Add description of va_arg_builtin and va_stack_arg_builtin.
@@ -66,6 +66,12 @@ examine existing files `mir-x86_64.c`, `mir-aarhc64.c`,
function argument. The generated function is used to implement
`MIR_BEND` insn in the interpreter
+ * `void *va_arg_builtin (void *p, uint64_t t)` returns address of
+ the next argument of MIR type `t`, where `p` is `va_list`
+
+ * `void *va_stack_arg_builtin (void *p, size_t s)` returns address of
+ the next argument of MIR type `MIR_T_BLK` of size `s`, where `p` is `va_list`
+
* `void *_MIR_get_interp_shim (MIR_context_t ctx, MIR_item_t
func_item, void *handler)` generates and returns a function behaving as usual
C function which calls function `void handler (MIR_context_t ctx,
