diff --git a/src/opcodes.h b/src/opcodes.h
index e42ab70..d1b1acf 100644
--- a/src/opcodes.h
+++ b/src/opcodes.h
@@ -105,7 +105,7 @@ typedef struct vm_s {
   u32 rp;  /* return stack pointer (top of stack) */
   u32 mp;  /* memory pointer (last allocated value) */
   u32 dc;  /* device count */
-  u32 acc; /* accumulator (temporary results like SYSCALL status) */
+  u32 flag; /* flag (temporary results like SYSCALL status) */
   Frame frames[FRAMES_SIZE];    /* function call frames */
   u32 stack[STACK_SIZE];        /* main stack */
   u32 return_stack[STACK_SIZE]; /* return stack (for call recursion) */
diff --git a/src/vm.c b/src/vm.c
index 395893c..5efb9bc 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -155,15 +155,15 @@ bool step_vm(VM *vm) {
 
         if (dev) {
           if (dev->ops->open) {
-            vm->acc = dev->ops->open(dev->data, mode);
+            vm->flag = dev->ops->open(dev->data, mode);
           } else {
-            vm->acc = 1; /* success, no open needed */
+            vm->flag = 1; /* success, no open needed */
           }
         } else {
-          vm->acc = 0; /* error */
+          vm->flag = 0; /* error */
         }
       } else {
-        vm->acc = 0; /* error: not enough arguments */
+        vm->flag = 0; /* error: not enough arguments */
       }
       return true;
     }
@@ -181,13 +181,13 @@ bool step_vm(VM *vm) {
 
         dev = find_device_by_path(vm, (const char *)&vm->memory[path_ptr + 4]);
         if (dev && dev->ops->read) {
-          vm->acc =
+          vm->flag =
               dev->ops->read(dev->data, (u8 *)&vm->memory[buffer_ptr], size);
         } else {
-          vm->acc = 0;
+          vm->flag = 0;
         }
       } else {
-        vm->acc = 0; /* error: not enough arguments */
+        vm->flag = 0; /* error: not enough arguments */
       }
       return true;
     }
@@ -204,13 +204,13 @@ bool step_vm(VM *vm) {
 
         dev = find_device_by_path(vm, (const char *)&vm->memory[path_ptr + 4]);
         if (dev && dev->ops->write) {
-          vm->acc = dev->ops->write(dev->data, (const u8 *)&vm->memory[buffer_ptr + 4],
+          vm->flag = dev->ops->write(dev->data, (const u8 *)&vm->memory[buffer_ptr + 4],
                                     size);
         } else {
-          vm->acc = 0;
+          vm->flag = 0;
         }
       } else {
-        vm->acc = 0; /* error: not enough arguments */
+        vm->flag = 0; /* error: not enough arguments */
       }
       return true;
     }
@@ -226,12 +226,12 @@ bool step_vm(VM *vm) {
 
         if (dev && dev->ops->close) {
           i32 result = dev->ops->close(dev->data);
-          vm->acc = result;
+          vm->flag = result;
         } else {
-          vm->acc = 0;
+          vm->flag = 0;
         }
       } else {
-        vm->acc = 0; /* error: not enough arguments */
+        vm->flag = 0; /* error: not enough arguments */
       }
       return true;
     }
@@ -251,12 +251,12 @@ bool step_vm(VM *vm) {
 
         if (dev && dev->ops && dev->ops->ioctl) {
           i32 result = dev->ops->ioctl(dev->data, cmd, &vm->memory[args_ptr]);
-          vm->acc = result;
+          vm->flag = result;
         } else {
-          vm->acc = 0; /* error or no ioctl support */
+          vm->flag = 0; /* error or no ioctl support */
         }
       } else {
-        vm->acc = 0; /* error: not enough arguments */
+        vm->flag = 0; /* error: not enough arguments */
       }
       return true;
     }
@@ -266,7 +266,7 @@ bool step_vm(VM *vm) {
     }
 
     default: {
-      vm->acc = 0; /* unknown syscall */
+      vm->flag = 0; /* unknown syscall */
       return true;
     }
     }