nec/pc9821.cpp: fix pc9821ce IDE loading

Author: angelosa

src/mame/nec/pc9821.cpp

@@ -29,8 +29,10 @@ TODO (pc9821as):
 - Update: it never goes into above after default of m_dma_access_ctrl changed to 0xfe?
 
 TODO (pc9821ce):
-- Needs SCSI to boot stuff, or 2.5" option IDE for 98NOTE;
-- Can't boot any floppy, thinks it's never ready/leaves motor off;
+- Throws random TIMER errors at POST (soft reset to bypass);
+- Takes forever to load a floppy, throws (A)bort / (R)etry / (F)ail on DOS;
+- 3.5" floppies won't load without changing SDIP floppy to Fixed Mode,
+  while 5.25" floppies want specifically Auto-Detect instead;
 
 TODO (pc9821cx3):
 - Incomplete bank mapping, keeps looping over the same routine when hopping to PnP BIOS after
@@ -1311,6 +1313,7 @@ ROM_START( pc9821ce )
 	// 0x0c000 sound BIOS
 	// 0x10000 sound BIOS copy
 	// 0x16000 <to be identified>
+	// 0x18000 IDE BIOS
 	// 0x1a000 setup menu
 	ROM_COPY( "biosrom", 0x38000, 0x28000, 0x08000 )
 	ROM_COPY( "biosrom", 0x30000, 0x20000, 0x08000 )
@@ -1324,8 +1327,9 @@ ROM_START( pc9821ce )
 	ROM_COPY( "biosrom", 0x0c000, 0x00000, 0x04000 )
 
 	LOAD_KANJI_ROMS(ROMREGION_ERASEFF)
-	// Uses SCSI not IDE
-//  LOAD_IDE_ROM
+
+	ROM_REGION( 0x4000, "ide", ROMREGION_ERASEVAL(0xcb) )
+	ROM_COPY( "biosrom", 0x18000, 0x00000, 0x02000 )
 ROM_END
 
 

src/mame/nec/pc98_sdip.h

@@ -20,10 +20,14 @@ class pc98_sdip_device : public device_t,
 	void bank_w(int state);
 
 	// legacy i/f
-	// TODO: not necessarily linear
+	// TODO: not necessarily linear, bit 7 is parity bit
 	ioport_value dsw1_r() { return m_sdip_ram[0]; }
 	ioport_value dsw2_r() { return m_sdip_ram[1]; }
-	ioport_value dsw3_r() { return m_sdip_ram[2]; }
+	ioport_value dsw3_r() {
+		const u8 fdc_setting = (m_sdip_ram[2] & 3) ^ 2;
+		//popmessage("%s %s", BIT(fdc_setting, 1) ? "2HD" : "2DD", BIT(fdc_setting, 0) ? "fixed" : "auto-detect");
+		return (fdc_setting) | (m_sdip_ram[2] & 0x7c) | (0 << 7);
+	}
 
 protected:
 	virtual void device_start() override ATTR_COLD;