Add read-only cassette emulation to IBM 5150 PC. Patch from JohnElliott.

src/808x.c

@@ -3484,14 +3484,6 @@ void execx86(int cycs)
                // if (instime) printf("%i %i %i %i\n",cycdiff,cycles,memcycs,fetchclocks);
                 FETCHADD(((cycdiff-cycles)-memcycs)-fetchclocks);
                 if ((cycdiff-cycles)<memcycs) cycles-=(memcycs-(cycdiff-cycles));
-                if (romset==ROM_IBMPC)
-                {
-                        if ((cs+cpu_state.pc)==0xFE4A7) /*You didn't seriously think I was going to emulate the cassette, did you?*/
-                        {
-                                CX=1;
-                                BX=0x500;
-                        }
-                }
                 memcycs=0;
 
                 insc++;

src/Makefile.am

@@ -23,13 +23,13 @@ wx-resources.cpp : pc.xrc
 	-wxrc -c pc.xrc -o wx-resources.cpp
 
 # PCem
-pcem_SOURCES = 386.c 386_dynarec.c 386_dynarec_ops.c 808x.c acc2036.c acc2168.c acc3221.c acer386sx.c ali1429.c  amstrad.c cbm_io.c cdrom-image.cc cdrom-null.c \
+pcem_SOURCES = 386.c 386_dynarec.c 386_dynarec_ops.c 808x.c acc2036.c acc2168.c acc3221.c acer386sx.c ali1429.c  amstrad.c cassette.c cbm_io.c cdrom-image.cc cdrom-null.c \
 cmd640.c codegen.c codegen_ops.c codegen_timing_486.c codegen_timing_686.c codegen_timing_common.c codegen_timing_pentium.c codegen_timing_winchip.c compaq.c config.c cpu.c \
 dells200.c device.c disc.c disc_fdi.c disc_img.c disc_sector.c dma.c esdi_at.c fdc.c fdc37c665.c fdd.c fdi2raw.c gameport.c \
 hdd.c hdd_esdi.c hdd_file.c headland.c i430hx.c i430lx.c i430fx.c i430vx.c ide.c ide_atapi.c intel.c intel_flash.c io.c jim.c joystick_ch_flightstick_pro.c joystick_standard.c joystick_sw_pad.c \
 joystick_tm_fcs.c keyboard.c keyboard_amstrad.c keyboard_at.c keyboard_olim24.c keyboard_pcjr.c keyboard_xt.c \
 laserxt.c lpt.c lpt_dac.c lpt_dss.c mca.c mcr.c mem.c mem_bios.c mfm_at.c mfm_xebec.c model.c mouse.c mouse_msystems.c mouse_ps2.c mouse_serial.c neat.c nmi.c nvr.c olivetti_m24.c \
-opti495.c paths.c pc.c pc87306.c pci.c pic.c piix.c pit.c ppi.c ps1.c ps2.c ps2_mca.c ps2_nvr.c nvr_tc8521.c rom.c rtc.c rtc_tc8521.c scat.c scsi.c scsi_53c400.c scsi_aha1540.c scsi_cd.c scsi_hd.c scsi_zip.c \
+opti495.c paths.c pc.c pc87306.c pci.c pic.c piix.c pit.c ppi.c ps1.c ps2.c ps2_mca.c ps2_nvr.c nvr_tc8521.c pzx.c rom.c rtc.c rtc_tc8521.c scat.c scsi.c scsi_53c400.c scsi_aha1540.c scsi_cd.c scsi_hd.c scsi_zip.c \
 serial.c sio.c sis496.c sl82c460.c sound.c sound_ad1848.c sound_adlib.c sound_adlibgold.c sound_audiopci.c sound_cms.c sound_emu8k.c sound_gus.c \
 sound_mpu401_uart.c sound_opl.c sound_pas16.c sound_ps1.c sound_pssj.c sound_sb.c sound_sb_dsp.c sound_sn76489.c \
 sound_speaker.c sound_ssi2001.c sound_wss.c sound_ym7128.c soundopenal.c tandy_eeprom.c tandy_rom.c \

