add rgbds syntax file

.config/nvim/syntax/rgbds.vim

+" Vim syntax file
+syn case ignore
+
+" asm opcodes
+syn keyword rgbInstruction adc add and bit call ccf cp cpl
+syn keyword rgbInstruction daa dec di ei ex halt inc jp jr ld ldd ldi ldh
+syn keyword rgbInstruction ldio nop or pop push res ret reti rl rla rlc rlca
+syn keyword rgbInstruction rr rra rrc rrca rst sbc scf set sla sra srl stop
+syn keyword rgbInstruction sub swap xor
+
+" section types
+syn keyword rgbType CODE DATA BSS HOME VRAM HRAM
+syn keyword rgbType ALIGNED_CODE ALIGNED_DATA ALIGNED_HOME
+
+" labels
+syn match rgbLabel		"[a-z_][a-z0-9_]*:"
+
+" Any other stuff
+syn match rgbIdentifier		"[a-z_][a-z0-9_]*"
+
+" RGBDS commands
+syn keyword rgbPreProc	DB
+syn keyword rgbPreProc	DW
+syn keyword rgbPreProc	DS
+syn keyword rgbPreProc	EQU
+syn keyword rgbPreProc	EQUS
+syn keyword rgbPreProc	IMPORT
+syn keyword rgbPreProc	EXPORT
+syn keyword rgbPreProc	GLOBAL
+syn keyword rgbPreProc	XREF
+syn keyword rgbPreProc	XDEF
+syn keyword rgbPreProc	DIV
+syn keyword rgbPreProc	MUL
+syn keyword rgbPreProc	SIN
+syn keyword rgbPreProc	COS
+syn keyword rgbPreProc	TAN
+syn keyword rgbPreProc	ASIN
+syn keyword rgbPreProc	ACOS
+syn keyword rgbPreProc	ATAN
+syn keyword rgbPreProc	ATAN2
+syn keyword rgbPreProc	FAIL
+syn keyword rgbPreProc	WARN
+syn keyword rgbPreCondit	IF
+syn keyword rgbPreCondit	ELSE
+syn keyword rgbPreCondit	ENDC
+syn keyword rgbPreProc	INCBIN
+syn keyword rgbPreProc	INCLUDE
+syn keyword rgbMacro	MACRO
+syn keyword rgbMacro	ENDM
+syn keyword rgbPreProc	BANK
+syn keyword rgbPreProc	DEF
+syn keyword rgbPreProc	OPT
+syn keyword rgbPreProc	POPO
+syn keyword rgbPreProc	PUSHO
+syn keyword rgbPreProc	POPS
+syn keyword rgbPreProc	PUSHS
+syn keyword rgbPreProc	PRINTT
+syn keyword rgbPreProc	PRINTV
+syn keyword rgbPreProc	PRINTF
+syn keyword rgbPreProc	PURGE
+syn keyword rgbPreProc	REPT
+syn keyword rgbPreProc	ENDR
+syn keyword rgbPreProc	RSSET
+syn keyword rgbPreProc	RERESET
+syn keyword rgbPreProc	RB
+syn keyword rgbPreProc	RW
+syn keyword rgbPreProc	SECTION
+" prefer to have it highlighted as instruction
+" syn keyword rgbPreProc	SET
+syn keyword rgbPreProc	SHIFT
+
+" strings
+syn match rgbString		"\".*\""
+" 'foo' is not a string
+
+" Numbers
+syn match rgbNumber		"[0-9]\+"
+syn match rgbNumber		"\$[0-9a-fA-F]\+"
+syn match rgbNumber		"%[0-1]\+"
+syn match rgbNumber		"0[xXhH][0-9a-fA-F]\+"
+syn match rgbNumber		"0[bB][0-1]*"
+syn match rgbNumber		"0[oO\@qQ][0-7]\+"
+syn match rgbNumber		"0[dD][0-9]\+"
+
+" predefined symbols
+syn match rgbPresym		"_PI"
+syn match rgbPresym		"_RS"
+syn match rgbPresym		"_NARG"
+syn match rgbPresym		"__LINE__"
+syn match rgbPresym		"__FILE__"
+syn match rgbPresym		"__DATE__"
+syn match rgbPresym		"__TIME__"
+
+" comments
+syn match rgbComment		";.*"
+
+syn case match
+
+" Define the default highlighting.
+if version >= 508 || !exists("did_rgb_syntax_inits")
+  if version < 508
+    let did_rgb_syntax_inits = 1
+    command -nargs=+ HiLink hi link <args>
+  else
+    command -nargs=+ HiLink hi def link <args>
+  endif
+
+  HiLink rgbSection		Special
+  HiLink rgbLabel		Label
+  HiLink rgbComment		Comment
+  HiLink rgbInstruction		Statement
+  HiLink rgbInclude		Include
+  HiLink rgbPreCondit		PreCondit
+  HiLink rgbMacro		Macro
+  HiLink rgbNumber		Number
+  HiLink rgbPreProc		PreProc
+  HiLink rgbString		String
+  HiLink rgbType		Type
+  HiLink rgbIdentifier		Identifier
+  HiLink rgbPresym		Constant
+
+  delcommand HiLink
+endif
+
+let b:current_syntax = "rgb"