Update runtime files.
diff --git a/runtime/syntax/psl.vim b/runtime/syntax/psl.vim
new file mode 100644
index 0000000..ff6e833
--- /dev/null
+++ b/runtime/syntax/psl.vim
@@ -0,0 +1,83 @@
+" Vim syntax file
+" Language: Property Specification Language (PSL)
+" Maintainer: Daniel Kho <daniel.kho@logik.haus>
+" Last Changed: 2021 Apr 17 by Daniel Kho
+
+" quit when a syntax file was already loaded
+if exists("b:current_syntax")
+ finish
+endif
+
+" Read in VHDL syntax files
+runtime! syntax/vhdl.vim
+unlet b:current_syntax
+
+let s:cpo_save = &cpo
+set cpo&vim
+
+" case is not significant
+syn case ignore
+
+" Add ! character to keyword recognition.
+setlocal iskeyword+=33
+
+" PSL keywords
+syn keyword pslOperator A AF AG AX
+syn keyword pslOperator E EF EG EX
+syn keyword pslOperator F G U W X X!
+syn keyword pslOperator abort always assert assume async_abort
+syn keyword pslOperator before before! before!_ before_ bit bitvector boolean
+syn keyword pslOperator clock const countones cover
+syn keyword pslOperator default
+syn keyword pslOperator ended eventually!
+syn keyword pslOperator fairness fell for forall
+syn keyword pslOperator hdltype
+syn keyword pslOperator in inf inherit isunknown
+syn keyword pslOperator mutable
+syn keyword pslOperator never next next! next_a next_a! next_e next_e! next_event next_event! next_event_a next_event_a! next_event_e next_event_e! nondet nondet_vector numeric
+syn keyword pslOperator onehot onehot0
+syn keyword pslOperator property prev
+syn keyword pslOperator report restrict restrict! rose
+syn keyword pslOperator sequence stable string strong sync_abort
+syn keyword pslOperator union until until! until!_ until_
+syn keyword pslOperator vmode vpkg vprop vunit
+syn keyword pslOperator within
+"" Common keywords with VHDL
+"syn keyword pslOperator and is not or to
+
+" PSL operators
+syn match pslOperator "=>\||=>"
+syn match pslOperator "<-\|->"
+syn match pslOperator "@"
+
+
+"Modify the following as needed. The trade-off is performance versus functionality.
+syn sync minlines=600
+
+" Define the default highlighting.
+" Only when an item doesn't have highlighting yet
+
+hi def link pslSpecial Special
+hi def link pslStatement Statement
+hi def link pslCharacter Character
+hi def link pslString String
+hi def link pslVector Number
+hi def link pslBoolean Number
+hi def link pslTodo Todo
+hi def link pslFixme Fixme
+hi def link pslComment Comment
+hi def link pslNumber Number
+hi def link pslTime Number
+hi def link pslType Type
+hi def link pslOperator Operator
+hi def link pslError Error
+hi def link pslAttribute Special
+hi def link pslPreProc PreProc
+
+
+let b:current_syntax = "psl"
+
+let &cpo = s:cpo_save
+unlet s:cpo_save
+
+" vim: ts=8