include/exec/gen-icount.h

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