// nameless linkname to export to assembly here and in x/sys. Additionally,
// entersyscall fetches the caller PC and SP and thus can't have a wrapper
// inbetween.

//go:linkname runtime_entersyscall runtime.entersyscall
func runtime_entersyscall()

//go:linkname runtime_exitsyscall runtime.exitsyscall
func runtime_exitsyscall()

// N.B. For the Syscall functions below:
//

//
// System call support for AMD64, Darwin
//

// Trap # in AX, args in DI SI DX, return in AX DX

// func Syscall(trap, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno);
TEXT	·Syscall(SB),NOSPLIT,$0-56
	CALL	runtime·entersyscall<ABIInternal>(SB)
	MOVQ	a1+8(FP), DI
	MOVQ	a2+16(FP), SI
	MOVQ	a3+24(FP), DX
	MOVQ	trap+0(FP), AX	// syscall entry
	ADDQ	$0x2000000, AX
	SYSCALL
	JCC	ok
	MOVQ	$-1, r1+32(FP)
	MOVQ	$0, r2+40(FP)

// func Syscall6(trap int32, a1, a2, a3, a4, a5, a6 int32) (r1, r2, err int32);
// Trap # in AX, args on stack above caller pc.

TEXT	·Syscall(SB),NOSPLIT,$0-28
	CALL	runtime·entersyscall(SB)
	MOVL	trap+0(FP), AX	// syscall entry
	// slide args down on top of system call number
	LEAL		a1+4(FP), SI
	LEAL		trap+0(FP), DI
	CLD
	MOVSL
	MOVSL
	MOVSL
	INT	$0x80
	JAE	ok

#include "textflag.h"

//
// System call support for ARM64, FreeBSD
//

#define SYS_syscall	0

// func Syscall(trap uintptr, a1, a2, a3 uintptr) (r1, r2, err uintptr)
TEXT ·Syscall(SB),NOSPLIT,$0-56
	BL	runtime·entersyscall<ABIInternal>(SB)
	MOVD	trap+0(FP), R8	// syscall entry
	MOVD	a1+8(FP), R0
	MOVD	a2+16(FP), R1
	MOVD	a3+24(FP), R2
	SVC	$SYS_syscall
	BCC	ok
	MOVD	$-1, R1
	MOVD	R1, r1+32(FP)
	MOVD	ZR, r2+40(FP)

#include "textflag.h"

//
// System call support for ARM64, Darwin
//

// func Syscall(trap uintptr, a1, a2, a3 uintptr) (r1, r2, err uintptr)
TEXT	·Syscall(SB),NOSPLIT,$0-56
	BL	runtime·entersyscall<ABIInternal>(SB)
	MOVD	trap+0(FP), R16
	MOVD	a1+8(FP), R0
	MOVD	a2+16(FP), R1
	MOVD	a3+24(FP), R2
	SVC	$0x80
	BCC	ok
	MOVD	$-1, R1
	MOVD	R1, r1+32(FP)	// r1
	MOVD	ZR, r2+40(FP)	// r2

// func Syscall6(trap int64, a1, a2, a3, a4, a5, a6 int64) (r1, r2, err int64)
// Trap # in AX, args in DI SI DX, return in AX DX

TEXT	·Syscall(SB),NOSPLIT,$0-56
	CALL	runtime·entersyscall<ABIInternal>(SB)
	MOVQ	trap+0(FP), AX	// syscall entry
	MOVQ	a1+8(FP), DI
	MOVQ	a2+16(FP), SI
	MOVQ	a3+24(FP), DX
	SYSCALL
	JCC	ok
	MOVQ	$-1, r1+32(FP)	// r1
	MOVQ	$0, r2+40(FP)	// r2

#include "textflag.h"

//
// System calls for riscv64, FreeBSD
//

// func Syscall(trap int64, a1, a2, a3 int64) (r1, r2, err int64)
TEXT ·Syscall(SB),NOSPLIT,$0-56
	CALL	runtime·entersyscall(SB)
	MOV	a1+8(FP), A0
	MOV	a2+16(FP), A1
	MOV	a3+24(FP), A2
	MOV	trap+0(FP), T0	// syscall entry
	ECALL
	BNE	T0, ZERO, err
	MOV	A0, r1+32(FP)	// r1
	MOV	A1, r2+40(FP)	// r2

#include "textflag.h"

//
// System call support for ARM64, NetBSD
//

#define	SYS_syscall	0

// func Syscall(trap uintptr, a1, a2, a3 uintptr) (r1, r2, err uintptr)
TEXT	·Syscall(SB),NOSPLIT,$0-56
	BL	runtime·entersyscall<ABIInternal>(SB)
	MOVD	trap+0(FP), R17
	MOVD	a1+8(FP), R0
	MOVD	a2+16(FP), R1
	MOVD	a3+24(FP), R2
	SVC	$SYS_syscall
	BCC	ok
	MOVD	$-1, R1
	MOVD	R1, r1+32(FP)	// r1
	MOVD	ZR, r2+40(FP)	// r2

// func socketcall(call int, a0, a1, a2, a3, a4, a5 uintptr) (n int, err int)
// Kernel interface gets call sub-number and pointer to a0.
TEXT ·socketcall(SB),NOSPLIT,$0-36
	CALL	runtime·entersyscall(SB)
	MOVL	$SYS_SOCKETCALL, AX	// syscall entry
	MOVL	call+0(FP), BX	// socket call number
	LEAL	a0+4(FP), CX	// pointer to call arguments
	MOVL	$0, DX
	MOVL	$0, SI
	MOVL	$0, DI
	INVOKE_SYSCALL

	JMP syscall·Syscall(SB)

TEXT ·Syscall6(SB),NOSPLIT,$0-40
	JMP syscall·Syscall6(SB)

TEXT ·Syscall9(SB),NOSPLIT,$0-52
	JMP syscall·Syscall9(SB)

TEXT ·SyscallNoError(SB),NOSPLIT,$0-24
	JAL	runtime·entersyscall(SB)
	MOVW	a1+4(FP), R4
	MOVW	a2+8(FP), R5
	MOVW	a3+12(FP), R6
	MOVW	R0, R7
	MOVW	trap+0(FP), R2	// syscall entry
	SYSCALL
	MOVW	R2, r1+16(FP)	// r1
	MOVW	R3, r2+20(FP)	// r2
	JAL	runtime·exitsyscall(SB)