ref: e1f02664d96e392a608d97c5bdd0c1c3c6a26c84 dir: /sys/src/libc/arm/tas.s/
TEXT _tas(SB), 1, $-4 MOVW R0,R1 MOVW $1,R0 SWPW R0,(R1) /* fix: deprecated in armv7 */ RET