From 25256300745631138bfc4227b169bb5ea6c06cbd Mon Sep 17 00:00:00 2001
From: Jeremiah Orians <jeremiah@pdp10.guru>
Date: Sat, 4 Jun 2016 17:13:38 -0400
Subject: [PATCH] Added a trivial disassembler could be massively improved

---
 disasm.c | 1000 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 1000 insertions(+)
 create mode 100644 disasm.c

diff --git a/disasm.c b/disasm.c
new file mode 100644
index 0000000..162653e
--- /dev/null
+++ b/disasm.c
@@ -0,0 +1,1000 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <string.h>
+
+FILE* binary_file;
+
+/* Unpacked instruction */
+struct Instruction
+{
+	uint32_t raw0, raw1, raw2, raw3;
+	char opcode[3];
+	uint32_t raw_XOP;
+	char XOP[6];
+	char operation[9];
+	int32_t raw_Immediate;
+	char Immediate[7];
+	uint32_t HAL_CODE;
+	uint8_t reg0;
+	uint8_t reg1;
+	uint8_t reg2;
+	uint8_t reg3;
+	bool invalid;
+};
+
+/* Useful unpacking functions */
+void unpack_byte(uint8_t a, char* c)
+{
+	char table[16] = {0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46};
+	c[0] = table[a / 16];
+	c[1] = table[a % 16];
+}
+
+void unpack_instruction(struct Instruction* c)
+{
+	unpack_byte(c->raw0, &(c->operation[0]));
+	unpack_byte(c->raw1, &(c->operation[2]));
+	unpack_byte(c->raw2, &(c->operation[4]));
+	unpack_byte(c->raw3, &(c->operation[6]));
+	c->opcode[0] = c->operation[0];
+	c->opcode[1] = c->operation[1];
+}
+
+/* Load instruction addressed at IP */
+void read_instruction(struct Instruction *current)
+{
+	memset(current, 0, sizeof(struct Instruction));
+
+	/* Read the actual bytes and increment the IP */
+
+	current->raw0 = fgetc(binary_file);
+	if(-1 == (int32_t)(current->raw0)) goto Broken;
+	current->raw1 = fgetc(binary_file);
+	if(-1 == (int32_t)(current->raw1)) goto Broken;
+	current->raw2 = fgetc(binary_file);
+	if(-1 == (int32_t)(current->raw2)) goto Broken;
+	current->raw3 = fgetc(binary_file);
+	if(-1 == (int32_t)(current->raw3)) goto Broken;
+	unpack_instruction(current);
+
+	return;
+
+	/* This disassembler doesn't support non-instructions */
+Broken:
+	fclose(binary_file);
+	exit(EXIT_FAILURE);
+}
+
+void decode_Integer_4OP(struct Instruction* c)
+{
+	/* Parse Raw Data */
+	c->raw_XOP = c->raw1;
+	c->XOP[0] = c->operation[2];
+	c->XOP[1] = c->operation[3];
+	c->raw_Immediate = 0;
+	c->reg0 = c->raw2/16;
+	c->reg1 = c->raw2%16;
+	c->reg2 = c->raw3/16;
+	c->reg3 = c->raw3%16;
+
+	char Name[20] = "ILLEGAL_4OP";
+
+	/* Convert to Human readable form */
+	switch(c->raw_XOP)
+	{
+		case 0x00: /* ADD.CI */
+		{
+			strncpy(Name, "ADD.CI", 19);
+			break;
+		}
+		case 0x01: /* ADD.CO */
+		{
+			strncpy(Name, "ADD.CO", 19);
+			break;
+		}
+		case 0x02: /* ADD.CIO */
+		{
+			strncpy(Name, "ADD.CIO", 19);
