The beginnings of the port of MartyPC's 808x emulation.

src/cpu/808x/CMakeLists.txt

@@ -0,0 +1,16 @@
+#
+# 86Box    A hypervisor and IBM PC system emulator that specializes in
+#          running old operating systems and software designed for IBM
+#          PC systems and compatibles from 1981 through fairly recent
+#          system designs based on the PCI bus.
+#
+#          This file is part of the 86Box distribution.
+#
+#          CMake build script.
+#
+# Authors: David Hrdlička, <hrdlickadavid@outlook.com>
+#
+#          Copyright 2020-2021 David Hrdlička.
+#
+
+add_library(808x.c OBJECT queue.c)

src/cpu/808x/queue.c

@@ -0,0 +1,190 @@
+/*
+ * 86Box    A hypervisor and IBM PC system emulator that specializes in
+ *          running old operating systems and software designed for IBM
+ *          PC systems and compatibles from 1981 through fairly recent
+ *          system designs based on the PCI bus.
+ *
+ *          This file is part of the 86Box distribution.
+ *
+ *          808x CPU emulation, mostly ported from reenigne's XTCE, which
+ *          is cycle-accurate.
+ *
+ * Authors: gloriouscow, <https://github.com/dbalsom>
+ *          Miran Grca, <mgrca8@gmail.com>
+ *
+ *          Copyright 2023 gloriouscow.
+ *          Copyright 2023 Miran Grca.
+ */
+#include <math.h>
+#include <stdarg.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#include <wchar.h>
+
+#define HAVE_STDARG_H
+#include <86box/86box.h>
+#include "cpu.h"
+#include "x86.h"
+#include <86box/machine.h>
+#include <86box/io.h>
+#include <86box/mem.h>
+#include <86box/rom.h>
+#include <86box/nmi.h>
+#include <86box/pic.h>
+#include <86box/ppi.h>
+#include <86box/timer.h>
+#include <86box/gdbstub.h>
+// #include "808x.h"
+#include "queue.h"
+
+/* TODO: Move to cpu.h so this can eventually be reused for 286+ as well. */
+#define QUEUE_MAX 6
+
+typedef struct queue_t
+{
+    size_t        size;
+    size_t        len;
+    size_t        back;
+    size_t        front;
+    uint8_t       q[QUEUE_MAX];
+    uint16_t      preload;
+    queue_delay_t delay;
+} queue_t;
+
+static queue_t queue;
+
+#ifdef ENABLE_QUEUE_LOG
+int queue_do_log = ENABLE_QUEUE_LOG;
+
+static void
+queue_log(const char *fmt, ...)
+{
+    va_list ap;
+
+    if (queue_do_log) {
+        va_start(ap, fmt);
+        pclog_ex(fmt, ap);
+        va_end(ap);
+    }
+}
+#else
+#    define queue_log(fmt, ...)
+#endif
+
+void
+queue_set_size(size_t size)
+{
+    if (size > QUEUE_MAX)
+        fatal("Requested prefetch queue of %i bytes is too big\n", size);
+
+    queue.size = size;
+}
+
+size_t
+queue_get_len(void)
+{
+    return queue.len;
+}
+
+int
+queue_is_full(void)
+{
+    return (queue.len != queue.size);
+}
+
+uint16_t
+queue_get_preload(void)
+{
+    uint16_t ret = queue.preload;
+    queue.preload = 0x0000;
+
+    return ret;
+}
+
+int
+queue_has_preload(void)
+{
+    return (queue.preload & FLAG_PRELOADED) ? 1 : 0;
+}
+
+void
+queue_set_preload(void)
+{
+    uint8_t byte;
+
+    if (queue.len > 0) {
+        byte = queue_pop();
+        queue.preload = ((uint16_t) byte) | FLAG_PRELOADED;
+    } else
+        fatal("Tried to preload with empty queue\n");
+}
+
+void
+queue_push8(uint8_t byte)
+{
+    if (queue.len < queue.size) {
+        queue.q[queue.front] = byte;
+        queue.front = (queue.front + 1) % queue.size;
+        queue.len++;
+
+        if (queue.len == 3)
+            queue.delay = DELAY_WRITE;
+        else
+            queue.delay = DELAY_NONE;
+    } else
+        fatal("Queue overrun\n");
+}
+
+void
+queue_push16(uint16_t word)
+{
+    queue_push8((uint8_t) (word & 0xff));
+    queue_push8((uint8_t) ((word >> 8) & 0xff));
+}
+
+uint8_t
+queue_pop(void)
+{
+    uint8_t byte = 0xff;
+
+    if (queue.len > 0) {
+        byte = queue.q[queue.back];
+
+        queue.back = (queue.back + 1) % queue.size;
+        queue.len--;
+
+        if (queue.len >= 3)
+            queue.delay = DELAY_READ;
+        else
+            queue.delay = DELAY_NONE;
+    } else
+        fatal("Queue underrun\n");
+
+    return byte;
+}
+
+queue_delay_t
+queue_get_delay(void)
+{
+    return queue.delay;
+}
+
+void
+queue_flush(void)
+{
+    memset(&queue, 0x00, sizeof(queue_t));
+
+    queue.delay = DELAY_NONE;
+}
+
+void
+queue_init(void)
+{
+    queue_flush();
+
+    if (is8086)
+        queue_set_size(6);
+    else
+        queue_set_size(4);
+}

