ref: ed11c46f4bd8bf0b20e4a997d8f1162789aee6ae
dir: /sys/src/libc/amd64/main9p.s/
TEXT _mainp(SB), 1, $0 MOVQ AX, _tos(SB) MOVQ $_profmain(SB), RARG PUSHQ RARG PUSHQ $0 JMPF _callmain(SB) TEXT _savearg(SB), 1, $0 MOVQ RARG, AX RET TEXT _saveret(SB), 1, $0 RET /* we want RARG in RARG */ TEXT _callpc(SB), 1, $0 MOVQ 8(RARG), AX RET