+			break;
+		}
+		case 0x03: /* ADDU.CI */
+		{
+			strncpy(Name, "ADDU.CI", 19);
+			break;
+		}
+		case 0x04: /* ADDU.CO */
+		{
+			strncpy(Name, "ADDU.CO", 19);
+			break;
+		}
+		case 0x05: /* ADDU.CIO */
+		{
+			strncpy(Name, "ADDU.CIO", 19);
+			break;
+		}
+		case 0x06: /* SUB.BI */
+		{
+			strncpy(Name, "SUB.BI", 19);
+			break;
+		}
+		case 0x07: /* SUB.BO */
+		{
+			strncpy(Name, "SUB.BO", 19);
+			break;
+		}
+		case 0x08: /* SUB.BIO */
+		{
+			strncpy(Name, "SUB.BIO", 19);
+			break;
+		}
+		case 0x09: /* SUBU.BI */
+		{
+			strncpy(Name, "SUBU.BI", 19);
+			break;
+		}
+		case 0x0A: /* SUBU.BO */
+		{
+			strncpy(Name, "SUBU.BO", 19);
+			break;
+		}
+		case 0x0B: /* SUBU.BIO */
+		{
+			strncpy(Name, "SUBU.BIO", 19);
+			break;
+		}
+		case 0x0C: /* MULTIPLY */
+		{
+			strncpy(Name, "MULTIPLY", 19);
+			break;
+		}
+		case 0x0D: /* MULTIPLYU */
+		{
+			strncpy(Name, "MULTIPLYU", 19);
+			break;
+		}
+		case 0x0E: /* DIVIDE */
+		{
+			strncpy(Name, "DIVIDE", 19);
+			break;
+		}
+		case 0x0F: /* DIVIDEU */
+		{
+			strncpy(Name, "DIVIDEU", 19);
+			break;
+		}
+		case 0x10: /* MUX */
+		{
+			strncpy(Name, "MUX", 19);
+			break;
+		}
+		case 0x11: /* NMUX */
+		{
+			strncpy(Name, "NMUX", 19);
+			break;
+		}
+		case 0x12: /* SORT */
+		{
+			strncpy(Name, "SORT", 19);
+			break;
+		}
+		case 0x13: /* SORTU */
+		{
+			strncpy(Name, "SORTU", 19);
+			break;
+		}
+		default: /* Unknown 4OP */
+		{
+			break;
+		}
+	}
+	fprintf(stdout, "%s reg%o reg%o reg%o reg%o\t", Name, c->reg0, c->reg1, c->reg2, c->reg3);
+	fprintf(stdout, "# %s\n", c->operation);
+}
+
+void decode_Integer_3OP(struct Instruction* c)
+{
+	/* Parse raw data */
+	c->raw_XOP = c->raw1*0x10 + c->raw2/16;
+	c->XOP[0] = c->operation[2];
+	c->XOP[1] = c->operation[3];
+	c->XOP[2] = c->operation[4];
+	c->raw_Immediate = 0;
+	c->reg0 = c->raw2%16;
+	c->reg1 = c->raw3/16;
+	c->reg2 = c->raw3%16;
+
+	char Name[20] = "ILLEGAL_3OP";
+
+	/* Convert to Human readable form */
+	switch(c->raw_XOP)
+	{
+		case 0x000: /* ADD */
+		{
+			strncpy(Name, "ADD", 19);
+			break;
+		}
+		case 0x001: /* ADDU */
+		{
+			strncpy(Name, "ADDU", 19);
+			break;
+		}
+		case 0x002: /* SUB */
+		{
+			strncpy(Name, "SUB", 19);
+			break;
+		}
+		case 0x003: /* SUBU */
+		{
+			strncpy(Name, "SUBU", 19);
+			break;
+		}
+		case 0x004: /* CMP */
+		{
+			strncpy(Name, "CMP", 19);
+			break;
+		}
+		case 0x005: /* CMPU */
+		{
+			strncpy(Name, "CMPU", 19);
+			break;
+		}
+		case 0x006: /* MUL */
+		{
+			strncpy(Name, "MUL", 19);
+			break;
+		}
+		case 0x007: /* MULH */
+		{
+			strncpy(Name, "MULH", 19);
+			break;
+		}
+		case 0x008: /* MULU */
+		{
+			strncpy(Name, "MULU", 19);
