purego: support pure go C call on macOS (#1)

commit: d5a24be3d13fe5609c069f2b9c1dcf1580fae31f
author: TotallyGamerJet · 4y ago · 2022-05-17 12:05 UTC
committer: GitHub · 4y ago · 2022-05-17 12:05 UTC
parent: e8e2aab
signature: GPG Unverified4AEE18F83AFDEB23 The key is unknown

7 files · +290 -0

A dl_darwin.go +46 -0

@@ -0,0 +1,46 @@
	1	+	// SPDX-License-Identifier: Apache-2.0
	2	+	// SPDX-FileCopyrightText: 2022 The Ebiten Authors
	3	+
	4	+	package purego
	5	+
	6	+	import (
	7	+	"runtime"
	8	+	"strings"
	9	+	"unsafe"
	10	+	)
	11	+
	12	+	const RTLD_DEFAULT = ^uintptr(1)
	13	+
	14	+	func cString(name string) *byte {
	15	+	if strings.HasSuffix(name, "\x00") {
	16	+	return &[]byte(name)[0]
	17	+	}
	18	+	var b = make([]byte, len(name)+1)
	19	+	copy(b, name)
	20	+	return &b[0]
	21	+	}
	22	+
	23	+	func Dlopen(name string, mode int) uintptr {
	24	+	bs := cString(name)
	25	+	ret, _, _ := SyscallN(dlopenABI0, uintptr(unsafe.Pointer(bs)), uintptr(mode), 0)
	26	+	runtime.KeepAlive(bs)
	27	+	return ret
	28	+	}
	29	+
	30	+	func Dlsym(handle uintptr, name string) uintptr {
	31	+	bs := cString(name)
	32	+	ret, _, _ := SyscallN(dlsymABI0, handle, uintptr(unsafe.Pointer(bs)), 0)
	33	+	runtime.KeepAlive(bs)
	34	+	return ret
	35	+	}
	36	+
	37	+	//go:cgo_import_dynamic _dlopen dlopen "/usr/lib/libSystem.B.dylib"
	38	+	//go:cgo_import_dynamic _dlsym dlsym "/usr/lib/libSystem.B.dylib"
	39	+
	40	+	var dlopenABI0 uintptr
	41	+
	42	+	func dlopen() // implemented in assembly
	43	+
	44	+	var dlsymABI0 uintptr
	45	+
	46	+	func dlsym() // implemented in assembly

@@ -0,0 +1,46 @@
	1	+	// SPDX-License-Identifier: Apache-2.0
	2	+	// SPDX-FileCopyrightText: 2022 The Ebiten Authors
	3	+
	4	+	package purego
	5	+
	6	+	import (
	7	+	"runtime"
	8	+	"strings"
	9	+	"unsafe"
	10	+	)
	11	+
	12	+	const RTLD_DEFAULT = ^uintptr(1)
	13	+
	14	+	func cString(name string) *byte {
	15	+	if strings.HasSuffix(name, "\x00") {
	16	+	return &[]byte(name)[0]
	17	+	}
	18	+	var b = make([]byte, len(name)+1)
	19	+	copy(b, name)
	20	+	return &b[0]
	21	+	}
	22	+
	23	+	func Dlopen(name string, mode int) uintptr {
	24	+	bs := cString(name)
	25	+	ret, _, _ := SyscallN(dlopenABI0, uintptr(unsafe.Pointer(bs)), uintptr(mode), 0)
	26	+	runtime.KeepAlive(bs)
	27	+	return ret
	28	+	}
	29	+
	30	+	func Dlsym(handle uintptr, name string) uintptr {
	31	+	bs := cString(name)
	32	+	ret, _, _ := SyscallN(dlsymABI0, handle, uintptr(unsafe.Pointer(bs)), 0)
	33	+	runtime.KeepAlive(bs)
	34	+	return ret
	35	+	}
	36	+
	37	+	//go:cgo_import_dynamic _dlopen dlopen "/usr/lib/libSystem.B.dylib"
	38	+	//go:cgo_import_dynamic _dlsym dlsym "/usr/lib/libSystem.B.dylib"
	39	+
	40	+	var dlopenABI0 uintptr
	41	+
	42	+	func dlopen() // implemented in assembly
	43	+
	44	+	var dlsymABI0 uintptr
	45	+
	46	+	func dlsym() // implemented in assembly

