1 files changed, 263 insertions, 0 deletions
diff --git a/src/runtime/sys_windows_arm64.s b/src/runtime/sys_windows_arm64.s
new file mode 100644
index 0000000..1f6d411
--- /dev/null
+++ b/src/runtime/sys_windows_arm64.s
@@ -0,0 +1,263 @@
+// Copyright 2018 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.
+
+#include "go_asm.h"
+#include "go_tls.h"
+#include "textflag.h"
+#include "funcdata.h"
+#include "time_windows.h"
+#include "cgo/abi_arm64.h"
+
+// Offsets into Thread Environment Block (pointer in R18)
+#define TEB_error 0x68
+#define TEB_TlsSlots 0x1480
+#define TEB_ArbitraryPtr 0x28
+
+// Note: R0-R7 are args, R8 is indirect return value address,
+// R9-R15 are caller-save, R19-R29 are callee-save.
+//
+// load_g and save_g (in tls_arm64.s) clobber R27 (REGTMP) and R0.
+
+TEXT runtime·asmstdcall_trampoline<ABIInternal>(SB),NOSPLIT,$0
+	B	runtime·asmstdcall(SB)
+
+// void runtime·asmstdcall(void *c);
+TEXT runtime·asmstdcall(SB),NOSPLIT,$16
+	STP	(R19, R20), 16(RSP) // save old R19, R20
+	MOVD	R0, R19	// save libcall pointer
+	MOVD	RSP, R20	// save stack pointer
+
+	// SetLastError(0)
+	MOVD	$0,	TEB_error(R18_PLATFORM)
+	MOVD	libcall_args(R19), R12	// libcall->args
+
+	// Do we have more than 8 arguments?
+	MOVD	libcall_n(R19), R0
+	CMP	$0,	R0; BEQ	_0args
+	CMP	$1,	R0; BEQ	_1args
+	CMP	$2,	R0; BEQ	_2args
+	CMP	$3,	R0; BEQ	_3args
+	CMP	$4,	R0; BEQ	_4args
+	CMP	$5,	R0; BEQ	_5args
+	CMP	$6,	R0; BEQ	_6args
+	CMP	$7,	R0; BEQ	_7args
+	CMP	$8,	R0; BEQ	_8args
+
+	// Reserve stack space for remaining args
+	SUB	$8, R0, R2
+	ADD	$1, R2, R3 // make even number of words for stack alignment
+	AND	$~1, R3
+	LSL	$3, R3
+	SUB	R3, RSP
+
+	// R4: size of stack arguments (n-8)*8
+	// R5: &args[8]
+	// R6: loop counter, from 0 to (n-8)*8
+	// R7: scratch
+	// R8: copy of RSP - (R2)(RSP) assembles as (R2)(ZR)
+	SUB	$8, R0, R4
+	LSL	$3, R4
+	ADD	$(8*8), R12, R5
+	MOVD	$0, R6
+	MOVD	RSP, R8
+stackargs:
+	MOVD	(R6)(R5), R7
+	MOVD	R7, (R6)(R8)
+	ADD	$8, R6
+	CMP	R6, R4
+	BNE	stackargs
+
+_8args:
+	MOVD	(7*8)(R12), R7
+_7args:
+	MOVD	(6*8)(R12), R6
+_6args:
+	MOVD	(5*8)(R12), R5
+_5args:
+	MOVD	(4*8)(R12), R4
+_4args:
+	MOVD	(3*8)(R12), R3
+_3args:
+	MOVD	(2*8)(R12), R2
+_2args:
+	MOVD	(1*8)(R12), R1
+_1args:
+	MOVD	(0*8)(R12), R0
+_0args:
+
+	MOVD	libcall_fn(R19), R12	// branch to libcall->fn
+	BL	(R12)
+
+	MOVD	R20, RSP			// free stack space
+	MOVD	R0, libcall_r1(R19)		// save return value to libcall->r1
+	// TODO(rsc) floating point like amd64 in libcall->r2?
+
+	// GetLastError
+	MOVD	TEB_error(R18_PLATFORM), R0
+	MOVD	R0, libcall_err(R19)
+
+	// Restore callee-saved registers.
+	LDP	16(RSP), (R19, R20)
+	RET
+
+TEXT runtime·getlasterror(SB),NOSPLIT,$0
+	MOVD	TEB_error(R18_PLATFORM), R0
+	MOVD	R0, ret+0(FP)
+	RET
+
+// Called by Windows as a Vectored Exception Handler (VEH).
+// R0 is pointer to struct containing
+// exception record and context pointers.
+// R1 is the kind of sigtramp function.
+// Return value of sigtrampgo is stored in R0.
+TEXT sigtramp<>(SB),NOSPLIT,$176
+	// Switch from the host ABI to the Go ABI, safe args and lr.
+	MOVD	R0, R5
+	MOVD	R1, R6
+	MOVD	LR, R7
+	SAVE_R19_TO_R28(8*4)
+	SAVE_F8_TO_F15(8*14)
+
+	BL	runtime·load_g(SB)	// Clobers R0, R27, R28 (g)
+
+	MOVD	R5, R0
+	MOVD	R6, R1
+	// Calling ABIInternal because TLS might be nil.
+	BL	runtime·sigtrampgo<ABIInternal>(SB)
+	// Return value is already stored in R0.
+
+	// Restore callee-save registers.
+	RESTORE_R19_TO_R28(8*4)
+	RESTORE_F8_TO_F15(8*14)
+	MOVD	R7, LR
+	RET
+
+// Trampoline to resume execution from exception handler.
