ref: fcc5e75d07e5bc6cb3ddac6d9a437e7ec62d0d95 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