src/Makefile.linux32-wx-sdl2

@@ -4,13 +4,13 @@ CC   = gcc
 WXRC = wxrc
 CFLAGS = -O3 -fomit-frame-pointer -msse2 -m32 $(shell wx-config --cxxflags) $(shell sdl2-config --cflags)
 CXXFLAGS = $(CFLAGS)
-OBJ = 386.o 386_dynarec.o 386_dynarec_ops.o 808x.o acc2036.o acc2168.o acc3221.o acer386sx.o ali1429.o amstrad.o cbm_io.o cdrom-ioctl-linux.o cdrom-image.o cdrom-null.o \
+OBJ = 386.o 386_dynarec.o 386_dynarec_ops.o 808x.o acc2036.o acc2168.o acc3221.o acer386sx.o ali1429.o amstrad.o cassette.o cbm_io.o cdrom-ioctl-linux.o cdrom-image.o cdrom-null.o \
 cmd640.o codegen.o codegen_ops.o codegen_timing_486.o codegen_timing_686.o codegen_timing_common.o codegen_timing_pentium.o codegen_timing_winchip.o codegen_x86.c compaq.o config.o cpu.o \
 dells200.o device.o disc.o disc_fdi.o disc_img.o disc_sector.o dma.o esdi_at.o fdc.o fdc37c665.o fdd.o fdi2raw.o gameport.o \
 hdd.o hdd_esdi.o hdd_file.o headland.o i430hx.o i430lx.o i430fx.o i430vx.o ide.o ide_atapi.o intel.o intel_flash.o io.o jim.o joystick_ch_flightstick_pro.o joystick_standard.o joystick_sw_pad.o \
 joystick_tm_fcs.o keyboard.o keyboard_amstrad.o keyboard_at.o keyboard_olim24.o keyboard_pcjr.o keyboard_xt.o \
 laserxt.o lpt.o lpt_dac.o lpt_dss.o mca.o mcr.o mem.o mem_bios.o mfm_at.o mfm_xebec.o model.o mouse.o mouse_msystems.o mouse_ps2.o mouse_serial.o neat.o nmi.o nvr.o nvr_tc8521.o olivetti_m24.o \
-opti495.o paths.o pc.o pc87306.o pci.o pic.o piix.o pit.o ppi.o ps1.o ps2.o ps2_mca.o ps2_nvr.o rom.o rtc.o rtc_tc8521.o scat.o scsi.o scsi_53c400.o scsi_aha1540.o scsi_cd.o scsi_hd.o scsi_zip.o \
+opti495.o paths.o pc.o pc87306.o pci.o pic.o piix.o pit.o ppi.o ps1.o ps2.o ps2_mca.o ps2_nvr.o pzx.o rom.o rtc.o rtc_tc8521.o scat.o scsi.o scsi_53c400.o scsi_aha1540.o scsi_cd.o scsi_hd.o scsi_zip.o \
 serial.o sio.o sis496.o sl82c460.o sound.o sound_ad1848.o sound_adlib.o sound_adlibgold.o sound_audiopci.o sound_cms.o sound_emu8k.o sound_gus.o \
 sound_mpu401_uart.o sound_opl.o sound_pas16.o sound_ps1.o sound_pssj.o sound_sb.o sound_sb_dsp.o sound_sn76489.o \
 sound_speaker.o sound_ssi2001.o sound_wss.o sound_ym7128.o soundopenal.o t1000.o t3100e.o tandy_eeprom.o tandy_rom.o \

src/Makefile.linux64-wx-sdl2

@@ -4,13 +4,13 @@ CC   = gcc
 WXRC = wxrc
 CFLAGS = -O3 -fomit-frame-pointer -msse2 -m64 $(shell wx-config --cxxflags) $(shell sdl2-config --cflags)
 CXXFLAGS = $(CFLAGS)
-OBJ = 386.o 386_dynarec.o 386_dynarec_ops.o 808x.o acc2036.o acc2168.o acc3221.o acer386sx.o ali1429.o amstrad.o cbm_io.o cdrom-ioctl-linux.o cdrom-image.o cdrom-null.o \
+OBJ = 386.o 386_dynarec.o 386_dynarec_ops.o 808x.o acc2036.o acc2168.o acc3221.o acer386sx.o ali1429.o amstrad.o cassette.o cbm_io.o cdrom-ioctl-linux.o cdrom-image.o cdrom-null.o \
 cmd640.o codegen.o codegen_ops.o codegen_timing_486.o codegen_timing_686.o codegen_timing_common.o codegen_timing_pentium.o codegen_timing_winchip.o codegen_x86-64.c compaq.o config.o cpu.o \
 dells200.o device.o disc.o disc_fdi.o disc_img.o disc_sector.o dma.o esdi_at.o fdc.o fdc37c665.o fdd.o fdi2raw.o gameport.o \
 hdd.o hdd_esdi.o hdd_file.o headland.o i430hx.o i430lx.o i430fx.o i430vx.o ide.o ide_atapi.o intel.o intel_flash.o io.o jim.o joystick_ch_flightstick_pro.o joystick_standard.o joystick_sw_pad.o \
 joystick_tm_fcs.o keyboard.o keyboard_amstrad.o keyboard_at.o keyboard_olim24.o keyboard_pcjr.o keyboard_xt.o \
 laserxt.o lpt.o lpt_dac.o lpt_dss.o mca.o mcr.o mem.o mem_bios.o mfm_at.o mfm_xebec.o model.o mouse.o mouse_msystems.o mouse_ps2.o mouse_serial.o neat.o nmi.o nvr.o nvr_tc8521.o olivetti_m24.o \
-opti495.o paths.o pc.o pc87306.o pci.o pic.o piix.o pit.o ppi.o ps1.o ps2.o ps2_mca.o ps2_nvr.o rom.o rtc.o rtc_tc8521.o scat.o scsi.o scsi_53c400.o scsi_aha1540.o scsi_cd.o scsi_hd.o scsi_zip.o \
+opti495.o paths.o pc.o pc87306.o pci.o pic.o piix.o pit.o ppi.o ps1.o ps2.o ps2_mca.o ps2_nvr.o pzx.o rom.o rtc.o rtc_tc8521.o scat.o scsi.o scsi_53c400.o scsi_aha1540.o scsi_cd.o scsi_hd.o scsi_zip.o \
 serial.o sio.o sis496.o sl82c460.o sound.o sound_ad1848.o sound_adlib.o sound_adlibgold.o sound_audiopci.o sound_cms.o sound_emu8k.o sound_gus.o \
 sound_mpu401_uart.o sound_opl.o sound_pas16.o sound_ps1.o sound_pssj.o sound_sb.o sound_sb_dsp.o sound_sn76489.o \
 sound_speaker.o sound_ssi2001.o sound_wss.o sound_ym7128.o soundopenal.o t1000.o t3100e.o tandy_eeprom.o tandy_rom.o \

