Hi, I am trying to understand how TCG works. For example, I look at the LLDT insn on x86.
In target-i386/translate.c, we translate LLDT to TCG code, like below: static TCGv_i32 cpu_tmp2_i32; // 1 ... gen_ldst_modrm(s, modrm, OT_WORD, OR_TMP0, 0); // 2 gen_jmp_im(pc_start - s->cs_base); // 3 tcg_gen_trunc_tl_i32(cpu_tmp2_i32, cpu_T[0]); // 4 gen_helper_lldt(cpu_tmp2_i32); // 5 This is quite confused. I understand that: - In line (2), we retrieve the operand and save it into cpu_T[0]. - Line (3) generates jump code, but I dont understand why we need that ???? - Line (4) generate the code to copy cpu_T[0] to the (local) variable cpu_tmp2_i32. However, as tcg_gen_trunc_tl_i32() put the *value* of that variable, but not its *address*, into the generated code, I dont see how next line (5) can generate code that use the same variable. Clearly there is no connection between cpu_tmp2_i32 on line (4) and line (5), so how the generated code works here?? Thanks a lot, Jun