Make `OP_JMP*` operand address to be relative.

Jump target address is `operand (16bit)` + `address of next instruction`.

In addition, `ilen` was made `uint32_t` so that `iseq` length limitation
of 65536 is removed. Only jump target address should be within signed
16bit (-32768 .. 32767).

2 files changed, 16 insertions, 10 deletions

diff --git a/src/codedump.c b/src/codedump.c
index 4f793b753..94d4f24c0 100644
--- a/src/codedump.c
+++ b/src/codedump.c
@@ -271,21 +271,26 @@ codedump(mrb_state *mrb, const mrb_irep *irep)
       print_lv_a(mrb, irep, a);
       break;
     CASE(OP_JMP, S);
-      printf("OP_JMP\t\t%03d\n", a);
+      i = pc - irep->iseq;
+      printf("OP_JMP\t\t%03d\n", (int)i+(int16_t)a);
       break;
     CASE(OP_JMPUW, S);
-      printf("OP_JMPUW\t\t%03d\n", a);
+      i = pc - irep->iseq;
+      printf("OP_JMPUW\t\t%03d\n", (int)i+(int16_t)a);
       break;
     CASE(OP_JMPIF, BS);
-      printf("OP_JMPIF\tR%d\t%03d\t", a, b);
+      i = pc - irep->iseq;
+      printf("OP_JMPIF\tR%d\t%03d\t", a, (int)i+(int16_t)b);
       print_lv_a(mrb, irep, a);
       break;
     CASE(OP_JMPNOT, BS);
-      printf("OP_JMPNOT\tR%d\t%03d\t", a, b);
+      i = pc - irep->iseq;
+      printf("OP_JMPNOT\tR%d\t%03d\t", a, (int)i+(int16_t)b);
       print_lv_a(mrb, irep, a);
       break;
     CASE(OP_JMPNIL, BS);
-      printf("OP_JMPNIL\tR%d\t%03d\t", a, b);
+      i = pc - irep->iseq;
+      printf("OP_JMPNIL\tR%d\t%03d\t", a, (int)i+(int16_t)b);
       print_lv_a(mrb, irep, a);
       break;
     CASE(OP_SENDV, BB);
diff --git a/src/vm.c b/src/vm.c
index a0d4c967b..85835149a 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -1274,26 +1274,26 @@ RETRY_TRY_BLOCK:
     }
 
     CASE(OP_JMP, S) {
-      pc = irep->iseq+a;
+      pc += (int16_t)a;
       JUMP;
     }
     CASE(OP_JMPIF, BS) {
       if (mrb_test(regs[a])) {
-        pc = irep->iseq+b;
+        pc += (int16_t)b;
         JUMP;
       }
       NEXT;
     }
     CASE(OP_JMPNOT, BS) {
       if (!mrb_test(regs[a])) {
-        pc = irep->iseq+b;
+        pc += (int16_t)b;
         JUMP;
       }
       NEXT;
     }
     CASE(OP_JMPNIL, BS) {
       if (mrb_nil_p(regs[a])) {
-        pc = irep->iseq+b;
+        pc += (int16_t)b;
         JUMP;
       }
       NEXT;
@@ -1306,6 +1306,7 @@ RETRY_TRY_BLOCK:
         mrb_assert(mrb_integer_p(target));
         a = (uint32_t)mrb_integer(target);
         mrb_assert(a >= 0 && a < irep->ilen);
+        a = a - (pc - irep->iseq);
       }
       CHECKPOINT_MAIN(RBREAK_TAG_JUMP) {
         ch = catch_handler_find(mrb, mrb->c->ci, pc, MRB_CATCH_FILTER_ENSURE);
@@ -1319,7 +1320,7 @@ RETRY_TRY_BLOCK:
       CHECKPOINT_END(RBREAK_TAG_JUMP);
 
       mrb->exc = NULL; /* clear break object */
-      pc = irep->iseq + a;
+      pc += (int16_t)a;
       JUMP;
     }