A go.mod +3 -0

@@ -0,0 +1,3 @@
	1	+	module github.com/ebiten/purego
	2	+
	3	+	go 1.15

@@ -0,0 +1,3 @@
	1	+	module github.com/ebiten/purego
	2	+
	3	+	go 1.15

A runtime.go +18 -0

@@ -0,0 +1,18 @@
	1	+	// SPDX-License-Identifier: Apache-2.0
	2	+	// SPDX-FileCopyrightText: 2022 The Ebiten Authors
	3	+
	4	+	//go:build darwin
	5	+	// +build darwin
	6	+
	7	+	package purego
	8	+
	9	+	import (
	10	+	"unsafe"
	11	+	)
	12	+
	13	+	//go:linkname runtime_libcCall runtime.libcCall
	14	+	//go:linkname runtime_entersyscall runtime.entersyscall
	15	+	//go:linkname runtime_exitsyscall runtime.exitsyscall
	16	+	func runtime_libcCall(fn, arg unsafe.Pointer) int32 // from runtime/sys_libc.go
	17	+	func runtime_entersyscall() // from runtime/proc.go
	18	+	func runtime_exitsyscall() // from runtime/proc.go

@@ -0,0 +1,18 @@
	1	+	// SPDX-License-Identifier: Apache-2.0
	2	+	// SPDX-FileCopyrightText: 2022 The Ebiten Authors
	3	+
	4	+	//go:build darwin
	5	+	// +build darwin
	6	+
	7	+	package purego
	8	+
	9	+	import (
	10	+	"unsafe"
	11	+	)
	12	+
	13	+	//go:linkname runtime_libcCall runtime.libcCall
	14	+	//go:linkname runtime_entersyscall runtime.entersyscall
	15	+	//go:linkname runtime_exitsyscall runtime.exitsyscall
	16	+	func runtime_libcCall(fn, arg unsafe.Pointer) int32 // from runtime/sys_libc.go
	17	+	func runtime_entersyscall() // from runtime/proc.go
	18	+	func runtime_exitsyscall() // from runtime/proc.go

A stubs.s +22 -0

@@ -0,0 +1,22 @@
	1	+	// SPDX-License-Identifier: Apache-2.0
	2	+	// SPDX-FileCopyrightText: 2022 The Ebiten Authors
	3	+
	4	+	//go:build darwin
	5	+	// +build darwin
	6	+
	7	+	#include "textflag.h"
	8	+
	9	+	// func dlopen(path *byte, mode int) (ret uintptr)
	10	+	GLOBL ·dlopenABI0(SB), NOPTR\|RODATA, $8
	11	+	DATA ·dlopenABI0(SB)/8, $·dlopen(SB)
	12	+	TEXT ·dlopen(SB), NOSPLIT, $0-0
	13	+	JMP _dlopen(SB)
	14	+	RET
	15	+
	16	+	// func dlsym(handle uintptr, symbol *byte) (ret uintptr)
	17	+	GLOBL ·dlsymABI0(SB), NOPTR\|RODATA, $8
	18	+	DATA ·dlsymABI0(SB)/8, $·dlsym(SB)
	19	+	TEXT ·dlsym(SB), NOSPLIT, $0-0
	20	+	JMP _dlsym(SB)
	21	+	RET
	22	+

