 format
+ * - Precision: ~5% error acceptable (tuning parameter)
+ * - No floating-point operations
+ *
+ * Implementation Strategy:
+ * 1. Use bit position (floor(log2(x))) as coarse estimate
+ * 2. Refine with Newton iteration (3-4 cycles for Q48.16 precision)
+ * 3. Keep all arithmetic in integer space
+ *
+ * Example: q48_log_approx(65536) = log(1.0) in Q48.16 ≈ 0
+ *          q48_log_approx(131072) = log(2.0) in Q48.16 ≈ 0x0000B172
+ *
+ * @param x Value to take logarithm of (x > 0)
+ * @return ln(x) in Q48.16 format
+ */
+q48_16_t q48_log_approx(uint64_t x);
+
+/*
+ * @brief Approximate exponential e^x in Q48.16 (integer-only, future use)
+ *
+ * Purpose: Might be needed for inverse operations or model validation
+ * Status: Defined but not required for Phase 1 inference engine
+ * Method: Similar to q48_log_approx (piecewise + Newton)
+ *
+ * @param q Q48.16 exponent
+ * @return e^q in Q48.16 format
+ */
+q48_16_t q48_exp_approx(q48_16_t q);
+
+/*
+ * @brief Approximate square root in Q48.16 (integer-only)
+ *
+ * Purpose: Compute R² (fit quality) for regression diagnostics
+ * Method: Newton-Raphson for integer-only sqrt
+ *
+ * @param q Q48.16 value
+ * @return sqrt(q) in Q48.16 format
+ */
+q48_16_t q48_sqrt_approx(q48_16_t q);
+
+/*
+ * @brief Approximate sin(q) in Q48.16 (integer-only, Taylor series)
+ *
+ * Purpose: Console drawing fabric's CIRCLE/ARC/ELLIPSE (FABRIC-0.md item 4.3.3b)
+ * Method: Range-reduce into [-pi, pi], then Taylor series
+ *
+ * @param q Angle in Q48.16 format (radians, any magnitude)
+ * @return sin(q) in Q48.16 format
+ */
+q48_16_t q48_sin_approx(q48_16_t q);
+
+/*
+ * @brief Approximate cos(q) in Q48.16 (integer-only, Taylor series)
+ *
+ * Purpose: Console drawing fabric's CIRCLE/ARC/ELLIPSE (FABRIC-0.md item 4.3.3b)
+ * Method: Range-reduce into [-pi, pi], then Taylor series
+ *
+ * @param q Angle in Q48.16 format (radians, any magnitude)
+ * @return cos(q) in Q48.16 format
+ */
+q48_16_t q48_cos_approx(q48_16_t q);
+
+/* ============================================================================
+ * Diagnostic / Testing Utilities
+ * ============================================================================
+ */
+
+/*
+ * @brief Pretty-print Q48.16 value to string for debugging
+ *
+ * Format: "integer.fractional" (e.g., "1.50000")
+ * Uses internal static buffer - NOT thread-safe
+ *
+ * @param q Q48.16 value
+ * @return Pointer to static string (valid until next call)
+ */
+const char* q48_to_string(q48_16_t q);
+
+/*
+ * @brief Validate Q48.16 value is within safe range
+ *
+ * Checks: Does not overflow on mul/div operations
+ * Returns: 1 if valid, 0 if risky
+ *
+ * @param q Q48.16 value
+ * @return 1 if safe, 0 if risky
+ */
+int q48_is_valid(q48_16_t q);
+
+#endif /* Q48_16_H */