src/Makefile.mingw-wx-sdl2

@@ -6,12 +6,12 @@ WXVERSION = 31
 WXINCLUDE = e:/MinGWget/include/wx/
 CFLAGS = -O3 -march=i686 -fomit-frame-pointer -msse2 -mstackrealign -Werror -fno-strict-aliasing
 CXXFLAGS = $(CFLAGS)
-OBJ = 386.o 386_dynarec.o 386_dynarec_ops.o 808x.o acc2036.o acc2168.o acc3221.o acer386sx.o ali1429.o amstrad.o cbm_io.o cdrom-ioctl.o cdrom-image.o \
+OBJ = 386.o 386_dynarec.o 386_dynarec_ops.o 808x.o acc2036.o acc2168.o acc3221.o acer386sx.o ali1429.o amstrad.o cassette.o cbm_io.o cdrom-ioctl.o cdrom-image.o \
 	cmd640.o codegen.o codegen_ops.o codegen_timing_486.o codegen_timing_686.o codegen_timing_common.o codegen_timing_pentium.o codegen_timing_winchip.o codegen_x86.o compaq.o config.o cpu.o \
 	device.o dells200.o disc.o disc_fdi.o disc_img.o disc_sector.o dma.o esdi_at.o fdc.o fdc37c665.o fdd.o fdi2raw.o gameport.o hdd.o hdd_esdi.o hdd_file.o headland.o i430hx.o i430lx.o i430fx.o \
 	i430vx.o ide.o ide_atapi.o intel.o intel_flash.o io.o jim.o joystick_ch_flightstick_pro.o joystick_standard.o joystick_sw_pad.o joystick_tm_fcs.o keyboard.o keyboard_amstrad.o keyboard_at.o \
 	keyboard_olim24.o keyboard_pcjr.o keyboard_xt.o laserxt.o lpt.o lpt_dac.o lpt_dss.o mca.o mcr.o mem.o mem_bios.o mfm_at.o mfm_xebec.o model.o mouse.o mouse_msystems.o mouse_ps2.o \
-	mouse_serial.o neat.o nmi.o nvr.o nvr_tc8521.o olivetti_m24.o opti495.o paths.o pc.o pc87306.o pci.o pic.o piix.o pit.o ppi.o ps1.o ps2.o ps2_mca.o ps2_nvr.o rom.o rtc.o rtc_tc8521.o \
+	mouse_serial.o neat.o nmi.o nvr.o nvr_tc8521.o olivetti_m24.o opti495.o paths.o pc.o pc87306.o pci.o pic.o piix.o pit.o ppi.o ps1.o ps2.o ps2_mca.o ps2_nvr.o pzx.o rom.o rtc.o rtc_tc8521.o \
 	scat.o scsi.o scsi_53c400.o scsi_aha1540.o scsi_cd.o scsi_hd.o scsi_zip.o serial.o sio.o sis496.o sl82c460.o sound.o sound_ad1848.o sound_adlib.o sound_adlibgold.o sound_audiopci.o sound_cms.o sound_dbopl.o \
 	sound_emu8k.o sound_gus.o sound_mpu401_uart.o sound_opl.o sound_pas16.o sound_ps1.o sound_pssj.o sound_resid.o \
 	sound_sb.o sound_sb_dsp.o sound_sn76489.o sound_speaker.o sound_ssi2001.o sound_wss.o \

src/Makefile.mingw-wx-sdl2-network

@@ -6,12 +6,12 @@ WXVERSION = 31
 WXINCLUDE = e:/mingwget/include/wx/
 CFLAGS = -O3 -march=i686 -fomit-frame-pointer -msse2 -mstackrealign -Werror -fno-strict-aliasing -DUSE_NETWORKING
 CXXFLAGS = $(CFLAGS)
-OBJ = 386.o 386_dynarec.o 386_dynarec_ops.o 808x.o acc2036.o acc2168.o acc3221.o acer386sx.o ali1429.o amstrad.o cbm_io.o cdrom-ioctl.o cdrom-image.o \
+OBJ = 386.o 386_dynarec.o 386_dynarec_ops.o 808x.o acc2036.o acc2168.o acc3221.o acer386sx.o ali1429.o amstrad.o cassette.o cbm_io.o cdrom-ioctl.o cdrom-image.o \
 	cmd640.o codegen.o codegen_ops.o codegen_timing_486.o codegen_timing_686.o codegen_timing_common.o codegen_timing_pentium.o codegen_timing_winchip.o codegen_x86.o compaq.o config.o cpu.o \
 	device.o dells200.o disc.o disc_fdi.o disc_img.o disc_sector.o dma.o esdi_at.o fdc.o fdc37c665.o fdd.o fdi2raw.o gameport.o hdd.o hdd_esdi.o hdd_file.o headland.o i430hx.o i430lx.o i430fx.o \
 	i430vx.o ide.o ide_atapi.o intel.o intel_flash.o io.o jim.o joystick_ch_flightstick_pro.o joystick_standard.o joystick_sw_pad.o joystick_tm_fcs.o keyboard.o keyboard_amstrad.o keyboard_at.o \
 	keyboard_olim24.o keyboard_pcjr.o keyboard_xt.o laserxt.o lpt.o lpt_dac.o lpt_dss.o mca.o mcr.o mem.o mem_bios.o mfm_at.o mfm_xebec.o model.o mouse.o mouse_msystems.o mouse_ps2.o \
-	mouse_serial.o neat.o nmi.o nvr.o nvr_tc8521.o olivetti_m24.o opti495.o paths.o pc.o pc87306.o pci.o pic.o piix.o pit.o ppi.o ps1.o ps2.o ps2_mca.o ps2_nvr.o rom.o rtc.o rtc_tc8521.o \
+	mouse_serial.o neat.o nmi.o nvr.o nvr_tc8521.o olivetti_m24.o opti495.o paths.o pc.o pc87306.o pci.o pic.o piix.o pit.o ppi.o ps1.o ps2.o ps2_mca.o ps2_nvr.o pzx.o rom.o rtc.o rtc_tc8521.o \
 	scat.o scsi.o scsi_53c400.o scsi_aha1540.o scsi_cd.o scsi_hd.o scsi_zip.o serial.o sio.o sis496.o sl82c460.o sound.o sound_ad1848.o sound_adlib.o sound_adlibgold.o sound_audiopci.o sound_cms.o sound_dbopl.o \
 	sound_emu8k.o sound_gus.o sound_mpu401_uart.o sound_opl.o sound_pas16.o sound_ps1.o sound_pssj.o sound_resid.o \
 	sound_sb.o sound_sb_dsp.o sound_sn76489.o sound_speaker.o sound_ssi2001.o sound_wss.o \

