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authorbellard <bellard@c046a42c-6fe2-441c-8c8c-71466251a162>2006-05-02 22:18:28 +0000
committerbellard <bellard@c046a42c-6fe2-441c-8c8c-71466251a162>2006-05-02 22:18:28 +0000
commitf5d2a381d1fb5f7def1c86c95d0c093e54e3aa67 (patch)
tree3dcda05b2803be4e205a4eeda5a2c3f372a6dbf5
parente553272d759b41e6d1de226c8fad0aab56fefdd6 (diff)
downloadqemu-f5d2a381d1fb5f7def1c86c95d0c093e54e3aa67.tar.gz
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
-rw-r--r--hw/mips_r4k.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/hw/mips_r4k.c b/hw/mips_r4k.c
index 6b6b6cb33b..0cb11683ae 100644
--- a/hw/mips_r4k.c
+++ b/hw/mips_r4k.c
@@ -27,11 +27,14 @@ void cpu_mips_irqctrl_init (void)
{
}
+/* XXX: do not use a global */
uint32_t cpu_mips_get_random (CPUState *env)
{
- uint32_t now = qemu_get_clock(vm_clock);
-
- return now % (MIPS_TLB_NB - env->CP0_Wired) + env->CP0_Wired;
+ static uint32_t seed = 0;
+ uint32_t idx;
+ seed = seed * 314159 + 1;
+ idx = (seed >> 16) % (MIPS_TLB_NB - env->CP0_Wired) + env->CP0_Wired;
+ return idx;
}
/* MIPS R4K timer */