1 files changed, 94 insertions, 0 deletions
diff --git a/include/exec/gen-icount.h b/include/exec/gen-icount.h
new file mode 100644
index 000000000..c57204dda
--- /dev/null
+++ b/include/exec/gen-icount.h
@@ -0,0 +1,94 @@
+#ifndef GEN_ICOUNT_H
+#define GEN_ICOUNT_H
+
+#include "exec/exec-all.h"
+#include "qemu/timer.h"
+
+/* Helpers for instruction counting code generation.  */
+
+static TCGOp *icount_start_insn;
+
+static inline void gen_io_start(void)
+{
+    TCGv_i32 tmp = tcg_const_i32(1);
+    tcg_gen_st_i32(tmp, cpu_env,
+                   offsetof(ArchCPU, parent_obj.can_do_io) -
+                   offsetof(ArchCPU, env));
+    tcg_temp_free_i32(tmp);
+}
+
+static inline void gen_tb_start(const TranslationBlock *tb)
+{
+    TCGv_i32 count;
+
+    if (tb_cflags(tb) & CF_USE_ICOUNT) {
+        count = tcg_temp_local_new_i32();
+    } else {
+        count = tcg_temp_new_i32();
+    }
+
+    tcg_gen_ld_i32(count, cpu_env,
+                   offsetof(ArchCPU, neg.icount_decr.u32) -
+                   offsetof(ArchCPU, env));
+
+    if (tb_cflags(tb) & CF_USE_ICOUNT) {
+        /*
+         * We emit a sub with a dummy immediate argument. Keep the insn index
+         * of the sub so that we later (when we know the actual insn count)
+         * can update the argument with the actual insn count.
+         */
+        tcg_gen_sub_i32(count, count, tcg_constant_i32(0));
+        icount_start_insn = tcg_last_op();
+    }
+
+    /*
+     * Emit the check against icount_decr.u32 to see if we should exit
+     * unless we suppress the check with CF_NOIRQ. If we are using
+     * icount and have suppressed interruption the higher level code
+     * should have ensured we don't run more instructions than the
+     * budget.
+     */
+    if (tb_cflags(tb) & CF_NOIRQ) {
+        tcg_ctx->exitreq_label = NULL;
+    } else {
+        tcg_ctx->exitreq_label = gen_new_label();
+        tcg_gen_brcondi_i32(TCG_COND_LT, count, 0, tcg_ctx->exitreq_label);
+    }
+
+    if (tb_cflags(tb) & CF_USE_ICOUNT) {
+        tcg_gen_st16_i32(count, cpu_env,
+                         offsetof(ArchCPU, neg.icount_decr.u16.low) -
+                         offsetof(ArchCPU, env));
+        /*
+         * cpu->can_do_io is cleared automatically here at the beginning of
+         * each translation block.  The cost is minimal and only paid for
+         * -icount, plus it would be very easy to forget doing it in the
+         * translator. Doing it here means we don't need a gen_io_end() to
+         * go with gen_io_start().
+         */
+        tcg_gen_st_i32(tcg_constant_i32(0), cpu_env,
+                       offsetof(ArchCPU, parent_obj.can_do_io) -
+                       offsetof(ArchCPU, env));
+    }
+
+    tcg_temp_free_i32(count);
+}
+
+static inline void gen_tb_end(const TranslationBlock *tb, int num_insns)
+{
+    if (tb_cflags(tb) & CF_USE_ICOUNT) {
+        /*
+         * Update the num_insn immediate parameter now that we know
+         * the actual insn count.
+         */
+        tcg_set_insn_param(icount_start_insn, 2,
+                           tcgv_i32_arg(tcg_constant_i32(num_insns)));
+    }
+
+    if (tcg_ctx->exitreq_label) {
+        gen_set_label(tcg_ctx->exitreq_label);
+        tcg_gen_exit_tb(tb, TB_EXIT_REQUESTED);
+    }
+}
+
+#endif