src/Makefile.osx64-wx-sdl2

@@ -3,13 +3,13 @@ CPP  = g++
 CC   = gcc
 WXRC = wxrc
 CFLAGS = -D__unix=1 -DPCEM_RENDER_WITH_TIMER -DPCEM_RENDER_TIMER_LOOP -Dfopen64=fopen -Dfseeko64=fseeko -Dftello64=ftello -Doff64_t=off_t -O3 -fomit-frame-pointer -msse2 -m64 $(shell wx-config --cxxflags) $(shell sdl2-config --cflags) -I/usr/local/opt/openal-soft/include -I/usr/local/include
-OBJ = 386.o 386_dynarec.o 386_dynarec_ops.o 808x.o acc2036.o acc2168.o acc3221.o acer386sx.o ali1429.o amstrad.o cbm_io.o cdrom-ioctl-osx.o cdrom-image.o cdrom-null.o \
+OBJ = 386.o 386_dynarec.o 386_dynarec_ops.o 808x.o acc2036.o acc2168.o acc3221.o acer386sx.o ali1429.o amstrad.o cassette.o cbm_io.o cdrom-ioctl-osx.o cdrom-image.o cdrom-null.o \
 cmd640.o codegen.o codegen_ops.o codegen_timing_486.o codegen_timing_686.o codegen_timing_common.o codegen_timing_pentium.o codegen_timing_winchip.o codegen_x86-64.c compaq.o config.o cpu.o \
 device.o dells200.o disc.o disc_fdi.o disc_img.o disc_sector.o dma.o esdi_at.o fdc.o fdc37c665.o fdd.o fdi2raw.o gameport.o \
 hdd.o hdd_esdi.o hdd_file.o headland.o i430hx.o i430lx.o i430fx.o i430vx.o ide.o ide_atapi.o intel.o intel_flash.o io.o jim.o joystick_ch_flightstick_pro.o joystick_standard.o joystick_sw_pad.o \
 joystick_tm_fcs.o keyboard.o keyboard_amstrad.o keyboard_at.o keyboard_olim24.o keyboard_pcjr.o keyboard_xt.o \
 laserxt.o lpt.o lpt_dac.o lpt_dss.o mca.o mcr.o mem.o mem_bios.o mfm_at.o mfm_xebec.o model.o mouse.o mouse_msystems.o mouse_ps2.o mouse_serial.o neat.o nmi.o nvr.o nvr_tc8521.o olivetti_m24.o \
-opti495.o paths.o pc.o pc87306.o pci.o pic.o piix.o pit.o ppi.o ps1.o ps2.o ps2_mca.o ps2_nvr.o rom.o rtc.o rtc_tc8521.o scat.o scsi.o scsi_53c400.o scsi_aha1540.o scsi_cd.o scsi_hd.o scsi_zip.o \
+opti495.o paths.o pc.o pc87306.o pci.o pic.o piix.o pit.o ppi.o ps1.o ps2.o ps2_mca.o ps2_nvr.o pzx.o rom.o rtc.o rtc_tc8521.o scat.o scsi.o scsi_53c400.o scsi_aha1540.o scsi_cd.o scsi_hd.o scsi_zip.o \
 serial.o sio.o sis496.o sl82c460.o sound.o sound_ad1848.o sound_adlib.o sound_adlibgold.o sound_audiopci.o sound_cms.o sound_emu8k.o sound_gus.o \
 sound_mpu401_uart.o sound_opl.o sound_pas16.o sound_ps1.o sound_pssj.o sound_sb.o sound_sb_dsp.o sound_sn76489.o \
 sound_speaker.o sound_ssi2001.o sound_wss.o sound_ym7128.o soundopenal.o t1000.o t3100e.o tandy_eeprom.o tandy_rom.o \

