diff --git a/scripts/target/mame/mess.lua b/scripts/target/mame/mess.lua index 5e68ffc8105..5d4f3e4907d 100644 --- a/scripts/target/mame/mess.lua +++ b/scripts/target/mame/mess.lua @@ -2221,6 +2221,7 @@ files { createMESSProjects(_target, _subtarget, "mos") files { MAME_DIR .. "src/mame/drivers/kim1.cpp", + MAME_DIR .. "src/mame/includes/kim1.h", } createMESSProjects(_target, _subtarget, "motorola") diff --git a/src/mame/drivers/kim1.cpp b/src/mame/drivers/kim1.cpp index 246692fa3de..93caac7ad3e 100644 --- a/src/mame/drivers/kim1.cpp +++ b/src/mame/drivers/kim1.cpp @@ -1,149 +1,46 @@ // license:GPL-2.0+ // copyright-holders:Juergen Buchmueller /****************************************************************************** - KIM-1 - system driver + kim1.cpp - KIM-1 - Juergen Buchmueller, Oct 1999 + LED: six 7-segment LEDs + left 4 digits (address) + right 2 digits (data) + Keyboard: 23 keys and SST switch + 0-F 16 keys to enter data + AD address entry mode + DA data entry mode + + increment address + PC recalls address stored in the Program Counter + RS system reset + GO execute program + ST program stop + SST single step slide switch - KIM-1 memory map - - range short description - 0000-03FF RAM - 1400-16FF ??? - 1700-173F 6530-003 see 6530 - 1740-177F 6530-002 see 6530 - 1780-17BF RAM internal 6530-003 - 17C0-17FF RAM internal 6530-002 - 1800-1BFF ROM internal 6530-003 - 1C00-1FFF ROM internal 6530-002 - - 6530 - offset R/W short purpose - 0 X DRA Data register A - 1 X DDRA Data direction register A - 2 X DRB Data register B - 3 X DDRB Data direction register B - 4 W CNT1T Count down from value, divide by 1, disable IRQ - 5 W CNT8T Count down from value, divide by 8, disable IRQ - 6 W CNT64T Count down from value, divide by 64, disable IRQ - R LATCH Read current counter value, disable IRQ - 7 W CNT1KT Count down from value, divide by 1024, disable IRQ - R STATUS Read counter statzs, bit 7 = 1 means counter overflow - 8 X DRA Data register A - 9 X DDRA Data direction register A - A X DRB Data register B - B X DDRB Data direction register B - C W CNT1I Count down from value, divide by 1, enable IRQ - D W CNT8I Count down from value, divide by 8, enable IRQ - E W CNT64I Count down from value, divide by 64, enable IRQ - R LATCH Read current counter value, enable IRQ - F W CNT1KI Count down from value, divide by 1024, enable IRQ - R STATUS Read counter statzs, bit 7 = 1 means counter overflow - - 6530-002 (U2) - DRA bit write read - --------------------------------------------- - 0-6 segments A-G key columns 1-7 - 7 PTR KBD - - DRB bit write read - --------------------------------------------- - 0 PTR -/- - 1-4 dec 1-3 key row 1-3 - 4 RW3 - 5-9 7-seg 1-6 - 6530-003 (U3) - DRA bit write read - --------------------------------------------- - 0-7 bus PA0-7 bus PA0-7 - - DRB bit write read - --------------------------------------------- - 0-7 bus PB0-7 bus PB0-7 - - -The cassette interface -====================== - -The KIM-1 stores data on