ref: 1e8a9ebb0f76b0ebe8eb31d79c44324c1c1ed70f 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