ref: 5c6357de8bda7c5fe0a7fa4ab31b365a9ae8e6fb 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