Initial commit 0.13.9.16

1 files changed, 94 insertions, 0 deletions

diff --git a/src/fake86/i8253.c b/src/fake86/i8253.c
new file mode 100755
index 0000000..49d30e1
--- /dev/null
+++ b/src/fake86/i8253.c
@@ -0,0 +1,94 @@
+/*
+  Fake86: A portable, open-source 8086 PC emulator.
+  Copyright (C)2010-2013 Mike Chambers
+
+  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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+*/
+
+/* i8253.c: functions to emulate the Intel 8253 programmable interval timer.
+   these are required for the timer interrupt and PC speaker to be
+   properly emulated! */
+
+#include <stdint.h>
+#include <stdio.h>
+#include <memory.h>
+#include "i8253.h"
+#include "mutex.h"
+
+extern void set_port_write_redirector (uint16_t startport, uint16_t endport, void *callback);
+extern void set_port_read_redirector (uint16_t startport, uint16_t endport, void *callback);
+
+struct i8253_s i8253;
+
+extern uint64_t hostfreq, lasttick, curtick, tickgap, totalexec;
+
+void out8253 (uint16_t portnum, uint8_t value) {
+	uint8_t curbyte;
+	portnum &= 3;
+	switch (portnum) {
+			case 0:
+			case 1:
+			case 2: //channel data
+				if ( (i8253.accessmode[portnum] == PIT_MODE_LOBYTE) || ( (i8253.accessmode[portnum] == PIT_MODE_TOGGLE) && (i8253.bytetoggle[portnum] == 0) ) ) curbyte = 0;
+				else if ( (i8253.accessmode[portnum] == PIT_MODE_HIBYTE) || ( (i8253.accessmode[portnum] == PIT_MODE_TOGGLE) && (i8253.bytetoggle[portnum] == 1) ) ) curbyte = 1;
+				if (curbyte == 0) { //low byte
+						i8253.chandata[portnum] = (i8253.chandata[portnum] & 0xFF00) | value;
+					}
+				else {   //high byte
+						i8253.chandata[portnum] = (i8253.chandata[portnum] & 0x00FF) | ( (uint16_t) value << 8);
+					}
+				if (i8253.chandata[portnum] == 0) i8253.effectivedata[portnum] = 65536;
+				else i8253.effectivedata[portnum] = i8253.chandata[portnum];
+				i8253.active[portnum] = 1;
+				tickgap = (uint64_t) ( (float) hostfreq / (float) ( (float) 1193182 / (float) i8253.effectivedata[0]) );
+				if (i8253.accessmode[portnum] == PIT_MODE_TOGGLE) i8253.bytetoggle[portnum] = (~i8253.bytetoggle[portnum]) & 1;
+				i8253.chanfreq[portnum] = (float) ( (uint32_t) ( ( (float) 1193182.0 / (float) i8253.effectivedata[portnum]) * (float) 1000.0) ) / (float) 1000.0;
+				//printf("[DEBUG] PIT channel %u counter changed to %u (%f Hz)\n", portnum, i8253.chandata[portnum], i8253.chanfreq[portnum]);
+				break;
+			case 3: //mode/command
+				i8253.accessmode[value>>6] = (value >> 4) & 3;
+				if (i8253.accessmode[value>>6] == PIT_MODE_TOGGLE) i8253.bytetoggle[value>>6] = 0;
+				break;
+		}
+}
+
+uint8_t in8253 (uint16_t portnum) {
+	uint8_t curbyte;
+	portnum &= 3;
+	switch (portnum) {
+			case 0:
+			case 1:
+			case 2: //channel data
+				if ( (i8253.accessmode[portnum] == 0) || (i8253.accessmode[portnum] == PIT_MODE_LOBYTE) || ( (i8253.accessmode[portnum] == PIT_MODE_TOGGLE) && (i8253.bytetoggle[portnum] == 0) ) ) curbyte = 0;
+				else if ( (i8253.accessmode[portnum] == PIT_MODE_HIBYTE) || ( (i8253.accessmode[portnum] == PIT_MODE_TOGGLE) && (i8253.bytetoggle[portnum] == 1) ) ) curbyte = 1;
+				if ( (i8253.accessmode[portnum] == 0) || (i8253.accessmode[portnum] == PIT_MODE_LOBYTE) || ( (i8253.accessmode[portnum] == PIT_MODE_TOGGLE) && (i8253.bytetoggle[portnum] == 0) ) ) curbyte = 0;
+				else if ( (i8253.accessmode[portnum] == PIT_MODE_HIBYTE) || ( (i8253.accessmode[portnum] == PIT_MODE_TOGGLE) && (i8253.bytetoggle[portnum] == 1) ) ) curbyte = 1;
+				if ( (i8253.accessmode[portnum] == 0) || (i8253.accessmode[portnum] == PIT_MODE_TOGGLE) ) i8253.bytetoggle[portnum] = (~i8253.bytetoggle[portnum]) & 1;
+				if (curbyte == 0) { //low byte
+						return ( (uint8_t) i8253.counter[portnum]);
+					}
+				else {   //high byte
+						return ( (uint8_t) (i8253.counter[portnum] >> 8) );
+					}
+				break;
+		}
+	return (0);
+}
+
+void init8253() {
+	memset (&i8253, 0, sizeof (i8253) );
+	set_port_write_redirector (0x40, 0x43, &out8253);
+	set_port_read_redirector (0x40, 0x43, &in8253);
+}