src/cassette.c

@@ -0,0 +1,186 @@
+/************************************************************************
+
+    PCem: IBM 5150 Cassette support
+
+    Copyright (C) 2019  John Elliott <seasip.webmaster@gmail.com>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*************************************************************************/
+
+#include <stdlib.h>
+#include "ibm.h"
+#include "cpu.h"
+#include "device.h"
+#include "pzx.h"
+
+char cassettefn[256];
+
+typedef struct cassette_t 
+{
+	uint8_t motor;		/* Motor status */
+	pzxfile_t pzx;
+	int cycles_last;	/* Cycle count at last cassette poll */
+
+} cassette_t;
+
+extern device_t cassette_device;
+
+
+static cassette_t *st_cas;
+
+
+
+#define CAS_LOG(x) pclog x
+// #define CAS_LOG(x) 
+
+
+/* The PCem CPU uses IBM cycles (4.77MHz). PZX uses Spectrum cycles (3.5MHz)
+ * so scale accordingly. */
+static int32_t pzx_cycles(int32_t pc)
+{
+	double d = pc;
+
+	return (int32_t)(((d * 3.5) / 4.772728) + 0.5);
+}
+
+void cassette_eject(void)
+{
+	if (st_cas->pzx.input)
+	{
+		pzx_close(&st_cas->pzx);
+	}
+	cassettefn[0] = 0;
+}
+
+void cassette_load(const char *filename)
+{
+	FILE *fp;
+	unsigned char magic[8];
+
+	if (!filename) return;
+
+	fp = fopen(filename, "rb");
+	if (!fp)
+	{
+		/* Warn user? */
+		CAS_LOG(("Failed to open cassette input %s\n", filename));
+		return;
+	}
+	memset(magic, 0, sizeof(magic));
+	fread(magic, 1, sizeof(magic), fp);	
+
+	/* Check for PZX signature. In due course support could be added for
+	 * other formats like TZX */
+	if (!memcmp(magic, "PZXT", 4))
+	{
+		const char *result;
+
+		result = pzx_open(&st_cas->pzx, fp);
+
+		if (result)
+		{
+			CAS_LOG(("Failed to open %s as PZX: %s\n",
+				filename, result));
+			fclose(fp);
+			return;			
+		}
+		strcpy(cassettefn, filename);
+	}
+}
+
+
+uint8_t cassette_input(void)
+{
+	int ticks;
+
+	/* While motor is off, result is loopback */
+	if (!st_cas->motor)
+	{
+		return ppispeakon;
+	}
+	/* If there is no tapefile open don't try to extract data */
+	if (st_cas->pzx.input == NULL) return 0;
+	/* Otherwise see how many ticks there have been since the last input */
+	if (st_cas->cycles_last == -1) 
+	{
+		st_cas->cycles_last = cycles;
+	}
+	if (cycles <= st_cas->cycles_last)
+	{
+		ticks = (st_cas->cycles_last - cycles);
+	}
+	else
+	{
+		ticks = (st_cas->cycles_last + (cpu_get_speed() / 100) - cycles);
+	}
+	st_cas->cycles_last = cycles;
+
+	return pzx_advance(&st_cas->pzx, pzx_cycles(ticks));	
+}
+
+
+
+void cassette_set_motor(uint8_t on)
+{
+	if (on && !st_cas->motor)
+	{
+		CAS_LOG(("Start cassette motor\n"));
+		st_cas->cycles_last = -1;
+	}
+	if (st_cas->motor && !on)
+	{
+		CAS_LOG(("Stop cassette motor\n"));
+		st_cas->cycles_last = -1;
+	}
+	st_cas->motor = on;
+}
+
+
+static void *cassette_init(void)
+{
+	cassette_t *cas = malloc(sizeof(cassette_t));
+
+	memset(cas, 0, sizeof(cassette_t));
+	pzx_init(&cas->pzx);
+
+	st_cas = cas;
+	return cas;
+}
+
+
+static void cassette_close(void *p)
+{
+	cassette_t *cas = (cassette_t *)p;
+
+	pzx_close(&cas->pzx);
+
+	free(cas);
+}
+
+
+device_t cassette_device = 
+{
+	"Cassette",
+	0,
+	cassette_init,
+	cassette_close,
+	NULL,
+	NULL,
+	NULL,
+	NULL,
+	NULL
+};
+

src/cassette.h

@@ -0,0 +1,30 @@
+/************************************************************************
+
+    PCem: IBM 5150 cassette support
+
+    Copyright (C) 2019  John Elliott <seasip.webmaster@gmail.com>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*************************************************************************/
+
+extern device_t cassette_device;
+
+uint8_t cassette_input(void);
+void cassette_set_motor(uint8_t on);
+void cassette_eject(void);
+void cassette_load(const char *filename);
+
+extern char cassettefn[256];

src/keyboard_xt.c

@@ -1,5 +1,6 @@
 #include "ibm.h"
 #include "device.h"
+#include "cassette.h"
 #include "fdd.h"
 #include "io.h"
 #include "mem.h"
@@ -126,7 +127,9 @@ void keyboard_xt_write(uint16_t port, uint8_t val, void *priv)
                 timer_process();
                 timer_update_outstanding();
                 
-                if (keyboard_xt.pb2_turbo)
+                if (romset == ROM_IBMPC)
+                	cassette_set_motor((val & 8) ? 0 : 1);
+                else if (keyboard_xt.pb2_turbo)
                         cpu_set_turbo((val & 4) ? 0 : 1);
         
                 speaker_update();
@@ -183,6 +186,8 @@ uint8_t keyboard_xt_read(uint16_t port, void *priv)
                                 temp = ((mem_size-64) / 32) & 0xf;
                         else
                                 temp = ((mem_size-64) / 32) >> 4;
+
+			temp |= (cassette_input()) ? 0x10 : 0;
                 }
                 else if (romset == ROM_ATARIPC3)
                 {

src/model.c

@@ -15,6 +15,7 @@
 #include "compaq.h"
 #include "dells200.h"
 #include "device.h"
+#include "cassette.h"
 #include "dma.h"
 #include "fdc.h"
 #include "fdc37c665.h"
@@ -301,6 +302,8 @@ void xt_init()
         keyboard_xt_init();
 	nmi_init();
         device_add(&gameport_device);
+	if (romset == ROM_IBMPC)
+		device_add(&cassette_device);
 }
 
 void compaq_pip_init()

src/pc.rc

@@ -24,6 +24,11 @@ BEGIN
                 MENUITEM SEPARATOR                
                 MENUITEM "&Configure hard discs...",IDM_HDCONF
         END
+	POPUP "C&assette"
+	BEGIN
+		MENUITEM "&Load tapefile...", IDM_CASSETTE_LOAD
+		MENUITEM "&Eject tape", IDM_CASSETTE_EJECT
+	END
         POPUP "&Settings"
         BEGIN
                 MENUITEM "&Configure...", IDM_CONFIG

