diff --git a/emulator_shell.c b/emulator_shell.c
index 65388f1..b0002fa 100644
--- a/emulator_shell.c
+++ b/emulator_shell.c
@@ -78,7 +78,7 @@ int emulate8080(State8080* state) {
             uint32_t res = h1 + bc;
             state->h = (res & 0xff) >> 8;
             state->l = res & 0xff;
-            state->cc.cy = ((res & 0xffff0000) > 0);
+            state->cc.cy = ((res & 0xffff0000) != 0);
             break;
         
         case 0x0d:              // DCR C
@@ -134,6 +134,12 @@ int emulate8080(State8080* state) {
             state->h = opcode[1];
             state->pc += 1;
             break;
+        case 0x29:              // DAD H
+            uint32_t h1 = (state->h << 8) | state->l;
+            uint32_t res = hl + hl;
+            state->h = (res & 0xff00) >> 8;
+            state->l = res & 0xff;
+            state->cc.cy = ((res & 0xffff0000) != 0);
         case 0x31:              // LXI SP, word
             state->sp = (opcode[2] << 8) | opcode[1]);
             state->pc += 2;