bios_emulator: Allow a custom interrupt handler to be installed

Sometime we want to provide an interrupt handler for the ROM, Add a
function to allow this.

Signed-off-by: Simon Glass <sjg@chromium.org>

drivers/bios_emulator/include/x86emu.h

@@ -153,6 +153,7 @@ extern "C" {			/* Use "C" linkage when in C++ mode */
 	void X86EMU_setupMemFuncs(X86EMU_memFuncs * funcs);
 	void X86EMU_setupPioFuncs(X86EMU_pioFuncs * funcs);
 	void X86EMU_setupIntrFuncs(X86EMU_intrFuncs funcs[]);
+	void X86EMU_setupIntrFunc(int intnum, X86EMU_intrFuncs func);
 	void X86EMU_prepareForInt(int num);
 
 /* decode.c */

drivers/bios_emulator/x86emu/sys.c

@@ -273,6 +273,11 @@ void X86EMU_setupPioFuncs(X86EMU_pioFuncs * funcs)
 	sys_outl = funcs->outl;
 }
 
+void X86EMU_setupIntrFunc(int intnum, X86EMU_intrFuncs func)
+{
+	_X86EMU_intrTab[intnum] = func;
+}
+
 /****************************************************************************
 PARAMETERS:
 funcs   - New interrupt vector table to make active