pulled in and adapted the dos code from eradicate

[retrobench] / src / dos / pit8254.h

diff --git a/src/dos/pit8254.h b/src/dos/pit8254.h
new file mode 100644 (file)
index 0000000..4389883
--- /dev/null
+++ b/src/dos/pit8254.h
@@ -0,0 +1,51 @@
+/*
+colcycle - color cycling image viewer
+Copyright (C) 2016  John Tsiombikas <nuclear@member.fsf.org>
+
+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 3 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, see <http://www.gnu.org/licenses/>.
+*/
+#ifndef PIT8254_H_
+#define PIT8254_H_
+
+/* frequency of the oscillator driving the 8254 timer */
+#define OSC_FREQ_HZ            1193182
+
+/* I/O ports connected to the 8254 */
+#define PORT_DATA0     0x40
+#define PORT_DATA1     0x41
+#define PORT_DATA2     0x42
+#define PORT_CMD       0x43
+
+/* command bits */
+#define CMD_CHAN0                      0
+#define CMD_CHAN1                      (1 << 6)
+#define CMD_CHAN2                      (2 << 6)
+#define CMD_RDBACK                     (3 << 6)
+
+#define CMD_LATCH                      0
+#define CMD_ACCESS_LOW         (1 << 4)
+#define CMD_ACCESS_HIGH                (2 << 4)
+#define CMD_ACCESS_BOTH                (3 << 4)
+
+#define CMD_OP_INT_TERM                0
+#define CMD_OP_ONESHOT         (1 << 1)
+#define CMD_OP_RATE                    (2 << 1)
+#define CMD_OP_SQWAVE          (3 << 1)
+#define CMD_OP_SW_STROBE       (4 << 1)
+#define CMD_OP_HW_STROBE       (5 << 1)
+
+#define CMD_MODE_BIN           0
+#define CMD_MODE_BCD           1
+
+#endif /* PIT8254_H_ */