Initial commit

tools/as.ebnf

@@ -0,0 +1,45 @@
+COMMENT: /\/\/[^\n]*/
+
+!opcode: "nop"i
+       | "load"i
+       | "store"i
+       | "add"i
+       | "sub"i
+       | "and"i
+       | "or"i
+       | "not"i
+       | "xor"i
+       | "seth"i
+       | "shr"i
+       | "cmp"i
+       | "mul"i
+       | "beq"i
+       | "set"i
+       | "bneq"i
+
+!register: REGISTER
+         | "sp"i
+         | "lr"i
+         | "pc"i
+
+LABEL: /[a-z_]\w*/i
+
+REGISTER: /[Rr]\d+/
+
+start: line*
+?line: label | statement | raw_word | symbol_def
+label: LABEL ":"
+statement: opcode [param ("," param)*]
+!label_ref: LABEL
+!immediate: SIGNED_NUMBER | HEX_LITTERAL
+?param: register | label_ref | reg_offset | immediate
+reg_offset: "[" register ("," immediate)? "]"
+raw_word: ".word" immediate
+symbol_def: ".global" label_ref
+
+HEX_LITTERAL: /0x[a-fA-F0-9]+/
+
+%import common.WS
+%import common.SIGNED_NUMBER
+%ignore COMMENT
+%ignore WS