@@ -0,0 +1,22 @@
	1	+	// SPDX-License-Identifier: Apache-2.0
	2	+	// SPDX-FileCopyrightText: 2022 The Ebiten Authors
	3	+
	4	+	//go:build darwin
	5	+	// +build darwin
	6	+
	7	+	#include "textflag.h"
	8	+
	9	+	// func dlopen(path *byte, mode int) (ret uintptr)
	10	+	GLOBL ·dlopenABI0(SB), NOPTR\|RODATA, $8
	11	+	DATA ·dlopenABI0(SB)/8, $·dlopen(SB)
	12	+	TEXT ·dlopen(SB), NOSPLIT, $0-0
	13	+	JMP _dlopen(SB)
	14	+	RET
	15	+
	16	+	// func dlsym(handle uintptr, symbol *byte) (ret uintptr)
	17	+	GLOBL ·dlsymABI0(SB), NOPTR\|RODATA, $8
	18	+	DATA ·dlsymABI0(SB)/8, $·dlsym(SB)
	19	+	TEXT ·dlsym(SB), NOSPLIT, $0-0
	20	+	JMP _dlsym(SB)
	21	+	RET
	22	+

A sys_darwin_amd64.s +82 -0

@@ -0,0 +1,82 @@
	1	+	// SPDX-License-Identifier: Apache-2.0
	2	+	// SPDX-FileCopyrightText: 2022 The Ebiten Authors
	3	+
	4	+	#include "textflag.h"
	5	+
	6	+	// syscall9X calls a function in libc on behalf of the syscall package.
	7	+	// syscall9X takes a pointer to a struct like:
	8	+	// struct {
	9	+	// fn uintptr
	10	+	// a1 uintptr
	11	+	// a2 uintptr
	12	+	// a3 uintptr
	13	+	// a4 uintptr
	14	+	// a5 uintptr
	15	+	// a6 uintptr
	16	+	// a7 uintptr
	17	+	// a8 uintptr
	18	+	// a9 uintptr
	19	+	// r1 uintptr
	20	+	// r2 uintptr
	21	+	// err uintptr
	22	+	// }
	23	+	// syscall9X must be called on the g0 stack with the
	24	+	// C calling convention (use libcCall).
	25	+	GLOBL ·syscall9XABI0(SB), NOPTR\|RODATA, $8
	26	+	DATA ·syscall9XABI0(SB)/8, $·syscall9X(SB)
	27	+	TEXT ·syscall9X(SB), NOSPLIT, $0
	28	+	PUSHQ BP
	29	+	MOVQ SP, BP
	30	+	SUBQ $32, SP
	31	+	MOVQ DI, -8(BP) // save the pointer
	32	+	MOVQ (0*8)(DI), R10 // fn
	33	+	MOVQ (2*8)(DI), SI // a2
	34	+	MOVQ (3*8)(DI), DX // a3
	35	+	MOVQ (4*8)(DI), CX // a4
	36	+	MOVQ (5*8)(DI), R8 // a5
	37	+	MOVQ (6*8)(DI), R9 // a6
	38	+	MOVQ (7*8)(DI), R11 // a7
	39	+	MOVQ (8*8)(DI), R12 // a8
	40	+	MOVQ (9*8)(DI), R13 // a9
	41	+	MOVQ (1*8)(DI), DI // a1
	42	+
	43	+	// these may be float arguments
	44	+	// so we put them also where C expects floats
	45	+	MOVQ DI, X0 // a1
	46	+	MOVQ SI, X1 // a2
	47	+	MOVQ DX, X2 // a3
	48	+	MOVQ CX, X3 // a4
	49	+	MOVQ R8, X4 // a5
	50	+	MOVQ R9, X5 // a6
	51	+	MOVQ R11, X6 // a7
	52	+	MOVQ R12, X7 // a8
	53	+
	54	+	// push the remainding paramters onto the stack
	55	+	MOVQ R11, 0(SP) // push a7
	56	+	MOVQ R12, 8(SP) // push a8
	57	+	MOVQ R13, 16(SP) // push a9
	58	+	XORL AX, AX // vararg: say "no float args"
	59	+
	60	+	CALL R10
	61	+
	62	+	MOVQ -8(BP), DI // get the pointer back
	63	+	MOVQ AX, (10*8)(DI) // r1
	64	+	MOVQ DX, (11*8)(DI) // r2
	65	+
	66	+	// Standard libc functions return -1 on error
	67	+	// and set errno.
	68	+	CMPQ AX, $-1
	69	+	JNE ok
	70	+
	71	+	// Get error code from libc.
	72	+	CALL libc_error(SB)
	73	+	MOVLQSX (AX), AX
	74	+	MOVQ (SP), DI
	75	+	MOVQ AX, (12*8)(DI) // err
	76	+
	77	+	ok:
	78	+	XORL AX, AX // no error (it's ignored anyway)
	79	+	ADDQ $32, SP
	80	+	MOVQ BP, SP
	81	+	POPQ BP
	82	+	RET