cassette using 2 frequencies: ~3700Hz (high) and ~2400Hz -(low). A high tone is output for 9 cycles and a low tone for 6 cycles. A logic bit -is encoded using 3 sequences of high and low tones. It always starts with a high -tone and ends with a low tone. The middle tone is high for a logic 0 and low for -0 logic 1. - -These high and low tone signals are fed to a circuit containing a LM565 PLL and -a 311 comparator. For a high tone a 1 is passed to DB7 of 6530-U2 for a low tone -a 0 is passed. The KIM-1 software measures the time it takes for the signal to -change from 1 to 0. - - - -Pasting: - 0-F : as is - + (inc) : ^ - AD : - - DA : = - GO : X - -(note: DA only works when addressing RAM) - -Test Paste: - =11^22^33^44^55^66^77^88^99^-0000 - Now press up-arrow to confirm the data has been entered. + How to use cassette: + 00F1 00 to clear decimal mode + 17F5-17F6 start address low and high + 17F7-17F8 end address low and high + 17F9 2 digit program ID + 1800 press GO to save tape + 1873 press GO to load tape + NOTE: save end address is next address from program end +TODO: +- LEDs should be dark at startup (RS key to activate) +- add software list +- hook up Single Step dip switch +- slots for expansion & application ports +- add TTY support ******************************************************************************/ -#include "emu.h" -#include "cpu/m6502/m6502.h" -#include "sound/dac.h" -#include "machine/mos6530.h" -#include "imagedev/cassette.h" -#include "formats/kim1_cas.h" +#include "includes/kim1.h" #include "kim1.lh" - -class kim1_state : public driver_device -{ -public: - kim1_state(const machine_config &mconfig, device_type type, const char *tag) - : driver_device(mconfig, type, tag), - m_maincpu(*this, "maincpu"), - m_riot2(*this, "miot_u2"), - m_cass(*this, "cassette"), - m_line0(*this, "LINE0"), - m_line1(*this, "LINE1"), - m_line2(*this, "LINE2"), - m_line3(*this, "LINE3") { } - - required_device m_maincpu; - required_device m_riot2; - required_device m_cass; - DECLARE_READ8_MEMBER(kim1_u2_read_a); - DECLARE_WRITE8_MEMBER(kim1_u2_write_a); - DECLARE_READ8_MEMBER(kim1_u2_read_b); - DECLARE_WRITE8_MEMBER(kim1_u2_write_b); - UINT8 m_u2_port_b; - UINT8 m_311_output; - UINT32 m_cassette_high_count; - UINT8 m_led_time[6]; - virtual void machine_start() override; - virtual void machine_reset() override; - DECLARE_INPUT_CHANGED_MEMBER(kim1_reset); - TIMER_DEVICE_CALLBACK_MEMBER(kim1_cassette_input); - TIMER_DEVICE_CALLBACK_MEMBER(kim1_update_leds); - -protected: - required_ioport m_line0; - required_ioport m_line1; - required_ioport m_line2; - required_ioport m_line3; -}; - - - - +//************************************************************************** +// ADDRESS MAPS +//************************************************************************** static ADDRESS_MAP_START(kim1_map, AS_PROGRAM, 8, kim1_state) AM_RANGE(0x0000, 0x03ff) AM_MIRROR(0xe000) AM_RAM @@ -155,50 +52,57 @@ static ADDRESS_MAP_START(kim1_map, AS_PROGRAM, 