ref: 0df3f94ecdd32b5ee4ca3f8f8a73f4a7a455ddfb 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