ref: 1c61d05cba15d7e93d3207d4f3ab3c6043d63b77
dir: /lib/thread/start+osx-x64.s/
// The entry point for thread start, registered with bsdthread_register
// %rdi: pthread (0, for us)
// %rsi: mach thread port (ignored)
// %rdx: func
// %rcx: env
// %r8: stack
// %r9: flags (= 0)
// %rsp: stack - C_64_REDZONE_LEN (= stack - 128)
.globl _thread$start
_thread$start:
/* call the function */
# movq %r8, %rsp /* set up stack */
movq %rcx, %rax /* set up env */
callq *%rdx /* call function */
/* exit the thread */
movq $0x2000169, %rax /* Sysbsdthread_terminate */
movq %rsp, %rdi /* stack */
movq $0, %rsi /* len */
movq $0, %rdx /* sem */
syscall