@@ -0,0 +1,82 @@
	1	+	// SPDX-License-Identifier: Apache-2.0
	2	+	// SPDX-FileCopyrightText: 2022 The Ebiten Authors
	3	+
	4	+	#include "textflag.h"
	5	+
	6	+	// syscall9X calls a function in libc on behalf of the syscall package.
	7	+	// syscall9X takes a pointer to a struct like:
	8	+	// struct {
	9	+	// fn uintptr
	10	+	// a1 uintptr
	11	+	// a2 uintptr
	12	+	// a3 uintptr
	13	+	// a4 uintptr
	14	+	// a5 uintptr
	15	+	// a6 uintptr
	16	+	// a7 uintptr
	17	+	// a8 uintptr
	18	+	// a9 uintptr
	19	+	// r1 uintptr
	20	+	// r2 uintptr
	21	+	// err uintptr
	22	+	// }
	23	+	// syscall9X must be called on the g0 stack with the
	24	+	// C calling convention (use libcCall).
	25	+	GLOBL ·syscall9XABI0(SB), NOPTR\|RODATA, $8
	26	+	DATA ·syscall9XABI0(SB)/8, $·syscall9X(SB)
	27	+	TEXT ·syscall9X(SB), NOSPLIT, $0
	28	+	PUSHQ BP
	29	+	MOVQ SP, BP
	30	+	SUBQ $32, SP
	31	+	MOVQ DI, -8(BP) // save the pointer
	32	+	MOVQ (0*8)(DI), R10 // fn
	33	+	MOVQ (2*8)(DI), SI // a2
	34	+	MOVQ (3*8)(DI), DX // a3
	35	+	MOVQ (4*8)(DI), CX // a4
	36	+	MOVQ (5*8)(DI), R8 // a5
	37	+	MOVQ (6*8)(DI), R9 // a6
	38	+	MOVQ (7*8)(DI), R11 // a7
	39	+	MOVQ (8*8)(DI), R12 // a8
	40	+	MOVQ (9*8)(DI), R13 // a9
	41	+	MOVQ (1*8)(DI), DI // a1
	42	+
	43	+	// these may be float arguments
	44	+	// so we put them also where C expects floats
	45	+	MOVQ DI, X0 // a1
	46	+	MOVQ SI, X1 // a2
	47	+	MOVQ DX, X2 // a3
	48	+	MOVQ CX, X3 // a4
	49	+	MOVQ R8, X4 // a5
	50	+	MOVQ R9, X5 // a6
	51	+	MOVQ R11, X6 // a7
	52	+	MOVQ R12, X7 // a8
	53	+
	54	+	// push the remainding paramters onto the stack
	55	+	MOVQ R11, 0(SP) // push a7
	56	+	MOVQ R12, 8(SP) // push a8
	57	+	MOVQ R13, 16(SP) // push a9
	58	+	XORL AX, AX // vararg: say "no float args"
	59	+
	60	+	CALL R10
	61	+
	62	+	MOVQ -8(BP), DI // get the pointer back
	63	+	MOVQ AX, (10*8)(DI) // r1
	64	+	MOVQ DX, (11*8)(DI) // r2
	65	+
	66	+	// Standard libc functions return -1 on error
	67	+	// and set errno.
	68	+	CMPQ AX, $-1
	69	+	JNE ok
	70	+
	71	+	// Get error code from libc.
	72	+	CALL libc_error(SB)
	73	+	MOVLQSX (AX), AX
	74	+	MOVQ (SP), DI
	75	+	MOVQ AX, (12*8)(DI) // err
	76	+
	77	+	ok:
	78	+	XORL AX, AX // no error (it's ignored anyway)
	79	+	ADDQ $32, SP
	80	+	MOVQ BP, SP
	81	+	POPQ BP
	82	+	RET

