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+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// System calls and other sys.stuff for 386, Darwin
+// See http://fxr.watson.org/fxr/source/bsd/kern/syscalls.c?v=xnu-1228
+// or /usr/include/sys/syscall.h (on a Mac) for system call numbers.
+
+#include "zasm_GOOS_GOARCH.h"
+#include "textflag.h"
+
+// Exit the entire program (like C exit)
+TEXT runtime·exit(SB),NOSPLIT,$0
+ MOVL $1, AX
+ INT $0x80
+ MOVL $0xf1, 0xf1 // crash
+ RET
+
+// Exit this OS thread (like pthread_exit, which eventually
+// calls __bsdthread_terminate).
+TEXT runtime·exit1(SB),NOSPLIT,$0
+ MOVL $361, AX
+ INT $0x80
+ JAE 2(PC)
+ MOVL $0xf1, 0xf1 // crash
+ RET
+
+TEXT runtime·open(SB),NOSPLIT,$0
+ MOVL $5, AX
+ INT $0x80
+ MOVL AX, ret+12(FP)
+ RET
+
+TEXT runtime·close(SB),NOSPLIT,$0
+ MOVL $6, AX
+ INT $0x80
+ MOVL AX, ret+4(FP)
+ RET
+
+TEXT runtime·read(SB),NOSPLIT,$0
+ MOVL $3, AX
+ INT $0x80
+ MOVL AX, ret+12(FP)
+ RET
+
+TEXT runtime·write(SB),NOSPLIT,$0
+ MOVL $4, AX
+ INT $0x80
+ MOVL AX, ret+12(FP)
+ RET
+
+TEXT runtime·raise(SB),NOSPLIT,$16
+ MOVL $20, AX // getpid
+ INT $0x80
+ MOVL AX, 4(SP) // pid
+ MOVL sig+0(FP), AX
+ MOVL AX, 8(SP) // signal
+ MOVL $1, 12(SP) // posix
+ MOVL $37, AX // kill
+ INT $0x80
+ RET
+
+TEXT runtime·mmap(SB),NOSPLIT,$0
+ MOVL $197, AX
+ INT $0x80
+ MOVL AX, ret+24(FP)
+ RET
+
+TEXT runtime·madvise(SB),NOSPLIT,$0
+ MOVL $75, AX
+ INT $0x80
+ // ignore failure - maybe pages are locked
+ RET
+
+TEXT runtime·munmap(SB),NOSPLIT,$0
+ MOVL $73, AX
+ INT $0x80
+ JAE 2(PC)
+ MOVL $0xf1, 0xf1 // crash
+ RET
+
+TEXT runtime·setitimer(SB),NOSPLIT,$0
+ MOVL $83, AX
+ INT $0x80
+ RET
+
+// OS X comm page time offsets
+// http://www.opensource.apple.com/source/xnu/xnu-1699.26.8/osfmk/i386/cpu_capabilities.h
+#define cpu_capabilities 0x20
+#define nt_tsc_base 0x50
+#define nt_scale 0x58
+#define nt_shift 0x5c
+#define nt_ns_base 0x60
+#define nt_generation 0x68
+#define gtod_generation 0x6c
+#define gtod_ns_base 0x70
+#define gtod_sec_base 0x78
+
+// called from assembly
+// 64-bit unix nanoseconds returned in DX:AX.
+// I'd much rather write this in C but we need
+// assembly for the 96-bit multiply and RDTSC.
+TEXT runtime·now(SB),NOSPLIT,$40
+ MOVL $0xffff0000, BP /* comm page base */
+
+ // Test for slow CPU. If so, the math is completely
+ // different, and unimplemented here, so use the
+ // system call.
+ MOVL cpu_capabilities(BP), AX
+ TESTL $0x4000, AX
+ JNZ systime
+
+ // Loop trying to take a consistent snapshot
+ // of the time parameters.
