cpu-exec: simplify icount code

[qemu.git] / cpu-exec.c

diff --git a/cpu-exec.c b/cpu-exec.c
index 3913de020b9106f3dc37baf12984c3694f5bedb6..67381176da8cdce50e2b1a5884215321ec22d996 100644 (file)
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -61,8 +61,7 @@ static void align_clocks(SyncClocks *sc, const CPUState *cpu)
         sleep_delay.tv_sec = sc->diff_clk / 1000000000LL;
         sleep_delay.tv_nsec = sc->diff_clk % 1000000000LL;
         if (nanosleep(&sleep_delay, &rem_delay) < 0) {
-            sc->diff_clk -= (sleep_delay.tv_sec - rem_delay.tv_sec) * 1000000000LL;
-            sc->diff_clk -= sleep_delay.tv_nsec - rem_delay.tv_nsec;
+            sc->diff_clk = rem_delay.tv_sec * 1000000000LL + rem_delay.tv_nsec;
         } else {
             sc->diff_clk = 0;
         }
@@ -101,10 +100,8 @@ static void init_delay_params(SyncClocks *sc,
     if (!icount_align_option) {
         return;
     }
-    sc->realtime_clock = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
-    sc->diff_clk = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) -
-                   sc->realtime_clock +
-                   cpu_get_clock_offset();
+    sc->realtime_clock = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL_RT);
+    sc->diff_clk = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) - sc->realtime_clock;
     sc->last_cpu_icount = cpu->icount_extra + cpu->icount_decr.u16.low;
     if (sc->diff_clk < max_delay) {
         max_delay = sc->diff_clk;
@@ -168,7 +165,9 @@ static inline tcg_target_ulong cpu_tb_exec(CPUState *cpu, uint8_t *tb_ptr)
     }
 #endif /* DEBUG_DISAS */
 
+    cpu->can_do_io = 0;
     next_tb = tcg_qemu_tb_exec(env, tb_ptr);
+    cpu->can_do_io = 1;
     trace_exec_tb_exit((void *) (next_tb & ~TB_EXIT_MASK),
                        next_tb & TB_EXIT_MASK);
 
@@ -202,14 +201,19 @@ static void cpu_exec_nocache(CPUArchState *env, int max_cycles,
 {
     CPUState *cpu = ENV_GET_CPU(env);
     TranslationBlock *tb;
+    target_ulong pc = orig_tb->pc;
+    target_ulong cs_base = orig_tb->cs_base;
+    uint64_t flags = orig_tb->flags;
 
     /* Should never happen.
        We only end up here when an existing TB is too long.  */
     if (max_cycles > CF_COUNT_MASK)
         max_cycles = CF_COUNT_MASK;
 
-    tb = tb_gen_code(cpu, orig_tb->pc, orig_tb->cs_base, orig_tb->flags,
-                     max_cycles);
+    /* tb_gen_code can flush our orig_tb, invalidate it now */
+    tb_phys_invalidate(orig_tb, -1);
+    tb = tb_gen_code(cpu, pc, cs_base, flags,
+                     max_cycles | CF_NOCACHE);
     cpu->current_tb = tb;
     /* execute the generated code */
     trace_exec_tb_nocache(tb, tb->pc);
@@ -353,7 +357,6 @@ int cpu_exec(CPUArchState *env)
     }
 
     cc->cpu_exec_enter(cpu);
-    cpu->exception_index = -1;
 
     /* Calculate difference between guest clock and host clock.
      * This delay includes the delay of the last cycle, so
@@ -373,6 +376,7 @@ int cpu_exec(CPUArchState *env)
                     if (ret == EXCP_DEBUG) {
                         cpu_handle_debug_exception(env);
                     }
+                    cpu->exception_index = -1;
                     break;
                 } else {
 #if defined(CONFIG_USER_ONLY)
@@ -383,6 +387,7 @@ int cpu_exec(CPUArchState *env)
                     cc->do_interrupt(cpu);
 #endif
                     ret = cpu->exception_index;
+                    cpu->exception_index = -1;
                     break;
 #else
                     cc->do_interrupt(cpu);
@@ -489,28 +494,22 @@ int cpu_exec(CPUArchState *env)
                          * interrupt_request) which we will handle
                          * next time around the loop.
                          */
-                        tb = (TranslationBlock *)(next_tb & ~TB_EXIT_MASK);
                         next_tb = 0;
                         break;
                     case TB_EXIT_ICOUNT_EXPIRED:
                     {
                         /* Instruction counter expired.  */
-                        int insns_left;
-                        tb = (TranslationBlock *)(next_tb & ~TB_EXIT_MASK);
-                        insns_left = cpu->icount_decr.u32;
+                        int insns_left = cpu->icount_decr.u32;
                         if (cpu->icount_extra && insns_left >= 0) {
                             /* Refill decrementer and continue execution.  */
                             cpu->icount_extra += insns_left;
-                            if (cpu->icount_extra > 0xffff) {
-                                insns_left = 0xffff;
-                            } else {
-                                insns_left = cpu->icount_extra;
-                            }
+                            insns_left = MIN(0xffff, cpu->icount_extra);
                             cpu->icount_extra -= insns_left;
                             cpu->icount_decr.u16.low = insns_left;
                         } else {
                             if (insns_left > 0) {
                                 /* Execute remaining instructions.  */
+                                tb = (TranslationBlock *)(next_tb & ~TB_EXIT_MASK);
                                 cpu_exec_nocache(env, insns_left, tb);
                                 align_clocks(&sc, cpu);
                             }
@@ -537,6 +536,7 @@ int cpu_exec(CPUArchState *env)
             cpu = current_cpu;
             env = cpu->env_ptr;
             cc = CPU_GET_CLASS(cpu);
+            cpu->can_do_io = 1;
 #ifdef TARGET_I386
             x86_cpu = X86_CPU(cpu);
 #endif