A sys_darwin_arm64.s +71 -0

@@ -0,0 +1,71 @@
	1	+	// SPDX-License-Identifier: Apache-2.0
	2	+	// SPDX-FileCopyrightText: 2022 The Ebiten Authors
	3	+
	4	+	#include "textflag.h"
	5	+
	6	+	// syscall9X calls a function in libc on behalf of the syscall package.
	7	+	// syscall9X takes a pointer to a struct like:
	8	+	// struct {
	9	+	// fn uintptr
	10	+	// a1 uintptr
	11	+	// a2 uintptr
	12	+	// a3 uintptr
	13	+	// a4 uintptr
	14	+	// a5 uintptr
	15	+	// a6 uintptr
	16	+	// a7 uintptr
	17	+	// a8 uintptr
	18	+	// a9 uintptr
	19	+	// r1 uintptr
	20	+	// r2 uintptr
	21	+	// err uintptr
	22	+	// }
	23	+	// syscall9X must be called on the g0 stack with the
	24	+	// C calling convention (use libcCall).
	25	+	GLOBL ·syscall9XABI0(SB), NOPTR\|RODATA, $8
	26	+	DATA ·syscall9XABI0(SB)/8, $·syscall9X(SB)
	27	+	TEXT ·syscall9X(SB), NOSPLIT, $0
	28	+	SUB $16, RSP // push structure pointer
	29	+	MOVD R0, 8(RSP)
	30	+
	31	+	MOVD 0(R0), R12 // fn
	32	+	MOVD 16(R0), R1 // a2
	33	+	MOVD 24(R0), R2 // a3
	34	+	MOVD 32(R0), R3 // a4
	35	+	MOVD 40(R0), R4 // a5
	36	+	MOVD 48(R0), R5 // a6
	37	+	MOVD 56(R0), R6 // a7
	38	+	MOVD 64(R0), R7 // a8
	39	+	MOVD 72(R0), R8 // a9
	40	+
	41	+	// these may be float arguments
	42	+	// so we put them also where C expects floats
	43	+	FMOVD R0, F0 // a1
	44	+	FMOVD R1, F1 // a2
	45	+	FMOVD R2, F2 // a3
	46	+	FMOVD R3, F3 // a4
	47	+	FMOVD R4, F4 // a5
	48	+	FMOVD R5, F5 // a6
	49	+	FMOVD R6, F6 // a4
	50	+	FMOVD R7, F7 // a5
	51	+
	52	+	MOVD R8, (RSP) // push a9 onto stack
	53	+	MOVD 8(R0), R0 // a1
	54	+	BL (R12)
	55	+
	56	+	MOVD 8(RSP), R2 // pop structure pointer
	57	+	ADD $16, RSP
	58	+	MOVD R0, 80(R2) // save r1
	59	+	MOVD R1, 88(R2) // save r2
	60	+	CMP $-1, R0
	61	+	BNE ok
	62	+	SUB $16, RSP // push structure pointer
	63	+	MOVD R2, (RSP)
	64	+	BL libc_error(SB)
	65	+	MOVW (R0), R0
	66	+	MOVD (RSP), R2 // pop structure pointer
	67	+	ADD $16, RSP
	68	+	MOVD R0, 96(R2) // save err
	69	+
	70	+	ok:
	71	+	RET