src/pc.xrc

@@ -137,6 +137,15 @@
 				<radio>1</radio>
 			</object>
 		</object>
+		<object class="wxMenu" name="IDM_CASSETTE">
+			<label>C_assette</label>
+			<object class="wxMenuItem" name="IDM_CASSETTE_LOAD">
+				<label>_Load tapefile...</label>
+			</object>
+			<object class="wxMenuItem" name="IDM_CASSETTE_EJECT">
+				<label>_Eject tape</label>
+			</object>
+		</object>
 		<object class="wxMenu">
 			<label>Video</label>
 			<object class="wxMenu">

src/pzx.c

@@ -0,0 +1,419 @@
+/************************************************************************
+
+    PCem: IBM 5150 Cassette support
+
+    Copyright (C) 2019  John Elliott <seasip.webmaster@gmail.com>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*************************************************************************/
+
+#include <stdlib.h>
+#include "ibm.h"
+#include "pzx.h"
+
+/* This module is intended to abstract all the details of a PZX file and 
+ * emit its contents as a bitstream in a form suitable for PCem. Similar
+ * modules could be written to add support for other tape formats such as TZX, 
+ * TAP or CSW. */
+
+#define CAS_LOG(x) pclog x
+/* #define CAS_LOG(x)  */
+
+static uint32_t peek2(uint8_t *data)
+{
+       return (((uint32_t)data[1]) <<  8) | data[0];
+}
+
+static uint32_t peek4(uint8_t *data)
+{
+	return (((uint32_t)data[3]) << 24) |
+	       (((uint32_t)data[2]) << 16) |
+	       (((uint32_t)data[1]) <<  8) | data[0];
+}
+
+/* Cue up the next pulse definition from the current PULS block. */
+static void pzx_parse_pulse(pzxfile_t *pzx)
+{
+	pzx->puls_duration = peek2(pzx->curblock + pzx->puls_ptr);
+	pzx->puls_ptr += 2;
+	if (pzx->puls_duration > 0x8000)
+	{
+		pzx->puls_count = pzx->puls_duration & 0x7FFF;
+		pzx->puls_duration = peek2(pzx->curblock + pzx->puls_ptr);
+		pzx->puls_ptr += 2;
+	}
+	if (pzx->puls_duration >= 0x8000)
+	{
+		pzx->puls_duration &= 0x7FFF;
+		pzx->puls_duration <<= 16;
+		pzx->puls_duration |= peek2(pzx->curblock + pzx->puls_ptr);
+		pzx->puls_ptr += 2;
+	}
+	if (!pzx->puls_count) pzx->puls_count = 1;
+}
+
+
+
+void pzx_init(pzxfile_t *pzx)
+{
+	memset(pzx, 0, sizeof(pzxfile_t));
+	pzx->state = PZX_CLOSED;
+}
+
+/* Load the next block from a PZX-format file. 
+ *
+ * Returns block if successful, NULL if end of file or error
+ * Caller must free the block with free(). */
+uint8_t *pzx_load_block(FILE *fp)
+{
+	uint8_t block_header[8];
+	uint8_t *block_data;
+	uint32_t block_len;
+
+	/* The first 8 bytes of a PZX block are fixed: the first 4 give
+	 * the ID, the second 4 the length (excluding the header itself) */
+	if (fread(block_header, 1, 8, fp) < 8) return NULL;	/* EoF */
+
+	block_len = peek4(block_header + 4);
+	block_data = malloc(8 + block_len);
+	if (!block_data) return NULL;
+	memcpy(block_data, block_header, 8);
+	if (!block_len)	/* Block is only the header */
+	{
+/*		CAS_LOG(("Loaded PZX block: %-4.4s\n", block_data)); */
+		return block_data;
+	}	
+	if (fread(block_data + 8, 1, block_len, fp) < block_len)
+	{
+		free(block_data);	/* Unexpected EoF */
+		return NULL;
+	}
+/* 	CAS_LOG(("Loaded PZX block: %-4.4s\n", block_data)); */
+	return block_data;	
+}
+
+
+/* Search the current file for PZX version headers and check they're all 1.x */
+static const char * pzx_check_version(FILE *fp)
+{
+	uint8_t *block;
+	static char message[80];
+
+	rewind(fp);
+	while ( (block = pzx_load_block(fp)) )
+	{
+		if (!memcmp(block, "PZXT", 4))
+		{
+			CAS_LOG(("PZX version %d.%d\n", block[8], block[9]));
+			if (block[8] != 1) 
+			{
+				sprintf(message, "Unsupported PZX version %d.%d\n", block[8], block[9]);
+				free(block);
+				return message;
+			}
+		}
+		free(block);
+	}
+	rewind(fp);
+	return NULL;
+}
+
+
+const char *pzx_open(pzxfile_t *pzx, FILE *fp)
+{
+	const char *result;
+
+	rewind(fp);
+	/* Check that this file is compatible */
+	result = pzx_check_version(fp);
+	if (result) return result;
+
+	pzx->level = 0;
+	pzx->state = PZX_IDLE;
+	pzx->input = fp;
+	return NULL;	
+}
+
+void pzx_close(pzxfile_t *pzx)
+{
+	if (pzx->input)
+	{
+		fclose(pzx->input);
+		pzx->input = NULL;
+	}
+	if (pzx->curblock)
+	{
+		free(pzx->curblock);
+		pzx->curblock = NULL;
+	}
+	pzx->state = PZX_CLOSED;
+}
+
+/* Read the next block of type DATA, PAUS or PULS */
+int pzx_next_block(pzxfile_t *pzx)
+{
+	long pos;
+
+	pos = ftell(pzx->input);
+	while (pzx->state == PZX_IDLE)
+	{
+		uint8_t *blk;
+
+		/* In idle state there should be no current block. But
+		 * make sure of that */
+		if (pzx->curblock)
+		{
+			free(pzx->curblock);
+			pzx->curblock = NULL;
+		}
+
+		/* Load the next block */
+		blk = pzx_load_block(pzx->input);
+
+		/* If that didn't load we've reached the end of file; wrap to
+		 * beginning. */
+		if (!blk)	
+		{
+			rewind(pzx->input);
+			blk = pzx_load_block(pzx->input);
+			if (!blk)	/* Couldn't even load first block */
+			{
+				pzx_close(pzx);
+				return 0;
+			}
+			/* Have we read the whole file and come back to where
