Thinking Flow

study qemu code: tcg_reg_alloc_op(): 1708

1. what is fixed_reg TCGemp 
1. in tcg_global_reg_new_internal, fixed_reg is set 1
2. in tcg_global_mem_new_internal, fixed_reg is set 0
3. so, it seems it indicates whether this temp is register or not
2. In TCGContext, what is reg_to_temp?
1. in tcg_reg_alloc(), s->reg_to_temp[reg] decides whether the HOST register is mapped to any TCGTemp.
2. So I think, reg_to_temp indicates current HOST reg represents reg_to_temp[reg].
3. What is val_type in TCGTemp?
1. NOT CLEAR
2. It seems it indicates the current type of this temp.
3. It is possible that ts->fixed_reg && ts->val_type == TEMP_VAL_MEM; or                            NOT ts->fixed_reg and ts->val_type == TEMP_VAL_REG.
4. When does TCGArgDef args_ct set?
1. 
   
5.