diff --git a/jdisa/main.c b/jdisa/main.c
new file mode 100644
--- /dev/null
+++ b/jdisa/main.c
@@ -0,0 +1,705 @@
+/**
+ * jdisa
+ *
+ * ByteCode Disassembler
+ * See http://java.sun.com/docs/books/jvms/second_edition/html/VMSpecTOC.doc.html
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <ctype.h>
+
+#define BUF_SIZE 1023
+
+typedef unsigned char uchar_t;
+
+typedef uchar_t u1[1];
+typedef uchar_t u2[2];
+typedef uchar_t u4[4];
+typedef uchar_t u8[8];
+
+struct Header {
+    u4 magic;
+    u2 minor_version;
+    u2 major_version;
+    u2 constant_pool_count;
+};
+
+typedef struct Header Header;
+
+int main (int argc, char **argv)
+{
+    FILE *f;
+    uchar_t buffer[BUF_SIZE];
+    int i;
+    size_t num;
+    int OPCODE;
+    Header *cf;
+
+    if (argc != 2) {
+        fprintf (stderr, "Usage: %s <FILE>\n", argv[0]);
+        return EXIT_FAILURE;
+    }
+
+    if ((f = fopen (argv[1], "r")) == NULL) {
+        perror ("FOPEN");
+        return EXIT_FAILURE;
+    }
+
+    if ((cf = malloc (sizeof (Header))) == NULL)
+        return EXIT_FAILURE;
+    if ((num = fread (cf, 1, sizeof (Header), f)) < 1)
+        return EXIT_FAILURE;
+
+    printf ("  MAGIC: %2X%2X%2X%2X\n", cf->magic[0], cf->magic[1], cf->magic[2], cf->magic[3]);
+    printf ("VERSION: %02d.%02d\n", cf->major_version[1], cf->major_version[0]);
+    printf ("POOLCTN: %2d:%2d\n", cf->constant_pool_count[1], cf->constant_pool_count[0]);
+
+    if (cf != NULL)
+        free (cf);
+
+    OPCODE = 1;
+    while (!feof (f)) {
+        num = fread (buffer, 1, sizeof (buffer), f);
+        for (i = 0; i < num; i++) {
+            if (OPCODE) {
+                switch (buffer[i]) {
+                case 50:
+                    printf ("aaload ");
+                    break;
+                case 83:
+                    printf ("aastore ");
+                    break;
+                case 1:
+                    printf ("aconst_null ");
+                    break;
+                case 25:
+                    printf ("aload ");
+                    break;
+                case 42:
+                    printf ("aload_0 ");
+                    break;
+                case 43:
+                    printf ("aload_1 ");
+                    break;
+                case 44:
+                    printf ("aload_2 ");
+                    break;
+                case 45:
+                    printf ("aload_3 ");
+                    break;
+                case 189:
+                    printf ("anewarray ");
+                    break;
+                case 176:
+                    printf ("areturn ");
+                    break;
+                case 190:
+                    printf ("arraylength ");
+                    break;
+                case 58:
+                    printf ("astore ");
+                    break;
+                case 75:
+                    printf ("astore_0 ");
+                    break;
+                case 76:
+                    printf ("astore_1 ");
+                    break;
+                case 77:
+                    printf ("astore_2 ");
+                    break;
+                case 78:
+                    printf ("astore_3 ");
+                    break;
+                case 191:
+                    printf ("athrow ");
+                    break;
+                case 51:
+                    printf ("baload ");
+                    break;
+                case 84:
+                    printf ("bastore ");
+                    break;
+                case 16:
+                    printf ("bipush ");
+                    break;
+                case 52:
+                    printf ("caload ");
+                    break;
+                case 85:
+                    printf ("castore ");
+                    break;
+                case 192:
+                    printf ("checkcast ");
+                    break;
+                case 144:
+                    printf ("d2f ");
+                    break;
+                case 142:
+                    printf ("d2i ");
+                    break;
+                case 143:
+                    printf ("d2l ");
+                    break;
+                case 99:
+                    printf ("dadd ");
+                    break;
+                case 49:
+                    printf ("daload ");
+                    break;
+                case 82:
+                    printf ("dastore ");
+                    break;
+                case 152:
+                    printf ("dcmp ");
+                    break;
+                case 14:
+                    printf ("dconst_0 ");
+                    break;
+                case 15:
+                    printf ("dconst_1 ");
+                    break;
+                case 111:
+                    printf ("ddiv ");
+                    break;
+                case 24:
+                    printf ("dload ");
+                    break;
+                case 38:
+                    printf ("dload_0 ");
+                    break;
+                case 39:
+                    printf ("dload_1 ");
+                    break;
+                case 40:
+                    printf ("dload_2 ");
+                    break;
+                case 41:
+                    printf ("dload_3 ");
+                    break;
+                case 107:
+                    printf ("dmul ");
+                    break;
+                case 119:
+                    printf ("dneg ");
+                    break;