+timeloop:
+ MOVL gtod_generation(BP), BX
+ TESTL BX, BX
+ JZ systime
+ MOVL nt_generation(BP), CX
+ TESTL CX, CX
+ JZ timeloop
+ RDTSC
+ MOVL nt_tsc_base(BP), SI
+ MOVL (nt_tsc_base+4)(BP), DI
+ MOVL SI, 0(SP)
+ MOVL DI, 4(SP)
+ MOVL nt_scale(BP), SI
+ MOVL SI, 8(SP)
+ MOVL nt_ns_base(BP), SI
+ MOVL (nt_ns_base+4)(BP), DI
+ MOVL SI, 12(SP)
+ MOVL DI, 16(SP)
+ CMPL nt_generation(BP), CX
+ JNE timeloop
+ MOVL gtod_ns_base(BP), SI
+ MOVL (gtod_ns_base+4)(BP), DI
+ MOVL SI, 20(SP)
+ MOVL DI, 24(SP)
+ MOVL gtod_sec_base(BP), SI
+ MOVL (gtod_sec_base+4)(BP), DI
+ MOVL SI, 28(SP)
+ MOVL DI, 32(SP)
+ CMPL gtod_generation(BP), BX
+ JNE timeloop
+
+ // Gathered all the data we need. Compute time.
+ // ((tsc - nt_tsc_base) * nt_scale) >> 32 + nt_ns_base - gtod_ns_base + gtod_sec_base*1e9
+ // The multiply and shift extracts the top 64 bits of the 96-bit product.
+ SUBL 0(SP), AX // DX:AX = (tsc - nt_tsc_base)
+ SBBL 4(SP), DX
+
+ // We have x = tsc - nt_tsc_base - DX:AX to be
+ // multiplied by y = nt_scale = 8(SP), keeping the top 64 bits of the 96-bit product.
+ // x*y = (x&0xffffffff)*y + (x&0xffffffff00000000)*y
+ // (x*y)>>32 = ((x&0xffffffff)*y)>>32 + (x>>32)*y
+ MOVL DX, CX // SI = (x&0xffffffff)*y >> 32
+ MOVL $0, DX
+ MULL 8(SP)
+ MOVL DX, SI
+
+ MOVL CX, AX // DX:AX = (x>>32)*y
+ MOVL $0, DX
+ MULL 8(SP)
+
+ ADDL SI, AX // DX:AX += (x&0xffffffff)*y >> 32
+ ADCL $0, DX
+
+ // DX:AX is now ((tsc - nt_tsc_base) * nt_scale) >> 32.
+ ADDL 12(SP), AX // DX:AX += nt_ns_base
+ ADCL 16(SP), DX
+ SUBL 20(SP), AX // DX:AX -= gtod_ns_base
+ SBBL 24(SP), DX
+ MOVL AX, SI // DI:SI = DX:AX
+ MOVL DX, DI
+ MOVL 28(SP), AX // DX:AX = gtod_sec_base*1e9
+ MOVL 32(SP), DX
+ MOVL $1000000000, CX
+ MULL CX
+ ADDL SI, AX // DX:AX += DI:SI
+ ADCL DI, DX
+ RET
+
+systime:
+ // Fall back to system call (usually first call in this thread)
+ LEAL 12(SP), AX // must be non-nil, unused
+ MOVL AX, 4(SP)
+ MOVL $0, 8(SP) // time zone pointer
+ MOVL $116, AX
+ INT $0x80
+ // sec is in AX, usec in DX
+ // convert to DX:AX nsec
+ MOVL DX, BX
+ MOVL $1000000000, CX
+ MULL CX
+ IMULL $1000, BX
+ ADDL BX, AX
+ ADCL $0, DX
+ RET
+
+// func now() (sec int64, nsec int32)
+TEXT time·now(SB),NOSPLIT,$0
+ CALL runtime·now(SB)
+ MOVL $1000000000, CX
+ DIVL CX
+ MOVL AX, sec+0(FP)
+ MOVL $0, sec+4(FP)
+ MOVL DX, nsec+8(FP)
+ RET
+
+// int64 nanotime(void) so really
+// void nanotime(int64 *nsec)
+TEXT runtime·nanotime(SB),NOSPLIT,$0
+ CALL runtime·now(SB)
+ MOVL AX, ret_lo+0(FP)
+ MOVL DX, ret_hi+4(FP)
+ RET
+
+TEXT runtime·sigprocmask(SB),NOSPLIT,$0
+ MOVL $329, AX // pthread_sigmask (on OS X, sigprocmask==entire process)
+ INT $0x80
+ JAE 2(PC)
+ MOVL $0xf1, 0xf1 // crash
+ RET
+
+TEXT runtime·sigaction(SB),NOSPLIT,$0
+ MOVL $46, AX
+ INT $0x80
+ JAE 2(PC)
+ MOVL $0xf1, 0xf1 // crash
+ RET
+
+// Sigtramp's job is to call the actual signal handler.