+// This is part of the control flow guard workaround.
+// It switches stacks and jumps to the continuation address.
+// R0 and R1 are set above at the end of sigtrampgo
+// in the context that starts executing at sigresume.
+TEXT runtime·sigresume(SB),NOSPLIT|NOFRAME,$0
+	// Important: do not smash LR,
+	// which is set to a live value when handling
+	// a signal by pushing a call to sigpanic onto the stack.
+	MOVD	R0, RSP
+	B	(R1)
+
+TEXT runtime·exceptiontramp(SB),NOSPLIT|NOFRAME,$0
+	MOVD	$const_callbackVEH, R1
+	B	sigtramp<>(SB)
+
+TEXT runtime·firstcontinuetramp(SB),NOSPLIT|NOFRAME,$0
+	MOVD	$const_callbackFirstVCH, R1
+	B	sigtramp<>(SB)
+
+TEXT runtime·lastcontinuetramp(SB),NOSPLIT|NOFRAME,$0
+	MOVD	$const_callbackLastVCH, R1
+	B	sigtramp<>(SB)
+
+TEXT runtime·callbackasm1(SB),NOSPLIT,$208-0
+	NO_LOCAL_POINTERS
+
+	// On entry, the trampoline in zcallback_windows_arm64.s left
+	// the callback index in R12 (which is volatile in the C ABI).
+
+	// Save callback register arguments R0-R7.
+	// We do this at the top of the frame so they're contiguous with stack arguments.
+	// The 7*8 setting up R14 looks like a bug but is not: the eighth word
+	// is the space the assembler reserved for our caller's frame pointer,
+	// but we are not called from Go so that space is ours to use,
+	// and we must to be contiguous with the stack arguments.
+	MOVD	$arg0-(7*8)(SP), R14
+	STP	(R0, R1), (0*8)(R14)
+	STP	(R2, R3), (2*8)(R14)
+	STP	(R4, R5), (4*8)(R14)
+	STP	(R6, R7), (6*8)(R14)
+
+	// Push C callee-save registers R19-R28.
+	// LR, FP already saved.
+	SAVE_R19_TO_R28(8*9)
+
+	// Create a struct callbackArgs on our stack.
+	MOVD	$cbargs-(18*8+callbackArgs__size)(SP), R13
+	MOVD	R12, callbackArgs_index(R13)	// callback index
+	MOVD	R14, R0
+	MOVD	R0, callbackArgs_args(R13)		// address of args vector
+	MOVD	$0, R0
+	MOVD	R0, callbackArgs_result(R13)	// result
+
+	// Call cgocallback, which will call callbackWrap(frame).
+	MOVD	$·callbackWrap<ABIInternal>(SB), R0	// PC of function to call, cgocallback takes an ABIInternal entry-point
+	MOVD	R13, R1	// frame (&callbackArgs{...})
+	MOVD	$0, R2	// context
+	STP	(R0, R1), (1*8)(RSP)
+	MOVD	R2, (3*8)(RSP)
+	BL	runtime·cgocallback(SB)
+
+	// Get callback result.
+	MOVD	$cbargs-(18*8+callbackArgs__size)(SP), R13
+	MOVD	callbackArgs_result(R13), R0
+
+	RESTORE_R19_TO_R28(8*9)
+
+	RET
+
+// uint32 tstart_stdcall(M *newm);
+TEXT runtime·tstart_stdcall(SB),NOSPLIT,$96-0
+	SAVE_R19_TO_R28(8*3)
+
+	MOVD	m_g0(R0), g
+	MOVD	R0, g_m(g)
+	BL	runtime·save_g(SB)
+
+	// Set up stack guards for OS stack.
+	MOVD	RSP, R0
+	MOVD	R0, g_stack+stack_hi(g)
+	SUB	$(64*1024), R0
+	MOVD	R0, (g_stack+stack_lo)(g)
+	MOVD	R0, g_stackguard0(g)
+	MOVD	R0, g_stackguard1(g)
+
+	BL	runtime·emptyfunc(SB)	// fault if stack check is wrong
+	BL	runtime·mstart(SB)
+
+	RESTORE_R19_TO_R28(8*3)
+
+	// Exit the thread.
+	MOVD	$0, R0
+	RET
+
+TEXT runtime·nanotime1(SB),NOSPLIT,$0-8
+	MOVD	$_INTERRUPT_TIME, R3
+	MOVD	time_lo(R3), R0
+	MOVD	$100, R1
+	MUL	R1, R0
+	MOVD	R0, ret+0(FP)
+	RET
+
+// This is called from rt0_go, which runs on the system stack
+// using the initial stack allocated by the OS.
+// It calls back into standard C using the BL below.
+TEXT runtime·wintls(SB),NOSPLIT,$0
+	// Allocate a TLS slot to hold g across calls to external code
+	MOVD	runtime·_TlsAlloc(SB), R0
+	SUB	$16, RSP	// skip over saved frame pointer below RSP
+	BL	(R0)
+	ADD	$16, RSP
+
+	// Assert that slot is less than 64 so we can use _TEB->TlsSlots
+	CMP	$64, R0
+	BLT	ok
+	// Fallback to the TEB arbitrary pointer.
+	// TODO: don't use the arbitrary pointer (see go.dev/issue/59824)
+	MOVD	$TEB_ArbitraryPtr, R0
+	B	settls
+ok:
+
+	// Save offset from R18 into tls_g.
+	LSL	$3, R0
+	ADD	$TEB_TlsSlots, R0
+settls:
+	MOVD	R0, runtime·tls_g(SB)
+	RET