+                case 115:
+                    printf ("drem ");
+                    break;
+                case 175:
+                    printf ("dreturn ");
+                    break;
+                case 57:
+                    printf ("dstore ");
+                    break;
+                case 71:
+                    printf ("dstore_0 ");
+                    break;
+                case 72:
+                    printf ("dstore_1 ");
+                    break;
+                case 73:
+                    printf ("dstore_2 ");
+                    break;
+                case 74:
+                    printf ("dstore_3 ");
+                    break;
+                case 103:
+                    printf ("dsub ");
+                    break;
+                case 89:
+                    printf ("dup ");
+                    break;
+                case 90:
+                    printf ("dup_x1 ");
+                    break;
+                case 91:
+                    printf ("dup_x2 ");
+                    break;
+                case 92:
+                    printf ("dup2 ");
+                    break;
+                case 93:
+                    printf ("dup2_x1 ");
+                    break;
+                case 94:
+                    printf ("dup2_x2 ");
+                    break;
+                case 141:
+                    printf ("f2d ");
+                    break;
+                case 139:
+                    printf ("f2i ");
+                    break;
+                case 140:
+                    printf ("f2l ");
+                    break;
+                case 98:
+                    printf ("fadd ");
+                    break;
+                case 48:
+                    printf ("faload ");
+                    break;
+                case 81:
+                    printf ("fastore ");
+                    break;
+                case 150:
+                    printf ("fcmpg ");
+                    break;
+                case 149:
+                    printf ("fcmpl ");
+                    break;
+                case 11:
+                    printf ("fconst_0 ");
+                    break;
+                case 12:
+                    printf ("fconst_1 ");
+                    break;
+                case 13:
+                    printf ("fconst_2 ");
+                    break;
+                case 110:
+                    printf ("fdiv ");
+                    break;
+                case 23:
+                    printf ("fload ");
+                    break;
+                case 34:
+                    printf ("fload_0 ");
+                    break;
+                case 35:
+                    printf ("fload_1 ");
+                    break;
+                case 36:
+                    printf ("fload_2 ");
+                    break;
+                case 37:
+                    printf ("fload_3 ");
+                    break;
+                case 106:
+                    printf ("fmul ");
+                    break;
+                case 118:
+                    printf ("fneg ");
+                    break;
+                case 114:
+                    printf ("frem ");
+                    break;
+                case 174:
+                    printf ("freturn ");
+                    break;
+                case 56:
+                    printf ("fstore ");
+                    break;
+                case 67:
+                    printf ("fstore_0 ");
+                    break;
+                case 68:
+                    printf ("fstore_1 ");
+                    break;
+                case 69:
+                    printf ("fstore_2 ");
+                    break;
+                case 70:
+                    printf ("fstore_3 ");
+                    break;
+                case 102:
+                    printf ("fsub ");
+                    break;
+                case 180:
+                    printf ("getfield ");
+                    break;
+                case 178:
+                    printf ("getstatic ");
+                    break;
+                case 167:
+                    printf ("goto ");
+                    break;
+                case 200:
+                    printf ("goto_w ");
+                    break;
+                case 145:
+                    printf ("i2b ");
+                    break;
+                case 146:
+                    printf ("i2c ");
+                    break;
+                case 135:
+                    printf ("i2d ");
+                    break;
+                case 134:
+                    printf ("i2f ");
+                    break;
+                case 133:
+                    printf ("i2l ");
+                    break;
+                case 147:
+                    printf ("i2s ");
+                    break;
+                case 96:
+                    printf ("iadd ");
+                    break;
+                case 46:
+                    printf ("iaload ");
+                    break;
+                case 126:
+                    printf ("iand ");
+                    break;
+                case 79:
+                    printf ("iastore ");
+                    break;
+                case 2:
+                    printf ("iconst_m1 ");
+                    break;
+                case 3:
+                    printf ("iconst_0 ");
+                    break;
+                case 4:
+                    printf ("iconst_1 ");
