video/pc_vga_tseng: implement extended start address register

src/devices/bus/isa/svga_tseng.cpp

@@ -163,7 +163,7 @@ isa16_svga_et4k_w32i_device::isa16_svga_et4k_w32i_device(const machine_config &m
 
 ROM_START( et4kw32i )
 	ROM_REGION(0x8000,"vga_rom", 0)
-	ROM_SYSTEM_BIOS(0, "v800n", "Tseng Version 8.00N 04/28/95")
+	ROM_SYSTEM_BIOS(0, "v800n", "Tseng Version 8.00N 04/28/95 ISA 06/17/95")
 	ROMX_LOAD("et4kw32i.vbi", 0x00000, 0x8000, CRC(14542962) SHA1(d5aee7205af8bd1fef0ecf1db2c07308a2b10b17), ROM_BIOS(0) )
 ROM_END
 
@@ -189,7 +189,7 @@ void isa16_svga_et4k_w32i_device::device_start()
 	set_isa_device();
 
 	remap(AS_PROGRAM, 0, 0xfffff);
-	remap(AS_IO, 0, 0x3ff);
+	remap(AS_IO, 0, 0xffff);
 }
 
 void isa16_svga_et4k_w32i_device::device_reset()

src/devices/video/pc_vga_tseng.cpp

@@ -22,8 +22,8 @@
 
 DEFINE_DEVICE_TYPE(TSENG_VGA,  tseng_vga_device,  "tseng_vga",  "Tseng Labs ET4000AX VGA i/f")
 
-tseng_vga_device::tseng_vga_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
+tseng_vga_device::tseng_vga_device(const machine_config &mconfig, const char *tag, device_type type, device_t *owner, uint32_t clock)
-	: svga_device(mconfig, TSENG_VGA, tag, owner, clock)
+	: svga_device(mconfig, type, tag, owner, clock)
 {
 	m_main_if_space_config = address_space_config("io_regs", ENDIANNESS_LITTLE, 8, 4, 0, address_map_constructor(FUNC(tseng_vga_device::io_3bx_3dx_map), this));
 	m_crtc_space_config = address_space_config("crtc_regs", ENDIANNESS_LITTLE, 8, 8, 0, address_map_constructor(FUNC(tseng_vga_device::crtc_map), this));
@@ -31,6 +31,11 @@ tseng_vga_device::tseng_vga_device(const machine_config &mconfig, const char *ta
 	m_atc_space_config = address_space_config("attribute_regs", ENDIANNESS_LITTLE, 8, 8, 0, address_map_constructor(FUNC(tseng_vga_device::attribute_map), this));
 }
 
+tseng_vga_device::tseng_vga_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
+	: tseng_vga_device(mconfig, tag, TSENG_VGA, owner, clock)
+{
+}
+
 void tseng_vga_device::device_start()
 {
 	svga_device::device_start();
@@ -120,7 +125,23 @@ void tseng_vga_device::crtc_map(address_map &map)
 //  map(0x30, 0x30) System Segment Map Comparator
 //  map(0x31, 0x31) General Purpose (& Clock Select 3/4)
 //  map(0x32, 0x32) RAS/CAS Configuration (RCCONF)
-//  map(0x33, 0x33) Extended Start Address
+	/*
+	 * ---- xx-- Cursor address bits 16-17
+	 * ---- --xx Start address bits 16-17
+	 */
+//  Extended Start Address
+	map(0x33, 0x33).lrw8(
+		NAME([this] (offs_t offset) {
+			return et4k.crtc_ext_start;
+		}),
+		NAME([this] (offs_t offset, u8 data) {
+			et4k.crtc_ext_start = data;
+			vga.crtc.start_addr_latch &= ~0x30000;
+			vga.crtc.start_addr_latch |= ((data & 0x3) << 16);
+			vga.crtc.cursor_addr &= ~0x30000;
+			vga.crtc.cursor_addr |= ((data & 0xc) << 14);
+		})
+	);
 	// Auxiliary Control
 	map(0x34, 0x34).lrw8(
 		NAME([this] (offs_t offset) {
@@ -274,3 +295,13 @@ void tseng_vga_device::mem_w(offs_t offset, uint8_t data)
 		vga_device::mem_w(offset,data);
 }
 
+uint32_t tseng_vga_device::latch_start_addr()
+{
+	// TODO: condition for this (SDD scroll/buffer tests)
+	if(svga.rgb8_en)
+	{
+		return vga.crtc.start_addr_latch << 2;
+	}
+	return vga.crtc.start_addr_latch;
+}
+

src/devices/video/pc_vga_tseng.h

@@ -23,6 +23,8 @@ public:
 	virtual void mem_w(offs_t offset, uint8_t data) override;
 
 protected:
+	tseng_vga_device(const machine_config &mconfig, const char *tag, device_type type, device_t *owner, uint32_t clock);
+
 	virtual void device_start() override ATTR_COLD;
 
 	virtual void io_3bx_3dx_map(address_map &map) override ATTR_COLD;
@@ -37,6 +39,8 @@ protected:
 	virtual void attribute_map(address_map &map) override ATTR_COLD;
 
 	virtual void recompute_params() override;
+
+	virtual uint32_t latch_start_addr() override;
 private:
 	struct
 	{
@@ -48,11 +52,13 @@ private:
 		bool ext_reg_ena;
 		uint8_t misc1;
 		uint8_t misc2;
+		uint8_t crtc_ext_start;
 	}et4k;
 };
 
 
 // device type definition
 DECLARE_DEVICE_TYPE(TSENG_VGA, tseng_vga_device)
+//DECLARE_DEVICE_TYPE(ET4KW32I_VGA, et4kw32i_vga_device)
 
 #endif // MAME_VIDEO_PC_VGA_TSENG_H