+// It is called with the following arguments on the stack:
+// 0(FP) "return address" - ignored
+// 4(FP) actual handler
+// 8(FP) signal number
+// 12(FP) siginfo style
+// 16(FP) siginfo
+// 20(FP) context
+TEXT runtime·sigtramp(SB),NOSPLIT,$40
+ get_tls(CX)
+
+ // check that g exists
+ MOVL g(CX), DI
+ CMPL DI, $0
+ JNE 6(PC)
+ MOVL sig+8(FP), BX
+ MOVL BX, 0(SP)
+ MOVL $runtime·badsignal(SB), AX
+ CALL AX
+ JMP sigtramp_ret
+
+ // save g
+ MOVL DI, 20(SP)
+
+ // g = m->gsignal
+ MOVL g_m(DI), BP
+ MOVL m_gsignal(BP), BP
+ MOVL BP, g(CX)
+
+ // copy arguments to sighandler
+ MOVL sig+8(FP), BX
+ MOVL BX, 0(SP)
+ MOVL info+12(FP), BX
+ MOVL BX, 4(SP)
+ MOVL context+16(FP), BX
+ MOVL BX, 8(SP)
+ MOVL DI, 12(SP)
+
+ MOVL handler+0(FP), BX
+ CALL BX
+
+ // restore g
+ get_tls(CX)
+ MOVL 20(SP), DI
+ MOVL DI, g(CX)
+
+sigtramp_ret:
+ // call sigreturn
+ MOVL context+16(FP), CX
+ MOVL style+4(FP), BX
+ MOVL $0, 0(SP) // "caller PC" - ignored
+ MOVL CX, 4(SP)
+ MOVL BX, 8(SP)
+ MOVL $184, AX // sigreturn(ucontext, infostyle)
+ INT $0x80
+ MOVL $0xf1, 0xf1 // crash
+ RET
+
+TEXT runtime·sigaltstack(SB),NOSPLIT,$0
+ MOVL $53, AX
+ INT $0x80
+ JAE 2(PC)
+ MOVL $0xf1, 0xf1 // crash
+ RET
+
+TEXT runtime·usleep(SB),NOSPLIT,$32
+ MOVL $0, DX
+ MOVL usec+0(FP), AX
+ MOVL $1000000, CX
+ DIVL CX
+ MOVL AX, 24(SP) // sec
+ MOVL DX, 28(SP) // usec
+
+ // select(0, 0, 0, 0, &tv)
+ MOVL $0, 0(SP) // "return PC" - ignored
+ MOVL $0, 4(SP)
+ MOVL $0, 8(SP)
+ MOVL $0, 12(SP)
+ MOVL $0, 16(SP)
+ LEAL 24(SP), AX
+ MOVL AX, 20(SP)
+ MOVL $93, AX
+ INT $0x80
+ RET
+
+// void bsdthread_create(void *stk, M *mp, G *gp, void (*fn)(void))
+// System call args are: func arg stack pthread flags.
+TEXT runtime·bsdthread_create(SB),NOSPLIT,$32
+ MOVL $360, AX
+ // 0(SP) is where the caller PC would be; kernel skips it
+ MOVL fn+12(FP), BX
+ MOVL BX, 4(SP) // func
+ MOVL mm+4(FP), BX
+ MOVL BX, 8(SP) // arg
+ MOVL stk+0(FP), BX
+ MOVL BX, 12(SP) // stack
+ MOVL gg+8(FP), BX
+ MOVL BX, 16(SP) // pthread
+ MOVL $0x1000000, 20(SP) // flags = PTHREAD_START_CUSTOM
+ INT $0x80
+ JAE 4(PC)
+ NEGL AX
+ MOVL AX, ret+16(FP)
+ RET
+ MOVL $0, AX
+ MOVL AX, ret+16(FP)
+ RET
+
+// The thread that bsdthread_create creates starts executing here,
+// because we registered this function using bsdthread_register
+// at startup.