+			break;
+		}
+		case 0x009: /* MULUH */
+		{
+			strncpy(Name, "MULUH", 19);
+			break;
+		}
+		case 0x00A: /* DIV */
+		{
+			strncpy(Name, "DIV", 19);
+			break;
+		}
+		case 0x00B: /* MOD */
+		{
+			strncpy(Name, "MOD", 19);
+			break;
+		}
+		case 0x00C: /* DIVU */
+		{
+			strncpy(Name, "DIVU", 19);
+			break;
+		}
+		case 0x00D: /* MODU */
+		{
+			strncpy(Name, "MODU", 19);
+			break;
+		}
+		case 0x010: /* MAX */
+		{
+			strncpy(Name, "MAX", 19);
+			break;
+		}
+		case 0x011: /* MAXU */
+		{
+			strncpy(Name, "MAXU", 19);
+			break;
+		}
+		case 0x012: /* MIN */
+		{
+			strncpy(Name, "MIN", 19);
+			break;
+		}
+		case 0x013: /* MINU */
+		{
+			strncpy(Name, "MINU", 19);
+			break;
+		}
+		case 0x014: /* PACK */
+		{
+			strncpy(Name, "PACK", 19);
+			break;
+		}
+		case 0x015: /* UNPACK */
+		{
+			strncpy(Name, "UNPACK", 19);
+			break;
+		}
+		case 0x016: /* PACK8.CO */
+		{
+			strncpy(Name, "PACK8.CO", 19);
+			break;
+		}
+		case 0x017: /* PACK8U.CO */
+		{
+			strncpy(Name, "PACK8U.CO", 19);
+			break;
+		}
+		case 0x018: /* PACK16.CO */
+		{
+			strncpy(Name, "PACK16.CO", 19);
+			break;
+		}
+		case 0x019: /* PACK16U.CO */
+		{
+			strncpy(Name, "PACK16.CO", 19);
+			break;
+		}
+		case 0x01A: /* PACK32.CO */
+		{
+			strncpy(Name, "PACK32.CO", 19);
+			break;
+		}
+		case 0x01B: /* PACK32U.CO */
+		{
+			strncpy(Name, "PACK32U.CO", 19);
+			break;
+		}
+		case 0x020: /* AND */
+		{
+			strncpy(Name, "AND", 19);
+			break;
+		}
+		case 0x021: /* OR */
+		{
+			strncpy(Name, "OR", 19);
+			break;
+		}
+		case 0x022: /* XOR */
+		{
+			strncpy(Name, "XOR", 19);
+			break;
+		}
+		case 0x023: /* NAND */
+		{
+			strncpy(Name, "NAND", 19);
+			break;
+		}
+		case 0x024: /* NOR */
+		{
+			strncpy(Name, "NOR", 19);
+			break;
+		}
+		case 0x025: /* XNOR */
+		{
+			strncpy(Name, "XNOR", 19);
+			break;
+		}
+		case 0x026: /* MPQ */
+		{
+			strncpy(Name, "MPQ", 19);
+			break;
+		}
+		case 0x027: /* LPQ */
+		{
+			strncpy(Name, "LPQ", 19);
+			break;
+		}
+		case 0x028: /* CPQ */
+		{
+			strncpy(Name, "CPQ", 19);
+			break;
+		}
+		case 0x029: /* BPQ */
+		{
+			strncpy(Name, "BPQ", 19);
+			break;
+		}
+		case 0x030: /* SAL */
+		{
+			strncpy(Name, "SAL", 19);
+			break;
+		}
+		case 0x031: /* SAR */
+		{
+			strncpy(Name, "SAR", 19);
+			break;
+		}
+		case 0x032: /* SL0 */
+		{
+			strncpy(Name, "SL0", 19);
+			break;
+		}
+		case 0x033: /* SR0 */
+		{
+			strncpy(Name, "SR0", 19);
+			break;
+		}
+		case 0x034: /* SL1 */
+		{
+			strncpy(Name, "SL1", 19);
+			break;
+		}
+		case 0x035: /* SR1 */
+		{
+			strncpy(Name, "SR1", 19);
+			break;
+		}
+		case 0x036: /* ROL */
+		{
+			strncpy(Name, "ROL", 19);
