Correct info about blk args.
* Textual presentation of block type argument in `func` has form `blk:<size>(<var_name>)`.
The corresponding argument in `call` insn should have analogous form
`blk:<the same size>(<local var name containing address of passed block data>)`
- * Block data are passed by value. How they are exactly passed is machine-defined:
- * they are always passed on stack for x86-64, aarch64, and s390x
- * they can (partially) passed through registers and on stack for ppc64
+ * Block data are passed by value. How they are exactly passed is machine-defined (please read files mir-<target>.c):
+ * they can be passed on stack, or (partially) in registers, or by address
* Non-argument function variables are created through API function
`MIR_reg_t MIR_new_func_reg (MIR_context_t ctx, MIR_func_t func, MIR_type_t type, const char *name)`
* The only permitted integer type for the variable is `MIR_T_I64` (or MIR_T_U64???)
