diff --git a/lib/include/lbox.h b/lib/include/lbox.h
index 3779558..80060b0 100644
--- a/lib/include/lbox.h
+++ b/lib/include/lbox.h
@@ -27,13 +27,18 @@ struct sLaikaB_box {
 };
 
 LAIKA_FORCEINLINE void* laikaB_unlock(struct sLaikaB_box *box, void *data) {
-    struct sLaikaV_vm vm = {.pc = 0};
+    struct sLaikaV_vm vm = {
+        /* boxes have 2 reserved constants, [0] for the output, [1] for the input */
+        .constList = {
+            LAIKA_MAKE_VM_PTR(box->unlockedData),
+            LAIKA_MAKE_VM_PTR(data),
+        },
+        .code = {0},
+        .stack = {0},
+        .pc = 0
+    };
+
     memcpy(vm.code, box->code, LAIKA_VM_CODESIZE);
-
-    /* boxes have 2 reserved constants, 0 for the output, 1 for the input */
-    vm.constList[0].ptr = box->unlockedData;
-    vm.constList[1].ptr = data;
-
     laikaV_execute(&vm);
     return (void*)box->unlockedData;
 }
diff --git a/lib/include/lvm.h b/lib/include/lvm.h
index e530f37..de63e3e 100644
--- a/lib/include/lvm.h
+++ b/lib/include/lvm.h
@@ -32,11 +32,11 @@ struct sLaikaV_vm {
     int pc;
 };
 
-#define LAIKA_MAKE_VM(_consts, _code) (struct sLaikaV_vm)({.constList = _consts, .code = _code, .pc = 0, .stack = {}})
+#define LAIKA_MAKE_VM(_consts, _code) {.constList = _consts, .code = _code, .pc = 0, .stack = {0}}
 
 /* constants */
-#define LAIKA_MAKE_VM_INT(_i) (struct sLaikaV_vm_val)({.i = _i})
-#define LAIKA_MAKE_VM_PTR(_ptr) (struct sLaikaV_vm_val)({.ptr = _ptr})
+#define LAIKA_MAKE_VM_INT(_i) {.i = _i}
+#define LAIKA_MAKE_VM_PTR(_ptr) {.ptr = _ptr}
 /* instructions */
 #define LAIKA_MAKE_VM_IA(opcode, a) opcode, a
 #define LAIKA_MAKE_VM_IAB(opcode, a, b) opcode, a, b
@@ -49,6 +49,7 @@ enum {
     OP_READ, /* stk_indx[uint8_t].i = *(int8_t*)stk_indx[uint8_t] */
     OP_WRITE, /* *(uint8_t*)stk_indx[uint8_t].ptr = stk_indx[uint8_t].i */
     OP_INCPTR, /* stk_indx[uint8_t].ptr++ */
+    OP_DECPTR, /* stk_indx[uint8_t].ptr-- */
 
     /* arithmetic */
     OP_ADD, /* stk_indx[uint8_t] = stk_indx[uint8_t] + stk_indx[uint8_t] */
@@ -110,6 +111,11 @@ LAIKA_FORCEINLINE void laikaV_execute(struct sLaikaV_vm *vm) {
                 vm->stack[ptr].ptr++;
                 break;
             }
+            case OP_DECPTR: {
+                uint8_t ptr = READBYTE;
+                vm->stack[ptr].ptr--;
+                break;
+            }
             case OP_ADD: BINOP(+);
             case OP_SUB: BINOP(-);
             case OP_MUL: BINOP(*);
diff --git a/tools/vmtest/src/main.c b/tools/vmtest/src/main.c
index 11f3cab..ede8134 100644
--- a/tools/vmtest/src/main.c
+++ b/tools/vmtest/src/main.c
@@ -18,13 +18,13 @@ int main(int argv, char **argc) {
     };
 
     struct sLaikaB_box box = {
-        {0}, /* reserved */
-        { /* stack layout:
+        .unlockedData = {0}, /* reserved */
+        .code = { /* stack layout:
                 [0] - unlockedData (ptr)
                 [1] - data (ptr)
                 [2] - key (uint8_t)
                 [3] - working data (uint8_t)
-         */
+            */
             LAIKA_MAKE_VM_IAB(OP_LOADCONST, 0, 0),
             LAIKA_MAKE_VM_IAB(OP_LOADCONST, 1, 1),
             LAIKA_MAKE_VM_IAB(OP_PUSHLIT, 2, 0xDE),