ref: eb4f514a94fdfb05ea0c8ce98cd6bac153c8b3f6 dir: /sys/src/libc/386/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4