allows assigning to mask_view elements

src/vm/vector_functions.h

@@ -53,10 +53,20 @@ struct vtype_t {
     bool vma();
     bool vta();
 };
+class mask_bit_reference {
+    uint8_t* start;
+    uint8_t pos;
+
+public:
+    mask_bit_reference& operator=(const bool new_value);
+    mask_bit_reference(uint8_t* start, uint8_t pos);
+    operator bool() const;
+};
+
 struct vmask_view {
     uint8_t* start;
     size_t elem_count;
-    bool operator[](size_t) const;
+    mask_bit_reference operator[](size_t) const;
 };
 enum class carry_t { NO_CARRY = 0, ADD_CARRY = 1, SUB_CARRY = 2 };
 vmask_view read_vmask(uint8_t* V, uint16_t VLEN, uint16_t elem_count, uint8_t reg_idx = 0);