+// AX = "pthread" (= g)
+// BX = mach thread port
+// CX = "func" (= fn)
+// DX = "arg" (= m)
+// DI = stack top
+// SI = flags (= 0x1000000)
+// SP = stack - C_32_STK_ALIGN
+TEXT runtime·bsdthread_start(SB),NOSPLIT,$0
+ // set up ldt 7+id to point at m->tls.
+ // m->tls is at m+40. newosproc left
+ // the m->id in tls[0].
+ LEAL m_tls(DX), BP
+ MOVL 0(BP), DI
+ ADDL $7, DI // m0 is LDT#7. count up.
+ // setldt(tls#, &tls, sizeof tls)
+ PUSHAL // save registers
+ PUSHL $32 // sizeof tls
+ PUSHL BP // &tls
+ PUSHL DI // tls #
+ CALL runtime·setldt(SB)
+ POPL AX
+ POPL AX
+ POPL AX
+ POPAL
+
+ // Now segment is established. Initialize m, g.
+ get_tls(BP)
+ MOVL AX, g(BP)
+ MOVL DX, g_m(AX)
+ MOVL BX, m_procid(DX) // m->procid = thread port (for debuggers)
+ CALL runtime·stackcheck(SB) // smashes AX
+ CALL CX // fn()
+ CALL runtime·exit1(SB)
+ RET
+
+// void bsdthread_register(void)
+// registers callbacks for threadstart (see bsdthread_create above
+// and wqthread and pthsize (not used). returns 0 on success.
+TEXT runtime·bsdthread_register(SB),NOSPLIT,$40
+ MOVL $366, AX
+ // 0(SP) is where kernel expects caller PC; ignored
+ MOVL $runtime·bsdthread_start(SB), 4(SP) // threadstart
+ MOVL $0, 8(SP) // wqthread, not used by us
+ MOVL $0, 12(SP) // pthsize, not used by us
+ MOVL $0, 16(SP) // dummy_value [sic]
+ MOVL $0, 20(SP) // targetconc_ptr
+ MOVL $0, 24(SP) // dispatchqueue_offset
+ INT $0x80
+ JAE 4(PC)
+ NEGL AX
+ MOVL AX, ret+0(FP)
+ RET
+ MOVL $0, AX
+ MOVL AX, ret+0(FP)
+ RET
+
+// Invoke Mach system call.
+// Assumes system call number in AX,
+// caller PC on stack, caller's caller PC next,
+// and then the system call arguments.
+//
+// Can be used for BSD too, but we don't,
+// because if you use this interface the BSD
+// system call numbers need an extra field
+// in the high 16 bits that seems to be the
+// argument count in bytes but is not always.
+// INT $0x80 works fine for those.
+TEXT runtime·sysenter(SB),NOSPLIT,$0
+ POPL DX
+ MOVL SP, CX
+ BYTE $0x0F; BYTE $0x34; // SYSENTER
+ // returns to DX with SP set to CX
+
+TEXT runtime·mach_msg_trap(SB),NOSPLIT,$0
+ MOVL $-31, AX
+ CALL runtime·sysenter(SB)
+ MOVL AX, ret+28(FP)
+ RET
+
+TEXT runtime·mach_reply_port(SB),NOSPLIT,$0
+ MOVL $-26, AX
+ CALL runtime·sysenter(SB)
+ MOVL AX, ret+0(FP)
+ RET
+
+TEXT runtime·mach_task_self(SB),NOSPLIT,$0
+ MOVL $-28, AX
+ CALL runtime·sysenter(SB)
+ MOVL AX, ret+0(FP)
+ RET
+
+// Mach provides trap versions of the semaphore ops,
+// instead of requiring the use of RPC.
