Annotation of qemu/gen-icount.h, revision 1.1.1.1

1.1       root        1: /* Helpers for instruction counting code generation.  */
                      2: 
                      3: static TCGArg *icount_arg;
                      4: static int icount_label;
                      5: 
                      6: static inline void gen_icount_start(void)
                      7: {
                      8:     TCGv_i32 count;
                      9: 
                     10:     if (!use_icount)
                     11:         return;
                     12: 
                     13:     icount_label = gen_new_label();
                     14:     /* FIXME: This generates lousy code.  We can't use tcg_new_temp because
                     15:        count needs to live over the conditional branch.  To workaround this
                     16:        we allow the target to supply a convenient register temporary.  */
                     17: #ifndef ICOUNT_TEMP
                     18:     count = tcg_temp_local_new_i32();
                     19: #else
                     20:     count = ICOUNT_TEMP;
                     21: #endif
                     22:     tcg_gen_ld_i32(count, cpu_env, offsetof(CPUState, icount_decr.u32));
                     23:     /* This is a horrid hack to allow fixing up the value later.  */
                     24:     icount_arg = gen_opparam_ptr + 1;
                     25:     tcg_gen_subi_i32(count, count, 0xdeadbeef);
                     26: 
                     27:     tcg_gen_brcondi_i32(TCG_COND_LT, count, 0, icount_label);
                     28:     tcg_gen_st16_i32(count, cpu_env, offsetof(CPUState, icount_decr.u16.low));
                     29: #ifndef ICOUNT_TEMP
                     30:     tcg_temp_free_i32(count);
                     31: #endif
                     32: }
                     33: 
                     34: static void gen_icount_end(TranslationBlock *tb, int num_insns)
                     35: {
                     36:     if (use_icount) {
                     37:         *icount_arg = num_insns;
                     38:         gen_set_label(icount_label);
                     39:         tcg_gen_exit_tb((long)tb + 2);
                     40:     }
                     41: }
                     42: 
                     43: static void inline gen_io_start(void)
                     44: {
                     45:     TCGv_i32 tmp = tcg_const_i32(1);
                     46:     tcg_gen_st_i32(tmp, cpu_env, offsetof(CPUState, can_do_io));
                     47:     tcg_temp_free_i32(tmp);
                     48: }
                     49: 
                     50: static inline void gen_io_end(void)
                     51: {
                     52:     TCGv_i32 tmp = tcg_const_i32(0);
                     53:     tcg_gen_st_i32(tmp, cpu_env, offsetof(CPUState, can_do_io));
                     54:     tcg_temp_free_i32(tmp);
                     55: }

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