+			 * we were? */
+			if (ftell(pzx->input) == pos)	
+			{
+				free(blk);
+				pzx_close(pzx);
+				return 0;
+			}
+		}
+		/* We have loaded the next block. What is it? */
+		if (!memcmp(blk, "PULS", 4))
+		{
+			pzx->state = PZX_IN_PULS;
+			pzx->curblock = blk;
+			pzx->puls_len = 8 + peek4(blk + 4);
+			pzx->puls_ptr = 8;
+			pzx->puls_count = 0;
+			pzx->puls_remain = 0;
+			pzx->puls_duration = 0;
+			pzx->level = 0;
+			CAS_LOG(("Beginning PULS block\n"));
+		}
+		else if (!memcmp(blk, "PAUS", 4))
+		{
+			pzx->state = PZX_IN_PAUS;
+			pzx->curblock = blk;
+			pzx->paus_remain = peek4(blk + 8);
+			pzx->level = (pzx->paus_remain >> 31);
+			pzx->paus_remain &= 0x7FFFFFFF;
+			CAS_LOG(("Beginning PAUS block, duration=%d\n",
+					pzx->paus_remain));
+		}
+		else if (!memcmp(blk, "DATA", 4))
+		{
+			pzx->state = PZX_IN_DATA;
+			pzx->curblock = blk;
+			pzx->data_bits = peek4(blk + 8);
+			pzx->level = (pzx->data_bits >> 31);
+			pzx->data_bits &= 0x7FFFFFFF;
+			pzx->data_tail = peek2(blk + 12);
+			pzx->data_p0   = blk[14];
+			pzx->data_p1   = blk[15];
+			pzx->data_p    = 0;
+			pzx->data_w    = 16;
+			pzx->data_remain = 0;
+			pzx->data_ptr = 16 + 2 * (pzx->data_p0 + pzx->data_p1);
+			pzx->data_mask = 0x80;
+			CAS_LOG(("Beginning DATA block, length=%d p0=%d p1=%d"
+				" data_ptr=%d\n",
+					pzx->data_bits, 
+					pzx->data_p0, pzx->data_p1, 
+					pzx->data_ptr));
+		}
+	}
+	return 1;
+}
+
+static void pzx_endblock(pzxfile_t *pzx)
+{
+	if (pzx->curblock) free(pzx->curblock);
+	pzx->curblock = NULL;
+	pzx->state = PZX_IDLE;
+}
+
+/* PAUS is easy - just run the timer down */
+static int pzx_advance_paus(pzxfile_t *pzx, int time)
+{
+	if (pzx->paus_remain > time)
+	{
+		pzx->paus_remain -= time;
+		return 0;
+	}
+	time -= pzx->paus_remain;
+	pzx_endblock(pzx);
+	return time;
+}
+
+
+
+
+	
+
+static int pzx_advance_puls(pzxfile_t *pzx, int time)
+{
+	/* At the start of a pulse sequence? */
+	if (pzx->puls_count == 0)
+	{
+		pzx_parse_pulse(pzx);
+		pzx->puls_remain = pzx->puls_duration;
+	}
+	/* Does sample trigger a pulse change? If not, that's easy. */
+	if (time < pzx->puls_remain)
+	{
+		pzx->puls_remain -= time;
+		return 0;
+	}
+	/* Sample does trigger a pulse change */
+	time -= pzx->puls_remain;
+	/* If there's another pulse in the current sequence, that's 
+	 * straightforward; just flip the level and continue */
+	--pzx->puls_count;
+	pzx->level = !pzx->level;
+	if (pzx->puls_count)
+	{
+		pzx->puls_remain = pzx->puls_duration;
+		return time;
+	}
+	/* If we've reached the end of the pulse sequence, there may be 
+	 * another one */
+	if (pzx->puls_ptr < pzx->puls_len)
+	{
+		return time;
+	}
+	/* If there isn't another one, it's the end of the block */
+	pzx_endblock(pzx);
+	return time;
+}
+
+
+/* Decode a DATA block */
+static int pzx_advance_data(pzxfile_t *pzx, int time)
+{
+	uint8_t bit;
+
+	/* Reached end of data? */
+	if (pzx->data_bits == 0)
+	{
+		/* Time interval is covered by the tail bit */
+		if (pzx->data_tail > time)
+		{
+			pzx->data_tail -= time;
+			return 0;	
+		}
+		/* Have run out of block */
+		time -= pzx->data_tail;
+		pzx_endblock(pzx);
+		return time;
+	}
+	/* No more time remaining on the current bit? */
+	if (pzx->data_p < 1 && !pzx->data_remain)	
+	{
+		bit = pzx->curblock[pzx->data_ptr] & pzx->data_mask;
+		pzx->data_mask >>= 1;
+		if (!pzx->data_mask)
+		{
+			pzx->data_mask = 0x80;
+			++pzx->data_ptr;
+		}
+		--pzx->data_bits;	
+
+		if (bit)
+		{
+			pzx->data_p = pzx->data_p1;
+			pzx->data_w = 16 + 2 * pzx->data_p0;
+			pzx->data_remain = 0;
+		}
+		else
+		{
+			pzx->data_p = pzx->data_p0;
+			pzx->data_w = 16;
+			pzx->data_remain = 0;
+		}
+	}
+	/* See if we've started processing the current waveform. If not, 
+	 * load its first element (assuming that there is one) */
+	if (!pzx->data_remain)
+	{
+		if (pzx->data_p)
+		{
+			pzx->data_remain = peek2(pzx->curblock + pzx->data_w);
+			pzx->data_w += 2;
+			pzx->data_p--;
+		}
+	}
+	if (pzx->data_remain > time)
+	{
+		/* Time advance is contained within current wave */
+		pzx->data_remain -= time;
+		return 0;
+	}
+	else	/* Move on to next element of wave / next bit / next block */
+	{
+		time -= pzx->data_remain;
+		pzx->data_remain = 0;
+		pzx->level = !pzx->level;
+	}
+
+	return time;
+}
+
+
+
+
+int pzx_advance(pzxfile_t *pzx, int time)
+{
+	if (pzx->state == PZX_CLOSED) return 0;	/* No tape loaded */
+
+	while (time)
+	{
+		switch (pzx->state)
+		{
+			case PZX_IDLE:
+				if (!pzx_next_block(pzx)) return 0;
+				break;
+			case PZX_IN_PULS:
+				time = pzx_advance_puls(pzx, time);
+				break;
+			case PZX_IN_PAUS:
+				time = pzx_advance_paus(pzx, time);
+				break;
+			case PZX_IN_DATA:
+				time = pzx_advance_data(pzx, time);
+				break;
+                        case PZX_CLOSED: /*Should never get here*/
+                                return 0;
+	
+		}
+	}
+	return pzx->level;
+}
+
+
+