+                    break;
+                case 5:
+                    printf ("iconst_2 ");
+                    break;
+                case 6:
+                    printf ("iconst_3 ");
+                    break;
+                case 7:
+                    printf ("iconst_4 ");
+                    break;
+                case 8:
+                    printf ("iconst_5 ");
+                    break;
+                case 108:
+                    printf ("idiv ");
+                    break;
+                case 165:
+                    printf ("if_acmpeq ");
+                    break;
+                case 166:
+                    printf ("if_acmpne ");
+                    break;
+                case 159:
+                    printf ("if_icmpeq ");
+                    break;
+                case 160:
+                    printf ("if_icmpne ");
+                    break;
+                case 161:
+                    printf ("if_icmplt ");
+                    break;
+                case 162:
+                    printf ("if_icmpge ");
+                    break;
+                case 163:
+                    printf ("if_icmpgt ");
+                    break;
+                case 164:
+                    printf ("if_icmple ");
+                    break;
+                case 153:
+                    printf ("ifeq ");
+                    break;
+                case 154:
+                    printf ("ifne ");
+                    break;
+                case 155:
+                    printf ("iflt ");
+                    break;
+                case 156:
+                    printf ("ifge ");
+                    break;
+                case 157:
+                    printf ("ifgt ");
+                    break;
+                case 158:
+                    printf ("ifle ");
+                    break;
+                case 199:
+                    printf ("ifnonnull ");
+                    break;
+                case 198:
+                    printf ("ifnull ");
+                    break;
+                case 132:
+                    printf ("iinc %d %d\n", buffer[i + 1], buffer[i + 2]);
+                    i += 2;
+                    continue;
+                    break;
+                case 21:
+                    printf ("iload ");
+                    break;
+                case 26:
+                    printf ("iload_0 ");
+                    break;
+                case 27:
+                    printf ("iload_1 ");
+                    break;
+                case 28:
+                    printf ("iload_2 ");
+                    break;
+                case 29:
+                    printf ("iload_3 ");
+                    break;
+                case 104:
+                    printf ("imul ");
+                    break;
+                case 116:
+                    printf ("ineg ");
+                    break;
+                case 193:
+                    printf ("instanceof ");
+                    break;
+                case 185:
+                    printf ("invokeinterface ");
+                    break;
+                case 183:
+                    printf ("invokespecial ");
+                    break;
+                case 184:
+                    printf ("invokestatic ");
+                    break;
+                case 182:
+                    printf ("invokevirtual ");
+                    break;
+                case 128:
+                    printf ("ior ");
+                    break;
+                case 112:
+                    printf ("irem ");
+                    break;
+                case 172:
+                    printf ("ireturn ");
+                    break;
+                case 120:
+                    printf ("ishl ");
+                    break;
+                case 122:
+                    printf ("ishr ");
+                    break;
+                case 54:
+                    printf ("istore ");
+                    break;
+                case 59:
+                    printf ("istore_0 ");
+                    break;
+                case 60:
+                    printf ("istore_1 ");
+                    break;
+                case 61:
+                    printf ("istore_2 ");
+                    break;
+                case 62:
+                    printf ("istore_3 ");
+                    break;
+                case 100:
+                    printf ("isub ");
+                    break;
+                case 124:
+                    printf ("iushr ");
+                    break;
+                case 130:
+                    printf ("ixor ");
+                    break;
+                case 168:
+                    printf ("jsr ");
+                    break;
+                case 201:
+                    printf ("jsr_w ");
+                    break;
+                case 138:
+                    printf ("l2d ");
+                    break;
+                case 137:
+                    printf ("l2f ");
+                    break;
+                case 136:
+                    printf ("l2i ");
+                    break;
+                case 97:
+                    printf ("ladd ");
+                    break;
+                case 47:
+                    printf ("laload ");
+                    break;
+                case 127:
+                    printf ("land ");
+                    break;
+                case 80:
+                    printf ("lastore ");
+                    break;