+			break;
+		}
+		case 0x037: /* ROR */
+		{
+			strncpy(Name, "ROR", 19);
+			break;
+		}
+		default: /* Unknown 3OP*/
+		{
+			break;
+		}
+	}
+
+	fprintf(stdout, "%s reg%o reg%o reg%o\t", Name, c->reg0, c->reg1, c->reg2);
+	fprintf(stdout, "# %s\n", c->operation);
+}
+
+void decode_Integer_2OP(struct Instruction* c)
+{
+	/* Parse Raw Data */
+	c->raw_XOP = c->raw1*0x100 + c->raw2;
+	c->XOP[0] = c->operation[2];
+	c->XOP[1] = c->operation[3];
+	c->XOP[2] = c->operation[4];
+	c->XOP[3] = c->operation[5];
+	c->raw_Immediate = 0;
+	c->reg0 = c->raw3/16;
+	c->reg1 = c->raw3%16;
+
+	char Name[20] = "ILLEGAL_2OP";
+
+	/* Convert to Human readable form */
+	switch(c->raw_XOP)
+	{
+		case 0x0000: /* NEG */
+		{
+			strncpy(Name, "NEG", 19);
+			break;
+		}
+		case 0x0001: /* ABS */
+		{
+			strncpy(Name, "ABS", 19);
+			break;
+		}
+		case 0x0002: /* NABS */
+		{
+			strncpy(Name, "NABS", 19);
+			break;
+		}
+		case 0x0003: /* SWAP */
+		{
+			strncpy(Name, "SWAP", 19);
+			break;
+		}
+		case 0x0004: /* COPY */
+		{
+			strncpy(Name, "COPY", 19);
+			break;
+		}
+		case 0x0005: /* MOVE */
+		{
+			strncpy(Name, "MOVE", 19);
+			break;
+		}
+		case 0x0100: /* BRANCH */
+		{
+			strncpy(Name, "BRANCH", 19);
+			break;
+		}
+		case 0x0101: /* CALL */
+		{
+			strncpy(Name, "CALL", 19);
+			break;
+		}
+		default: /* Unknown 2OP*/
+		{
+			break;
+		}
+	}
+
+	fprintf(stdout, "%s reg%o reg%o\t", Name, c->reg0, c->reg1);
+	fprintf(stdout, "# %s\n", c->operation);
+}
+
+void decode_1OP(struct Instruction* c)
+{
+	/* Parse Raw Data */
+	c->raw_XOP = c->raw1*0x1000 + c->raw2*0x10 + c->raw3/16;
+	c->XOP[0] = c->operation[2];
+	c->XOP[1] = c->operation[3];
+	c->XOP[2] = c->operation[4];
+	c->XOP[3] = c->operation[5];
+	c->XOP[4] = c->operation[6];
+	c->raw_Immediate = 0;
+	c->reg0 = c->raw3%16;
+
+	char Name[20] = "ILLEGAL_1OP";
+
+	/* Convert to Human readable form */
+	switch(c->raw_XOP)
+	{
+		case 0x00000: /* READPC */
+		{
+			strncpy(Name, "READPC", 19);
+			break;
+		}
+		case 0x00001: /* READSCID */
+		{
+			strncpy(Name, "READSCID", 19);
+			break;
+		}
+		case 0x00002: /* FALSE */
+		{
+			strncpy(Name, "FALSE", 19);
+			break;
+		}
+		case 0x00003: /* TRUE */
+		{
+			strncpy(Name, "TRUE", 19);
+			break;
+		}
+		case 0x01000: /* JSR_COROUTINE */
+		{
+			strncpy(Name, "JSR_COROUTINE", 19);
+			break;
+		}
+		case 0x01001: /* RET */
+		{
+			strncpy(Name, "RET", 19);
+			break;
+		}
+		case 0x02000: /* PUSHPC */
+		{
+			strncpy(Name, "PUSHPC", 19);
+			break;
+		}
+		case 0x02001: /* POPPC */
+		{
+			strncpy(Name, "POPPC", 19);
+			break;
+		}
+		default: /* Unknown 1OP*/
+		{
+			break;
+		}
+	}
+
+	fprintf(stdout, "%s reg%o\t", Name, c->reg0);