src/pzx.h

@@ -0,0 +1,71 @@
+/************************************************************************
+
+    PCem: IBM 5150 cassette support
+
+    Copyright (C) 2019  John Elliott <seasip.webmaster@gmail.com>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*************************************************************************/
+
+typedef enum
+{
+	PZX_CLOSED,	/* File is not open */
+	PZX_IDLE,	/* File is open, no block loaded */
+	PZX_IN_PULS,	/* File is open, current block is a PULS block */
+	PZX_IN_DATA,	/* File is open, current block is a DATA block */
+	PZX_IN_PAUS,	/* File is open, current block is a PAUS block */
+} PZX_STATE;
+
+
+typedef struct pzxfile_t
+{
+	FILE *input;		/* Input PZX file */
+	uint8_t *curblock;	/* Currently-loaded block, if any */
+	int level;		/* Current signal level */
+	PZX_STATE state;	/* State machine current status */
+/* State variables for PULS */
+	uint32_t puls_ptr;	/* Pointer within PULS block */
+	uint32_t puls_len;	/* Length of PULS block */
+	uint32_t puls_count;	/* Count of pulses */
+	uint32_t puls_duration;	/* Duration of each pulse */
+	uint32_t puls_remain;	/* Time remaining in this pulse */
+/* State variables for PAUS */
+	uint32_t paus_remain;	/* Time remaining in this pause */
+/* State variables for DATA */
+	uint32_t data_ptr;	/* Pointer within DATA block */
+	uint32_t data_bits; 	/* Count of bits */
+	uint16_t data_tail;	/* Length of pulse after last bit */
+	uint8_t  data_mask;	/* Mask for current bit */
+	uint8_t	 data_p0;	/* Length of 0 encoding */	
+	uint8_t	 data_p1;	/* Length of 1 encoding */	
+	int	 data_p;	/* Current sequence being emitted */
+	uint32_t data_w;	/* Current waveform */
+	uint32_t data_remain;	/* Current data pulse time remaining */
+} pzxfile_t;
+
+uint8_t *pzx_load_block(FILE *fp);
+
+/* Initialise structure */
+void pzx_init(pzxfile_t *pzx);
+
+/* Open file for input */
+const char *pzx_open(pzxfile_t *pzx, FILE *fp);
+
+/* Close file */
+void pzx_close(pzxfile_t *pzx);
+
+/* Advance by 'time' samples (3.5MHz sample rate) and return current state */
+int pzx_advance(pzxfile_t *pzx, int time);

src/resources.h

@@ -10,6 +10,8 @@
 #define IDM_BPB_DISABLE    40015
 #define IDM_CONFIG         40020
 #define IDM_STATUS         40030
+#define IDM_CASSETTE_LOAD  40040
+#define IDM_CASSETTE_EJECT 40041
 #define IDM_VID_RESIZE     40050
 #define IDM_VID_REMEMBER   40051
 #define IDM_VID_ASPECT     40052

src/wx-sdl2.c

@@ -18,6 +18,8 @@
 #include <stdlib.h>
 #include <math.h>
 #include "ibm.h"
+#include "device.h"
+#include "cassette.h"
 #include "cdrom-ioctl.h"
 #include "cdrom-image.h"
 #include "config.h"
@@ -899,6 +901,22 @@ int wx_handle_command(void* hwnd, int wParam, int checked)
         {
                 zip_eject();
         }
+        else if (ID_IS("IDM_CASSETTE_LOAD"))
+        {
+                if (!getfile(hwnd,
+                                "Tape image (*.pzxi;*.pzx)|*.pzxi;*.pzx|All files (*.*)|*.*",
+                                cassettefn))
+                {
+                        cassette_eject();
+                        cassette_load(openfilestring);
+                        saveconfig(NULL);
+                }
+        }
+	else if (ID_IS("IDM_CASSETTE_EJECT"))
+	{
+		cassette_eject();
+                saveconfig(NULL);
+	}
         else if (ID_IS("IDM_MACHINE_TOGGLE"))
         {
                 if (emulation_state != EMULATION_STOPPED)