gwj / at91sam9263 · Commits

Commit f5d2a381d1fb5f7def1c86c95d0c093e54e3aa67

Authored by bellard
1 parent e553272d

performance boost (on P4 hosts at least, rdtsc is a _very_ bad random generator) 


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@1892 c046a42c-6fe2-441c-8c8c-71466251a162
Inline Side-by-side
Showing 1 changed file with 6 additions and 3 deletions
hw/mips_r4k.c
  View file @f5d2a38
... ... @@ -27,11 +27,14 @@ void cpu_mips_irqctrl_init (void)
27 27 {
28 28 }
29 29  
  30 +/* XXX: do not use a global */
30 31 uint32_t cpu_mips_get_random (CPUState *env)
31 32 {
32   - uint32_t now = qemu_get_clock(vm_clock);
33   -
34   - return now % (MIPS_TLB_NB - env->CP0_Wired) + env->CP0_Wired;
  33 + static uint32_t seed = 0;
  34 + uint32_t idx;
  35 + seed = seed * 314159 + 1;
  36 + idx = (seed >> 16) % (MIPS_TLB_NB - env->CP0_Wired) + env->CP0_Wired;
  37 + return idx;
35 38 }
36 39  
37 40 /* MIPS R4K timer */
... ...