ref: 3cdaf6ea5f649e9b89608d7fbd2ddb0e5cb52af4 dir: /sys/src/libc/arm/tas.s/
TEXT _tas(SB), $-4 MOVW R0,R1 MOVW $1,R0 SWPW R0,(R1) /* fix: deprecated in armv7 */ RET