@@ -0,0 +1,71 @@
	1	+	// SPDX-License-Identifier: Apache-2.0
	2	+	// SPDX-FileCopyrightText: 2022 The Ebiten Authors
	3	+
	4	+	#include "textflag.h"
	5	+
	6	+	// syscall9X calls a function in libc on behalf of the syscall package.
	7	+	// syscall9X takes a pointer to a struct like:
	8	+	// struct {
	9	+	// fn uintptr
	10	+	// a1 uintptr
	11	+	// a2 uintptr
	12	+	// a3 uintptr
	13	+	// a4 uintptr
	14	+	// a5 uintptr
	15	+	// a6 uintptr
	16	+	// a7 uintptr
	17	+	// a8 uintptr
	18	+	// a9 uintptr
	19	+	// r1 uintptr
	20	+	// r2 uintptr
	21	+	// err uintptr
	22	+	// }
	23	+	// syscall9X must be called on the g0 stack with the
	24	+	// C calling convention (use libcCall).
	25	+	GLOBL ·syscall9XABI0(SB), NOPTR\|RODATA, $8
	26	+	DATA ·syscall9XABI0(SB)/8, $·syscall9X(SB)
	27	+	TEXT ·syscall9X(SB), NOSPLIT, $0
	28	+	SUB $16, RSP // push structure pointer
	29	+	MOVD R0, 8(RSP)
	30	+
	31	+	MOVD 0(R0), R12 // fn
	32	+	MOVD 16(R0), R1 // a2
	33	+	MOVD 24(R0), R2 // a3
	34	+	MOVD 32(R0), R3 // a4
	35	+	MOVD 40(R0), R4 // a5
	36	+	MOVD 48(R0), R5 // a6
	37	+	MOVD 56(R0), R6 // a7
	38	+	MOVD 64(R0), R7 // a8
	39	+	MOVD 72(R0), R8 // a9
	40	+
	41	+	// these may be float arguments
	42	+	// so we put them also where C expects floats
	43	+	FMOVD R0, F0 // a1
	44	+	FMOVD R1, F1 // a2
	45	+	FMOVD R2, F2 // a3
	46	+	FMOVD R3, F3 // a4
	47	+	FMOVD R4, F4 // a5
	48	+	FMOVD R5, F5 // a6
	49	+	FMOVD R6, F6 // a4
	50	+	FMOVD R7, F7 // a5
	51	+
	52	+	MOVD R8, (RSP) // push a9 onto stack
	53	+	MOVD 8(R0), R0 // a1
	54	+	BL (R12)
	55	+
	56	+	MOVD 8(RSP), R2 // pop structure pointer
	57	+	ADD $16, RSP
	58	+	MOVD R0, 80(R2) // save r1
	59	+	MOVD R1, 88(R2) // save r2
	60	+	CMP $-1, R0
	61	+	BNE ok
	62	+	SUB $16, RSP // push structure pointer
	63	+	MOVD R2, (RSP)
	64	+	BL libc_error(SB)
	65	+	MOVW (R0), R0
	66	+	MOVD (RSP), R2 // pop structure pointer
	67	+	ADD $16, RSP
	68	+	MOVD R0, 96(R2) // save err
	69	+
	70	+	ok:
	71	+	RET

