qemu

FORK: QEMU emulator
git clone https://git.neptards.moe/neptards/qemu.git
Log | Files | Refs | Submodules | LICENSE

gen-icount.h (2988B)

      1 #ifndef GEN_ICOUNT_H
      2 #define GEN_ICOUNT_H
      3 
      4 #include "exec/exec-all.h"
      5 #include "qemu/timer.h"
      6 
      7 /* Helpers for instruction counting code generation.  */
      8 
      9 static TCGOp *icount_start_insn;
     10 
     11 static inline void gen_io_start(void)
     12 {
     13     TCGv_i32 tmp = tcg_const_i32(1);
     14     tcg_gen_st_i32(tmp, cpu_env,
     15                    offsetof(ArchCPU, parent_obj.can_do_io) -
     16                    offsetof(ArchCPU, env));
     17     tcg_temp_free_i32(tmp);
     18 }
     19 
     20 static inline void gen_tb_start(const TranslationBlock *tb)
     21 {
     22     TCGv_i32 count;
     23 
     24     if (tb_cflags(tb) & CF_USE_ICOUNT) {
     25         count = tcg_temp_local_new_i32();
     26     } else {
     27         count = tcg_temp_new_i32();
     28     }
     29 
     30     tcg_gen_ld_i32(count, cpu_env,
     31                    offsetof(ArchCPU, neg.icount_decr.u32) -
     32                    offsetof(ArchCPU, env));
     33 
     34     if (tb_cflags(tb) & CF_USE_ICOUNT) {
     35         /*
     36          * We emit a sub with a dummy immediate argument. Keep the insn index
     37          * of the sub so that we later (when we know the actual insn count)
     38          * can update the argument with the actual insn count.
     39          */
     40         tcg_gen_sub_i32(count, count, tcg_constant_i32(0));
     41         icount_start_insn = tcg_last_op();
     42     }
     43 
     44     /*
     45      * Emit the check against icount_decr.u32 to see if we should exit
     46      * unless we suppress the check with CF_NOIRQ. If we are using
     47      * icount and have suppressed interruption the higher level code
     48      * should have ensured we don't run more instructions than the
     49      * budget.
     50      */
     51     if (tb_cflags(tb) & CF_NOIRQ) {
     52         tcg_ctx->exitreq_label = NULL;
     53     } else {
     54         tcg_ctx->exitreq_label = gen_new_label();
     55         tcg_gen_brcondi_i32(TCG_COND_LT, count, 0, tcg_ctx->exitreq_label);
     56     }
     57 
     58     if (tb_cflags(tb) & CF_USE_ICOUNT) {
     59         tcg_gen_st16_i32(count, cpu_env,
     60                          offsetof(ArchCPU, neg.icount_decr.u16.low) -
     61                          offsetof(ArchCPU, env));
     62         /*
     63          * cpu->can_do_io is cleared automatically here at the beginning of
     64          * each translation block.  The cost is minimal and only paid for
     65          * -icount, plus it would be very easy to forget doing it in the
     66          * translator. Doing it here means we don't need a gen_io_end() to
     67          * go with gen_io_start().
     68          */
     69         tcg_gen_st_i32(tcg_constant_i32(0), cpu_env,
     70                        offsetof(ArchCPU, parent_obj.can_do_io) -
     71                        offsetof(ArchCPU, env));
     72     }
     73 
     74     tcg_temp_free_i32(count);
     75 }
     76 
     77 static inline void gen_tb_end(const TranslationBlock *tb, int num_insns)
     78 {
     79     if (tb_cflags(tb) & CF_USE_ICOUNT) {
     80         /*
     81          * Update the num_insn immediate parameter now that we know
     82          * the actual insn count.
     83          */
     84         tcg_set_insn_param(icount_start_insn, 2,
     85                            tcgv_i32_arg(tcg_constant_i32(num_insns)));
     86     }
     87 
     88     if (tcg_ctx->exitreq_label) {
     89         gen_set_label(tcg_ctx->exitreq_label);
     90         tcg_gen_exit_tb(tb, TB_EXIT_REQUESTED);
     91     }
     92 }
     93 
     94 #endif