runtime: syscall to return both AX and DX for windows/386

Fixes #2181.

R=golang-dev, jp
CC=golang-dev
https://golang.org/cl/5000042

src/pkg/runtime/runtime.h

@@ -307,7 +307,8 @@ struct	WinCall
 	void	(*fn)(void*);
 	uintptr	n;	// number of parameters
 	void*	args;	// parameters
-	uintptr	r;	// return value
+	uintptr	r1;	// return values
+	uintptr	r2;
 	uintptr	err;	// error number
 };
 

src/pkg/runtime/syscall_windows_test.go

@@ -39,6 +39,77 @@ func TestStdCall(t *testing.T) {
 	}
 }
 
+func Test64BitReturnStdCall(t *testing.T) {
+
+	const (
+		VER_BUILDNUMBER      = 0x0000004
+		VER_MAJORVERSION     = 0x0000002
+		VER_MINORVERSION     = 0x0000001
+		VER_PLATFORMID       = 0x0000008
+		VER_PRODUCT_TYPE     = 0x0000080
+		VER_SERVICEPACKMAJOR = 0x0000020
+		VER_SERVICEPACKMINOR = 0x0000010
+		VER_SUITENAME        = 0x0000040
+
+		VER_EQUAL         = 1
+		VER_GREATER       = 2
+		VER_GREATER_EQUAL = 3
+		VER_LESS          = 4
+		VER_LESS_EQUAL    = 5
+
+		ERROR_OLD_WIN_VERSION = 1150
+	)
+
+	type OSVersionInfoEx struct {
+		OSVersionInfoSize uint32
+		MajorVersion      uint32
+		MinorVersion      uint32
+		BuildNumber       uint32
+		PlatformId        uint32
+		CSDVersion        [128]uint16
+		ServicePackMajor  uint16
+		ServicePackMinor  uint16
+		SuiteMask         uint16
+		ProductType       byte
+		Reserve           byte
+	}
+
+	kernel32, e := syscall.LoadLibrary("kernel32.dll")
+	if e != 0 {
+		t.Fatalf("LoadLibrary(kernel32.dll) failed: %s", syscall.Errstr(e))
+	}
+	setMask, e := syscall.GetProcAddress(kernel32, "VerSetConditionMask")
+	if e != 0 {
+		t.Fatalf("GetProcAddress(kernel32.dll, VerSetConditionMask) failed: %s", syscall.Errstr(e))
+	}
+	verifyVersion, e := syscall.GetProcAddress(kernel32, "VerifyVersionInfoW")
+	if e != 0 {
+		t.Fatalf("GetProcAddress(kernel32.dll, VerifyVersionInfoW) failed: %s", syscall.Errstr(e))
+	}
+
+	var m1, m2 uintptr
+	m1, m2, _ = syscall.Syscall6(setMask, 4, m1, m2, VER_MAJORVERSION, VER_GREATER_EQUAL, 0, 0)
+	m1, m2, _ = syscall.Syscall6(setMask, 4, m1, m2, VER_MINORVERSION, VER_GREATER_EQUAL, 0, 0)
+	m1, m2, _ = syscall.Syscall6(setMask, 4, m1, m2, VER_SERVICEPACKMAJOR, VER_GREATER_EQUAL, 0, 0)
+	m1, m2, _ = syscall.Syscall6(setMask, 4, m1, m2, VER_SERVICEPACKMINOR, VER_GREATER_EQUAL, 0, 0)
+
+	vi := OSVersionInfoEx{
+		MajorVersion:     5,
+		MinorVersion:     1,
+		ServicePackMajor: 2,
+		ServicePackMinor: 0,
+	}
+	vi.OSVersionInfoSize = uint32(unsafe.Sizeof(vi))
+	r, _, e2 := syscall.Syscall6(verifyVersion,
+		4,
+		uintptr(unsafe.Pointer(&vi)),
+		VER_MAJORVERSION|VER_MINORVERSION|VER_SERVICEPACKMAJOR|VER_SERVICEPACKMINOR,
+		m1, m2, 0, 0)
+	if r == 0 && e2 != ERROR_OLD_WIN_VERSION {
+		t.Errorf("VerifyVersionInfo failed: (%d) %s", e2, syscall.Errstr(int(e2)))
+	}
+}
+
 func TestCDecl(t *testing.T) {
 	h, e := syscall.LoadLibrary("user32.dll")
 	if e != 0 {

src/pkg/runtime/windows/386/sys.s

@@ -6,35 +6,35 @@
 
 // void runtime·asmstdcall(void *c);
 TEXT runtime·asmstdcall(SB),7,$0
-	MOVL	c+0(FP), DX
+	MOVL	c+0(FP), BX
 