+	fprintf(stdout, "# %s\n", c->operation);
+}
+
+void decode_0OP(struct Instruction* c)
+{
+	/* Parse Raw Data*/
+	uint32_t FULL_OP;
+	FULL_OP = c->raw0*0x1000000 + c->raw1*0x10000 + c->raw2*0x100 + c->raw3;
+
+	char Name[20] = "ILLEGAL_0OP";
+
+	/* Convert to Human readable form */
+	switch(FULL_OP)
+	{
+		case 0x00000000: /* NOP */
+		{
+			strncpy(Name, "NOP", 19);
+			break;
+		}
+		case 0x00000001 ... 0x00FFFFFF: /* IMPROPER_NOP */
+		{
+			strncpy(Name, "IMPROPER_NOP", 19);
+			break;
+		}
+		case 0xFF000000 ... 0xFFFFFFFE: /* IMPROPER_HALT */
+		{
+			strncpy(Name, "IMPROPER_HALT", 19);
+			break;
+		}
+		case 0xFFFFFFFF: /* HALT */
+		{
+			strncpy(Name, "HALT", 19);
+			break;
+		}
+		default: /* Unknown 1OP*/
+		{
+			break;
+		}
+	}
+
+	fprintf(stdout, "%s\t", Name);
+	fprintf(stdout, "# %s\n", c->operation);
+}
+
+void decode_Integer_2OPI(struct Instruction* c)
+{
+	/* Parse Raw Data */
+	c->raw_Immediate = c->raw2*0x100 + c->raw3;
+	c->Immediate[0] = c->operation[4];
+	c->Immediate[1] = c->operation[5];
+	c->Immediate[2] = c->operation[6];
+	c->Immediate[3] = c->operation[7];
+	c->reg0 = c->raw1/16;
+	c->reg1 = c->raw1%16;
+
+	char Name[20] = "ILLEGAL_2OPI";
+
+	/* Convert to Human readable form */
+	switch(c->raw0)
+	{
+		case 0x0E: /* ADDI */
+		{
+			strncpy(Name, "ADDI", 19);
+			break;
+		}
+		case 0x0F: /* ADDUI */
+		{
+			strncpy(Name, "ADDUI", 19);
+			break;
+		}
+		case 0x10: /* SUBI */
+		{
+			strncpy(Name, "SUBI", 19);
+			break;
+		}
+		case 0x11: /* SUBUI */
+		{
+			strncpy(Name, "SUBUI", 19);
+			break;
+		}
+		case 0x12: /* CMPI */
+		{
+			strncpy(Name, "", 19);
+			break;
+		}
+		case 0x13: /* LOAD */
+		{
+			strncpy(Name, "LOAD", 19);
+			break;
+		}
+		case 0x14: /* LOAD8 */
+		{
+			strncpy(Name, "LOAD8", 19);
+			break;
+		}
+		case 0x15: /* LOADU8 */
+		{
+			strncpy(Name, "LOADU8", 19);
+			break;
+		}
+		case 0x16: /* LOAD16 */
+		{
+			strncpy(Name, "LOAD16", 19);
+			break;
+		}
+		case 0x17: /* LOADU16 */
+		{
+			strncpy(Name, "LOADU16", 19);
+			break;
+		}
+		case 0x18: /* LOAD32 */
+		{
+			strncpy(Name, "LOAD32", 19);
+			break;
+		}
+		case 0x19: /* LOADU32 */
+		{
+			strncpy(Name, "LOADU32", 19);
+			break;
+		}
+		case 0x1F: /* CMPUI */
+		{
+			strncpy(Name, "CMPUI", 19);
+			break;
+		}
+		case 0x20: /* STORE */
+		{
+			strncpy(Name, "STORE", 19);
+			break;
+		}
+		case 0x21: /* STORE8 */
+		{
+			strncpy(Name, "STORE8", 19);
+			break;
+		}
+		case 0x22: /* STOREU8 */
+		{
+			strncpy(Name, "STOREU8", 19);
+			break;
+		}
+		case 0x23: /* STORE16 */
+		{
+			strncpy(Name, "STORE16", 19);
+			break;
+		}
+		case 0x24: /* STOREU16 */
+		{
+			strncpy(Name, "STOREU16", 19);
+			break;
+		}
