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diff --git a/src/coff.h b/src/coff.h
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+#pragma once
+
+/* SPDX-License-Identifier: Unlicense
+ *
+ * Common Object File Format loader implementation.
+ *
+ * A section "11. COMMON OBJECT FILE FORMAT (COFF)" from the document named
+ * "SYSTEM V/68 Release 3 Programmer's Guide" or "MU43715PG/D2" dated 12/01/87
+ * was used for reference to implement this functionality.
+ *
+ * A "TI-89 / TI-92 Plus Sierra C Assembler Reference Manual, Beta Version"
+ * dated "February 2, 2001" was used for reference to implement this
+ * functionality.
+ */
+
+#include "common.h"
+
+#include <cstdint>
+
+namespace COFF {
+
+constexpr size_t kFileHeaderSize = 20;
+constexpr size_t kOptionalHeaderSize = 28;
+constexpr size_t kSectionHeaderSize = 40;
+
+/// Relocation information stripped from the file
+constexpr uint16_t F_RELFG = 0x1;
+/// File is executable (i.be. no unresolved external references)
+constexpr uint16_t F_EXEC = 0x2;
+/// Line numbers stripped from the file
+constexpr uint16_t F_LNNO = 0x4;
+/// Local symbols stripped from the file
+constexpr uint16_t F_LSYMS = 0x8;
+/// Global symbols stripped from the file
+constexpr uint16_t F_GSYMS = 0x10;
+/// Error in object file
+constexpr uint16_t F_ERROR = 0x80;
+
+struct FileHeader {
+    uint16_t magic; ///< Magic number
+    /// Number of section headers (equals to number of sections)
+    uint16_t nsections;
+    /// Time and date stamp indicating when the file was created, expressed as
+    /// the number of elapsed seconds since 00:00:00 GMT, January 1, 1970
+    int32_t timedate;
+    /// File pointer containing the starting address of the symbol table
+    uint32_t symtable_offset;
+    uint32_t nsymbols; ///< Number of entries in the symbol table
+    uint16_t optional_header_nbytes; ///< Number of bytes in the optional header
+    uint16_t flags; ///< Flags (see F_* constexpr values)
+    static constexpr inline auto FromBytes(const uint8_t *data)
+    {
+        const bool be = true;
+        return FileHeader{
+            /* .magic */ GetU16(data + 0, be),
+            /* .nsections */ GetU16(data + 2, be),
+            /* .timedate */ GetI32(data + 4, be),
+            /* .symtable_offset */ GetU32(data + 8, be),
+            /* .nsymbols */ GetU32(data + 12, be),
+            /* .optional_header_nbytes */ GetU16(data + 16, be),
+            /* .flags */ GetU16(data + 18, be),
+        };
+    }
+    static constexpr uint16_t kMagicSierraM68k = 0x150;
+};
+
+struct OptionalHeader {
+    uint16_t magic; ///< Magic number
+    uint16_t version; ///< Version stamp
+    uint32_t tsize; ///< Size of text in bytes
+    uint32_t dsize; ///< Size of initialized data in bytes
+    uint32_t bsize; ///< Size of uninitialized data in bytes
+    uint32_t entry; ///< Program entry point
+    uint32_t text_start; ///< Base address of text
+    uint32_t data_start; ///< Base address of data
+    static constexpr inline auto FromBytes(const uint8_t *data)
+    {
+        const bool be = true;
+        return OptionalHeader{
+            /* .magic */ GetU16(data + 0, be),
+            /* .version */ GetU16(data + 2, be),
+            /* .tsize */ GetU32(data + 4, be),
+            /* .dsize */ GetU32(data + 8, be),
+            /* .bsize */ GetU32(data + 12, be),
+            /* .entry */ GetU32(data + 16, be),
+            /* .text_start */ GetU32(data + 20, be),
+            /* .data_start */ GetU32(data + 24, be),
+        };
+    }
+};
+
+enum class SectionType: uint32_t {
+    /// Regular section (allocated, relocated, loaded)
+    Regular = 0,
+    /// Dummy section (not allocated, relocated, not loaded)
+    Dummy = 0x1,
+    /// Noload section (allocated, relocated, not loaded)
+    NoLoad = 0x2,
+    /// Grouped section (formed from input sections)
+    Grouped = 0x4,
+    /// Padding section (not allocated, not relocated, loaded)
+    Padding = 0x8,
+    /// Copy section (for a decision function used in updating fields; not
+    /// allocated, not relocated, loaded, relocation and line number entries
+    /// processed normally)
+    Copy = 0x10,
+    /// Section contains executable text
+    Text = 0x20,
+    /// Section contains initialized data
+    Data = 0x40,
+    /// Section contains only uninitialized data
+    Bss = 0x80,
+    /// Section contains ORG'd (absolute) data
+    Org = 0x100,
+    /// Comment section (not allocated, not relocated, not loaded)
+    Info = 0x200,
+    /// Overlay section (not allocated, relocated, not loaded)
+    Overlay = 0x400,
+    /// For .lib section (treated like STYP_INFO)
+    Lib = 0x800,
+};
+
+struct SectionHeader {
+    char name[8]; ///< 8-character null-padded section name
+    uint32_t paddr; ///< Physical address of section
+    uint32_t vaddr; ///< Virtual address of section
+    uint32_t size; ///< Seciton size in bytes
+    uint32_t section_offset; ///< File pointer to raw data
+    uint32_t reloc_offset; ///< File pointer to relocation entries
+    uint32_t lineno_offset; ///< File pointer to line number entries
+    uint16_t nreloc; ///< Number of relocation entries
+    uint16_t nlineno; ///< Number of line number entries
+    uint32_t flags; ///< Flags (see STYP_* constexpr values)
+    static constexpr inline auto FromBytes(const void *data)
+    {
+        const uint8_t *d = static_cast<const uint8_t *>(data);
+        const char *c = static_cast<const char *>(data);
+        const bool be = true;
+        return SectionHeader{
+            /* .name */ {
+                c[0], c[1], c[2], c[3], c[4], c[5], c[6], c[7],
+            },
+            /* .paddr */ GetU32(d + 8, be),
+            /* .vaddr */ GetU32(d + 12, be),
+            /* .size */ GetU32(d + 16, be),
+            /* .section_offset */ GetU32(d + 20, be),
+            /* .reloc_offset */ GetU32(d + 24, be),
+            /* .lineno_offset */ GetU32(d + 28, be),
+            /* .nreloc */ GetU16(d + 32, be),
+            /* .nlineno */ GetU16(d + 34, be),
+            /* .flags */ GetU32(d + 36, be),
+        };
+    }
+};
+
+}