1 files changed, 68 insertions, 0 deletions
diff --git a/src/emu/opc.h b/src/emu/opc.h
new file mode 100644
index 0000000..45d21a8
--- /dev/null
+++ b/src/emu/opc.h
@@ -0,0 +1,68 @@
+#ifndef _OPC_H
+#define _OPC_H
+
+#include <stdint.h>
+
+/* instructions formats:
+ * ---------------------
+ *
+ *  arithmetic:
+ *     |000|xxx|aaaaa|bbbbb|ccccc|00000000000|
+ *  logic:
+ *     |001|xxx|aaaaa|bbbbb|ccccc|00000000000|
+ *  load & store:
+ *     |010|xxx|aaaaa|bbbbb|cccccccccccccccc|
+ *  branch:
+ *     |011|xxx|aaaaa|bbbbb|cccccccccccccccc|
+ *  jump:
+ *     |100|xxx|aaaaa|000000000000000000000|
+ *  misc:
+ *     |111|xxx|??????????????????????????|
+ *
+ */
+
+/* arithmetic */
+#define OPC_ADD  000
+#define OPC_SUB  001
+#define OPC_MUL  002
+#define OPC_DIV  003
+#define OPC_MOD  004
+#define OPC_SHL  005
+#define OPC_SHR  006
+
+/* logic */
+#define OPC_AND  010
+#define OPC_OR   011
+#define OPC_XOR  012
+#define OPC_NOR  013
+
+/* load & store */
+#define OPC_MOV  020
+#define OPC_LB   021
+#define OPC_LH   022
+#define OPC_LW   023
+#define OPC_SB   024
+#define OPC_SH   025
+#define OPC_SW   026
+
+/* branch instructions */
+#define OPC_CMP  030
+#define OPC_BEQ  031
+#define OPC_BNE  032
+#define OPC_BLT  033
+#define OPC_BGE  034
+#define OPC_BLE  035
+#define OPC_BGT  036
+
+/* jump instructions */
+#define OPC_J    040
+#define OPC_JAL  041
+
+/* misc */
+#define OPC_SYS  070
+
+/* conversion functions */
+uint32_t mnemonic2opc(const char *mnemonic);
+const char *opc2mnemonic(uint32_t IR);
+
+#endif