 	// SetLastError(0).
 	MOVL	$0, 0x34(FS)
 
 	// Copy args to the stack.
 	MOVL	SP, BP
-	MOVL	wincall_n(DX), CX	// words
-	MOVL	CX, BX
-	SALL	$2, BX
-	SUBL	BX, SP			// room for args
+	MOVL	wincall_n(BX), CX	// words
+	MOVL	CX, AX
+	SALL	$2, AX
+	SUBL	AX, SP			// room for args
 	MOVL	SP, DI
-	MOVL	wincall_args(DX), SI
+	MOVL	wincall_args(BX), SI
 	CLD
 	REP; MOVSL
 
 	// Call stdcall or cdecl function.
 	// DI SI BP BX are preserved, SP is not
-	MOVL	wincall_fn(DX), AX
-	CALL	AX
+	CALL	wincall_fn(BX)
 	MOVL	BP, SP
 
 	// Return result.
-	MOVL	c+0(FP), DX
-	MOVL	AX, wincall_r(DX)
+	MOVL	c+0(FP), BX
+	MOVL	AX, wincall_r1(BX)
+	MOVL	DX, wincall_r2(BX)
 
 	// GetLastError().
-	MOVL	0x34(FS), BX
-	MOVL	BX, wincall_err(DX)
+	MOVL	0x34(FS), AX
+	MOVL	AX, wincall_err(BX)
 
 	RET
 

src/pkg/runtime/windows/amd64/sys.s

@@ -49,7 +49,7 @@ loadregs:
 
 	// Return result.
 	POPQ	CX
-	MOVQ	AX, wincall_r(CX)
+	MOVQ	AX, wincall_r1(CX)
 
 	// GetLastError().
 	MOVQ	0x30(GS), DI

src/pkg/runtime/windows/os.h

@@ -12,7 +12,6 @@ extern void *runtime·GetProcAddress;
 #pragma	varargck	type		runtime·stdcall	uintptr
 void runtime·asmstdcall(void *c);
 void *runtime·stdcall(void *fn, int32 count, ...);
-uintptr runtime·syscall(void *fn, uintptr nargs, void *args, uintptr *err);
 
 uintptr runtime·getlasterror(void);
 void runtime·setlasterror(uintptr err);

src/pkg/runtime/windows/syscall.goc

@@ -5,15 +5,28 @@
 package syscall
 #include "runtime.h"
 #include "os.h"
+#include "cgocall.h"
 
 func loadlibraryex(filename uintptr) (handle uintptr) {
 	uintptr args[3] = { filename };
-	handle = runtime·syscall(runtime·LoadLibraryEx, 3, args, nil);
+	WinCall c;
+
+	c.fn = runtime·LoadLibraryEx;
+	c.n = 3;
+	c.args = &args[0];
+	runtime·cgocall(runtime·asmstdcall, &c);
+	handle = c.r1;
 }
 
 func getprocaddress(handle uintptr, procname uintptr) (proc uintptr) {
+	WinCall c;
+
 	USED(procname);
-	proc = runtime·syscall(runtime·GetProcAddress, 2, &handle, nil);
+	c.fn = runtime·GetProcAddress;
+	c.n = 2;
+	c.args = &handle;
+	runtime·cgocall(runtime·asmstdcall, &c);
+	proc = c.r1;
 }
 
 func NewCallback(fn Eface) (code uintptr) {
@@ -25,23 +38,39 @@ func NewCallbackCDecl(fn Eface) (code uintptr) {
 }
 
