ref: 6fbb1acc8fa0b6655b14e8c46240a4a8d2d8c672 dir: /sys/src/libc/68000/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4