ref: 2dea7c2f8e55b4de0c79448c3ce03351a8f75e3b dir: /sys/src/libc/386/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4