ref: 613fd6b4294ad3277a91c9a2e58b2b2d4f22ab1c dir: /sys/src/libc/68000/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4