Replace XMSrequest external asm with inline asm for GCC.

The external asm did not preserve the si register which
was problematic.


git-svn-id: https://svn.code.sf.net/p/freedos/svn/freecom/trunk@1834 6ac86273-5f31-0410-b378-82cca8765d1b

include/cswap.h

@@ -44,7 +44,14 @@ extern unsigned long (far *far XMSdriverAdress)(unsigned request,
 #pragma aux XMSdriverAdress = parm [ax] [dx] [si]
 #elif defined(__GNUC__)
 extern unsigned far *far XMSdriverAdress;
-extern unsigned long XMSrequest(unsigned request, unsigned dx, void *si);
+static inline unsigned long XMSrequest(unsigned request, unsigned dx, void *si)
+{
+	long ret;
+	asm volatile("lcall *%%cs:XMSdriverAdress" :
+		     "=A"(ret) :
+		     "a"(request), "d"(dx), "S"(si));
+	return ret;
+}
 #else
 extern unsigned (far *far XMSdriverAdress)(void);
 extern void far XMSrequest(void);

shell/cswap.asm

@@ -354,14 +354,6 @@ exec_error2:
 	;; Note: Because [CS:driverAdress] == [residentCS:driverAdress]
 	;; we need not use a similiar approach as with XMSexec
 XMSrequest:
-%ifidn __OUTPUT_FORMAT__,elf 	; GCC, calling near with stdcall conv.
-		pop cx		; return address
-		pop ax		; AX
-		pop dx		; DX
-		pop si		; SI
-		push cs
-		push cx		; far return from XMS driver
-%endif
 		jmp far [cs:XMSdriverAdress]
 
 ;; Added here to make it more easier for the C-part to call functions