ref: 7c9fe270231e6061ea98c63c6de9756b6d03e1ba dir: /sys/src/libc/68000/tas.s/
TEXT _tas(SB), $0 MOVL $0, R0 MOVL a+0(FP), A0 TAS (A0) BEQ tas_1 MOVL $1, R0 tas_1: RTS