+
+// uint32 mach_semaphore_wait(uint32)
+TEXT runtime·mach_semaphore_wait(SB),NOSPLIT,$0
+ MOVL $-36, AX
+ CALL runtime·sysenter(SB)
+ MOVL AX, ret+4(FP)
+ RET
+
+// uint32 mach_semaphore_timedwait(uint32, uint32, uint32)
+TEXT runtime·mach_semaphore_timedwait(SB),NOSPLIT,$0
+ MOVL $-38, AX
+ CALL runtime·sysenter(SB)
+ MOVL AX, ret+12(FP)
+ RET
+
+// uint32 mach_semaphore_signal(uint32)
+TEXT runtime·mach_semaphore_signal(SB),NOSPLIT,$0
+ MOVL $-33, AX
+ CALL runtime·sysenter(SB)
+ MOVL AX, ret+4(FP)
+ RET
+
+// uint32 mach_semaphore_signal_all(uint32)
+TEXT runtime·mach_semaphore_signal_all(SB),NOSPLIT,$0
+ MOVL $-34, AX
+ CALL runtime·sysenter(SB)
+ MOVL AX, ret+4(FP)
+ RET
+
+// setldt(int entry, int address, int limit)
+// entry and limit are ignored.
+TEXT runtime·setldt(SB),NOSPLIT,$32
+ MOVL address+4(FP), BX // aka base
+
+ /*
+ * When linking against the system libraries,
+ * we use its pthread_create and let it set up %gs
+ * for us. When we do that, the private storage
+ * we get is not at 0(GS) but at 0x468(GS).
+ * 8l rewrites 0(TLS) into 0x468(GS) for us.
+ * To accommodate that rewrite, we translate the
+ * address and limit here so that 0x468(GS) maps to 0(address).
+ *
+ * See cgo/gcc_darwin_386.c:/468 for the derivation
+ * of the constant.
+ */
+ SUBL $0x468, BX
+
+ /*
+ * Must set up as USER_CTHREAD segment because
+ * Darwin forces that value into %gs for signal handlers,
+ * and if we don't set one up, we'll get a recursive
+ * fault trying to get into the signal handler.
+ * Since we have to set one up anyway, it might as
+ * well be the value we want. So don't bother with
+ * i386_set_ldt.
+ */
+ MOVL BX, 4(SP)
+ MOVL $3, AX // thread_fast_set_cthread_self - machdep call #3
+ INT $0x82 // sic: 0x82, not 0x80, for machdep call
+
+ XORL AX, AX
+ MOVW GS, AX
+ RET
+
+TEXT runtime·sysctl(SB),NOSPLIT,$0
+ MOVL $202, AX
+ INT $0x80
+ JAE 4(PC)
+ NEGL AX
+ MOVL AX, ret+24(FP)
+ RET
+ MOVL $0, AX
+ MOVL AX, ret+24(FP)
+ RET
+
+// int32 runtime·kqueue(void);
+TEXT runtime·kqueue(SB),NOSPLIT,$0
+ MOVL $362, AX
+ INT $0x80
+ JAE 2(PC)
+ NEGL AX
+ MOVL AX, ret+0(FP)
+ RET
+
+// int32 runtime·kevent(int kq, Kevent *changelist, int nchanges, Kevent *eventlist, int nevents, Timespec *timeout);
+TEXT runtime·kevent(SB),NOSPLIT,$0
+ MOVL $363, AX
+ INT $0x80
+ JAE 2(PC)
+ NEGL AX
+ MOVL AX, ret+24(FP)
+ RET
+
+// int32 runtime·closeonexec(int32 fd);
+TEXT runtime·closeonexec(SB),NOSPLIT,$32
+ MOVL $92, AX // fcntl
+ // 0(SP) is where the caller PC would be; kernel skips it
+ MOVL fd+0(FP), BX
+ MOVL BX, 4(SP) // fd
+ MOVL $2, 8(SP) // F_SETFD
+ MOVL $1, 12(SP) // FD_CLOEXEC
+ INT $0x80
+ JAE 2(PC)
+ NEGL AX
+ RET