syntax_data: {"ast_node_type":"other","tokens":[{"end":56,"kind":"keyword","start":0,"text":"r21:"}]}
source_snippet:         r21: reg = ["r21","t5"],// feature high-register
context_before:         r20: reg = ["r20","t4"],// feature high-register
context_after:         r22: reg = ["r22","t6"],// feature high-register