ref: a67842e7631d8c01fd991defdb219444b11bd4dc
dir: /lib9/lock-MacOSX-power.s/
#include <architecture/ppc/asm_help.h> LEAF(__tas) sync mr r4,r3 addi r5,0,0x1 1: lwarx r3,0,r4 cmpwi r3,0x0 bne- 2f stwcx. r5,0,r4 bne- 1b /* Lost reservation, try again */ 2: sync blr END(__tas)