+		case 0x25: /* STORE32 */
+		{
+			strncpy(Name, "STORE32", 19);
+			break;
+		}
+		case 0x26: /* STOREU32 */
+		{
+			strncpy(Name, "STOREU32", 19);
+			break;
+		}
+		default: /* Unknown 2OPI*/
+		{
+			break;
+		}
+	}
+
+	fprintf(stdout, "%s reg%o reg%o 0x%x\t", Name, c->reg0, c->reg1, c->raw_Immediate);
+	fprintf(stdout, "# %s\n", c->operation);
+}
+
+void decode_1OPI(struct Instruction* c)
+{
+	/* Parse Raw Data */
+	c->raw_Immediate = (c->raw1%16)*0x10000 + c->raw2*0x100 + c->raw3;
+	/* Sign extend immediate*/
+	c->raw_Immediate = c->raw_Immediate << 12;
+	c->raw_Immediate = c->raw_Immediate >> 12;
+	c->Immediate[0] = c->operation[3];
+	c->Immediate[1] = c->operation[4];
+	c->Immediate[2] = c->operation[5];
+	c->Immediate[3] = c->operation[6];
+	c->Immediate[4] = c->operation[7];
+	c->HAL_CODE = 0;
+	c->reg0 = c->raw1/16;
+
+	char Name[20] = "ILLEGAL_1OPI";
+
+	/* Convert to Human readable form */
+	switch(c->raw0)
+	{
+		case 0x2C: /* JUMP.C */
+		{
+			strncpy(Name, "JUMP.C", 19);
+			break;
+		}
+		case 0x2D: /* JUMP.B */
+		{
+			strncpy(Name, "JUMP.B", 19);
+			break;
+		}
+		case 0x2E: /* JUMP.O */
+		{
+			strncpy(Name, "JUMP.O", 19);
+			break;
+		}
+		case 0x2F: /* JUMP.G */
+		{
+			strncpy(Name, "JUMP.G", 19);
+			break;
+		}
+		case 0x30: /* JUMP.GE */
+		{
+			strncpy(Name, "JUMP.GE", 19);
+			break;
+		}
+		case 0x31: /* JUMP.E */
+		{
+			strncpy(Name, "JUMP.E", 19);
+			break;
+		}
+		case 0x32: /* JUMP.NE */
+		{
+			strncpy(Name, "JUMP.NE", 19);
+			break;
+		}
+		case 0x33: /* JUMP.LE */
+		{
+			strncpy(Name, "JUMP.LE", 19);
+			break;
+		}
+		case 0x34: /* JUMP.L */
+		{
+			strncpy(Name, "JUMP.L", 19);
+			break;
+		}
+		case 0x35: /* JUMP.Z */
+		{
+			strncpy(Name, "JUMP.Z", 19);
+			break;
+		}
+		case 0x36: /* JUMP.NZ */
+		{
+			strncpy(Name, "JUMP.NZ", 19);
+			break;
+		}
+		default: /* Unknown 1OPI*/
+		{
+			break;
+		}
+	}
+
+	fprintf(stdout, "%s reg%o %d\t", Name, c->reg0, c->raw_Immediate);
+	fprintf(stdout, "# %s\n", c->operation);
+}
+
+void decode_0OPI(struct Instruction* c)
+{
+	/* Parse Raw Data */
+	c->raw_Immediate = c->raw1*0x10000 + c->raw2*0x100 + c->raw3;
+	/* Sign extend immediate*/
+	c->raw_Immediate = c->raw_Immediate << 8;
+	c->raw_Immediate = c->raw_Immediate >> 8;
+	c->Immediate[0] = c->operation[2];
+	c->Immediate[1] = c->operation[3];
+	c->Immediate[2] = c->operation[4];
+	c->Immediate[3] = c->operation[5];
+	c->Immediate[4] = c->operation[6];
+	c->Immediate[5] = c->operation[7];
+
+	char Name[20] = "ILLEGAL_0OPI";
+
+	/* Convert to Human readable form */
+	switch(c->raw0)
+	{
+		case 0x3C: /* JUMP */
+		{
+			strncpy(Name, "JUMP", 19);
+			break;
+		}
+		default: /* Unknown 1OPI*/