8, kim1_state) AM_RANGE(0x1c00, 0x1fff) AM_MIRROR(0xe000) AM_ROM ADDRESS_MAP_END - -INPUT_CHANGED_MEMBER(kim1_state::kim1_reset) +// RS and ST key input +INPUT_CHANGED_MEMBER(kim1_state::trigger_reset) { - if (newval == 0) - m_maincpu->reset(); + m_maincpu->set_input_line(INPUT_LINE_RESET, newval ? CLEAR_LINE : ASSERT_LINE); } +INPUT_CHANGED_MEMBER(kim1_state::trigger_nmi) +{ + m_maincpu->set_input_line(INPUT_LINE_NMI, newval ? CLEAR_LINE : ASSERT_LINE); +} + +//************************************************************************** +// INPUT PORTS +//************************************************************************** static INPUT_PORTS_START( kim1 ) - PORT_START("LINE0") /* IN0 keys row 0 */ + PORT_START("ROW0") PORT_BIT( 0x80, 0x00, IPT_UNUSED ) - PORT_BIT( 0x40, 0x40, IPT_KEYBOARD ) PORT_NAME("0") PORT_CODE(KEYCODE_0) PORT_CHAR('0') - PORT_BIT( 0x20, 0x20, IPT_KEYBOARD ) PORT_NAME("1") PORT_CODE(KEYCODE_1) PORT_CHAR('1') - PORT_BIT( 0x10, 0x10, IPT_KEYBOARD ) PORT_NAME("2") PORT_CODE(KEYCODE_2) PORT_CHAR('2') - PORT_BIT( 0x08, 0x08, IPT_KEYBOARD ) PORT_NAME("3") PORT_CODE(KEYCODE_3) PORT_CHAR('3') - PORT_BIT( 0x04, 0x04, IPT_KEYBOARD ) PORT_NAME("4") PORT_CODE(KEYCODE_4) PORT_CHAR('4') - PORT_BIT( 0x02, 0x02, IPT_KEYBOARD ) PORT_NAME("5") PORT_CODE(KEYCODE_5) PORT_CHAR('5') - PORT_BIT( 0x01, 0x01, IPT_KEYBOARD ) PORT_NAME("6") PORT_CODE(KEYCODE_6) PORT_CHAR('6') + PORT_BIT( 0x40, 0x40, IPT_KEYBOARD ) PORT_NAME("0") PORT_CODE(KEYCODE_0) PORT_CHAR('0') PORT_CODE(KEYCODE_0_PAD) + PORT_BIT( 0x20, 0x20, IPT_KEYBOARD ) PORT_NAME("1") PORT_CODE(KEYCODE_1) PORT_CHAR('1') PORT_CODE(KEYCODE_1_PAD) + PORT_BIT( 0x10, 0x10, IPT_KEYBOARD ) PORT_NAME("2") PORT_CODE(KEYCODE_2) PORT_CHAR('2') PORT_CODE(KEYCODE_2_PAD) + PORT_BIT( 0x08, 0x08, IPT_KEYBOARD ) PORT_NAME("3") PORT_CODE(KEYCODE_3) PORT_CHAR('3') PORT_CODE(KEYCODE_3_PAD) + PORT_BIT( 0x04, 0x04, IPT_KEYBOARD ) PORT_NAME("4") PORT_CODE(KEYCODE_4) PORT_CHAR('4') PORT_CODE(KEYCODE_4_PAD) + PORT_BIT( 0x02, 0x02, IPT_KEYBOARD ) PORT_NAME("5") PORT_CODE(KEYCODE_5) PORT_CHAR('5') PORT_CODE(KEYCODE_5_PAD) + PORT_BIT( 0x01, 0x01, IPT_KEYBOARD ) PORT_NAME("6") PORT_CODE(KEYCODE_6) PORT_CHAR('6') PORT_CODE(KEYCODE_6_PAD) - PORT_START("LINE1") /* IN1 keys row 1 */ + PORT_START("ROW1") PORT_BIT( 0x80, 0x00, IPT_UNUSED ) - PORT_BIT( 0x40, 0x40, IPT_KEYBOARD ) PORT_NAME("7") PORT_CODE(KEYCODE_7) PORT_CHAR('7') - PORT_BIT( 0x20, 0x20, IPT_KEYBOARD ) PORT_NAME("8") PORT_CODE(KEYCODE_8) PORT_CHAR('8') - PORT_BIT( 0x10, 0x10, IPT_KEYBOARD ) PORT_NAME("9") PORT_CODE(KEYCODE_9) PORT_CHAR('9') - PORT_BIT( 0x08, 0x08, IPT_KEYBOARD ) PORT_NAME("A") PORT_CODE(KEYCODE_A) PORT_CHAR('A') - PORT_BIT( 0x04, 0x04, IPT_KEYBOARD ) PORT_NAME("B") PORT_CODE(KEYCODE_B) PORT_CHAR('B') - PORT_BIT( 0x02, 0x02, IPT_KEYBOARD ) PORT_NAME("C") PORT_CODE(KEYCODE_C) PORT_CHAR('C') - PORT_BIT( 0x01, 0x01, IPT_KEYBOARD ) PORT_NAME("D") PORT_CODE(KEYCODE_D) PORT_CHAR('D') + PORT_BIT( 0x40, 0x40, IPT_KEYBOARD ) PORT_NAME("7") PORT_CODE(KEYCODE_7) PORT_CHAR('7') PORT_CODE(KEYCODE_7_PAD) + PORT_BIT( 0x20, 0x20, IPT_KEYBOARD ) PORT_NAME("8") PORT_CODE(KEYCODE_8) PORT_CHAR('8') PORT_CODE(KEYCODE_8_PAD) + PORT_BIT( 0x10, 0x10, IPT_KEYBOARD ) PORT_NAME("9") PORT_CODE(KEYCODE_9) PORT_CHAR('9') PORT_CODE(KEYCODE_9_PAD) + PORT_BIT( 0x08, 0x08, IPT_KEYBOARD ) PORT_NAME("A") PORT_CODE(KEYCODE_A) PORT_CHAR('A') + PORT_BIT( 0x04, 0x04, IPT_KEYBOARD ) PORT_NAME("B") PORT_CODE(KEYCODE_B) PORT_CHAR('B') + PORT_BIT( 0x02, 0x02, IPT_KEYBOARD ) PORT_NAME("C") PORT_CODE(KEYCODE_C) PORT_CHAR('C') + PORT_BIT( 0x01, 0x01, IPT_KEYBOARD ) PORT_NAME("D") PORT_CODE(KEYCODE_D) PORT_CHAR('D') - PORT_START("LINE2") /* IN2 keys row 2 */ + PORT_START("ROW2") PORT_BIT( 0x80, 0x00, IPT_UNUSED ) - PORT_BIT( 0x40, 0x40, IPT_KEYBOARD ) PORT_NAME("E") PORT_CODE(KEYCODE_E) PORT_CHAR('E') - PORT_BIT( 0x20, 0x20, IPT_KEYBOARD ) PORT_NAME("F") PORT_CODE(KEYCODE_F) PORT_CHAR('F') - PORT_BIT( 0x10, 0x10, IPT_KEYBOARD ) PORT_NAME("AD") PORT_CODE(KEYCODE_MINUS) PORT_CHAR('-') + PORT_BIT( 0x40, 0x40, IPT_KEYBOARD ) PORT_NAME("E") PORT_CODE(KEYCODE_E) PORT_CHAR('E') + PORT_BIT( 0x20, 0x20, IPT_KEYBOARD ) PORT_NAME("F") PORT_CODE(KEYCODE_F) PORT_CHAR('F') + PORT_BIT( 0x10, 0x10, IPT_KEYBOARD ) PORT_NAME("AD") PORT_CODE(KEYCODE_MINUS) PORT_CHAR('-') PORT_CODE(KEYCODE_MINUS_PAD) PORT_BIT( 0x08, 0x08, IPT_KEYBOARD ) PORT_NAME("DA") PORT_CODE(KEYCODE_EQUALS) PORT_CHAR('=') - PORT_BIT( 0x04, 0x04, IPT_KEYBOARD ) PORT_NAME("+") PORT_CODE(KEYCODE_UP) PORT_CHAR('^') - PORT_BIT( 0x02, 0x02, IPT_KEYBOARD ) PORT_NAME("GO") PORT_CODE(KEYCODE_X) PORT_CHAR('X') + PORT_BIT( 0x04, 0x04, IPT_KEYBOARD ) PORT_NAME("+") PORT_CODE(KEYCODE_UP) PORT_CHAR(' ') PORT_CODE(KEYCODE_PLUS_PAD) + PORT_BIT( 0x02, 0x02, IPT_KEYBOARD ) PORT_NAME("GO") PORT_CODE(KEYCODE_ENTER) PORT_CHAR(13) PORT_CODE(KEYCODE_ENTER_PAD) PORT_BIT( 0x01, 0x01, IPT_KEYBOARD ) PORT_NAME("PC") PORT_CODE(KEYCODE_F6) - PORT_START("LINE3") /* IN3 STEP and RESET keys, MODE switch */ + PORT_START("SPECIAL") PORT_BIT( 0x80, 0x00, IPT_UNUSED ) - PORT_BIT( 0x40, 0x40, IPT_KEYBOARD ) PORT_NAME("sw1: ST") PORT_CODE(KEYCODE_F7) - PORT_BIT( 0x20, 0x20, IPT_KEYBOARD ) PORT_NAME("sw2: RS") PORT_CODE(KEYCODE_F3) PORT_CHANGED_MEMBER(DEVICE_SELF, kim1_state, kim1_reset, nullptr) - PORT_DIPNAME(0x10, 0x10, "sw3: SS") PORT_CODE(KEYCODE_NUMLOCK) PORT_TOGGLE + PORT_BIT( 0x40, 0x40, IPT_KEYBOARD ) PORT_NAME("sw1: ST") PORT_CODE(KEYCODE_F7) PORT_CHANGED_MEMBER(DEVICE_SELF, kim1_state, trigger_nmi, nullptr) + PORT_BIT( 0x20, 0x20, IPT_KEYBOARD ) PORT_NAME("sw2: RS") PORT_CODE(KEYCODE_F3) PORT_CHANGED_MEMBER(DEVICE_SELF, kim1_state, trigger_reset, nullptr) + PORT_DIPNAME(0x10, 0x10, "sw3: SS") PORT_CODE(KEYCODE_NUMLOCK) PORT_TOGGLE PORT_DIPSETTING( 0x00, "single step") PORT_DIPSETTING( 0x10, "run") PORT_BIT( 0x08, 0x00, IPT_UNUSED ) @@ -207,7 +111,7 @@ static INPUT_PORTS_START( kim1 ) PORT_BIT( 0x01, 0x00, IPT_UNUSED ) INPUT_PORTS_END - +// Read from keyboard READ8_MEMBER( kim1_state::kim1_u2_read_a ) { UINT8 data = 0xff; @@ -215,19 +119,19 @@ READ8_MEMBER( kim1_state::kim1_u2_read_a ) switch( ( m_u2_port_b >> 1 ) & 0x0f ) { case 0: - data = m_line0->read(); + data = m_row0->read(); break; case 1: - data = m_line1->read(); + data = m_row1->read(); break; case 2: - data = m_line2->read(); + data = m_row2->read(); break; } return data; } - +// Write to 7-Segment LEDs WRITE8_MEMBER( kim1_state::kim1_u2_write_a ) { UINT8 idx = ( m_u2_port_b >> 1 ) & 0x0f; @@ -242,6 +146,7 @@ WRITE8_MEMBER( kim1_state::kim1_u2_write_a ) } } +// Load from cassette READ8_MEMBER( kim1_state::kim1_u2_read_b ) { if ( m_riot2->portb_out_get() & 0x20 ) @@ -250,7 +155,7 @@ READ8_MEMBER( kim1_state::kim1_u2_read_b ) return 0x7F | ( m_311_output ^ 0x80 ); } - +// Save to cassette WRITE8_MEMBER( kim1_state::kim1_u2_write_b ) { m_u2_port_b = data; @@ -262,7 +167,6 @@ WRITE8_MEMBER( kim1_state::kim1_u2_write_b ) /* Set IRQ when bit 7 is cleared */ } - TIMER_DEVICE_CALLBACK_MEMBER(kim1_state::kim1_cassette_input) { double tap_val = m_cass->input(); @@ -280,7 +184,7 @@ TIMER_DEVICE_CALLBACK_MEMBER(kim1_state::kim1_cassette_input) m_cassette_high_count++; } - +// Blank LEDs during cassette operations TIMER_DEVICE_CALLBACK_MEMBER(kim1_state::kim1_update_leds) { UINT8 i; @@ -294,7 +198,7 @@ TIMER_DEVICE_CALLBACK_MEMBER(kim1_state::kim1_update_leds) } } - +// Register for save states void kim1_state::machine_start() { save_item(NAME(m_u2_port_b)); @@ -302,7 +206,6 @@ void kim1_state::machine_start() save_item(NAME(m_cassette_high_count)); } - void kim1_state::machine_reset() { UINT8 i; @@ -314,23 +217,25 @@ void kim1_state::machine_reset() m_cassette_high_count = 0; } +//************************************************************************** +// MACHINE DRIVERS +//************************************************************************** static MACHINE_CONFIG_START( kim1, kim1_state ) - /* basic machine hardware */ + // basic machine hardware MCFG_CPU_ADD("maincpu", M6502, 1000000) /* 1 MHz */ MCFG_CPU_PROGRAM_MAP(kim1_map) MCFG_QUANTUM_TIME(attotime::from_hz(60)) - - /* video */ + // video hardware MCFG_DEFAULT_LAYOUT( layout_kim1 ) - /* sound hardware */ + // sound hardware MCFG_SPEAKER_STANDARD_MONO("mono") MCFG_SOUND_ADD("dac", DAC, 0) MCFG_SOUND_ROUTE(ALL_OUTPUTS, "mono", 1.00) - /* devices */ + // devices MCFG_DEVICE_ADD("miot_u2", MOS6530, 1000000) MCFG_MOS6530_IN_PA_CB(READ8(kim1_state, kim1_u2_read_a)) MCFG_MOS6530_OUT_PA_CB(WRITE8(kim1_state, kim1_u2_write_a)) @@ -345,8 +250,12 @@ static MACHINE_CONFIG_START( kim1, kim1_state ) MCFG_TIMER_DRIVER_ADD_PERIODIC("led_timer", kim1_state, kim1_update_leds, attotime::from_hz(60)) MCFG_TIMER_DRIVER_ADD_PERIODIC("cassette_timer", kim1_state, kim1_cassette_input, attotime::from_hz(44100)) + MACHINE_CONFIG_END +//************************************************************************** +// ROM DEFINITIONS +//************************************************************************** ROM_START(kim1) ROM_REGION(0x10000,"maincpu",0) @@ -354,6 +263,9 @@ ROM_START(kim1) ROM_LOAD("6530-002.bin", 0x1c00, 0x0400, CRC(2b08e923) SHA1(054f7f6989af3a59462ffb0372b6f56f307b5362)) ROM_END +//************************************************************************** +// SYSTEM DRIVERS +//************************************************************************** -/* YEAR NAME PARENT COMPAT MACHINE INPUT INIT COMPANY FULLNAME FLAGS */ -COMP( 1975, kim1, 0, 0, kim1, kim1, driver_device, 0, "MOS Technologies", "KIM-1" , MACHINE_SUPPORTS_SAVE) +// YEAR NAME PARENT COMPAT MACHINE INPUT INIT COMPANY FULLNAME FLAGS +COMP( 1975, kim1, 0, 0, kim1, kim1, driver_device, 0, "MOS Technologies", "KIM-1" , MACHINE_NO_SOUND_HW | MACHINE_SUPPORTS_SAVE) diff --git a/src/mame/includes/kim1.h b/src/mame/includes/kim1.h new file mode 100644 index 00000000000..255957b0eec --- /dev/null +++ b/src/mame/includes/kim1.h @@ -0,0 +1,67 @@ +// license:GPL-2.0+ +// copyright-holders:Juergen Buchmueller +/************************************************************************* + + includes/kim1.h + +*************************************************************************/ + +#pragma once + +#ifndef __KIM1__ +#define __KIM1__ + +#include "emu.h" +#include "cpu/m6502/m6502.h" +#include "machine/mos6530.h" +#include "imagedev/cassette.h" +#include "formats/kim1_cas.h" +#include "sound/dac.h" + +//************************************************************************** +// TYPE DEFINITIONS +//************************************************************************** + +class kim1_state : public driver_device +{ +public: + kim1_state(const machine_config &mconfig, device_type type, const char *tag) + : driver_device(mconfig, type, tag), + m_maincpu(*this, "maincpu"), + m_riot2(*this, "miot_u2"), + m_cass(*this, "cassette"), + m_row0(*this, "ROW0"), + m_row1(*this, "ROW1"), + m_row2(*this, "ROW2"), + m_special(*this, "SPECIAL") { } + + // devices + required_device m_maincpu; + required_device m_riot2; + required_device m_cass; + DECLARE_READ8_MEMBER(kim1_u2_read_a); + DECLARE_WRITE8_MEMBER(kim1_u2_write_a); + DECLARE_READ8_MEMBER(kim1_u2_read_b); + DECLARE_WRITE8_MEMBER(kim1_u2_write_b); + UINT8 m_u2_port_b; + UINT8 m_311_output; + UINT32 m_cassette_high_count; + UINT8 m_led_time[6]; + + // device overrides + virtual void machine_start() override; + virtual void machine_reset() override; + + DECLARE_INPUT_CHANGED_MEMBER(trigger_reset); + DECLARE_INPUT_CHANGED_MEMBER(trigger_nmi); + TIMER_DEVICE_CALLBACK_MEMBER(kim1_cassette_input); + TIMER_DEVICE_CALLBACK_MEMBER(kim1_update_leds); + +protected: + required_ioport m_row0; + required_ioport m_row1; + required_ioport m_row2; + required_ioport m_special; +}; + +#endif /* KIM1_H */ diff --git a/src/mame/layout/kim1.lay b/src/mame/layout/kim1.lay index 65cbe26b5ff..74e58865bbb 100644 --- a/src/mame/layout/kim1.lay +++ b/src/mame/layout/kim1.lay @@ -1,44 +1,44 @@ - + + + + + + - - - - - - - - - - - - - - - - - - - - - + + - + + + + + + + + + + + + + + + - + - +