A syscall.go +48 -0

@@ -0,0 +1,48 @@
	1	+	// SPDX-License-Identifier: Apache-2.0
	2	+	// SPDX-FileCopyrightText: 2022 The Ebiten Authors
	3	+
	4	+	//go:build darwin
	5	+	// +build darwin
	6	+
	7	+	package purego
	8	+
	9	+	import "unsafe"
	10	+
	11	+	const maxArgs = 9
	12	+
	13	+	// SyscallN takes fn, a C function pointer and a list of arguments as uintptr.
	14	+	// There is an internal maximum number of arguments that SyscallN can take. It panics
	15	+	// when the maximum is exceeded. It returns the result and the libc error code if there is one.
	16	+	//
	17	+	// NOTE: SyscallN does not properly call functions that have both integer and float parameters.
	18	+	// See discussion comment https://github.com/ebiten/purego/pull/1#issuecomment-1128057607
	19	+	// for an explanation of why that is.
	20	+	func SyscallN(fn uintptr, args ...uintptr) (r1, r2, err uintptr) {
	21	+	if len(args) > maxArgs {
	22	+	panic("too many arguments to SyscallN")
	23	+	}
	24	+	if len(args) < maxArgs {
	25	+	// add padding so there is no out-of-bounds slicing
	26	+	var tmp = make([]uintptr, maxArgs)
	27	+	copy(tmp, args)
	28	+	args = tmp
	29	+	}
	30	+	return syscall_syscall9X(fn, args[0], args[1], args[2], args[3], args[4], args[5], args[6], args[7], args[8])
	31	+	}
	32	+
	33	+	func callc(fn uintptr, args unsafe.Pointer) {
	34	+	runtime_entersyscall()
	35	+	runtime_libcCall(unsafe.Pointer(fn), args)
	36	+	runtime_exitsyscall()
	37	+	}
	38	+
	39	+	var syscall9XABI0 uintptr
	40	+
	41	+	func syscall9X() // implemented in assembly
	42	+
	43	+	func syscall_syscall9X(fn, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2, err uintptr) {
	44	+	args := struct{ fn, a1, a2, a3, a4, a5, a6, a7, a8, a9, r1, r2, err uintptr }{
	45	+	fn, a1, a2, a3, a4, a5, a6, a7, a8, a9, r1, r2, err}
	46	+	callc(syscall9XABI0, unsafe.Pointer(&args))
	47	+	return args.r1, args.r2, args.err
	48	+	}

@@ -0,0 +1,48 @@
	1	+	// SPDX-License-Identifier: Apache-2.0
	2	+	// SPDX-FileCopyrightText: 2022 The Ebiten Authors
	3	+
	4	+	//go:build darwin
	5	+	// +build darwin
	6	+
	7	+	package purego
	8	+
	9	+	import "unsafe"
	10	+
	11	+	const maxArgs = 9
	12	+
	13	+	// SyscallN takes fn, a C function pointer and a list of arguments as uintptr.
	14	+	// There is an internal maximum number of arguments that SyscallN can take. It panics
	15	+	// when the maximum is exceeded. It returns the result and the libc error code if there is one.
	16	+	//
	17	+	// NOTE: SyscallN does not properly call functions that have both integer and float parameters.
	18	+	// See discussion comment https://github.com/ebiten/purego/pull/1#issuecomment-1128057607
	19	+	// for an explanation of why that is.
	20	+	func SyscallN(fn uintptr, args ...uintptr) (r1, r2, err uintptr) {
	21	+	if len(args) > maxArgs {
	22	+	panic("too many arguments to SyscallN")
	23	+	}
	24	+	if len(args) < maxArgs {
	25	+	// add padding so there is no out-of-bounds slicing
	26	+	var tmp = make([]uintptr, maxArgs)
	27	+	copy(tmp, args)
	28	+	args = tmp
	29	+	}
	30	+	return syscall_syscall9X(fn, args[0], args[1], args[2], args[3], args[4], args[5], args[6], args[7], args[8])
	31	+	}
	32	+
	33	+	func callc(fn uintptr, args unsafe.Pointer) {
	34	+	runtime_entersyscall()
	35	+	runtime_libcCall(unsafe.Pointer(fn), args)
	36	+	runtime_exitsyscall()
	37	+	}
	38	+
	39	+	var syscall9XABI0 uintptr
	40	+
	41	+	func syscall9X() // implemented in assembly
	42	+
	43	+	func syscall_syscall9X(fn, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2, err uintptr) {
	44	+	args := struct{ fn, a1, a2, a3, a4, a5, a6, a7, a8, a9, r1, r2, err uintptr }{
	45	+	fn, a1, a2, a3, a4, a5, a6, a7, a8, a9, r1, r2, err}
	46	+	callc(syscall9XABI0, unsafe.Pointer(&args))
	47	+	return args.r1, args.r2, args.err
	48	+	}