// Note: Obviously this code doesn't compile as is, I just copy pasted the relevant files into a single pastebin

// ========== ENTRY POINT ==========
#include "uefi/uefi.h"

EFI_HANDLE IH;
EFI_SYSTEM_TABLE* ST;

EFIAPI EFI_STATUS efi_main(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE* SystemTable) {
    // Save arguments
    IH = ImageHandle;
    ST = SystemTable;

    // Print message
    ST->ConOut->OutputString(ST->ConsoleOutHandle, u"Hello World!\n");

    return EFI_SUCCESS;
}


// ========== SYSTEM TABLE DEFINITION ==========
#pragma pack(push, 1)
struct _EFI_TABLE_HEADER {
    uint64_t Signature;
    uint32_t Revision;
    uint32_t HeaderSize;
    uint32_t CRC32;
    uint32_t Reserved;
};
typedef struct _EFI_TABLE_HEADER EFI_TABLE_HEADER;

struct _EFI_SYSTEM_TABLE {
    EFI_TABLE_HEADER                    Hdr;
    CHAR16*                             FirmwareVendor;
    uint32_t                            FirmwareRevision;
    EFI_HANDLE                          ConsoleInHandle;
    void*                               ConIn;
    EFI_HANDLE                          ConsoleOutHandle;
    EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL*    ConOut;
    EFI_HANDLE                          StandardErrorHandle;
    EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL*    StdErr;
    void*                               RuntimeServices;
    void*                               BootServices;
    uint64_t                            NumberOfTableEntries;
    void*                               ConfigurationTable;
};
typedef struct _EFI_SYSTEM_TABLE EFI_SYSTEM_TABLE;
#pragma pack(pop)


// ========== SIMPLE TEXT OUTPUT PROTO DEFINITION ==========
#pragma pack(push, 1)
struct _EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL {
    EFIAPI EFI_STATUS (*Reset)(struct _EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL* This, BOOLEAN ExtendedVerification);
    EFIAPI EFI_STATUS (*OutputString)(struct _EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL* This, CHAR16* String);
};
typedef struct _EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL;
#pragma pack(pop)