+                case 148:
+                    printf ("lcmd ");
+                    break;
+                case 9:
+                    printf ("lconst_0 ");
+                    break;
+                case 10:
+                    printf ("lconst_1 ");
+                    break;
+                case 18:
+                    printf ("ldc ");
+                    break;
+                case 19:
+                    printf ("ldc_w ");
+                    break;
+                case 20:
+                    printf ("ldc2_w ");
+                    break;
+                case 109:
+                    printf ("ldiv ");
+                    break;
+                case 22:
+                    printf ("lload ");
+                    break;
+                case 30:
+                    printf ("lload_0 ");
+                    break;
+                case 31:
+                    printf ("lload_1 ");
+                    break;
+                case 32:
+                    printf ("lload_2 ");
+                    break;
+                case 33:
+                    printf ("lload_3 ");
+                    break;
+                case 105:
+                    printf ("lmul ");
+                    break;
+                case 117:
+                    printf ("lneg ");
+                    break;
+                case 171:
+                    printf ("lookupswitch ");
+                    break;
+                case 129:
+                    printf ("lor ");
+                    break;
+                case 113:
+                    printf ("lrem ");
+                    break;
+                case 173:
+                    printf ("lreturn ");
+                    break;
+                case 121:
+                    printf ("lshl ");
+                    break;
+                case 123:
+                    printf ("lshr ");
+                    break;
+                case 55:
+                    printf ("lstore ");
+                    break;
+                case 63:
+                    printf ("lstore_0 ");
+                    break;
+                case 64:
+                    printf ("lstore_1 ");
+                    break;
+                case 65:
+                    printf ("lstore_2 ");
+                    break;
+                case 66:
+                    printf ("lstore_3 ");
+                    break;
+                case 101:
+                    printf ("lsub ");
+                    break;
+                case 125:
+                    printf ("lushr ");
+                    break;
+                case 131:
+                    printf ("lxor ");
+                    break;
+                case 194:
+                    printf ("monitorenter ");
+                    break;
+                case 195:
+                    printf ("monitorexit ");
+                    break;
+                case 197:
+                    printf ("multianewarray ");
+                    break;
+                case 187:
+                    printf ("new ");
+                    break;
+                case 188:
+                    printf ("newarray ");
+                    break;
+                case 0:
+                    printf ("nop ");
+                    break;
+                case 87:
+                    printf ("pop ");
+                    break;
+                case 88:
+                    printf ("pop2 ");
+                    break;
+                case 181:
+                    printf ("putfield ");
+                    break;
+                case 179:
+                    printf ("putstatic ");
+                    break;
+                case 169:
+                    printf ("ret ");
+                    break;
+                case 177:
+                    printf ("return ");
+                    break;
+                case 53:
+                    printf ("saload ");
+                    break;
+                case 86:
+                    printf ("sastore ");
+                    break;
+                case 17:
+                    printf ("sipush ");
+                    break;
+                case 95:
+                    printf ("swap ");
+                    break;
+                case 170:
+                    printf ("tableswitch ");
+                    break;
+                case 196:
+                    printf ("wide ");
+                    break;
+                case 202:      /* reserved item */
+                    printf ("breakpoint ");
+                    break;
+                case 254:      /* reserved item */
+                    printf ("impdep1 ");
+                    break;
+                case 255:      /* reserved item */
+                    printf ("impdep2 ");
+                    break;
+                default:
+                    printf ("OPCODE %02X(%d) ", buffer[i], buffer[i]);
+                }
+                OPCODE = 0;
+            } else
+                switch (buffer[i]) {
+                case '\0':
+                case '>':
+                case '<':
+                    printf ("\n");
+                    OPCODE = 1;
+                    break;
+                default:
+                    if (isprint (buffer[i]))
+                        printf ("%c", buffer[i]);
+                    else
+                        printf ("%02X ", buffer[i]);
+                }
+        }
+    }
+
+    printf ("\n");
+
+    if (f != NULL)
+        fclose (f);
+
+    return EXIT_SUCCESS;
+}