 func Syscall(fn uintptr, nargs uintptr, a1 uintptr, a2 uintptr, a3 uintptr) (r1 uintptr, r2 uintptr, err uintptr) {
+	WinCall c;
+
 	USED(a2);
 	USED(a3);
-	r1 = runtime·syscall((void*)fn, nargs, &a1, &err);
-	r2 = 0;
+	c.fn = (void*)fn;
+	c.n = nargs;
+	c.args = &a1;
+	runtime·cgocall(runtime·asmstdcall, &c);
+	err = c.err;
+	r1 = c.r1;
+	r2 = c.r2;
 }
 
 func Syscall6(fn uintptr, nargs uintptr, a1 uintptr, a2 uintptr, a3 uintptr, a4 uintptr, a5 uintptr, a6 uintptr) (r1 uintptr, r2 uintptr, err uintptr) {
+	WinCall c;
+
 	USED(a2);
 	USED(a3);
 	USED(a4);
 	USED(a5);
 	USED(a6);
-	r1 = runtime·syscall((void*)fn, nargs, &a1, &err);
-	r2 = 0;
+	c.fn = (void*)fn;
+	c.n = nargs;
+	c.args = &a1;
+	runtime·cgocall(runtime·asmstdcall, &c);
+	err = c.err;
+	r1 = c.r1;
+	r2 = c.r2;
 }
 
 func Syscall9(fn uintptr, nargs uintptr, a1 uintptr, a2 uintptr, a3 uintptr, a4 uintptr, a5 uintptr, a6 uintptr, a7 uintptr, a8 uintptr, a9 uintptr) (r1 uintptr, r2 uintptr, err uintptr) {
+	WinCall c;
+
 	USED(a2);
 	USED(a3);
 	USED(a4);
@@ -50,11 +79,18 @@ func Syscall9(fn uintptr, nargs uintptr, a1 uintptr, a2 uintptr, a3 uintptr, a4
 	USED(a7);
 	USED(a8);
 	USED(a9);
-	r1 = runtime·syscall((void*)fn, nargs, &a1, &err);
-	r2 = 0;
+	c.fn = (void*)fn;
+	c.n = nargs;
+	c.args = &a1;
+	runtime·cgocall(runtime·asmstdcall, &c);
+	err = c.err;
+	r1 = c.r1;
+	r2 = c.r2;
 }
 
 func Syscall12(fn uintptr, nargs uintptr, a1 uintptr, a2 uintptr, a3 uintptr, a4 uintptr, a5 uintptr, a6 uintptr, a7 uintptr, a8 uintptr, a9 uintptr, a10 uintptr, a11 uintptr, a12 uintptr) (r1 uintptr, r2 uintptr, err uintptr) {
+	WinCall c;
+
 	USED(a2);
 	USED(a3);
 	USED(a4);
@@ -66,6 +102,11 @@ func Syscall12(fn uintptr, nargs uintptr, a1 uintptr, a2 uintptr, a3 uintptr, a4
 	USED(a10);
 	USED(a11);
 	USED(a12);
-	r1 = runtime·syscall((void*)fn, nargs, &a1, &err);
-	r2 = 0;
+	c.fn = (void*)fn;
+	c.n = nargs;
+	c.args = &a1;
+	runtime·cgocall(runtime·asmstdcall, &c);
+	err = c.err;
+	r1 = c.r1;
+	r2 = c.r2;
 }

src/pkg/runtime/windows/thread.c

@@ -6,7 +6,6 @@
 #include "type.h"
 #include "defs.h"
 #include "os.h"
-#include "cgocall.h"
 
 #pragma dynimport runtime·CloseHandle CloseHandle "kernel32.dll"
 #pragma dynimport runtime·CreateEvent CreateEventA "kernel32.dll"
@@ -228,21 +227,7 @@ runtime·stdcall(void *fn, int32 count, ...)
 	c.n = count;
 	c.args = (uintptr*)&count + 1;
 	runtime·asmcgocall(runtime·asmstdcall, &c);
-	return (void*)c.r;
-}
-
-uintptr
-runtime·syscall(void *fn, uintptr nargs, void *args, uintptr *err)
-{
-	WinCall c;
-
-	c.fn = fn;
-	c.n = nargs;
-	c.args = args;
-	runtime·cgocall(runtime·asmstdcall, &c);
-	if(err)
-		*err = c.err;
-	return c.r;
+	return (void*)c.r1;
 }
 
 uint32