include/exec/gen-icount.h

   1 #ifndef GEN_ICOUNT_H
   2 #define GEN_ICOUNT_H
   3
   4 #include "qemu/timer.h"
   5
   6 /* Helpers for instruction counting code generation.  */
   7
   8 static TCGOp *icount_start_insn;
   9
  10 static inline void gen_io_start(void)
  11 {
  12     TCGv_i32 tmp = tcg_const_i32(1);
  13     tcg_gen_st_i32(tmp, cpu_env,
  14                    offsetof(ArchCPU, parent_obj.can_do_io) -
  15                    offsetof(ArchCPU, env));
  16     tcg_temp_free_i32(tmp);
  17 }
  18
  19 /*
  20  * cpu->can_do_io is cleared automatically at the beginning of
  21  * each translation block.  The cost is minimal and only paid
  22  * for -icount, plus it would be very easy to forget doing it
  23  * in the translator.  Therefore, backends only need to call
  24  * gen_io_start.
  25  */
  26 static inline void gen_io_end(void)
  27 {
  28     TCGv_i32 tmp = tcg_const_i32(0);
  29     tcg_gen_st_i32(tmp, cpu_env,
  30                    offsetof(ArchCPU, parent_obj.can_do_io) -
  31                    offsetof(ArchCPU, env));
  32     tcg_temp_free_i32(tmp);
  33 }
  34
  35 static inline void gen_tb_start(const TranslationBlock *tb)
  36 {
  37     TCGv_i32 count;
  38
  39     tcg_ctx->exitreq_label = gen_new_label();
  40     if (tb_cflags(tb) & CF_USE_ICOUNT) {
  41         count = tcg_temp_local_new_i32();
  42     } else {
  43         count = tcg_temp_new_i32();
  44     }
  45
  46     tcg_gen_ld_i32(count, cpu_env,
  47                    offsetof(ArchCPU, neg.icount_decr.u32) -
  48                    offsetof(ArchCPU, env));
  49
  50     if (tb_cflags(tb) & CF_USE_ICOUNT) {
  51         /*
  52          * We emit a sub with a dummy immediate argument. Keep the insn index
  53          * of the sub so that we later (when we know the actual insn count)
  54          * can update the argument with the actual insn count.
  55          */
  56         tcg_gen_sub_i32(count, count, tcg_constant_i32(0));
  57         icount_start_insn = tcg_last_op();
  58     }
  59
  60     tcg_gen_brcondi_i32(TCG_COND_LT, count, 0, tcg_ctx->exitreq_label);
  61
  62     if (tb_cflags(tb) & CF_USE_ICOUNT) {
  63         tcg_gen_st16_i32(count, cpu_env,
  64                          offsetof(ArchCPU, neg.icount_decr.u16.low) -
  65                          offsetof(ArchCPU, env));
  66         gen_io_end();
  67     }
  68
  69     tcg_temp_free_i32(count);
  70 }
  71
  72 static inline void gen_tb_end(const TranslationBlock *tb, int num_insns)
  73 {
  74     if (tb_cflags(tb) & CF_USE_ICOUNT) {
  75         /*
  76          * Update the num_insn immediate parameter now that we know
  77          * the actual insn count.
  78          */
  79         tcg_set_insn_param(icount_start_insn, 2,
  80                            tcgv_i32_arg(tcg_constant_i32(num_insns)));
  81     }
  82
  83     gen_set_label(tcg_ctx->exitreq_label);
  84     tcg_gen_exit_tb(tb, TB_EXIT_REQUESTED);
  85 }
  86
  87 #endif