syntax_data: {"ast_node_type":"other","tokens":[{"end":54,"kind":"keyword","start":0,"text":"si:"}]}
source_snippet:         si: reg = ["si", "esi", "rsi"] % esi_reserved,
context_before:         dx: reg, reg_abcd = ["dx", "edx", "rdx"],
context_after:         di: reg = ["di", "edi", "rdi"],