+		{
+			break;
+		}
+	}
+
+	fprintf(stdout, "%s %d\t", Name, c->raw_Immediate);
+	fprintf(stdout, "# %s\n", c->operation);
+}
+
+void decode_HALCODE(struct Instruction* c)
+{
+	/* Parse Raw Data */
+	c->HAL_CODE = c->raw1*0x10000 + c->raw2*0x100 + c->raw3;
+
+	char Name[20] = "ILLEGAL_HALCODE";
+
+	/* Convert to Human readable form */
+	switch(c->HAL_CODE)
+	{
+		case 0x100000: /* FOPEN */
+		{
+			strncpy(Name, "FOPEN", 19);
+			break;
+		}
+		case 0x100001: /* FCLOSE */
+		{
+			strncpy(Name, "FCLOSE", 19);
+			break;
+		}
+		case 0x100002: /* FSEEK */
+		{
+			strncpy(Name, "FSEEK", 19);
+			break;
+		}
+		case 0x100003: /* REWIND */
+		{
+			strncpy(Name, "REWIND", 19);
+			break;
+		}
+		case 0x100100: /* FGETC */
+		{
+			strncpy(Name, "FGETC", 19);
+			break;
+		}
+		case 0x100200: /* FPUTC */
+		{
+			strncpy(Name, "FPUTC", 19);
+			break;
+		}
+		default: /* Unknown HALCODE*/
+		{
+			break;
+		}
+	}
+
+	fprintf(stdout, "%s\t", Name);
+	fprintf(stdout, "# %s\n", c->operation);
+}
+
+void eval_instruction(struct Instruction* c)
+{
+	switch(c->raw0)
+	{
+		case 0x01: /* Integer 4OP */
+		{
+			decode_Integer_4OP(c);
+			break;
+		}
+		case 0x05: /* Integer 3OP */
+		{
+			decode_Integer_3OP(c);
+			break;
+		}
+		case 0x09: /* Integer 2OP */
+		{
+			decode_Integer_2OP(c);
+			break;
+		}
+		case 0x0D: /* 1OP */
+		{
+			decode_1OP(c);
+			break;
+		}
+		case 0x0E ... 0x2B: /* Core 2OPI */
+		{
+			decode_Integer_2OPI(c);
+			break;
+		}
+		case 0x2C ... 0x3B: /* Core 1OPI */
+		{
+			decode_1OPI(c);
+			break;
+		}
+		case 0x3C: /* Core 0OPI */
+		{
+			decode_0OPI(c);
+			break;
+		}
+		case 0x42: /* HALCODE */
+		{
+			decode_HALCODE(c);
+			break;
+		}
+		case 0x00: /* NOP */
+		case 0xFF: /* HALT */
+		{
+			decode_0OP(c);
+			break;
+		}
+		default: /* Not supported by this disassembler */
+		{
+			fprintf(stderr, "Unable to decode the following instruction:\n%c %c %c %c\n", c->raw0, c->raw1, c->raw2, c->raw3);
+			fprintf(stderr, "%s\n\n", c->operation);
+		}
+	}
+}
+
+/* Standard C main program */
+int main(int argc, char **argv)
+{
+	/* Make sure we have a program tape to run */
+	if (argc < 2)
+	{
+		fprintf(stderr, "Usage: %s $FileName\nWhere $FileName is the name of program being disassembled\n", argv[0]);
+		return EXIT_FAILURE;
+	}
+
+	binary_file = fopen(argv[1], "r");
+	struct Instruction* current;
+	current = calloc(1, sizeof(struct Instruction));
+
+	int32_t byte;
+	byte = fgetc(binary_file);
+	ungetc(byte, binary_file);
+
+	while(EOF != byte)
+	{
+		read_instruction(current);
+		eval_instruction(current);
+		byte = fgetc(binary_file);
+		ungetc(byte, binary_file);
+	}
+
+	fclose(binary_file);
+
+	return EXIT_SUCCESS;
+}