first commit. UEFI hello world works

.gitignore

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+*.code-workspace
+*.efi
+image/

bootx64.asm

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+format pe64 dll efi
+entry main
+
+section '.text' code executable readable
+
+
+
+;for 32/64 portability and automatic natural align in structure definitions
+
+struc int8 {
+  . db ?
+}
+struc int16 {
+  align 2
+  . dw ?
+}
+struc int32 {
+  align 4
+  . dd ?
+}
+struc int64 {
+  align 8
+  . dq ?
+}
+struc intn {
+  align 8
+  . dq ?
+}
+struc dptr {
+  align 8
+  . dq ?
+}
+
+;symbols
+
+EFIERR = 0x8000000000000000
+EFI_SUCCESS			= 0
+EFI_LOAD_ERROR			= EFIERR or 1
+EFI_INVALID_PARAMETER		= EFIERR or 2
+EFI_UNSUPPORTED 		= EFIERR or 3
+EFI_BAD_BUFFER_SIZE		= EFIERR or 4
+EFI_BUFFER_TOO_SMALL		= EFIERR or 5
+EFI_NOT_READY			= EFIERR or 6
+EFI_DEVICE_ERROR		= EFIERR or 7
+EFI_WRITE_PROTECTED		= EFIERR or 8
+EFI_OUT_OF_RESOURCES		= EFIERR or 9
+EFI_VOLUME_CORRUPTED		= EFIERR or 10
+EFI_VOLUME_FULL 		= EFIERR or 11
+EFI_NO_MEDIA			= EFIERR or 12
+EFI_MEDIA_CHANGED		= EFIERR or 13
+EFI_NOT_FOUND			= EFIERR or 14
+EFI_ACCESS_DENIED		= EFIERR or 15
+EFI_NO_RESPONSE 		= EFIERR or 16
+EFI_NO_MAPPING			= EFIERR or 17
+EFI_TIMEOUT			= EFIERR or 18
+EFI_NOT_STARTED 		= EFIERR or 19
+EFI_ALREADY_STARTED		= EFIERR or 20
+EFI_ABORTED			= EFIERR or 21
+EFI_ICMP_ERROR			= EFIERR or 22
+EFI_TFTP_ERROR			= EFIERR or 23
+EFI_PROTOCOL_ERROR		= EFIERR or 24
+
+;helper macro for definition of relative structure member offsets
+
+macro struct name
+{
+  virtual at 0
+    name name
+  end virtual
+}
+
+;structures
+
+struc EFI_TABLE_HEADER {
+ .Signature    int64
+ .Revision     int32
+ .HeaderSize   int32
+ .CRC32        int32
+ .Reserved     int32
+}
+struct EFI_TABLE_HEADER
+
+struc EFI_SYSTEM_TABLE {
+ .Hdr		       EFI_TABLE_HEADER
+ .FirmwareVendor       dptr
+ .FirmwareRevision     int32
+ .ConsoleInHandle      dptr
+ .ConIn 	       dptr
+ .ConsoleOutHandle     dptr
+ .ConOut	       dptr
+ .StandardErrorHandle  dptr
+ .StdErr	       dptr
+ .RuntimeServices      dptr
+ .BootServices	       dptr
+ .NumberOfTableEntries intn
+ .ConfigurationTable   dptr
+}
+struct EFI_SYSTEM_TABLE
+
+struc SIMPLE_TEXT_OUTPUT_INTERFACE {
+ .Reset 	    dptr
+ .OutputString	    dptr
+ .TestString	    dptr
+ .QueryMode	    dptr
+ .SetMode	    dptr
+ .SetAttribute	    dptr
+ .ClearScreen	    dptr
+ .SetCursorPosition dptr
+ .EnableCursor	    dptr
+ .Mode		    dptr
+}
+struct SIMPLE_TEXT_OUTPUT_INTERFACE
+
+
+
+main:
+ sub rsp, 4*8              ; reserve space for 4 arguments
+
+ mov [Handle], rcx         ; ImageHandle
+ mov [SystemTable], rdx    ; pointer to SystemTable
+
+ lea rdx, [_hello]
+ mov rcx, [SystemTable]
+ mov rcx, [rcx + EFI_SYSTEM_TABLE.ConOut]
+ push rcx rdx
+ call [rcx + SIMPLE_TEXT_OUTPUT_INTERFACE.ClearScreen]  ;; TODO : what calling convention? clobbers rcx, what else?  
+ ; TODO: use more modern UEFI.inc like stuff
+ ; TODO: update scripts build run. maybe makefile, also generating iso? 
+ ; TODO: what is NvVars who generates it why it need
+ ; TODO: print some info provided by eufi like versions etc..
+ ; TODO: print memory map
+ ; TODO: how to load kernel . See https://github.com/BrianOtto/nasm-uefi 
+ pop rdx rcx
+ call [rcx + SIMPLE_TEXT_OUTPUT_INTERFACE.OutputString]
+
+ jmp $
+
+ add rsp, 4*8
+ mov eax, EFI_SUCCESS
+ retn
+
+
+section '.data' data readable writeable
+
+Handle      dq ?
+SystemTable dq ?
+_hello      du 'Hello World',13,10,0
+
+section '.reloc' fixups data discardable
+

build.sh

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+fasm bootx64.asm
+mkdir -p image/EFI/BOOT
+cp bootx64.efi image/EFI/BOOT
+qemu-system-x86_64 -cpu qemu64 -bios OVMF.fd -drive driver=vvfat,rw=on,dir=image/