src/cpu/808x/queue.h

@@ -0,0 +1,43 @@
+/*
+ * 86Box    A hypervisor and IBM PC system emulator that specializes in
+ *          running old operating systems and software designed for IBM
+ *          PC systems and compatibles from 1981 through fairly recent
+ *          system designs based on the PCI bus.
+ *
+ *          This file is part of the 86Box distribution.
+ *
+ *          Prefetch queue implementation header.
+ *
+ * Authors: gloriouscow, <https://github.com/dbalsom>
+ *          Miran Grca, <mgrca8@gmail.com>
+ *
+ *          Copyright 2023 gloriouscow.
+ *          Copyright 2023 Miran Grca.
+ */
+#ifndef EMU_QUEUE_H
+#define EMU_QUEUE_H
+
+typedef enum queue_delay_t
+{
+    DELAY_READ,
+    DELAY_WRITE,
+    DELAY_NONE
+} queue_delay_t;
+
+#define FLAG_PRELOADED    0x8000
+
+extern void               queue_set_size(size_t size);
+extern size_t             queue_get_len(void);
+extern int                queue_is_full(void);
+extern uint16_t           queue_get_preload(void);
+extern int                queue_has_preload(void);
+extern void               queue_set_preload(void);
+extern void               queue_push8(uint8_t byte);
+extern void               queue_push16(uint16_t word);
+extern uint8_t            queue_pop(void);
+extern queue_delay_t      queue_get_delay(void);
+extern void               queue_flush(void);
+
+extern void               queue_init(void);
+
+#endif /*EMU_QUEUE_H*/

src/cpu/CMakeLists.txt

@@ -35,3 +35,6 @@ endif()
 
 add_subdirectory(softfloat)
 target_link_libraries(86Box softfloat)
+
+add_subdirectory(808x)
+target_link_libraries(86Box 808x)

src/win/Makefile.mingw

@@ -242,7 +242,7 @@ PROG := 86Box
 #              Nothing should need changing from here on..              #
 #########################################################################
 VPATH := $(EXPATH) . $(CODEGEN) minitrace cpu cpu/softfloat \
-         cdrom chipset device disk disk/minivhd floppy \
+         cpu/808x cdrom chipset device disk disk/minivhd floppy \
          game machine mem printer \
          sio sound \
          sound/munt sound/munt/c_interface sound/munt/sha1 \
@@ -547,6 +547,8 @@ MAINOBJ := 86box.o config.o log.o random.o timer.o io.o acpi.o apm.o dma.o ddma.
 
 MEMOBJ := catalyst_flash.o i2c_eeprom.o intel_flash.o mem.o rom.o row.o smram.o spd.o sst_flash.o
 
+CPU808XOBJ := queue.o
+
 CPUOBJ := $(DYNARECOBJ) \
           $(CGTOBJ) \
           cpu.o cpu_table.o fpu.o x86.o \
@@ -773,7 +775,7 @@ ifeq ($(RTMIDI), y)
  SNDOBJ += midi_rtmidi.o
 endif
 
-OBJ := $(MAINOBJ) $(CPUOBJ) $(CHIPSETOBJ) $(MCHOBJ) $(DEVOBJ) $(MEMOBJ) \
+OBJ := $(MAINOBJ) $(CPU808XOBJ) $(CPUOBJ) $(CHIPSETOBJ) $(MCHOBJ) $(DEVOBJ) $(MEMOBJ) \
        $(FDDOBJ) $(GAMEOBJ) $(CDROMOBJ) $(ZIPOBJ) $(MOOBJ) $(HDDOBJ) $(MINIVHDOBJ) \
        $(NETOBJ) $(PRINTOBJ) $(SCSIOBJ) $(SIOOBJ) $(SNDOBJ) $(VIDOBJ) $(VOODOOOBJ) \
        $(PLATOBJ) $(UIOBJ) $(FSYNTHOBJ) $(MUNTOBJ) $(DEVBROBJ) $(MINITRACEOBJ) $(THREADOBJ)